,,pr9ciples ,,( ,,m9+ ---------------------------------------- ---------------------- ,publi%$ by ! ,mc,graw-,hill ,book ,company ,new ,york ,successors to ! ,book ,dep>tm5ts ( ! ,mc,graw ,publi%+ ,company ,hill ,publi%+ ,company ,publi%]s ( ,books = ,electrical ,_w ,! ,eng9e]+ & ,m9+ ,j\rnal ,eng9e]+ ,record ,p[] & ,! ,eng9e] ,electric ,railway ,j\rnal ,am]ican ,ma*9i/ ,metallurgical & ,*emical ,eng9e]+ ---------------------------------------- ---------------------- ,,pr9ciples ,,( ,,m9+ ,,valuation1 ,,organization ,,& ,,adm9i/ration ,,copp]1 ,,gold1 ,,lead1 ,,silv]1 ,,t9 ,,& ,,z9c ,,by ,,h]b]t ,c4 ,,hoov] ,memb] ,am]ican ,in/itute ( ,m9+ ,eng9e]s1 ,m9+ & ,metallurgical ,society ( ,am]ica1 ,socit des ,+nieurs ,civils de ,france1 ,fell[ ,royal ,geographical ,society1 etc4 ,fir/ ,edition ,,f\r? ,,?\s& ,mc,g,r,a,w-,,hill ,,book ,,company #bci ,,we/ #ci,,? ,,/reet1 ,,new ,,york ,,b\v]ie ,,/reet1 ,,london1 ,e4,c4 #aiji ,,preface4 ,?is volume is a cond5sation ( a s]ies ( lectures deliv]$ 9 "p at ,/an=d & 9 "p at ,columbia ,univ]sities4 ,x is int5d$ nei!r = ^? :olly ignorant ( m9+1 nor = ^? long exp]i5c$ 9 ! pr(ession4 ,! bulk ( ! mat]ial pres5t$ is ! common h]itage ( ! pr(ession1 & if any "o may ?9k !re is insuffici5t ref]5ce to previ\s writ]s1 let him endeavor to f9d to :om ! orig9 ( our me?ods %\ld be cr$it$4 ,! sci5ce has gr[n by small contributions ( exp]i5ce s9ce1 or be=e1 ^? unnam$ ,egyptian eng9e]s1 ^: works prove _! k ( _m fundam5tals ( m9e eng9e]+ six ?\s& eight hundr$ ye>s ago4 ,if ,i h contribut$ "o s5t5ce to ! accumulat$ k ( a ?\s& g5]ations ( eng9e]s1 or h ?r[n "o new ray ( light on ! "w1 ,i %all h done my %>e4 ,i !re=e mu/ ackn[l$ge my obligations to all ^? :o h gone be=e1 to all t has be5 writt5 t ,i h read1 to ^? eng9e]s ) :om ,i h be5 associat$ = _m ye>s1 & 9 p>ticul> to _m fri5ds = k9dly reply to inquiry ^u po9ts h]e9 discuss$4 ,,cont5ts4 ,,*apt] #a4 ,valuation ( ,copp]1 ,gold1 ,lead1 ,silv]1 ,t91 & ,z9c ,lode ,m9es ,det]m9ation ( av]age metal cont5t2 sampl+1 assay plans1 calculations ( av]ages1 p]c5tage ( errors 9 e/imate f sampl+4 ,,*apt] ,,ii4 ,m9e ,valuation 7,cont9u$7 ,calculation ( quantities ( ore1 & classification ( ore 9 sight4 ,,*apt] ,,iii4 ,m9e ,valuation 7,cont9u$7 ,prospective value4 ,ext5sion 9 dep?2 orig9 & /ructural "* ( ! deposit2 second>y enri*m5t2 developm5t 9 neighbor+ m9es2 dep? ( exhau/ion4 ,,*apt] ,,iv4 ,m9e ,valuation 7,cont9u$7 ,recov]able p]c5tage ( ! gross assay value2 price ( metals2 co/ ( production4 ,,*apt] ,v4 ,m9e ,valuation 7,cont9u$7 ,r$emption or amortization ( capital & int]e/4 ,,*apt] ,,vi4 ,m9e ,valuation 7,conclud$7 ,valuation ( m9es ) little or no ore 9 sight2 valuations on second-h& data2 g5]al conduct ( exam9ations2 reports4 ,,*apt] ,,vii4 ,developm5t ( ,m9es ,entry to ! m9e2 tunnels2 v]tical1 incl9$1 & comb9$ %afts2 location & numb] ( %afts4 ,,*apt] ,,viii4 ,developm5t ( ,m9es 7,cont9u$7 ,%ape & size ( %afts2 spe$ ( s9k+2 tunnels4 ,,*apt] ,,ix4 ,developm5t ( ,m9es 7,conclud$7 ,subsidi>y developm5t3 /ations2 crosscuts2 levels2 int]val betwe5 levels2 protection ( levels2 w9zes & rises4 ,developm5t 9 ! prospect+ /age2 drill+4 ,,*apt] ,x4 ,/op+ ,me?ods ( ore-break+2 und]h& /opes2 ov]h& /opes2 comb9$ /ope4 ,valu+ ore 9 c\rse ( break+4 ,,*apt] ,,xi4 ,me?ods ( ,support+ ,excavation ,timb]+2 fill+ ) wa/e2 fill+ ) brok5 ore2 pill>s ( ore2 artificial pill>s2 cav+ sy/em4 ,,*apt] ,,xii4 ,me*anical ,equipm5t ,conditions be>+ on m9e equipm5t2 w9d+ appliances2 haulage equipm5t 9 %afts2 lat]al und]gr\nd transport2 transport 9 /opes4 ,,*apt] ,,xiii4 ,me*anical ,equipm5t 7,cont9u$7 ,dra9age3 controll+ factors2 volume & head ( wat]2 flexibility2 reliability2 p[] conditions2 me*anical effici5cy2 capital outlay4 ,sy/ems ( dra9age1--/eam pumps1 compress$-air pumps1 electrical pumps1 rod-driv5 pumps1 bail+2 comp>ative value ( v>i\s sy/ems4 ,,*apt] ,,xiv4 ,me*anical ,equipm5t 7,conclud$7 ,ma*9e drill+3 p[] transmission2 compress$ air vs4 electricity2 air drills2 ma*9e vs4 h& drill+4 ,work%ops4 ,improvem5t 9 equipm5t4 ,,*apt] ,,xv4 ,ratio ( ,output to ! ,m9e ,det]m9ation ( possible maximum2 limit+ factors2 co/ ( equipm5t2 life ( ! m9e2 me*anical ineffici5cy ( pat*work plant2 ov]production ( base metal2 security ( inve/m5t4 ,,*apt] ,,xvi4 ,adm9i/ration ,labor effici5cy2 skill2 intellig5ce2 application cord9ation2 contract "w2 labor unions2 real basis ( wages4 ,,*apt] ,,xvii4 ,adm9i/ration 7,cont9u$7 ,acc\nts & te*nical data & reports2 work+ co/s2 division ( exp5diture2 inh]5t limitations 9 accuracy ( work+ co/s2 work+ co/ %eets4 ,g5]al te*nical data2 labor1 supplies1 p[]1 surveys1 sampl+1 & assay+4 ,,*apt] ,,xviii4 ,adm9i/ration 7,conclud$7 ,adm9i/rative reports4 ,,*apt] ,,xix4 ,! ,am\nt ( ,risk 9 ,m9+ ,inve/m5ts ,risk 9 valuation ( m9es2 9 m9es z comp>$ ) o!r comm]cial ent]prises4 ,,*apt] ,,xx4 ,! ,"*1 ,tra9+1 & ,obligations ( ! ,m9+ ,eng9e]+ ,pr(ession ,index ,,pr9ciples ,,( ,,m9+4 ,,*apt] ,i4 ,valuation ( ,copp]1 ,gold1 ,lead1 ,silv]1 ,t91 & ,z9c ,lode ,m9es4 ,,det]m9ation ,,( ,,av]age ,,metal ,,cont5t2 ,,sampl+1 ,,assay ,,plans1 ,,calculations ,,( ,,av]ages1 ,,p]c5tage ,,( ,,errors ,,9 ,,e/imate ,,f ,,sampl+4 ,! foll[+ discussion is limit$ to 9 situ deposits ( copp]1 gold1 lead1 silv]1 t91 & z9c4 ,! valuation ( alluvial deposits1 iron1 coal1 & o!r m9es is ea* a special sci5ce to itself & _c be adequately discuss$ 9 common ) ! type ( deposits m5tion$ above4 ,! value ( a metal m9e ( ! ord] "u discussion dep5ds ^u3-- a4 ,! pr(it t may be won f ore expos$2 b4 ,! prospective pr(it to be d]iv$ f ext5sion ( ! ore beyond exposures2 c4 ,! effect ( a high] or l[] price ( metal 7except 9 gold m9es72 d4 ,! effici5cy ( ! managem5t dur+ realization4 ,! fir/ may be t]m$ ! positive value1 & c be approximately det]m9$ by sampl+ or te/-treatm5t runs4 ,! second & ! ?ird may be t]m$ ! speculative values1 & are l>gely a matt] ( judgm5t bas$ on geological evid5ce & ! indu/rial outlook4 ,! f\r? is a "q ( developm5t1 equipm5t1 & eng9e]+ me?od adapt$ to ! prospects ( ! ent]prise1 toge!r ) capable executive control ( ^! works4 ,x %\ld be /at$ at ! outset t x is utt]ly impossible to accurately value any m9e1 ow+ to ! _m speculative factors involv$4 ,! be/ t c be done is to /ate t ! value lies betwe5 c]ta9 limits1 & t v>i\s /ages above ! m9imum giv5 repres5t v>i\s degrees ( risk4 ,fur!r1 x w\ld be b /at+ truisms to ^? engag$ 9 valu+ m9es to repeat t1 because ( ! limit$ life ( e m9e1 valuation ( su* inve/m5ts _c be bas$ ^u ! pr9ciple ( simple int]e/2 nor t any inve/m5t is ju/ifi$ )\t a consid]ation ( ! managem5t to ensue4 ,yet ! ignorance ( ^! ess5tials is s preval5t among ! public t !y w>rant repetition on e available occasion4 ,to su* an ext5t is ! realization ( pr(its indicat$ f ! o!r factors dep5d5t ^u ! subsequ5t managem5t ( ! ent]prise t ! au?or consid]s a review ( und]gr\nd eng9e]+ & adm9i/ration f an economic po9t ( view an ess5tial to any essay ^u ! subject4 ,:ile ! metallurgical treatm5t ( ores is an ess5tial factor 9 m9e economics1 x is consid]$ t a detail$ discussion ( ! myriad ( processes "u hypo!tic conditions w\ld lead too f> afield4 ,!re=e ! discussion is l>gely limit$ to und]gr\nd & adm9i/rative matt]s4 ,! valuation ( m9es arises n only f _! *ange ( own]%ip1 b f ! necessity 9 s\nd adm9i/ration = a k ( "s ( ! fundam5tals ( valuation1 su* z ore res]ves & av]age values1 t manag]ial & f9ancial policy may be guid$ aright4 ,also ) ! gr[? ( corporate own]%ip !re is a dem& f own]s & /ockhold]s = p]iodic in=mation z to ! intr9sic condition ( _! prop]ties4 ,! gr[? ( a body ( speculators & inve/ors 9 m9+ /ocks & securities :o desire pr(essional guidance :i* _c be bas$ ^u fir/-h& data is creat+ fur!r dem& on ! eng9e]4 ,op9ions 9 ^! cases mu/ be =m$ on casual visits or second-h& in=mation1 & a k ( m5 & ?+s g5]ally4 ,despite ! feel+ ( "s eng9e]s t ! latt] employm5t is n prop]ly bas$ pr(essionally1 x is an exp&+ phase ( eng9e]s' "w1 & mu/ be tak5 s]i\sly4 ,al?\gh x lacks satisfactory f\ndation = accurate judgm5t1 yet ! eng9e] c1 & %\ld1 give 8 exp]i5ce to x :5 ! call comes1 out ( int]e/ to ! indu/ry z a :ole4 ,n only c he 9 a measure protect ! lamb1 by insi/5ce on no inve/m5t )\t ! provision ( prop]ly organiz$ data & s\nd adm9i/ration = 8 cli5t1 b he c d mu* to direct ! indu/ry f gambl+ into indu/rial l9es4 ,an exam9ation ( ! factors :i* arise on ! valuation ( m9es involves a wide range ( subjects4 ,= purposes ( ?is discussion !y may be divid$ into ! foll[+ heads3-- #a4 ,det]m9ation ( ,av]age ,metal ,cont5ts ( ! ,ore4 #b4 ,det]m9ation ( ,quantities ( ,ore4 #c4 ,prospective ,value4 #d4 ,recov]able ,p]c5tage ( ,gross ,value4 #e4 ,price ( ,metals4 #f4 ,co/ ( ,production4 #g4 ,r$emption or ,amortization ( ,capital & ,int]e/4 #h4 ,valuation ( ,m9es )\t ,ore 9 ,sight4 #i4 ,g5]al ,conduct ( ,exam9ation & ,reports4 ,,det]m9ation ,,( ,,av]age ,,metal ,,cont5ts ,,( ,,! ,,ore4 ,?ree means ( det]m9ation ( ! av]age metal cont5t ( /&+ ore are 9 use--,previ\s ,yield1 ,te/-treatm5t ,runs1 & ,sampl+4 ,,previ\s ,,yield4--,!re are c]ta9 types ( ore :]e ! previ\s yield f kn[n space becomes ! ess5tial basis ( det]m9ation ( quantity & metal cont5ts ( ore /&+ & ( ! future probabilities4 ,:]e metals occur l plums 9 a pudd+1 sampl+ becomes difficult & unreliable1 & :]e exp]i5ce has prov$ a sort ( regul>ity ( recurr5ce ( ^! plums1 dep5d5ce mu/ necess>ily be plac$ on pa/ records1 = if _! reliability is to be que/ion$1 resort mu/ be _h to ext5sive te/-treatm5t runs4 ,! ,lake ,sup]ior copp] m9es & ! ,miss\ri lead & z9c m9es are ( ?is type ( deposit4 ,on ! o!r sorts ( deposits ! previ\s yield is (t5 put =w>d z ( important be>+ on ! value ( ! ore /&+1 b su* yield1 unless x c be au!ntically connect$ ) blocks ( ore rema9+1 is n necess>ily a crit]ion ( _! cont5ts4 ,except 9 ! cases m5tion$1 & z a *eck on o!r me?ods ( det]m9ation1 x has little place 9 f9al conclusions4 ,,te/ ,,p>cels4--,treatm5t on a consid]able scale ( suffici5tly regulat$ p>cels1 al?\gh !oretically ! ideal me?od1 is1 h[ev]1 n (t5 )9 ! realm ( ?+s practical4 ,9 exam9ation on behalf ( int5d+ pur*as]s1 ! "t1 exp5se1 or opportunity to fraud are usually prohibitive1 ev5 :]e ! plant & facilities = su* "w exi/4 ,ev5 9 cases :]e ! eng9e] 9 managem5t ( produc+ m9es is desir\s ( det]m9+ ! value ( /&+ ore1 ) ! exception ( deposits ( ! type m5tion$ above1 x is ord9>ily done by actual sampl+1 because sep>ate m9+ & treatm5t ( te/ lots is g5]ally inconv5i5t & exp5sive4 ,z a result1 ! det]m9ation ( ! value ( /&+ ore is1 9 ! great majority ( cases1 done by sampl+ & assay+4 ,,sampl+4--,! :ole !ory ( sampl+ is bas$ on ! di/ribution ( metals ?r\gh ! ore-body ) m or less regul>ity1 s t if small portions1 t is samples1 be tak5 f a suffici5t numb] ( po9ts1 _! av]age w repres5t fairly closely ! unit value ( ! ore4 ,if ! ore is ( ! extreme type ( irregul> metal di/ribution m5tion$ "u previ\s yield1 !n sampl+ has no place4 ,h[ frequ5tly samples mu/ be tak51 ! mann] ( tak+ !m1 & ! quantity t con/itutes a fair sample1 are matt]s t v>y ) ea* m9e4 ,s mu* dep5ds ^u ! prop] p]=mance ( ?is task t x is 9 fact ! mo/ critical feature ( m9e exam9ation4 ,t5 samples prop]ly tak5 are m valuable ?an five hundr$ slov5ly ones1 l grab samples1 = su* a numb] ( bad ones w\ld ( a surety lead to :olly wrong conclusions4 ,giv5 a good sampl+ & a prop] assay plan1 ! valuation ( a m9e is two-?irds accompli%$4 ,x %\ld be an inflexible pr9ciple 9 exam9ations = pur*ase t e sample mu/ be tak5 "u ! p]sonal sup]vision ( ! exam9+ eng9e] or 8 tru/$ assi/ants4 ,aside f ?r[+ op5 ! doors to fraud1 ! av]age workman w n c>ry out ! "w 9 a prop] mann]1 unless "u con/ant sup]vision1 because ( 8 lack ( appreciation ( ! issues involv$4 ,sampl+ is h>d1 uncong5ial1 manual labor4 ,x requires a deal ( consci5ti\sness to take en\gh samples & to take !m ?or\ghly4 ,! eng9e] does n exi/ :o1 ^u completion ( ?is task1 consid]s t he has got too _m1 & mo/ wi% t !y _h tak5 m4 ,! accuracy ( sampl+ z a me?od ( det]m9+ ! value ( /&+ ore is a factor ( ! numb] ( samples tak54 ,! av]age1 = example1 ( sep>ate samples f ea* squ>e in* w\ld be m accurate ?an ^? f ea* alt]nate squ>e in*4 ,h[ev]1 ! accumulat$ k & exp]i5ce z to ! di/ribution ( metals ?r\gh ore has det]m9$ approximately ! mann] ( tak+ su* samples1 & ! lea/ numb] :i* w /ill by ! law ( av]ages secure a degree ( accuracy comm5surate ) ! o!r factors ( e/imation4 ,z metals are di/ribut$ ?r\gh ore-bodies ( fissure orig9 ) mo/ regul>ity on l9es p>allel to ! /rike & dip1 an equal portion ( ore f e po9t along cross-sections at "r angles to ! /rike w repres5t fairly well ! av]age values = a c]ta9 di/ance along ! /rike ei!r side ( ^! cross-sections4 ,9 massive deposits1 sample sections are tak5 9 all directions4 ,! int]vals at :i* sample sections mu/ be cut is obvi\sly dep5d5t ^u ! g5]al "* ( ! deposit4 ,if ! values are well di/ribut$1 a long] int]val may be employ$ ?an 9 "o subject to m>k$ fluctuations4 ,z a g5]al rule1 five feet is ! di/ance mo/ accept$4 ,?is1 9 cases ( regul> di/ribution ( values1 may be /ret*$ to t5 feet1 or 9 rev]se may be dim9i%$ to two or ?ree feet4 ,! wid? ( ore :i* may be includ$ = "o sample is dep5d5t n only ^u ! wid? ( ! deposit1 b also ^u its "*4 ,:]e ! ore is wid] ?an ! necess>y /op+ wid?1 ! sample %\ld be regulat$ s z to %[ ! possible locus ( values4 ,! metal cont5ts may be1 & (t5 are1 p>ticul>ly 9 deposits ( ! impregnation or replacem5t type1 great] along "s /reak 9 ! ore-body1 & ?is diff]5ce may be su* z to make x desirable to /ope only a portion ( ! total ?ickness4 ,= deposits n>r[] ?an ! necess>y /op+ wid? ! full bread? ( ore %\ld be includ$ 9 "o sample1 because usually ! :ole ( ! deposit w require to be brok54 ,9 ord] t a payable section may n possibly be dilut$ ) mat]ial unnecess>y to m9e1 if ! deposit is ov] f\r feet & "u eight feet1 ! di/ance across ! ve9 or lode is usually divid$ into two samples4 ,if /ill wid]1 ea* is conf9$ to a span ( ab\t f\r feet1 n only = ! reason giv5 above1 b because ! m num]\s ! samples1 ! great] ! accuracy4 ,?us1 9 a deposit tw5ty feet wide x may be tak5 z a good guide t a te/ section across ! ore-body %\ld be divid$ into five p>ts4 ,z to ! physical details ( sample tak+1 e eng9e] has 8 own me?ods & safegu>ds aga9/ fraud & error4 ,9 a l>ge organization ( :i* ! writ] _h = "s ye>s ! direction1 & :]e sampl+ ( m9es 0 con/antly 9 progress on an ext5sive scale1 n only 9 contemplation ( pur*ase1 b :]e x 0 also sy/ematically conduct$ 9 op]at+ m9es = work+ data1 he adopt$ ! above g5]al l9es & requir$ ! foll[+ details4 ,a fre% face ( ore is fir/ brok5 & !n a tr5* cut ab\t five in*es wide & two in*es deep4 ,?is tr5* is cut ) a hamm] & moil1 or1 :]e compress$ air is available & ! rock h>d1 a small air-drill ( ! hamm] type is us$4 ,! spoil f ! tr5* =ms ! sample1 & x is brok5 d[n ^u a l>ge canvas clo?4 ,aft]w>ds x is cru%$ s t all pieces w pass a half-in* scre51 mix$ & qu>t]$1 ?us r$uc+ ! weight to half4 ,:e!r x is aga9 cru%$ & qu>t]$ dep5ds ^u :at ! conditions are z to assay+4 ,if conv5i5t to assay (fice1 z on a go+ m9e1 ! :ole ( ! cru%+ & qu>t]+ "w c be done at t (fice1 :]e !re are usually suitable me*anical appliances4 ,if ! samples mu/ be tak5 a long di/ance1 ! bulk = transport c be r$uc$ by f9] break+ & repeat$ qu>t]+1 until !re rema9 only a few ounces4 ,,precautions ,,aga9/ ,,fraud4--,mu* has be5 writt5 ab\t ! precautions to be tak5 aga9/ fraud 9 cases ( valuations = pur*ase4 ,! be/ safegu>ds are an al]t eye & a /rong "r arm4 ,h[ev]1 c]ta9 small details help4 ,a l>ge lea!r bag1 arrang$ to lock aft] ! ord] ( a mail sack1 into :i* samples c be put und]gr\nd & :i* is nev] unfa/5$ except by responsible m51 n only aids security b relieves ! m9d4 ,a few samples ( c\ntry rock =m a good *eck1 & notes z to ! probable value ( ! ore1 f inspection :5 sampl+1 are useful4 ,a great help 9 exam9ation is to h ! assays or analyses done co9cid5tally ) ! sampl+4 ,a d\bt c !n always be settl$ by resampl+ at once1 & mu* k c be ga9$ :i* may relieve s exhau/ive a program z might be necess>y 7 results n kn[n until aft] leav+ ! m9e4 ,,assay ,,( ,,samples4--,two assays1 or z ! case may be1 analyses1 are usually made ( e sample & _! av]age tak54 ,9 ! case ( erratic diff]5ces a ?ird det]m9ation is necess>y4 ,,assay ,,plans4--,an assay plan is a plan ( ! work+s1 ) ! location1 assay value1 & wid? ( ! sample ent]$ ^u x4 ,9 a m9e ) a n>r[ ve9 or ore-body1 a longitud9al section is suffici5t base = su* entries1 b ) a great] wid? ?an "o sample span x is desirable to make prelim9>y plans ( sep>ate levels1 w9zes1 etc41 & to av]age ! value ( ! :ole payable wid?s on su* plans be=e entry ^u a longitud9al section4 ,su* a longitud9al section w1 ?r\gh ! indicat$ di/ribution ( values1 %[ ! %ape ( ! ore-body--a /ep necess>y 9 e/imat+ quantities & ( ! mo/ fundam5tal importance 9 e/imat+ ! probabilities ( ore ext5sion beyond ! range ( ! op5+s4 ,! f9al assay plan %\ld %[ ! av]age value ( ! sev]al blocks ( ore1 & x is f ^! av]ages t e/imates ( quantities mu/ be made up4 ,,calculations ,,( ,,av]ages4--,! fir/ /ep 9 arriv+ at av]age values is to r$uce erratic high assays to ! g5]al t5or ( o!r adjac5t samples4 ,?is po9t has be5 disput$ at "s l5g?1 m (t5 by promot]s ?an by eng9e]s1 b ! cu/om is v g5]ally & rightly adopt$4 ,erratically high samples may indicate pres5ce ( undue metal 9 ! assay attributable to unconsci\s salt+1 = if ! value be conf9$ to a few l>ge p>ticles !y may f9d _! way ?r\gh all ! qu>t]+ into ! assay4 ,or ! sample may actually indicate ri* spots ( ore2 b 9 any ev5t exp]i5ce tea*es t no dep5d5ce c be put ^u regul> recurr5ce ( su* abnormally ri* spots4 ,z w be discuss$ "u p]c5tage ( error 9 sampl+1 samples usually indicate high] ?an ! true value1 ev5 :]e erratic assays h be5 elim9at$4 ,!re are cases ( pr(itable m9es :]e ! values 7 all 9 spots1 & an assay plan w\ld %[ #hj ( ! assays nil1 yet ^! pockets 7 s ri* z to give value to ! :ole4 ,pocket m9es1 z /at$ be=e1 are beyond valuation by sampl+1 & aside f ! previ\s yield rec\rse mu/ be _h to actual treatm5t runs on e block ( ore sep>ately4 ,aft] r$uction ( erratic assays1 a prelim9>y /udy ( ! runs ( value or %apes ( ! ore-bodies is necess>y be=e any calculation ( av]ages4 ,a prelim9>y del9eation ( ! b\nd>ies ( ! payable areas on ! assay plan w indicate ! sections ( ! m9e :i* are unpayable1 & f :i* !re=e samples c be rightly exclud$ 9 arriv+ at an av]age ( ! payable ore 7,fig4 #a74 ,9 a g5]al way1 only ! ore :i* mu/ be m9$ ne$ be includ$ 9 av]ag+4 ,! calculation ( ! av]age assay value ( /&+ ore f samples is "o :i* seems to require "s /atem5t ( elem5tals4 ,al?\gh x may seem primitive1 x c d no h>m to recall t if a dump ( two tons ( ore assay+ tw5ty ounces p] ton be add$ to a dump ( five tons av]ag+ "o ounce p] ton1 ! result has n an av]age assay ( tw5ty-"o ounces divid$ by ! numb] ( dumps4 ,likewise "o sample ov] a wid? ( two feet1 assay+ tw5ty ounces p] ton1 if av]ag$ ) ano!r sample ov] a wid? ( five feet1 assay+ "o ounce1 is no m tw5ty-"o ounces divid$ by two samples ?an 9 ! case ( ! two dumps4 ,if common s5se 7 n suffici5t demon/ration ( ?is1 x c be %[n algebraically4 ,7 samples equidi/ant f ea* o!r1 & 7 !y ( equal wid?1 ! av]age value w\ld be ! simple ari?metical mean ( ! assays4 ,b ?is is seldom ! case4 ,! numb] ( in/ances1 n only 9 practice b also 9 te*nical lit]ature1 :]e ! fundam5tal di/9ction betwe5 an ari?metical & a geometrical mean is lo/ sight ( is amaz+4 ,to arrive at ! av]age value ( samples1 x is necess>y1 9 effect1 to r$uce !m to ! actual quantity ( ! metal & volume ( ore repres5t$ by ea*4 ,! me?od ( calculation !re=e is "o :i* gives e sample an importance dep5d+ ^u ! metal cont5t ( ! volume ( ore x repres5ts4 ,! volume ( ore app]ta9+ to any giv5 sample c be consid]$ z a prismoid1 ! dim5sions ( :i* may be /at$ z foll[s3-- ,w ,wid? 9 feet ( ore sampl$4 ,l ,l5g? 9 feet ( ore repres5t$ by ! sample4 ,d ,dep? into ! block to :i* values are assum$ to p5etrate4 ,we may also let3-- ,c ,! numb] ( cubic feet p] ton ( ore4 ,v ,assay value ( ! sample4 ,!n ,,wld_/,c tonnage ( ! prismoid499 ,v ,,wld_/,c total metal cont5ts4 ,footnote 993 ,/rictly1 ! prismoidal =mula %\ld be us$1 b x complicates ! /udy unduly1 & = practical purposes ! above may be tak5 z ! volume4 ,! av]age value ( a numb] ( samples is ! total metal cont5ts ( _! respective prismoids1 divid$ by ! total tonnage ( ^! prismoids4 ,if we let ,w1 ,w#a1 ,v1 ,v#a etc41 repres5t diff]5t samples1 we h3-- ,v7,,wld_/,c7 ,v#a 7,w#a ,l#a ,d#a_/;,c7 ,v#b 7,w#b ,l#b ,d#b_/;,c7 ---------------------------------------- ----------------------------- ,,wld_/,c ,w#a ,l#a ,d#a_/;,c ,w#b ,l#b ,d#b_/;,c av]age value4 ,?is may be r$uc$ to3-- 7,,vwld7 7,v#a ,w#a ,l#a ,d#a7 7,v#b ,w#b ,l#b ,d#b171 etc4 ---------------------------------------- ----------------------- 7,,wld7 7,w#a ,l#a ,d#a7 7,w#b ,l#b ,d#b71 etc4 ,z a matt] ( fact1 samples actually repres5t ! value ( ! out] %ell ( ! block ( ore only1 & ! cont9uity ( ! same values ?r\gh ! block is a geological assumption4 ,f ! out] %ell1 all ! values c be tak5 to p5etrate equal di/ances into ! block1 & !re=e ,d1 ,d#a1 ,d#b may be consid]$ z equal & ! equation becomes3-- 7,,vwl7 7,v#a ,w#a ,l#a7 7,v#b ,w#b ,l#b71 etc4 ---------------------------------------- ----------- 7,,wl7 7,w#a ,l#a7 7,w#b ,l#b71 etc4 ,! l5g? ( ! prismoid base ,l = any giv5 sample w be a di/ance equal to "o-half ! sum ( ! di/ances to ! two adjac5t samples4 ,z a matt] ( practice1 samples are usually tak5 at regul> int]vals1 & ! l5g?s ,l1 ,l#a1 ,l#b becom+ ?us equal c 9 su* case be elim9at$1 & ! equation becomes3-- 7,,vw7 7,v#a ,w#a7 7,v#b ,w#b71 etc4 ---------------------------------------- ,w ,w#a ,w#b 1 etc4 ,! "n assay foot or foot value has be5 giv5 to ! relation ,,vw1 t is1 ! assay value multipli$ by ! wid? sampl$499 ,x is by ?is me?od t all samples mu/ be av]ag$4 ,! same relation obvi\sly c be evolv$ by us+ an in* in/ead ( a foot1 & 9 n>r[ ve9s ! assay in* is g5]ally us$4 ,footnote 993 ,an error w be f\nd 9 ?is me?od unless ! two end samples be halv$1 b 9 a long run ( samples ?is may be disreg>d$4 ,:]e ! payable cross-section is divid$ into m ?an "o sample1 ! diff]5t samples 9 ! section mu/ be av]ag$ by ! above =mula1 be=e be+ comb9$ ) ! adjac5t section4 ,:]e ! wid? sampl$ is n>r[] ?an ! necess>y /op+ wid?1 & :]e ! wa/e _c be brok5 sep>ately1 ! sample value mu/ be dilut$ to a /op+ wid?4 ,to dilute n>r[ samples to a /op+ wid?1 a blank value ov] ! extra wid? :i* x is necess>y to include mu/ be av]ag$ ) ! sample f ! ore on ! above =mula4 ,cases arise :]e1 al?\gh a c]ta9 wid? ( wa/e mu/ be brok5 ) ! ore1 x subsequ5tly c be p>tially sort$ out4 ,practically no?+ b exp]i5ce on ! deposit itself w det]m9e h[ f> ?is w re/ore ! value ( ! ore to ! av]age ( ! payable seam4 ,9 any ev5t1 no sort+ c elim9ate all su* wa/e2 & x is necess>y to calculate ! value on ! break+ wid?1 & !n d$uct f ! gross tonnage to be brok5 a p]c5tage f sort+4 ,!re is always an all[ance to be made 9 sort+ = a loss ( good ore ) ! disc>ds4 ,,p]c5tage ,,( ,,error ,,9 ,,e/imates ,,f ,,sampl+4--,x mu/ be rememb]$ t ! :ole !ory ( e/imation by sampl+ is f\nd$ ^u c]ta9 assumptions z to ev5ness ( cont9uity & transition 9 value & volume4 ,x is b a basis = an e/imate1 & an e/imate is n a /atem5t ( fact4 ,x _c !re=e be too =cibly repeat$ t an e/imate is inh]5tly b an approximation1 take :at c>e "o may 9 its f\nd+4 ,:ile x is possible to ref9e ma!matical calculation ( av]ages to almo/ any nicety1 beyond c]ta9 ess5tials x adds no?+ to accuracy & is (t5 mislead+4 ,x is desirable to consid] :]e errors are mo/ likely to creep 91 assum+ t all fundam5tal data are bo? accurately tak5 & consid]$4 ,sampl+ ( ore 9 situ 9 g5]al has a t5d5cy to give high] av]age value ?an ! actual r$uction ( ! ore w %[4 ,on ?ree ,we/ ,au/ralian gold m9es1 9 records cov]+ a p]iod ( ov] two ye>s1 :]e sampl+ 0 mo/ exhau/ive z a daily rgime ( ! m9es1 ! values indicat$ by sampl+ 7 #ab high] ?an ! mill yield plus ! cont5ts ( ! residues4 ,on ! ,witwat]sr& gold m9es1 ! actual extractable value is g5]ally consid]$ to be ab\t #gh to #hj ( ! av]age %[n by sampl+1 :ile ! mill extractions are on av]age ab\t #ij to #ib ( ! head value com+ to ! mill4 ,9 o!r words1 !re is a con/ant discrepancy ( ab\t #aj to #ab betwe5 ! e/imat$ value z indicat$ by m9e samples1 & ! actual value z %[n by yield plus ! residues4 ,at ,brok5 ,hill1 on ?ree lead m9es1 ! yield is ab\t #ab less ?an sampl+ w\ld indicate4 ,?is con/ancy ( error 9 "o direction has n be5 s g5]ally ackn[l$g$ z w\ld be desirable1 & x mu/ be all[$ = 9 calculat+ f9al results4 ,! causes ( ! exagg]ation seem to be3-- ,fir/1 inability to /ope a m9e to su* f9e limitations ( wid?1 or exclusion ( unpayable pat*es1 z w\ld appe> practicable :5 sampl+1 t is by ! inclusion :5 m9+ ( a c]ta9 am\nt ( b>r5 rock4 ,ev5 9 deposits ( ab\t normal /op+ wid?1 x is impossible to prev5t ! break+ ( a c]ta9 am\nt ( wa/e1 ev5 if ! ore occurr5ce is regul>ly conf9$ by walls4 ,if ! m9e be ( ! impregnation type1 su* z ^? at ,goldfield1 or ,kalgoorlie1 ) values l plums 9 a pudd+1 & ! /opes !mselves direct$ m by assays ?an by any physical diff]5ces 9 ! ore1 ! discrepancy becomes v mu* increas$4 ,9 m9es :]e ! range ( values is n>r[] ?an ! normal /op+ wid?1 "s wall rock mu/ be brok54 ,al?\gh x is cu/om>y to all[ = ?is 9 calculat+ ! av]age value f samples1 ! all[ance seldom seems en\gh4 ,9 m9es :]e ! ore is brok5 on to ! top ( /opes fill$ ) wa/e1 !re is "s loss und]gr\nd ?r\gh mixture ) ! fill+4 ,second1 ! metal cont5t ( ores1 especially :5 9 ! =m ( sulphides1 is usually m friable ?an ! matrix1 & 9 actual break+ ( samples an undue proportion ( friable mat]ial usually creeps 94 ,?is is true m 9 lead1 copp]1 & z9c1 ?an 9 gold ores4 ,on sev]al gold m9es1 h[ev]1 te/s on accumulat$ samples = _! sulphide p]c5tage %[$ a di/9ctly great] ratio ?an ! t5or ( ! ore itself 9 ! mill4 ,z ! gold is usually associat$ ) ! sulphides1 ! samples %[$ high] values ?an ! mill4 ,9 g5]al1 "s consid]able factor ( safety mu/ be all[$ aft] arriv+ at calculat$ av]age ( samples1--h[ mu* x is difficult to say1 b1 9 any ev5t1 n less ?an #aj4 ,,*apt] ,,ii4 ,m9e ,valuation 7,cont9u$74 ,,calculation ,,( ,,quantities ,,( ,,ore1 ,,& ,,classification ,,( ,,ore ,,9 ,,sight4 ,z m9es are op5$ by levels1 rises1 etc41 ?r\gh ! ore1 an ext5sion ( ^! work+s has ! effect ( divid+ x into blocks4 ,! obvi\s proc$ure 9 det]m9+ tonnages is to calculate ! volume & value ( ea* block sep>ately4 ,"u ! law ( av]ages1 ! multiplicity ( ^! blocks t5ds 9 proportion to _! numb] to comp5sate ! p]c5tage ( error :i* might arise 9 ! sampl+ or e/imat+ ( any p>ticul> "o4 ,! %apes ( ^! blocks1 on longitud9al section1 are (t5 n regul> geometrical figures4 ,z a matt] ( practice1 h[ev]1 !y c be subdivid$ into su* figures t ! total w approximate ! :ole ) suffici5t clos5ess = calculations ( _! areas4 ,! av]age wid? ( ! ore 9 any p>ticul> block is ! ari?metical mean ( ! wid? ( ! sample sections 9 x199 if ! samples be an equal di/ance ap>t4 ,if !y are n equidi/ant1 ! av]age wid? is ! sum ( ! areas betwe5 samples1 divid$ by ! total l5g? sampl$4 ,! cubic foot cont5ts ( a p>ticul> block is obvi\sly ! wid? multipli$ by ! area ( its longitud9al section4 ,footnote 993 ,?is is n /rictly true unless ! sum ( ! wid?s ( ! two end-sections be divid$ by two & ! result incorporat$ 9 calculat+ ! means4 ,9 a long s]ies t error is ( little importance4 ,! ratio ( cubic feet to tons dep5ds on ! specific gravity ( ! ore1 its porosity1 & moi/ure4 ,! v>iability ( ores ?r\gh\t ! m9e 9 all ^! p>ticul>s r5d]s any me?od ( calculation simply an approximation 9 ! end4 ,! factors :i* mu/ rema9 unkn[n necess>ily lead ! eng9e] to ! provision ( a m>g9 ( safety1 :i* makes ma!matical ref9em5t & algebraic =mul ridicul\s4 ,!re are 9 g5]al ?ree me?ods ( det]m9ation ( ! specific volume ( ores3-- ,fir/1 by f9d+ ! true specific gravity ( a suffici5t numb] ( repres5tative specim5s2 ?is1 h[ev]1 w\ld n acc\nt = ! l>g] voids 9 ! ore-body & 9 any ev5t1 to be any?+ l accurate1 w\ld be z exp5sive z sampl+ & is !re=e ( little m ?an academic int]e/4 ,second1 by det]m9+ ! weight ( quantities brok5 f measur$ spaces4 ,?is also w\ld require sev]al te/s f diff]5t portions ( ! m9e1 &1 9 exam9ations1 is usually inconv5i5t & difficult4 ,yet x is necess>y 9 cases ( unusual mat]ials1 su* z lea*$ gossans1 & x is desirable to h x done soon] or lat] 9 go+ m9es1 z a *eck4 ,?ird1 by an approximation bas$ ^u a calculation f ! specific gravities ( ! pr$om9ant m9]als 9 ! ore4 ,ores are a mixture ( _m m9]als2 ! proportions v>y ?r\gh ! same ore-body4 ,despite ?is1 a few p>tial analyses1 :i* are usually available f assays ( samples & metallurgical te/s1 & a g5]al inspection z to ! compactness ( ! ore1 give a fairly reliable basis = approximation1 especially if a reasonable disc\nt be all[$ = safety4 ,9 su* disc\nt mu/ be reflect$ reg>d = ! porosity ( ! ore1 & ! m>g9 ( safety necess>y may v>y f #aj to #be4 ,if ! ore is ( unusual "*1 z 9 lea*$ deposits1 z said be=e1 resort mu/ be _h to ! second me?od4 ,! foll[+ table ( ! weights p] cubic foot & ! numb] ( cubic feet p] ton ( "s ( ! pr9cipal ore-=m+ m9]als & gangue rocks w be useful = approximat+ ! weight ( a cubic foot ( ore by ! ?ird me?od4 ,weights are 9 p\nds avoirdupois1 & two ?\s& p\nds are reckon$ to ! ton4 ,numb] ( ,weight p] ,cubic ,feet ,cubic ,foot p] ,ton ( #bjjj lb4 ---------------------------------------- -- ,antimony #dag4ej #d4gi ,sulphide #bhe4jj #g4ja ,ars5ical ,pyrites #cga4hg #e4cg ,b>ium ,sulphate #bgh4ab #g4ai ,calcium3 ,fluorite #aih4ge #aj4jf ,gypsum #ade4fb #ac4gc ,calcite #afi4cg #aa4hj ,copp] #eeb4ej #c4fb ,calcopyrite #bfb4ej #g4fa ,bornite #cba4hg #f4ba ,mala*ite #bdg4ej #h4jd ,azurite #bcg4ej #h4db ,*rysocolla #acb4ej #ae4ji ,iron 7,ca/7 #dej4jj #d4dd ,magnetite #cae4fb #f4cc ,hematite #cjf4be #f4ec ,limonite #bcg4ej #h4db ,pyrite #cab4ej #f4dj ,c>bonate #bdj4fb #h4ca ,lead #gaj4fb #b4ha ,gal5a #dfh4ge #d4bg ,c>bonate #djf4hg #d4ha ,manganese ,oxide #bfh4ge #f4ah ,rhodonite #bba4be #i4jd ,magnesite #ahg4ej #aj4ff ,dolomite #agh4ab #aa4bc ,qu>tz #afe4fb #ab4jg ,quicksilv] #hdi4ge #b4ce ,c9nab> #eca4be #c4gf ,sulphur #abg4ab #ae4gd ,t9 #dei4jj #d4ce ,oxide #dah4ge #d4gg ,z9c #dcg4ej #d4eg ,bl5de #bec4ab #g4ij ,c>bonate #bgc4ab #g4cb ,silicate #bae4fb #i4bh ,&esite #afe4fb #ab4jg ,granite #afb4fb #ab4cj ,diabase #aha4be #aa4jc ,diorite #aga4hg #aa4fc ,slates #afe4fb #ab4jg ,s&/ones #afb4ej #ab4cj ,rhyolite #aef4be #ab4hj ,! specific gravity ( any p>ticul> m9]al has a consid]able range1 & a m$ium has be5 tak54 ,! possible error is inconsequ5tial = ! purpose ( ^! calculations4 ,= example1 a repres5tative gold ore may conta9 9 ! ma9 #if qu>tz1 & #d iron pyrite1 & ! weight ( ! ore may be d$uc$ z foll[s3-- ,qu>tz1 #if x #ab4jg #aa4eh ,iron ,pyrite1 #d x #f4dj 4#be ----- #aa4hc cubic feet p] ton4 ,mo/ eng9e]s1 to comp5sate porosity1 w\ld all[ twelve to ?irte5 cubic feet p] ton4 ,,classification ,,( ,,ore ,,9 ,,sight4 ,! risk 9 e/imates ( ! av]age value ( /&+ ore is dep5d5t l>gely ^u h[ f> values disclos$ by sampl+ are assum$ to p5etrate beyond ! te/$ face1 & ?is dep5ds ^u ! geological "* ( ! deposit4 ,f !oretical gr\nds & exp]i5ce1 x is kn[n t su* values w h "s ext5sion1 & ! assumption ( any giv5 di/ance is a calculation ( risk4 ,! multiplication ( developm5t op5+s results 9 an increase ( sampl+ po9ts available & less5s ! haz>ds4 ,! frequ5cy ( su* op5+s v>ies 9 diff]5t portions ( e m9e1 & ?us !re are inequalities ( risk4 ,x is !re=e cu/om>y 9 giv+ e/imates ( /&+ ore to classify ! ore accord+ to ! degree ( risk assum$1 ei!r by /at+ ! numb] ( sides expos$ or by o!r phrases4 ,mu* discussion & ink h be5 devot$ to try+ to def9e :at risk may be tak5 9 su* matt]s1 t is 9 reality h[ f> values may be assum$ to p5etrate into ! unbrok5 ore4 ,/ill m has be5 consum$ 9 attempts to co9 t]ms & make classifications :i* w indicate :at ratio ( haz>d has be5 tak5 9 /at+ quantities & values4 ,! old t]ms ore 9 sight & pr(it 9 sight h be5 ( late ye>s subject to mu* mal$iction on ! "p ( eng9e]s because ^! expressions h be5 s badly abus$ by ! *>latans ( m9+ 9 attempts to cov] ! flights ( _! imag9ations4 ,a l>ge "p ( ,volume ,x ( ! ,in/itution ( ,m9+ & ,metallurgy has be5 devot$ to heap+ infamy on ^! t]ms1 yet n only h !y pres]v$ _! places 9 pr(essional nom5clature1 b no?+ has be5 f\nd to sup]s$e !m4 ,"s g5]al t]m is requir$ 9 daily practice to cov] ! :ole field ( visible ore1 & if ! phrase ore 9 sight be def9$1 x w be easi] to tea* ! laym5 its prop] use ?an to aboli% x4 ,9 fact1 ! sub/itutes are becom+ abus$ z mu* z ! orig9als ev] 74 ,all conv9c+ expressions w be misus$ by somebody4 ,! legitimate direction ( re=m has be5 to divide ! g5]al t]m ( ore 9 sight into classes1 & give !m names :i* w indicate ! v>iable am\nt ( risk ( cont9uity 9 diff]5t p>ts ( ! m9e4 ,z ! frequ5cy ( sample po9ts1 & consequ5tly ! risk ( cont9uity1 w dep5d ^u ! detail ) :i* ! m9e is cut into blocks by ! developm5t op5+s1 & ^u ! numb] ( sides ( su* blocks :i* are accessible1 mo/ classifications ( ! degree ( risk ( cont9uity h be5 def9$ 9 t]ms ( ! numb] ( sides expos$ 9 ! blocks4 ,_m phrases h be5 co9$ to express su* classifications2 ^? mo/ curr5tly us$ are ! foll[+3-- ,positive ,ore ,ore expos$ on f\r sides 9 blocks ( a size ,ore ,develop$ _/ v>i\sly prescrib$4 ,ore ,block$ ,out ,ore expos$ on ?ree sides )9 reasonable di/ance ( ea* o!r4 ,probable ,ore ,ore ,develop+ _/ ,ore expos$ on two sides4 ,possible ,ore ,! :ole or a "p ( ! ore bel[ ! ,ore ,expectant _/ l[e/ level or beyond ! range ( vision4 ,no two ( ^! p>allel expressions mean q ! same ?+2 ea* m or less ov]lies into ano!r class1 & 9 fact none ( !m is bas$ ^u a logical foot+ = su* a classification4 ,= example1 values c be assum$ to p5etrate "s di/ance f e sampl$ face1 ev5 if x be only t5 feet1 s t ore expos$ on "o side w %[ "s positive or develop$ ore :i*1 on ! l9es laid d[n above1 might be probable or ev5 possible ore4 ,likewise1 ore may be fully develop$ or block$ out s f> z x is necess>y = /op+ purposes ) mod]n wide int]vals betwe5 levels1 & /ill be 9 blocks too l>ge to w>rant an assumption ( cont9uity ( values to _! c5t]s 7,fig4 #a74 ,z to ! ?ird class ( possible ore1 x conveys an impression ( tangibility to a nebul\s haz>d1 & %\ld nev] be us$ 9 connection ) positive tonnages4 ,?is "p ( ! m9e's value comes "u ext5sion ( ! deposit a long di/ance beyond op5+s1 :i* is a speculation & _c be def9$ 9 absolute tons )\t exhau/ive explanation ( ! risks atta*$1 9 :i* case any phrase int5d$ to %ort5 description is likely to be mislead+4 ,illu/ration3 ,fig4 #a4--,longitud9al section ( a m9e1 %[+ classification ( ! expos$ ore4 ,scale1 #djj feet #a in*4 ,!re=e empirical expressions 9 t]ms ( developm5t op5+s _c be made to cov] a geologic factor su* z ! di/ribution ( metals ?r\gh a rock mass4 ,! only logical basis ( ore classification = e/imation purposes is "o :i* is f\nd$ on ! *ances ( ! values p5etrat+ f ! surface ( ! exposures = ea* p>ticul> m9e4 ,ore t may be calculat$ ^u to a c]ta9ty is t :i*1 tak+ into consid]ation ! "* ( ! deposit1 c be said to be s suffici5tly surr\nd$ by sampl$ faces t ! di/ance into ! mass to :i* values are assum$ to ext5d is r$uc$ to a m9imum risk4 ,ore s f> remov$ f ! sampl$ face z to leave "s d\bt1 yet af=d+ great reason = expectation ( cont9uity1 is probable ore4 ,! ?ird class ( ore m5tion$1 :i* is t dep5d+ ^u ext5sion ( ! deposit & 9 :i*1 z said above1 !re is great risk1 %\ld be treat$ sep>ately z ! speculative value ( ! m9e4 ,"s expressions are desirable = ^! classifications1 & ! writ]'s own pref]5ce is = ! foll[+1 ) a def9ition bas$ ^u ! controll+ factor itself4 ,!y are3-- ,prov$ ,ore ,ore :]e !re is practically no risk ( failure ( cont9uity4 ,probable ,ore ,ore :]e !re is "s risk1 yet w>rantable ju/ification = assumption ( cont9uity4 ,prospective ,ore ,ore :i* _c be includ$ 9 ! above classes1 nor def9itely kn[n or /at$ 9 any t]ms ( tonnage4 ,:at ext5t ( op5+s1 & !re=e ( sample faces1 is requir$ = ! ore to be call$ prov$ v>ies naturally ) ! type ( deposit1--9 fact ) ea* m9e4 ,9 a g5]al way1 a fair rule 9 gold qu>tz ve9s bel[ influ5ce ( second>y alt]ation is t no po9t 9 ! block %all be ov] fifty feet f ! po9ts sampl$4 ,9 lime/one or &esite replacem5ts1 z by gold or lead or copp]1 ! radius mu/ be less4 ,9 def9$ lead & copp] lodes1 or 9 l>ge l5ticul> bodies su* z ! ,t5nessee copp] m9es1 ! radius may (t5 be consid]ably great]1--say "o hundr$ feet4 ,9 gold deposits ( su* extraord9>y regul>ity ( values z ! ,witwat]sr& bankets1 x c well be two hundr$ or two hundr$ & fifty feet4 ,probable ore %\ld be ore :i* entails cont9uity ( values ?r\gh a great] di/ance ?an ! above1 & su* di/ance mu/ dep5d ^u ! collat]al evid5ce f ! "* ( ! deposit1 ! position ( op5+s1 etc4 ,ore beyond ! range ( ! probable zone is dep5d5t ^u ! ext5sion ( ! deposit beyond ! realm ( developm5t & w be discuss$ sep>ately4 ,al?\gh ! expression ore 9 sight may be deprecat$1 ow+ to its abuse1 "s g5]al t]m to cov] bo? positive & probable ore is desirable2 & :]e a g5]al t]m is requir$1 x is ! int5tion h]e9 to hold to ! phrase ore 9 sight "u ! limitations specifi$4 ,,*apt] ,,iii4 ,m9e ,valuation 7,cont9u$74 ,,prospective ,,value499 ,,ext5sion ,,9 ,,dep?2 ,,orig9 ,,& ,,/ructural ,,"* ,,( ,,! ,,deposit2 ,,second>y ,,enri*m5t2 ,,developm5t ,,9 ,,neighbor+ ,,m9es2 ,,dep? ,,( ,,exhau/ion4 ,footnote 993 ,! t]m ext5sion 9 dep? is pref]r$ by _m to ! phrase prospective value4 ,! =m] is n entirely satisfactory1 z x has a m specific ?an g5]al application4 ,x is1 h[ev]1 a curr5t m9]'s phrase1 & is m expressive4 ,9 ?is discussion ext5sion 9 dep? is us$ synonym\sly1 & x may be tak5 to include n alone ! d[nw>d prolongation ( ! ore bel[ work+s1 b also ! occasional cases ( lat]al ext5sion beyond ! range ( developm5t "w4 ,! commone/ in/ance is cont9uance bel[ ! bottom level4 ,9 any ev5t1 to ! majority ( cases ( diff]5t ext5sion ! same reason+ applies4 ,x is a knotty problem to value ! ext5sion ( a deposit beyond a %ort di/ance f ! la/ op5+4 ,a %ort di/ance beyond x is prov$ ore1 & = a fur!r %ort di/ance is probable ore4 ,m9es are v seldom pric$ at a sum s mod]ate z t repres5t$ by ! pr(it to be won f ! ore 9 sight1 & :at value %\ld be assign$ to ?is unkn[n portion ( ! deposit admits ( no c]ta9ty4 ,no eng9e] c approa* ! prospective value ( a m9e ) optimism1 yet ! m9+ indu/ry w\ld be non-exi/5t to-day 7 x approa*$ ) pessimism4 ,any value assess$ mu/ be a matt] ( judgm5t1 & ?is judgm5t bas$ on geological evid5ce4 ,geology is n a ma!matical sci5ce1 & to atta* a money equival5ce to =eca/s bas$ on su* evid5ce is ! mo/ difficult task set = ! m9+ eng9e]4 ,x is "h t 8 view ( geology mu/ diff] f t ( 8 f9ancially m irresponsible bro!r 9 ! sci5ce4 ,! geologi/1 contribut+ to human k 9 g5]al1 f9ds 8 mo/ valuable field 9 ! exam9ation ( m9es l>gely exhau/$4 ,! eng9e]'s mo/ valuable "w arises f 8 ability to anticipate 9 ! y\? ( ! m9e ! symptoms ( its old age4 ,! "w ( our geologic fri5ds is1 h[ev]1 ! v f\ndation on :i* we lay our =eca/s4 ,geologi/s h1 z ! result ( long obs]vation1 prop\nd$ = u c]ta9 hypo!ses :i*1 :ile /ill hypo!ses1 h prov$ to acc\nt s widely = our und]gr\nd exp]i5ce t no eng9e] c af=d to lose sight ( !m4 ,al?\gh !re is a lack ( safety 9 fix$ !ories z to ore deposition1 & al?\gh su* conclusions _c be translat$ into feet & metal value1 !y are nev]!less useful weights on ! scale :]e probabilities are to be weigh$4 ,a me?od 9 vogue ) _m eng9e]s is1 :]e ! bottom level is good1 to assume ! value ( ! ext5sion 9 dep? z a sum proportion$ to ! pr(it 9 sight1 & ?us evade ! use ( geological evid5ce4 ,! addition ( v>i\s p]c5tages to ! pr(it 9 sight has be5 us$ by eng9e]s1 & propos$ 9 te*nical publications1 z v>y+ f #be to #ej4 ,t is1 !y r\ghly assess ! ext5sion 9 dep? to be wor? "o-fif? to "o-?ird ( ! :ole value ( an equipp$ m9e4 ,:ile exp]i5ce may h sometimes demon/rat$ ?is to be a practical me?od1 x c]ta9ly has little f\ndation 9 ei!r sci5ce or logic1 & ! writ]'s exp]i5ce is t su* e/imates are untrue 9 practice4 ,! quantity ( ore :i* may be 9 sight is l>gely ! result ( manag]ial policy4 ,a small mill on a l>ge m9e1 "u rapid developm5t1 w result 9 ext5sive ore-res]ves1 :ile a l>ge mill eat+ away rapidly on ! same m9e "u ! same scale ( developm5t w\ld leave small res]ves4 ,on ! above s*eme ( valuation ! ext5sion 9 dep? w\ld be wor? v diff]5t sums1 ev5 :5 ! deepe/ level might be at ! same horizon 9 bo? cases4 ,moreov]1 no m9e />ts at ! surface ) a l>ge am\nt ( ore 9 sight4 ,yet z a g5]al rule ?is is ! p]iod :5 its ext5sion is mo/ valuable1 = :5 ! deposit is exhau/$ to #bjjj feet1 x is n likely to h su* ext5sion 9 dep? z :5 op5$ "o hundr$ feet1 no matt] :at ! ore-res]ves may be4 ,fur!r1 su* bases ( valuation fail to take into acc\nt ! widely v>y+ geologic "* ( diff]5t m9es1 & !y disreg>d any collat]al evid5ce ei!r ( cont9uity f neighbor+ developm5t1 or f exp]i5ce 9 ! di/rict4 ,logically1 ! prospective value c be simply a factor ( h[ f> ! ore 9 ! individual m9e may be expect$ to ext5d1 & n a factor ( ! remnant ( ore t may /ill be unwork$ above ! l[e/ level4 ,an e/imation ( ! *ances ( ?is ext5sion %\ld be bas$ solely on ! local factors :i* be> on su* ext5sion1 & ^! are almo/ :olly dep5d5t ^u ! "* ( ! deposit4 ,^! v>i\s geological factors f a m9+ eng9e]'s po9t ( view are3-- #a4 ,! orig9 & /ructural "* ( ! ore-deposit4 #b4 ,! position ( op5+s 9 relation to second>y alt]ation4 #c4 ,! size ( ! deposit4 #d4 ,! dep? to :i* ! m9e has already be5 exhau/$4 #e4 ,! g5]al exp]i5ce ( ! di/rict = cont9uity & ! developm5t ( adjo9+ m9es4 ,,! ,,orig9 ,,& ,,/ructural ,,"* ,,( ,,! ,,deposit4--,9 a g5]al way1 ! ore-deposits ( ! ord] "u discussion orig9ate prim>ily ?r\gh ! deposition ( metals f gases or solutions circulat+ along av5ues 9 ! e>?'s cru/499 ,! orig9al s\rce ( metals is a matt] ( great disagreem5t1 & does n mu* conc]n ! m9]4 ,to him1 h[ev]1 ! orig9 & "* ( ! av5ue ( circulation1 ! enclos+ rock1 ! influ5ce ( ! rocks on ! solution1 & ( ! solutions on ! rocks1 h a great be>+ on ! probable cont9uity ( ! volume & value ( ! ore4 ,footnote 993 ,! class ( magmatic segregations is omitt$1 z n be+ ( suffici5tly frequ5t occurr5ce 9 payable m9es to w>rant tr\bl+ ) x "h4 ,all ore-deposits v>y 9 value &1 9 ! m9]'s view1 only ^? portions above ! pay limit are ore-bodies1 or ore-%oots4 ,! localization ( values into su* pay areas 9 an ore-deposit are app>5tly influ5c$ by3 #a4 ,! di/ribution ( ! op5 spaces creat$ by /ructural movem5t1 fissur+1 or fold+ z at ,b5digo4 #b4 ,! int]section ( o!r fractures :i*1 by m+l+ ( solutions f diff]5t s\rces1 provid$ precipitat+ conditions1 z %[n by enri*m5ts at cross-ve9s4 #c4 ,! influ5ce ( ! enclos+ rocks by3-- 7a7 ,_! solubility1 & !re=e susceptibility to replacem5t4 7b7 ,_! influ5ce z a precipitat+ ag5t on solutions4 7c7 ,_! influ5ce z a s\rce ( metal itself4 7d7 ,_! texture1 9 its influ5ce on ! "* ( ! fracture4 ,9 homog5e\s rocks ! t5d5cy is to op5 clean-cut fissures2 9 friable rocks1 zones ( brecciation2 9 slates or s*i/ose rocks1 l9k$ l5ticul> op5 spaces2--^! influ5ces exhibit+ !mselves 9 m9]'s t]ms respectively 9 well-def9$ fissure ve9s1 lodes1 & l5ses4 7e7 ,! physical "* ( ! rock mass & ! dynamic =ces br\ght to be> ^u x4 ,?is is a difficult /udy into ! physics ( /ress 9 cases ( fractur+1 b its local application has n be5 )\t results ( an important ord]4 #d4 ,second>y alt]ation ne> ! surface1 m fully discuss$ lat]4 ,x is evid5t en\gh t ! :ole /ructure ( ! deposit is a necess>y /udy1 & ev5 a dige/ ( ! subject is n to be compress$ into a few p>agraphs4 ,f ! po9t ( view ( cont9uity ( values1 ore-deposits may be r\ghly divid$ into ?ree classes4 ,!y are3-- #a4 ,deposits ( ! infiltration type 9 por\s b$s1 su* z ,lake ,sup]ior copp] conglom]ates & ,african gold bankets4 #b4 ,deposits ( ! fissure ve9 type1 su* z ,cali=nia qu>tz ve9s4 #c4 ,replacem5t or impregnation deposits on ! l9es ( fissur+ or o!rwise4 ,9 a g5]al way1 ! uni=mity ( conditions ( deposition 9 ! fir/ class has result$ 9 ! mo/ satisfactory cont9uity ( ore & ( its metal cont5ts4 ,9 ! second1 dep5d+ mu* ^u ! pr(undity ( ! e>? movem5ts involv$1 !re is lat]ally & v]tically a reasonable basis = expectation ( cont9uity b ?r\gh mu* less di/ance ?an 9 ! fir/ class4 ,! ?ird class ( deposits exhibits widely diff]5t ph5om5a z to cont9uity & no g5]alization is ( any value4 ,9 gold deposits ( ?is type 9 ,we/ ,au/ralia1 ,colorado1 & ,nevada1 cont9uity f> beyond a sampl$ face mu/ be receiv$ ) ! greate/ skepticism4 ,mu* ! same may be said ( mo/ copp] replacem5ts 9 lime/one4 ,on ! o!r h& ! mo/ ph5om5al regul>ity ( values h be5 %[n 9 c]ta9 ,utah & ,arizona copp] m9es1 ! result ( second>y infiltration 9 porphyritic gangues4 ,! ,mississippi ,valley lead & z9c deposits1 :ile irregul> 9 detail1 %[ rem>kable cont9uity by way ( reoccurr5ce ov] wide areas4 ,! e/imation ( ! prospective value ( m9es :]e cont9uity ( production is dep5d5t on reoccurr5ce ( ore-bodies some:at proportional to ! area1 su* z ^! ,mississippi deposits or to "s ext5t z 9 ,cobalt silv] ve9s1 is an int]e/+ /udy1 b "o t (f]s little field = g5]alization4 ,,! ,,position ,,( ,,! ,,op5+s ,,9 ,,relation ,,to ,,second>y ,,alt]ation4--,! pr(\nd alt]ation ( ! upp] section ( ore-deposits by oxidation due to ! action ( desc5d+ surface wat]s1 & _! associat$ *emical ag5cies1 has be5 g5]ally recogniz$ = a great _m ye>s4 ,only rec5tly1 h[ev]1 has x be5 appreciat$ t ?is second>y alt]ation ext5ds into ! sulphide zone z well4 ,! be>+ ( ! second>y alt]ation1 bo? 9 ! oxidiz$ & upp] sulphide zones1 is ( ! mo/ sweep+ economic "*4 ,9 consid]+ ext5sion ( values 9 dep?1 x dem&s ! mo/ rigor\s inve/igation4 ,n only does ! metallurgical "* ( ! ores *ange ) oxidation1 b ! complex reactions due to desc5d+ surface wat]s cause lea*+ & a migration ( metals f "o horizon to ano!r l[] d[n1 & also 9 _m cases a r$i/ribution ( _! sequ5ce 9 ! upp] zones ( ! deposit4 ,! effect ( ^! ag5cies has be5 s great 9 _m cases z to entirely alt] ! "* ( ! m9e & ext5sion 9 dep? has necessitat$ a complete requipm5t4 ,= in/ance1 ! ,mt4 ,morgan gold m9e1 ,que5sl&1 has n[ become a copp] m9e2 ! copp] m9es at ,butte 7 =m]ly silv] m9es2 ,leadville has become l>gely a z9c produc] in/ead ( lead4 ,f ?is alt]ation aspect ore-deposits may be consid]$ to h f\r horizons3-- #a4 ,! zone ne> ! outcrop1 :]e ! dom9at+ feature is oxidation & lea*+ ( ! soluble m9]als4 #b4 ,a l[] horizon1 /ill 9 ! zone ( oxidation1 :]e ! pr$om9ant feature is ! deposition ( metals z native1 oxides1 & c>bonates4 #c4 ,! upp] horizon ( ! sulphide zone1 :]e ! special feature is ! enri*m5t due to second>y deposition z sulphides4 #d4 ,! region bel[ ^! zones ( second>y alt]ation1 :]e ! deposit is 9 its prim>y /ate4 ,^! zones are seldom %>ply def9$1 nor are !y always all 9 evid5ce4 ,h[ f> !y are 9 evid5ce w dep5d1 among o!r ?+s1 ^u ! am\nt & rapidity ( erosion1 ! /ructure & m9]alogical "* ( ! deposit1 & ^u ! enclos+ rock4 ,if erosion is extremely rapid1 z 9 cold1 wet climates1 & r\gh topography1 or z 9 ! case ( glaciation ( ! ,lake copp] deposits1 d5udation foll[s close on ! heels ( alt]ation1 & ! surface is s rapidly remov$ t we may h ! prim>y ore practically at ! surface4 ,flat1 arid regions pres5t ! o!r extreme1 = d5udation is mu* sl[]1 & conditions are mo/ p]fect = deep p5etration ( oxidiz+ ag5cies1 & ! consequ5t alt]ation & conc5tration ( ! metals4 ,! migration ( metals f ! top ( ! oxidiz$ zone leaves b a b>r5 cap = erosion4 ,! consequ5t effect ( d5udation t lags beh9d alt]ation is to raise sl[ly ! conc5trat$ metals t[>d ! surface1 & ?us subject !m to r5ew$ attack & repeat$ migration4 ,9 ?is mann] we c acc\nt = ! enorm\s conc5tration ( values 9 ! l[] oxidiz$ & upp] sulphide zones ov]ly+ v lean sulphides 9 dep?4 ,"s m9]als are m freely soluble & m readily precipitat$ ?an o!rs4 ,f ?is cause !re is 9 complex metal deposits a re>rangem5t ( horizontal sequ5ce1 9 addition to enri*m5t at c]ta9 horizons & impov]i%m5t at o!rs4 ,! :ole subject is "o ( too great complexity = adequate consid]ation 9 ?is discussion4 ,no eng9e] is prop]ly equipp$ to give judgm5t on ext5sion 9 dep? )\t a ?or\gh grasp ( ! great pr9ciples laid d[n by ,van ,hise1 ,emmons1 ,l9dgr51 ,we$1 & o!rs4 ,we may1 h[ev]1 briefly exam9e "s ( ! !oretical effects ( su* alt]ation4 ,z9c1 iron1 & lead sulphides are a common prim>y comb9ation4 ,^! metals are r5d]$ soluble f _! usual prim>y =ms by oxidiz+ ag5cies1 9 ! ord] giv54 ,!y reprecipitate z sulphides 9 ! rev]se sequ5ce4 ,! result is ! lea*+ ( z9c & iron readily 9 ! oxidiz$ zone1 ?us diff]5tially enri*+ ! lead :i* lags beh9d1 & a fur!r ext5sion ( ! lead horizon is provid$ by ! e>ly precipitation ( su* lead z does migrate4 ,!re=e1 ! lead (t5 pr$om9ates 9 ! second & ! upp] portion ( ! ?ird zone1 ) ! z9c & iron bel[4 ,al?\gh ! action ( all surface wat]s is t[>d oxidation & c>bonation ( ^! metals1 ! c>bonate developm5t ( oxidiz$ zones is m m>k$ :5 ! enclos+ rocks are calc>e\s4 ,9 copp]-iron deposits1 ! comp>atively easy decomposition & solubility & precipitation ( ! copp] & "s iron salts g5]ally result 9 m ext5sive impov]i%m5t ( ^! metals ne> ! surface1 & m pr$om9ant enri*m5t at a l[] horizon ?an is ! case ) any o!r metals4 ,! b>r5 iron hat at ! fir/ zone1 ! c>bonates & oxides at ! second1 ! enri*m5t ) second>y copp] sulphides at ! top ( ! ?ird1 & ! occurr5ce ( second>y copp]-iron sulphides bel[1 are (t5 mo/ cle>ly def9$4 ,9 ! easy recognition ( ! second>y copp] sulphides1 *alcocite1 bornite1 etc41 ! eng9e] f9ds a f+]-po/ on ! road to ext5sion 9 dep?2 & ! directions ^u ?is po/ are n to be disreg>d$4 ,! numb] ( copp] deposits enri*$ f unpayability 9 ! fir/ zone to a pr(itable "* 9 ! next two1 & unpayability aga9 9 ! f\r?1 is legion4 ,silv] occurs mo/ abundantly 9 comb9ation ) ei!r lead1 copp]1 iron1 or gold4 ,z x resi/s oxidation & solution m /r5u\sly ?an copp] & iron1 its t5d5cy :5 9 comb9ation ) !m is to lag beh9d 9 migration4 ,!re is ?us a diff]5tial enri*m5t ( silv] 9 ! upp] two zones1 due to ! r$uction 9 specific gravity ( ! ore by ! removal ( associat$ metals4 ,silv] does migrate some:at1 h[ev]1 & z x precipitates m readily ?an copp]1 lead1 z9c1 or iron1 its t5d5cy :5 9 comb9ation ) !m is t[>ds enri*m5t above ! horizons ( enri*m5t ( ^! metals4 ,:5 x is 9 comb9ation ) lead & z9c1 its v ready precipitation f solution by ! gal5a leaves x 9 comb9ation m pr$om9antly ) ! lead4 ,! second>y enri*m5t ( silv] deposits at ! top ( ! sulphide zone is sometimes a mo/ pron\nc$ feature1 & x seems to be ! explanation ( ! orig9 ( _m bonanzas4 ,9 gold deposits1 ! great] resi/ance to solubility ( ?is metal ?an mo/ ( ! o!rs1 r5d]s ! ph5om5a ( migration to dep? less m>k$4 ,fur!r ?an ?is1 migration is (t5 int]f]$ ) by ! m imp]vi\s qu>tz matrix ( _m gold deposits4 ,:]e gold is associat$ ) l>ge quantities ( base metals1 h[ev]1 ! lea*+ ( ! latt] 9 ! oxidiz$ zone leaves ! ore diff]5tially ri*]1 & z gold is also slightly soluble1 9 su* cases ! migration ( ! base metals does c>ry "s ( ! gold4 ,9 ! in/ance especially ( impregnation or replacem5t deposits1 :]e ! matrix is easily p]meable1 ! upp] sulphide zone is di/9ctly ri*] ?an l[] d[n1 & ?is enri*m5t is accompani$ by a consid]able increase 9 sulphides & tellurides4 ,! pr$om9ant *>act]i/ic ( alt]ation 9 gold deposits is1 h[ev]1 enri*m5t 9 ! oxidiz$ zone ) ! maximum values ne> ! surface4 ,! reasons = ?is appe> to be t gold 9 its resi/ance to oxidation & :olesale migration gives opportunities to a sort ( comb9$ me*anical & *emical enri*m5t4 ,9 dry climates1 especially1 ! g5tl5ess ( erosion all[s ( m ?or\gh decomposition ( ! outcropp+s1 & a me*anical sep>ation ( ! gold f ! detritus4 ,x rema9s on or ne> ! deposit1 ready to be c>ri$ bel[1 me*anically or o!rwise4 ,9 wet climates ?is is less pron\nc$1 = erosion be>s away ! cropp+s be=e su* an ext5sive decomposition & free+ ( ! gold p>ticles4 ,! ,we/ ,au/ralian gold fields pres5t an especially prom95t example ( ?is type ( sup]ficial enri*m5t4 ,dur+ ! la/ fifte5 ye>s ne>ly eight hundr$ companies h be5 =m$ = work+ m9es 9 ?is region4 ,al?\gh f f\r hundr$ ( ^! high-grade ore has be5 produc$1 "s ?irty-?ree only h ev] paid divid5ds4 ,! great majority h be5 unpayable bel[ oxidation1--a di/ance ( "o or two hundr$ feet4 ,! writ]'s unv>y+ exp]i5ce ) gold is t x is ri*] 9 ! oxidiz$ zone ?an at any po9t bel[4 ,:ile cases d occur ( gold deposits ri*] 9 ! upp] sulphide zone ?an bel[1 ev5 ! upp] sulphides are usually poor] ?an ! oxidiz$ region4 ,9 qu>tz ve9s prem95tly1 evid5ce ( enri*m5t 9 ! ?ird zone is likely to be practically abs5t4 ,t9 ores pres5t an anomaly among ! base metals "u discussion1 9 t ! prim>y =m ( ?is metal 9 mo/ workable deposits is an oxide4 ,t9 9 ?is =m is mo/ difficult ( solution f gr\nd ag5cies1 z witness ! great alluvial deposits1 (t5 ( consid]able geologic age4 ,9 consequ5ce ! ph5om5a ( migration & enri*m5t are almo/ :olly abs5t1 except su* z are due to me*anical p5etration ( t9 f surface decomposition ( ! matrix ak9 to t describ$ 9 gold deposits4 ,9 g5]al1 ?ree or f\r ess5tial facts f second>y alt]ation mu/ be kept 9 view :5 progno/icat+ ext5sions4 ,oxidation usually alt]s treatm5t problems1 & oxidiz$ ore ( ! same grade z sulphides c (t5 be treat$ m *eaply4 ,?is is n univ]sal4 ,l[-grade ores ( lead1 copp]1 & z9c may be treatable by conc5tration :5 9 ! =m ( sulphides1 & may be valueless :5 oxidiz$1 ev5 ?\gh ( ! same grade4 ,copp] ores g5]ally %[ viol5t enri*m5t at ! base ( ! oxidiz$1 & at ! top ( ! sulphide zone4 ,lead-z9c ores %[ lead enri*m5t & z9c impov]i%m5t 9 ! oxidiz$ zone b h usually less pron\nc$ enri*m5t bel[ wat] level ?an copp]4 ,! re>rangem5t ( ! metals by ! deep] migration ( ! z9c1 also r5d]s !m metallurgically ( less value ) dep?4 ,silv] deposits are (t5 diff]5tially enri*$ 9 ! oxidiz$ zone1 & at times t5d to conc5trate 9 ! upp] sulphide zone4 ,gold deposits usually decrease 9 value f ! surface ?r\gh ! :ole ( ! ?ree alt]ation zones4 ,,size ,,( ,,deposits4--,! prov]b ( a relation betwe5 ext5sion 9 dep? & size ( ore-bodies expresses "o ( ! olde/ ( m9]s' beliefs4 ,x has "s basis 9 exp]i5ce1 especially 9 fissure ve9s1 b has little f\ndation 9 !ory & is applicable ov] b limit$ areas & "u limit$ conditions4 ,f a /ructural view1 ! dep? ( fissur+ is likely to be m or less 9 proportion to its l5g? & bread? & !re=e ! volume ( ve9 fill+ ) dep? is likely to be proportional to l5g? & wid? ( ! fissure4 ,z to ! di/ribution ( values1 if we elim9ate ! influ5ce ( *ang+ wall rocks1 or o!r precipitat+ ag5cies :i* (t5 cause ! values to arrange !mselves 9 floors1 & ( second>y alt]ation1 !re may be "s reason to assume di/ribution ( values ( an ext5t equal v]tically to t display$ horizontally4 ,!re is1 z said1 m reason 9 exp]i5ce = ?is assumption ?an 9 !ory4 ,a /udy ( ! %ape ( a great _m ore-%oots 9 m9es ( fissure type indicates t :5 ! ore-%oots or ore-bodies are approa*+ v]tical exhau/ion !y d n end abruptly1 b gradually %ort5 & decrease 9 value1 _! bottom b\nd>ies be+ m (t5 w$ge-%ap$ ?an ev5 l5ticul>4 ,if ?is c\ld be tak5 z ! usual occurr5ce1 x w\ld be possible 7elim9at+ ! evid5t exceptions m5tion$ above7 to /ate r\ghly t ! m9imum ext5sion ( an ore-body or ore-%oot 9 dep? bel[ any giv5 horizon w\ld be a di/ance repres5t$ by a radius equal to "o-half its l5g?4 ,by l5g? is n meant necess>ily ! l5g? ( a horizontal section1 b ( "o at "r angles to ! d[nw>d axis4 ,on ^! gr\nds1 :i* h be5 ren=c$ by mu* exp]i5ce among m9]s1 ! probabilities ( ext5sion are some:at 9 proportion to ! l5g? & wid? ( ea* ore-body4 ,= in/ance1 9 ! ,a m9e1 ) an ore-%oot #ajjj feet long & #aj feet wide1 on its bottom level1 ! m9imum ext5sion "u ?is hypo!sis w\ld be a w$ge-%ap$ ore-body ) its deepe/ po9t #ejj feet bel[ ! l[e/ level1 or a m9imum ( say #bjj1jjj tons4 ,simil>ly1 ! ,b m9e ) five ore-bodies1 ea* #cjj hundr$ feet long & #aj feet wide1 expos$ on its l[e/ level1 w\ld h a m9imum ( five w$ges #ajj feet deep at _! deepe/ po9ts1 or say #ej1jjj tons4 ,?is is n propos$ z a =mula giv+ ! total am\nt ( ext5sion 9 dep?1 b z a sort ( y>d/ick :i* has exp]i5ce beh9d x4 ,?is exp]i5ce applies 9 a mu* less degree to deposits orig9at+ f impregnation along l9es ( fissur+ & n at all to replacem5ts4 ,,developm5t ,,9 ,,neighbor+ ,,m9es4--,m9es ( a di/rict are usually f\nd "u ! same geological conditions1 & %[ some:at ! same habits z to ext5sion 9 dep? or lat]ally1 & especially simil> conduct ( ore-bodies & ore-%oots4 ,z a practical crit]ion1 "o ( ! mo/ intimate guides is ! actual developm5t 9 adjo9+ m9es4 ,= in/ance1 9 ,kalgoorlie1 ! ,great ,b\ld] m9e is 7,m>*1 #aijh7 work+ ! ext5sion ( ,ivanhoe lodes at po9ts #ejj feet bel[ ! l[e/ level 9 ! ,ivanhoe2 likewise1 ! ,block #aj lead m9e at ,brok5 ,hill is work+ ! ,c5tral ore-body on ! ,c5tral b\nd>y "s #cej feet bel[ ! ,c5tral work+s4 ,su* facts z ^! mu/ h a be>+ on assess+ ! d[nw>d ext5sion4 ,,dep? ,,( ,,exhau/ion4--,all m9es become completely exhau/$ at "s po9t 9 dep?4 ,!re=e ! actual di/ance to :i* ore c be expect$ to ext5d bel[ ! l[e/ level gr[s less ) e deep] work+ horizon4 ,! really sup]ficial "* ( ore-deposits1 ev5 outside ( ! region ( second>y enri*m5t is becom+ e ye> bett] recogniz$4 ,! prospector's idea t %e gets ri*] deep] d[n1 may h "s basis ne> ! surface 9 "s metals1 b x is n an idea :i* prevails 9 ! m9ds ( eng9e]s :o h to "w 9 dep?4 ,! writ]1 ) "s o!rs1 prep>$ a li/ ( sev]al hundr$ divid5d-pay+ metal m9es ( all sorts1 ext5d+ ov] ,nor? & ,s\? ,am]ica1 ,au/ralasia1 ,engl&1 & ,africa4 ,notes 7 made z f> z possible ( ! dep?s at :i* values gave out1 & also at :i* divid5ds ceas$4 ,al?\gh by no means a complete c5sus1 ! li/ indicat$ t n #f ( m9es 7outside banket7 t h yield$ pr(its1 ev] made !m f ore won bel[ #bjjj feet4 ,( m9es t paid divid5ds1 #hj did n %[ pr(itable value bel[ #aejj feet1 & a sad majority di$ above #ejj4 ,failures at %ort dep?s may be blam$ ^u second>y enri*m5t1 b ! majority t rea*$ bel[ ?is influ5ce also gave out4 ,! geological reason = su* g5]al unseemly conduct is n s evid5t4 ,,conclusion4--,z a practical problem1 ! assessm5t ( prospective value is usually a case ( cut & try4 ,! portion ( ! capital to be inve/$1 :i* dep5ds ^u ext5sion1 w require s _m tons ( ore ( ! same value z t indicat$ by ! /&+ ore1 9 ord] to ju/ify ! price4 ,to produce ?is tonnage at ! cont9u$ av]age size ( ! ore-bodies w require _! ext5sion 9 dep? s _m feet--or ! discov]y ( new ore-bodies ( a c]ta9 size4 ,! five geological weights m5tion$ above may !n be put into ! scale & a basis ( judgm5t rea*$4 ,,*apt] ,,iv4 ,m9e ,valuation 7,cont9u$74 ,,recov]able ,,p]c5tage ,,( ,,! ,,gross ,,assay ,,value2 ,,price ,,( ,,metals2 ,,co/ ,,( ,,production4 ,! me?od ( treatm5t = ! ore mu/ be kn[n be=e a m9e c be valu$1 because a k ( ! recov]able p]c5tage is z important z t ( ! gross value ( ! ore itself4 ,! recov]able p]c5tage is usually a factor ( work+ co/s4 ,practically e ore c be treat$ & all ! metal cont5ts recov]$1 b ! real problem is to "k ! me?od & p]c5tage ( recov]y :i* w yield ! mo/ remun]ative result1 if any4 ,?is limit to pr(itable recov]y regulates ! am\nt ( metal :i* %\ld be lo/1 & ! am\nt ( metal :i* consequ5tly mu/ be d$uct$ f ! gross value be=e ! real net value ( ! ore c be calculat$4 ,"h1 z ev]y:]e else 9 m9+1 a compromise has to be made ) nature1 & we take :at we c get--pr(itably4 ,= in/ance1 a copp] ore may be smelt$ & a #ii recov]y obta9$4 ,"u c]ta9 conditions ?is might be done at a loss1 :ile ! same ore might be conc5trat$ be=e smelt+ & yield a pr(it ) a #gj recov]y4 ,an additional #bj might be obta9$ by roa/+ & lea*+ ! residues f conc5tration1 b ?is w\ld probably result 9 an exp5diture f> great] ?an ! value ( ! #bj recov]$4 ,if ! ore is n already "u treatm5t on ! m9e1 or exactly simil> ore is n "u treatm5t else:]e1 ) kn[n results1 ! me?od mu/ be det]m9$ exp]im5tally1 ei!r by ! exam9+ eng9e] or by a special metallurgi/4 ,:]e p>tially treat$ products1 su* z conc5trates1 are to be sold1 n only w !re be fur!r losses1 b d$uctions w be made by ! smelt] = delet]i\s metals & o!r *>ges4 ,all ( ^! factors mu/ be f\nd out1--& a few sample smelt+ returns f a simil> ore are useful4 ,to cov] ! :ole field ( metallurgy & discuss :at might apply1 & h[ x might apply1 "u a hundr$ supposititi\s conditions w\ld be too great a digression f ! subject 9 h&4 ,x is en\gh to call att5tion "h to ! fact t ! residues f e treatm5t c>ry "s metal1 & t ?is loss has to be d$uct$ f ! gross value ( ! ore 9 any calculations ( net values4 ,,price ,,( ,,metals4 ,un=tunately = ! m9+ eng9e]1 n only has he to weigh ! am\nt ( risk inh]5t 9 calculations involv$ 9 ! m9e itself1 b also t due to fluctuations 9 ! value ( metals4 ,if ! ore is %ipp$ to cu/om works1 he has to contemplate also v>iations 9 freights & smelt+ *>ges4 ,gold f ! m9e valu]'s po9t ( view has no fluctuations4 ,x alone among ! e>?'s products gives no conc]n z to ! m>ket price4 ,! price to be tak5 = all o!r metals has to be decid$ be=e ! m9e c be valu$4 ,?is introduces a fur!r speculation &1 z 9 all calculations ( probabilities1 am\nts to an e/imate ( ! am\nt ( risk4 ,9 a free m>ket ! law ( supply & dem& gov]ns ! value ( metals z x does t ( all o!r commodities4 ,s f>1 except = t>iff walls & smelt+ r+s1 !re is a free m>ket 9 ! metals "u discussion4 ,! dem& = metals v>ies ) ! unequal fluctuations ( ! indu/rial tides4 ,! sea ( comm]cial activity is subject to heavy /orms1 & ! m9e valu] is compell$ to s]ve z wea!r prophet on ?is ocean ( tr\ble4 ,high prices1 :i* are ! result ( indu/rial booms1 br+ ab\t ov]production1 & ! collapse ( ^! begets a %r9kage ( dem&1 :]e9 consequ5tly ! tide ( price turns back4 ,9 m9+ = metals ea* p\nd is produc$ actually at a diff]5t co/4 ,9 case ( an ov]supply ( base metals ! price w fall until x has rea*$ a po9t :]e a portion ( ! production is no long] pr(itable1 & ! equilibrium is e/abli%$ ?r\gh decl9e 9 output4 ,h[ev]1 9 ! backw>d sw+1 due to l+]+ ov]production1 prices usually fall l[] ?an ! co/ ( produc+ ev5 a mu*-dim9i%$ supply4 ,!re is at ?is po9t :at we may call ! basic price1 t at :i* production is insuffici5t & ! price rises aga94 ,! basic price :i* is due to ?is undue backw>d sw+ is no m ! real price ( ! metal to be contemplat$ ov] s long a t]m ( ye>s ?an is ! highe/ price4 ,at h[ mu* above ! basic price ( depress$ times ! product c be safely expect$ to f9d a m>ket is ! real "q4 ,few m9es c be b\ght or valu$ at ?is basic price4 ,an indication ( :at ?is is c be ga9$ f a /udy ( fluctuations ov] a long t]m ( ye>s4 ,x is common to he> ! av]age price ov] an ext5d$ p]iod consid]$ ! normal price1 b ?is basis = value is "o :i* mu/ be us$ ) discretion1 = x is n ! :ole "q :5 m9+4 ,! normal price is ! av]age price ov] a long t]m4 ,! lives ( m9es1 & especially ore 9 sight1 may n necess>ily enjoy ! p]iod ( ?is normal price4 ,! eng9e] mu/ balance 8 judgm5ts by ! imm$iate outlook ( ! indu/rial wea!r4 ,:5 lead 0 fall+ /eadily 9 ,decemb]1 #aijg1 no eng9e] w\ld accept ! price ( t date1 al?\gh x 0 !n bel[ normal2 8 product might g to m>ket ev5 l[] yet4 ,x is desirable to asc]ta9 :at ! basic & normal prices are1 = betwe5 !m lies safety4 ,s9ce #ahhd !re h be5 ?ree cycles ( comm]cial expansion & contraction4 ,if ! av]age prices are tak5 = ^! ?ree cycles sep>ately 7#ahhe-ie71 #ahie-aijb1 #aijb-jh7 x w be se5 t !re has be5 a /eady advance 9 prices4 ,= ! succe$+ cycles lead on ! ,london ,ex*ange199 ! free/ ( ! _w's m>kets 0 #ab #abs4 #d;d41 #ac #cs4 #g;d41 & #ag #gs4 #j;d4 respectively2 z9c1 #ag #ads4 #aj;d41 #ai #cs4 #h;d41 & #bc #cs4 #j;d42 & /&>d copp]1 #dh #afs4 #j;d41 #ei #ajs4 #j;d41 & #fe #gs4 #j;d4 ,x seems1 !re=e1 t a high] /&>d ( prices c be assum$ z ! basic & normal ?an w\ld be indicat$ if ! g5]al av]age (1 say1 tw5ty ye>s 7 tak54 ,dur+ ?is p]iod1 ! _w's gold output has ne>ly quadrupl$1 &1 :e!r ! quantitative !ory ( gold be accept$ or n1 x _c be d5i$ t !re has be5 a /eady increase 9 ! price ( commodities4 ,9 all base-metal m9+ x is well to rememb] t ! production ( ^! metals is liable to great /imulus at times f ! discov]y ( new deposits or new processes ( recov]y f hi!rto unpr(itable ores4 ,x is !re=e = ?is reason haz>d\s 9 ! extreme to prophesy :at prices w be f> 9 ! future1 ev5 :5 ! indu/rial wea!r is cle>4 ,b "s basis mu/ be arriv$ at1 & f ! available outlook x w\ld seem t ! foll[+ metal prices are ju/ifiable = "s "t to come1 provid$ ! pres5t t>iff s*$ules are ma9ta9$ 9 ! ,unit$ ,/ates3 ,footnote 993 ,all ,london prices are bas$ on ! long ton ( #b1bdj lbs4 ,mu* confusion exi/s 9 ! copp] trade z to ! classification ( ! metal4 ,new ,york prices are quot$ 9 electrolytic & ,lake2 ,london's 9 ,/&>d4 ,/&>d has n[ become practically an arbitr>y t]m peculi> to ,london1 = ! great bulk ( copp] dealt 9 is electrolytic valu$ consid]ably ov] ,/&>d4 ,lead ,spelt] ,copp] ,t9 ,silv] ---------------------------------------- ----------------- ,london ,n4,y4,lon4 ,n4,y4,lon4 ,n4,y4,lon4 ,n4,y4 ,lon4 ,n4,y4 ,ton ,p\nd,ton ,p\nd,ton ,p\nd,ton ,p\nd,p] oz4,p] oz4 ---------------------------------------- ------------------------ ,basic ,price #aa4 4#jceag 4#jdjeb 4#aaeajj4bbj #bb;d44#dd ,normal ,price #ac4e 4#jdc #ba 4#jej #fe 4#adj #acj 4#bij #bf 4#eb ,9 ^! figures ! writ] has n foll[$ /rict av]ages1 b has tak5 ! g5]al outlook comb9$ ) ! previ\s records4 ,! likelihood ( high] prices = lead is m enc\rag+ ?an = any o!r metal1 z no new deposits ( importance h come =w>d = ye>s1 & ! old m9es are rea*+ consid]able dep?s4 ,nor does ! fr5zi$ prospect+ ( ! _w's surface dur+ ! pa/ t5 ye>s appe> to =eca/ any v di/urb+ developm5ts4 ,! z9c future is n s bright1 = metallurgy has done wond]s 9 provid+ me?ods ( sav+ ! z9c =m]ly disc>d$ f lead ores1 & enorm\s supplies w come =w>d :5 requir$4 ,! t9 outlook is enc\rag+1 = ! supply f a m9+ po9t ( view seems unlikely to m ?an keep pace ) ! _w's ne$s4 ,9 copp] ! dem& is gr[+ prodigi\sly1 b ! supplies ( copp] ores & ! numb] ( copp] m9es t are ready to produce :5ev] normal prices recur 0 nev] s great z to-day4 ,"o v hopeful fact c be d$uc$ = ! com=t ( ! base metal m9+ indu/ry z a :ole4 ,if ! gr[? ( dem& cont9ues ?r\gh ! next ?irty ye>s 9 ! ratio ( ! pa/ ?ree decades1 ! annual dem& = copp] w be ov] #c1jjj1jjj tons1 ( lead ov] #a1hjj1jjj tons1 ( spelt] #b1hjj1jjj tons1 ( t9 #bej1jjj tons4 ,:]e su* /up5d\s am\nts ( ^! metals are to come f at ! pres5t range ( prices1 & ev5 ) r$uc$ co/s ( production1 is f> beyond any app>5t s\rce ( supply4 ,! outlook = silv] prices is 9 ! long run n bright4 ,z ! major portion ( ! silv] produc$ is a bye product f base metals1 any increase 9 ! latt] w increase ! silv] production despite v mu* l[] prices = ! preci\s metal4 ,9 ! meantime ! gradual conv]sion ( all nations to ! gold /&>d seems a matt] ( c]ta9ty4 ,fur!r1 silv] may yet be ab&on$ z a subsidi>y co9age inasmu* z x has n[ b a tok5 value 9 gold /&>d c\ntries if d5ud$ ( s5tim5t4 ,,co/ ,,( ,,production4 ,x is h>dly necess>y to argue ! relative importance ( ! det]m9ation ( ! co/ ( production & ! det]m9ation ( ! recov]able cont5ts ( ! ore4 ,obvi\sly1 ! aim ( m9e valuation is to "k ! pr(its to be won1 & ! pr(it is ! value ( ! metal won1 less ! co/ ( production4 ,! co/ ( production embraces developm5t1 m9+1 treatm5t1 managem5t4 ,fur!r ?an ?is1 x is (t5 cont5d$ t1 z ! capital exp5d$ 9 pur*ase & equipm5t mu/ be r$eem$ )9 ! life ( ! m9e1 ?is item %\ld also be includ$ 9 production co/s4 ,x is true t mills1 smelt]s1 %afts1 & all ! p>aph]nalia ( a m9e are ( virtually negligible value :5 x is exhau/$2 & t all m9es are exhau/$ sometime & e ton tak5 out contributes to t exhau/ion2 & t e ton ( ore mu/ be> its contribution to ! return ( ! inve/m5t1 z well z pr(it ^u x4 ,!re=e x may well be said t ! r$emption ( ! capital & its int]e/ %\ld be consid]$ 9 co/s p] ton4 ,! difficulty 9 deal+ ) ! subject f ! po9t ( view ( production co/ arises f ! fact t1 except possibly 9 ! case ( banket gold & "s conglom]ate copp] m9es1 ! life ( a metal m9e is unkn[n beyond ! "t requir$ to exhau/ ! ore res]ves4 ,! visible life at ! "t ( pur*ase or equipm5t may be only ?ree or f\r ye>s1 yet ! av]age equipm5t has a long] life ?an ?is1 & ! anticipation = e m9e is also = long] duration ?an ! b>e ore 9 sight4 ,= cl>ity ( conclusions 9 m9e valuation ! mo/ advisable c\rse is to det]m9e ! pr(it 9 sight irrespective ( capital r$emption 9 ! fir/ in/ance4 ,! que/ions ( capital r$emption1 pur*ase price1 or equipm5t co/ c !n be weigh$ aga9/ ! m>g9 ( pr(it4 ,"o phase ( r$emption w be fur!r discuss$ "u ,amortization ( ,capital & ,ratio ( ,output to ! ,m9e4 ,! co/ ( production dep5ds ^u _m ?+s1 su* z ! co/ ( labor1 supplies1 ! size ( ! ore-body1 ! treatm5t necess>y1 ! volume ( output1 etc42 & to discuss !m all w\ld lead into a wild]ness ( supposititi\s cases4 ,if ! m9e is a go+ conc]n1 f :i* reliable data c be obta9$1 ! problem is mu* simplifi$4 ,if x is virg91 ! exp]i5ce ( o!r m9es 9 ! same region is ! next res\rce2 :]e no su* data c be _h1 ! eng9e] mu/ fall back ^u ! exp]i5ce ) m9es /ill f>!r afield4 ,use is sometimes made ( ! comp>ison ton 9 calculat+ co/s ^u m9es :]e data ( actual exp]i5ce are n available4 ,z co/s w dep5d 9 ! ma9 ^u items m5tion$ above1 if ! kn[n co/s ( a go+ m9e else:]e be tak5 z a basis1 & subtractions & additions made = m unfavorable or favorable effect ( ! diff]5ces 9 ! above items1 a fairly close result c be approximat$4 ,m9e exam9ations are v (t5 inspir$ by ! belief t ext5d$ op]ations or new metallurgical applications to ! m9e w exp& ! pr(its4 ,9 su* cases ! p>am\nt que/ions are ! r$uction ( co/s by bett] plant1 l>g] outputs1 new processes1 or alt]ation ( metallurgical basis & bett] me?ods4 ,if e item ( previ\s exp5diture be gone ov] & consid]$1 toge!r ) ! equipm5t1 & me?od by :i* x 0 obta9$1 ! possible sav+s c be fairly well d$uc$1 & ju/ification = any p>ticul> l9e ( action det]m9$4 ,"o view ( ?is subject w be fur!r discuss$ "u ,ratio ( ,output to ! ,m9e4 ,! conditions :i* gov]n ! work+ co/s are on e m9e s special to itself1 t no am\nt ( advice is v useful4 ,volumes ( advice h be5 publi%$ on ! subject1 b 9 ! ma9 _! burd5 is n to und]e/imate4 ,9 consid]+ ! work+ co/s ( base-metal m9es1 mu* dep5ds ^u ! opportunity = treatm5t 9 cu/oms works1 smelt]s1 etc4 ,su* treatm5t means a sav+ ( a l>ge portion ( equipm5t co/1 & !re=e ( ! capital to be inve/$ & subsequ5tly recov]$4 ,! economics ( home treatm5t mu/ be weigh$ aga9/ ! sum :i* w\ld ne$ to be set aside = r$emption ( ! plant1 & unless !re is a v di/9ct advantage to be _h by ! =m]1 no risks %\ld be tak54 ,m eng9e]s g wrong by ! erection ( treatm5t works :]e o!r treatm5t facilities are available1 ?an d s by cont9u$ %ipp+4 ,!re are _m m9es :]e ! co/ ( equipm5t c\ld nev] be return$1 & :i* w\ld be valueless unless ! ore c\ld be %ipp$4 ,ano!r phase ( =eign treatm5t arises f ! necessity or advantage ( a mixture ( ores1--! opportunity ( su* mixtures (t5 gives ! public smelt] an advantage 9 treatm5t ) :i* treatm5t on ! m9e c\ld nev] compete4 ,fluctuation 9 ! price ( base metals is a factor s mu* to be tak5 into consid]ation1 t x is desirable 9 e/imat+ m9e values to r$uce ! work+ co/s to a basis ( a p] unit ( f9i%$ metal4 ,?is me?od has ! great advantage ( indicat+ s simply ! involv$ risks ( *ang+ prices t :oso runs may read4 ,:]e "o metal pr$om9ates ov] ! o!r to su* an ext5t z to =m ! backbone ( ! value ( ! m9e1 ! value ( ! subsidi>y metals is (t5 d$uct$ f ! co/ ( ! pr9cipal metal1 9 ord] to indicate m pla9ly ! v>y+ value ( ! m9e ) ! fluctuat+ prices ( ! pr$om9ant metal4 ,= example1 x is usual to /ate t ! co/ ( copp] production f a giv5 ore w be s _m c5ts p] p\nd1 or s _m p\nds /]l+ p] ton4 ,kn[+ ! total metal extractable f ! ore 9 sight1 ! pr(its at giv5 prices ( metal c be readily d$uc$4 ,! po9t at :i* su* calculation dep>ts f ! p]-ton-(-ore unto ! p]-unit-co/-(-metal basis1 usually lies at ! po9t 9 ore dress+ :]e x is ready = ! smelt]4 ,to take a simple case ( a lead ore av]ag+ #bj3 ?is is to be fir/ conc5trat$ & ! lead r$uc$ to a conc5trate av]ag+ #gj & %[+ a recov]y ( #ge ( ! total metal cont5t4 ,! co/ p] ton ( developm5t1 m9+1 conc5tration1 managem5t1 is to ?is po9t say #d p] ton ( orig9al crude ore4 ,! smelt] buys ! conc5trate = #ie ( ! value ( ! metal1 less ! smelt+ *>ge ( #ae p] ton1 or !re is a work+ co/ ( a simil> sum by home equipm5t4 ,9 ?is case #d4ff tons ( ore are requir$ to produce "o ton ( conc5trates1 & !re=e ea* ton ( conc5trates co/s #ah4fd4 ,?is am\nt1 add$ to ! smelt+ *>ge1 gives a total ( #cc4fd = ! creation ( #gj ( "o ton ( f9i%$ lead1 or equal to #b4dj c5ts p] p\nd :i* c be comp>$ ) ! m>ket price less #e4 ,if ! ore 7 to conta9 #bj ounces ( silv] p] ton1 ( :i* #ae ounces 7 recov]$ into ! leady conc5trates1 & ! smelt] price = ! silv] 7 #ej c5ts p] ounce1 !n ! #g4ej ?us recov]$ w\ld be subtract$ f #cc4fd1 mak+ ! app>5t co/ ( ! lead #a4hf c5ts p] p\nd4 ,,*apt] ,v4 ,m9e ,valuation 7,cont9u$74 ,,r$emption ,,or ,,amortization ,,( ,,capital ,,& ,,int]e/4 ,x is desirable to /ate 9 "s detail ! !ory ( amortization be=e consid]ation ( its application 9 m9e valuation4 ,z e m9e has a limit$ life1 ! capital inve/$ 9 x mu/ be r$eem$ dur+ ! life ( ! m9e4 ,x is n suffici5t t !re be a b>e pr(it ov] work+ co/s4 ,9 ?is p>ticul>1 m9es diff] :olly f _m o!r types ( inve/m5t1 su* z railways4 ,9 ! latt]1 if prop] appropriation is made = ma9t5ance1 ! total income to ! inve/or c be consid]$ z int]e/ or pr(it2 b 9 m9es1 a portion ( ! annual income mu/ be consid]$ z a return ( capital4 ,!re=e1 be=e ! yield on a m9e inve/m5t c be det]m9$1 a portion ( ! annual e>n+s mu/ be set aside 9 su* a mann] t :5 ! m9e is exhau/$ ! orig9al inve/m5t w h be5 re/or$4 ,if we consid] ! date due = ! return ( ! capital z ! "t :5 ! m9e is exhau/$1 we may consid] ! annual in/alm5ts z paym5ts be=e ! due date1 & !y c be put out at comp\nd int]e/ until ! "t = re/oration arrives4 ,if !y be inve/$ 9 safe securities at ! usual rate ( ab\t #d1 ! addition ( ?is am\nt ( comp\nd int]e/ w assi/ 9 ! repaym5t ( ! capital at ! due date1 s t ! annual contributions to a s9k+ fund ne$ n !mselves aggregate ! total capital to be re/or$1 b may be small] by ! defici5cy :i* w be made up by _! int]e/ e>n+s4 ,su* a sy/em ( r$emption ( capital is call$ ,amortization4 ,obvi\sly x is n suffici5t = ! m9e inve/or t 8 capital %all h be5 re/or$1 b !re is requir$ an excess e>n+ ov] & above ! necessities ( ?is annual fund+ ( capital4 ,:at rate ( excess return ! m9e mu/ yield is a matt] ( ! risks 9 ! v5ture & ! dem&s ( ! inve/or4 ,m9+ bus9ess is "o :]e #g above provision = capital return is an absolute m9imum dem&$ by ! risks inh]5t 9 m9es1 ev5 :]e ! pr(it 9 sight gives w>ranty to ! return ( capital4 ,:]e ! pr(it 9 sight 7:i* is ! only real gu>antee 9 m9e inve/m5t7 is bel[ ! price ( ! inve/m5t1 ! annual return %\ld increase 9 proportion4 ,!re are ?us two di/9ct directions 9 :i* int]e/ mu/ be comput$1--fir/1 ! int]nal influ5ce ( int]e/ 9 ! amortization ( ! capital1 & second1 ! p]c5tage return ^u ! :ole inve/m5t aft] provid+ = capital return4 ,!re are _m limitations to ! introduction ( su* ref9em5ts z int]e/ calculations 9 m9e valuation4 ,x is a subject n easy to discuss ) f9ality1 = n only is ! t]m ( ye>s unkn[n1 b1 ( m importance1 !re are _m factors ( a highly speculative ord] to be consid]$ 9 valu+4 ,x may be said t a c]ta9 life is kn[n 9 any case f ! pr(it 9 sight1 & t 9 calculat+ ?is pr(it a d$uction %\ld be made f ! gross pr(it = loss ( int]e/ on x p5d+ recov]y4 ,?is is true1 b z m9es are seldom dealt ) on ! basis ( pr(it 9 sight alone1 & z ! pur*ase price includes usually "s proportion = ext5sion 9 dep?1 an unkn[n factor is introduc$ :i* outweighs ! kn[n quantities4 ,!re=e ! application ( ! culm9ative effect ( int]e/ accumulations is mu* dep5d5t ^u ! sort ( m9e "u consid]ation4 ,9 mo/ cases ( unc]ta9 cont9uity 9 dep? x introduces a ma!matical ref9em5t n w>rant$ by ! speculative elem5ts4 ,= in/ance1 9 a m9e :]e ! :ole value is dep5d5t ^u ext5sion ( ! deposit beyond op5+s1 & :]e an expect$ return ( at lea/ #ej p] annum is requir$ to w>rant ! risk1 su* ref9em5t w\ld be absurd4 ,on ! o!r h&1 9 a ,witwat]sr& gold m9e1 9 gold & t9 gravels1 or 9 massive copp] m9es su* z ,b+ham & ,lake ,sup]ior1 :]e at lea/ "s sort ( life c be approximat$1 x becomes a mo/ vital elem5t 9 valuation4 ,9 g5]al x may be said t ! l[] ! total annual return expect$ ^u ! capital inve/$1 ! great] does ! am\nt dem&$ = amortization become 9 proportion to ?is total income1 & !re=e ! great] ne$ ( its introduction 9 calculations4 ,especially is ?is s :]e ! co/ ( equipm5t is l>ge proportionately to ! annual return4 ,fur!r1 x may be said t su* calculations are ( decreas+ use ) increas+ proportion ( speculative elem5ts 9 ! price ( ! m9e4 ,! risk ( ext5sion 9 dep?1 ( ! price ( metal1 etc41 may s outweigh ! comp>atively m9or factors "h introduc$ z to r5d] !m useless ( att5tion4 ,9 ! practical conduct ( m9es or m9+ companies1 s9k+ funds = amortization ( capital are nev] e/abli%$4 ,9 ! va/ majority ( m9es ( ! class "u discussion1 ! ultimate duration ( life is unkn[n1 & !re=e !re is no basis ^u :i* to =mulate su* a def9ite f9ancial policy ev5 7 x desir$4 ,7 x possible to arrive at ! annual sum to be set aside1 ! /ockhold]s ( ! m9+ type w\ld pref] to d _! own re9ve/m5t4 ,! purpose ( ^! calculations does n lie 9 ! application ( amortization to adm9i/rative f9ance4 ,x is nev]!less "o ( ! t\*/ones 9 ! valuation ( c]ta9 m9es or m9+ inve/m5ts4 ,t is1 by a sort ( inv]sion su* calculations c be made to s]ve z a means to expose ! am\nt ( risk1--to furni% a y>d/ick = measur+ ! am\nt ( risk 9 ! v speculations ( ext5sion 9 dep? & price ( metals :i* atta* to a m9e4 ,giv5 ! annual income be+ receiv$1 or expect$1 ! problem c be =mulat$ into ! det]m9ation ( h[ _m ye>s x mu/ be cont9u$ 9 ord] to amortize ! inve/m5t & pay a giv5 rate ( pr(it4 ,a c]ta9 l5g? ( life is evid5t f ! ore 9 sight1 :i* may be call$ ! life 9 sight4 ,if ! t]m ( ye>s requir$ to r$eem ! capital & pay an int]e/ ^u x is great] ?an ! life 9 sight1 !n ?is ext5d$ life mu/ come f ext5sion 9 dep?1 or ore f o!r direction1 or increas$ price ( metals4 ,if we !n take ! volume & pr(it on ! ore z disclos$ we c calculate ! numb] ( feet ! deposit mu/ ext5d 9 dep?1 or additional tonnage t mu/ be obta9$ ( ! same grade1 or ! diff]5t prices ( metal t mu/ be secur$1 9 ord] to satisfy ! dem&$ t]m ( ye>s4 ,^! dem&s 9 actual measure ( ore or feet or high] price c !n be weigh$ aga9/ ! geological & indu/rial probabilities4 ,! foll[+ tables & examples may be ( assi/ance 9 ^! calculations4 ,table #a4 ,to apply ?is table1 ! am\nt ( annual income or divid5d & ! t]m ( ye>s x w la/ mu/ be kn[n or e/imat$ factors4 ,x is !n possible to det]m9e ! pres5t value ( ?is annual income aft] provid+ = amortization & int]e/ on ! inve/m5t at v>i\s rates giv51 by multiply+ ! annual income by ! factor set out4 ,a simple illu/ration w\ld be t ( a m9e e>n+ a pr(it ( #bjj1jjj annually1 & hav+ a total ( #a1jjj1jjj tons 9 sight1 yield+ a pr(it ( #b a ton1 or a total pr(it 9 sight ( #b1jjj1jjj1 ?us recov]able 9 t5 ye>s4 ,on a basis ( a #g return on ! inve/m5t & amortization ( capital 7,table ,i71 ! factor is #f4eb x #bjj1jjj #a1cjd1jjj z ! pres5t value ( ! gross pr(its expos$4 ,t is1 ?is sum ( #a1cjd1jjj1 if paid = ! m9e1 w\ld be repaid out ( ! pr(it 9 sight1 toge!r ) #g int]e/ if ! annual paym5ts into s9k+ fund e>n #d4 ,,table ,i4 ,pres5t ,value ( an ,annual ,divid5d ,ov] -- ,ye>s at -- & ,replac+ ,capital by ,re9ve/m5t ( an ,annual ,sum at #d4 ,ye>s #e #f #g #h #i #aj ---------------------------------------- --------- #a 4#ie 4#id 4#ic 4#ib 4#ib 4#ia #b #a4he #a4hb #a4gh #a4ge #a4gb #a4fi #c #b4gj #b4fc #b4ef #b4ej #b4dd #b4ch #d #c4ej #c4ch #c4bg #c4ag #c4jg #b4ih #e #d4bf #d4ji #c4ic #c4gh #c4fd #c4ea #f #d4ih #d4gd #d4ec #d4cc #d4ae #c4ii #g #e4ff #e4cf #e4ji #d4hd #d4fb #d4da #h #f4ca #e4ic #e4fj #e4cj #e4jd #d4gi #i #f4ib #f4dg #f4jh #e4gc #e4db #e4ad #aj #g4ej #f4ih #f4eb #f4ab #e4gg #e4de #aa #h4je #g4de #f4id #f4di #f4ji #e4gd #ab #h4eh #g4ij #g4cb #f4hb #f4ci #f4jj #ac #i4jh #h4cb #g4fh #g4ac #f4ff #f4bd #ad #i4ee #h4gb #h4jb #g4db #f4ia #f4df #ae #aj4jj #i4ji #h4cd #g4gi #g4ad #f4fg #af #aj4dc #i4de #h4fc #g4ie #g4cf #f4hf #ag #aj4he #i4gh #h4ia #h4ah #g4ef #g4jc #ah #aa4bd #aj4aj #i4ag #h4dj #g4ge #g4ai #ai #aa4fa #aj4dj #i4db #h4fa #g4ic #g4cd #bj #aa4if #aj4fh #i4fe #h4hj #h4ji #g4di #ba #ab4cj #aj4ie #i4hg #h4ii #h4bd #g4fb #bb #ab4fb #aa4ba #aj4jh #i4af #h4ci #g4gd #bc #ab4ic #aa4de #aj4bh #i4cb #h4eb #g4he #bd #ac4bc #aa4fh #aj4df #i4dg #h4fe #g4if #be #ac4ea #aa4ij #aj4fd #i4fa #h4gg #h4jf #bf #ac4gh #ab4aa #aj4hj #i4ge #h4hh #h4af #bg #ad4jd #ab4ca #aj4if #i4hh #h4ii #h4be #bh #ad4bh #ab4ej #aa4aa #aj4jj #i4ji #h4cc #bi #ad4eb #ab4fh #aa4be #aj4aa #i4ah #h4da #cj #ad4gd #ab4he #aa4ch #aj4bb #i4bg #h4di #ca #ad4if #ac4ja #aa4ea #aj4cb #i4cf #h4ef #cb #ae4af #ac4ag #aa4fc #aj4db #i4dd #h4fb #cc #ae4cf #ac4ca #aa4ge #aj4ea #i4ea #h4fi #cd #ae4ee #ac4df #aa4hf #aj4fj #i4ei #h4ge #ce #ae4gc #ac4ei #aa4if #aj4fg #i4fe #h4hj #cf #ae4ij #ac4gb #ab4jf #aj4gf #i4gb #h4hf #cg #af4jg #ac4hd #ab4af #aj4hd #i4gh #h4ia #ch #af4bb #ac4if #ab4be #aj4ia #i4hd #h4if #ci #af4ch #ad4jg #ab4cd #aj4ih #i4hi #i4jj #dj #af4eb #ad4ah #ab4db #aa4je #i4ie #i4je ,cond5s$ f ,inwood's ,tables4 ,table ,,ii is practically a comp\nd disc\nt table4 ,t is1 by x c be det]m9$ ! pres5t value ( a fix$ sum payable at ! end ( a giv5 t]m ( ye>s1 int]e/ be+ disc\nt$ at v>i\s giv5 rates4 ,its use may be illu/rat$ by cont9u+ ! example prec$+4 ,,table ,,ii4 ,pres5t ,value ( #a1 or #a1 payable 9 -- ,ye>s1 ,int]e/ tak5 at --4 ,ye>s #d #e #f #g ------------------------------- #a 4#ifa 4#ieb 4#idc 4#icd #b 4#ibd 4#ijg 4#hij 4#hgc #c 4#hhi 4#hfd 4#hdj 4#haf #d 4#hed 4#hbc 4#gib 4#gfc #e 4#hba 4#ghc 4#gdg 4#gac #f 4#gij 4#gdf 4#gje 4#fff #g 4#gfj 4#gaa 4#ffe 4#fbc #h 4#gca 4#fgg 4#fbg 4#ehb #i 4#gjb 4#fde 4#eib 4#edd #aj 4#fge 4#fad 4#eeh 4#ejh #aa 4#fdi 4#ehe 4#ebg 4#dge #ab 4#fbe 4#eeg 4#dig 4#ddd #ac 4#fjj 4#ecj 4#dfi 4#dae #ad 4#egg 4#eje 4#ddb 4#chh #ae 4#eee 4#dha 4#dag 4#cfb #af 4#ecd 4#deh 4#cid 4#cci #ag 4#eac 4#dcf 4#cga 4#caf #ah 4#did 4#dae 4#cej 4#bif #ai 4#dge 4#cif 4#ccj 4#bgf #bj 4#def 4#cgg 4#caa 4#beh #ba 4#dci 4#cei 4#bid 4#bda #bb 4#dbb 4#cdb 4#bgg 4#bff #bc 4#djf 4#cbe 4#bfb 4#baa #bd 4#cij 4#caj 4#bdg 4#aig #be 4#cge 4#bie 4#bcc 4#ahd #bf 4#cfa 4#bha 4#bbj 4#agb #bg 4#cdg 4#bfh 4#bjg 4#afa #bh 4#ccc 4#bee 4#aif 4#aej #bi 4#cba 4#bdc 4#ahd 4#adj #cj 4#cjh 4#bca 4#agd 4#aca #ca 4#bif 4#bbj 4#afd 4#abc #cb 4#bhe 4#baj 4#aee 4#aae #cc 4#bgd 4#bjj 4#adf 4#ajg #cd 4#bfc 4#aij 4#ach 4#ajj #ce 4#bec 4#aha 4#acj 4#jid #cf 4#bdd 4#agb 4#abc 4#jhg #cg 4#bcd 4#afd 4#aaf 4#jhb #ch 4#bbe 4#aef 4#aji 4#jgf #ci 4#baf 4#adi 4#ajc 4#jga #dj 4#bjh 4#adb 4#jig 4#jfg ,cond5s$ f ,inwood's ,tables4 ,if su* a m9e is n equipp$1 & x is assum$ t #bjj1jjj are requir$ to equip ! m9e1 & t two ye>s are requir$ = ?is equipm5t1 ! value ( ! ore 9 sight is /ill less1 because ( ! fur!r loss ( int]e/ 9 delay & ! co/ ( equipm5t4 ,9 ?is case ! pres5t value ( #a1cjd1jjj 9 two ye>s1 int]e/ at #g1 ! factor is 4#hg ,x #a1cjd1jjj #a1acd1dhj4 ,f ?is comes (f ! co/ ( equipm5t1 or #bjj1jjj1 leav+ #icd1dhj z ! pres5t value ( ! pr(it 9 sight4 ,a fur!r ref9em5t c\ld be add$ by calculat+ ! int]e/ *>geable aga9/ ! #bjj1jjj equipm5t co/ up to ! "t ( production4 ,,table ,,iii4 ,annual ,numb] ( ye>s ( life requir$ to yield-- int]e/1 & 9 ,rate ( addition to furni% annual in/alm5ts :i*1 if re9ve/$ at ,divid5d4 #d w return ! orig9al inve/m5t at ! end ( ! p]iod4 ---------------------------------------- ---------------------------------- #e #f #g #h #i #aj #f #da4j #g #bh4j #da4j #h #ba4f #bh4j #da4j #i #ag4g #ba4f #bh4j #da4j #aj #ae4j #ag4g #ba4f #bh4j #da4j #aa #ac4j #ae4j #ag4g #ba4f #bh4j #da4j #ab #aa4e #ac4j #ae4j #ag4g #ba4f #bh4j #ac #aj4c #aa4e #ac4j #ae4j #ag4g #ba4f #ad #i4d #aj4c #aa4e #ac4j #ae4j #ag4g #ae #h4f #i4d #aj4c #aa4e #ac4j #ae4j #af #g4i #h4f #i4d #aj4c #aa4e #ac4j #ag #g4c #g4i #h4f #i4d #aj4c #aa4e #ah #f4h #g4c #g4i #h4f #i4d #aj4c #ai #f4d #f4h #g4c #g4i #h4f #i4d #bj #f4j #f4d #f4h #g4c #g4i #h4f #ba #e4g #f4j #f4d #f4h #g4c #g4i #bb #e4d #e4g #f4j #f4d #f4h #g4c #bc #e4a #e4d #e4g #f4j #f4d #f4h #bd #d4i #e4a #e4d #e4g #f4j #f4d #be #d4g #d4i #e4a #e4d #e4g #f4j #bf #d4e #d4g #d4i #e4a #e4d #e4g #bg #d4c #d4e #d4g #d4i #e4a #e4d #bh #d4a #d4c #d4e #d4g #d4i #e4a #bi #c4i #d4a #d4c #d4e #d4g #d4i #cj #c4h #c4i #d4a #d4c #d4e #d4g ,table ,,iii4 ,?is table is calculat$ by inv]sion ( ! factors 9 ,table ,i1 & is ! mo/ useful ( all su* tables1 z x is a direct calculation ( ! numb] ( ye>s t a giv5 rate ( income on ! inve/m5t mu/ cont9ue 9 ord] to amortize ! capital 7! annual s9k+ fund be+ plac$ at comp\nd int]e/ at #d7 & to repay v>i\s rates ( int]e/ on ! inve/m5t4 ,! application ( ?is me?od 9 te/+ ! value ( divid5d-pay+ %>es is v helpful1 especially 9 weigh+ ! risks involv$ 9 ! portion ( ! pur*ase or inve/m5t unsecur$ by ! pr(it 9 sight4 ,giv5 ! annual p]c5tage income on ! inve/m5t f ! divid5ds ( ! m9e 7or on a non-produc+ m9e assum+ a giv5 rate ( production & pr(it f ! factors expos$71 by ref]5ce to ! table ! numb] ( ye>s c be se5 9 :i* ?is p]c5tage mu/ cont9ue 9 ord] to amortize ! inve/m5t & pay v>i\s rates ( int]e/ on x4 ,z said be=e1 ! ore 9 sight at a giv5 rate ( exhau/ion c be r$uc$ to t]ms ( life 9 sight4 ,?is c]ta9 p]iod d$uct$ f ! total t]m ( ye>s requir$ gives ! life :i* mu/ be provid$ by fur!r discov]y ( ore1 & ?is c be r$uc$ to tons or feet ( ext5sion ( giv5 ore-bodies & a tangible position arriv$ at4 ,! te/ c be appli$ 9 ?is mann] to ! v>i\s prices :i* mu/ be realiz$ f ! base metal 9 sight to w>rant ! price4 ,tak+ ! la/ example & assum+ t ! m9e is equipp$1 & t ! price is #b1jjj1jjj1 ! ye>ly return on ! price is #aj4 ,if x is desir$ besides amortiz+ or r$eem+ ! capital to secure a return ( #g on ! inve/m5t1 x w be se5 by ref]5ce to ! table t !re w be requir$ a life ( #ba4f ye>s4 ,z ! life visible 9 ! ore 9 sight is t5 ye>s1 !n ! ext5sions 9 dep? mu/ produce ore = #aa4f ye>s long]--#a1afj1jjj tons4 ,if ! ore-body is #a1jjj feet long & #ac feet wide1 x w furni% ( gold ore #a1jjj tons p] foot ( dep?2 h5ce ! ore-body mu/ ext5d #a1afj feet deep] to ju/ify ! price4 ,m9es are seldom s simple a proposition z ?is example4 ,!re are usually probabilities ( o!r ore2 & 9 ! case ( base metal1 !n v>iability ( price & o!r elem5ts mu/ be c\nt$4 ,h[ev]1 once ! ext5sion 9 dep? :i* is necess>y is det]m9$ = v>i\s assumptions ( metal value1 !re is some?+ tangible to consid] & to weigh ) ! five geological weights set out 9 ,*apt] ,,iii4 ,! example giv5 c be exp&$ to indicate n only ! importance ( int]e/ & r$emption 9 ! long ext5sion 9 dep? requir$1 b a matt] discuss$ f ano!r po9t ( view "u ,ratio ( ,output4 ,if ! plant on ?is m9e 7 d\bl$ & ! e>n+s increas$ to #bj 7#djj1jjj p] annum7 7disreg>d+ ! r$uction 9 work+ exp5ses t mu/ foll[ expansion ( equipm5t71 x w be f\nd t ! life requir$ to repay ! pur*ase money1--#b1jjj1jjj1--;& #g int]e/ ^u x1 is ab\t #f4h ye>s4 ,z at ?is increas$ rate ( production !re is 9 ! ore 9 sight a life ( five ye>s1 ! ext5sion 9 dep? mu/ be dep5d$ ^u = #a4h ye>s1 or only #cfj1jjj tons1--t is1 #cfj feet ( ext5sion4 ,simil>ly1 ! pres5t value ( ! ore 9 sight is #bfh1jjj great] if ! m9e be giv5 d\ble ! equipm5t1 = ?us ! idle money lock$ 9 ! ore is br\ght into ! int]e/ m>ket at an e>li] date4 ,aga9/ ?is increas$ pr(it mu/ be weigh$ ! increas$ co/ ( equipm5t4 ,! value ( l[ grade m9es1 especially1 is v mu* a factor ( ! volume ( output contemplat$4 ,,*apt] ,,vi4 ,m9e ,valuation 7,conclud$74 ,,valuation ,,( ,,m9es ,,) ,,little ,,or ,,no ,,ore ,,9 ,,sight2 ,,valuations ,,on ,,second-,,h& ,,data2 ,,g5]al ,,conduct ,,( ,,exam9ations2 ,,reports4 ,a l>ge numb] ( exam9ations arise ^u prospect+ v5tures or p>tially develop$ m9es :]e ! value is almo/ :olly prospective4 ,! risks 9 su* ent]prises am\nt to ! possible loss ( ! :ole inve/m5t1 & ! possible returns mu/ consequ5tly be comm5surate4 ,su* bus9ess is !re=e necess>ily highly speculative1 b n unju/ifiable1 z ! :ole hi/ory ( ! indu/ry atte/s2 b ?is makes ! matt] no easi] = ! m9e valu]4 ,_m devices ( f9ancial proc$ure assi/ 9 ! limitation ( ! sum risk$1 & (f] a middle c\rse to ! inve/or betwe5 pur*ase ( a :olly prospective value & ! loss ( a possible opportunity to pr(it by x4 ,! usual =m is an option to buy ! prop]ty aft] a p]iod :i* p]mits a c]ta9 am\nt ( developm5t "w by ! pur*as] be=e f9al decision z to pur*ase4 ,aside f "y m9es su* ent]prises (t5 arise f ! possibility ( lat]al ext5sion ( ! ore-deposit outside ! b\nd>ies ( ! prop]ty ( orig9al discov]y 7,fig4 #c71 9 :i* cases !re is (t5 no visible ore )9 ! prop]ty "u consid]ation ^u :i* to f\nd op9ion4 ,9 regions :]e v]tical side l9es obta91 !re is always ! possibility ( a deep level 9 incl9$ deposits4 ,!re=e ! gr\nd surr\nd+ kn[n deposits has a c]ta9 speculative value1 ^u :i* eng9e]s are (t5 call$ to pass judgm5t4 ,except 9 su* unusual occurr5ces z ,s\? ,african bankets1 or ,lake ,sup]ior copp]s1 prospect+ = deep level ( ext5sion is also a highly speculative phase ( m9+4 ,! :ole basis ( op9ion 9 bo? classes ( v5tures mu/ be ! few geological weights1--! geology ( ! prop]ty & ! di/rict1 ! developm5t ( surr\nd+ m9es1 etc4 ,9 any ev5t1 !re is a v great p]c5tage ( risk1 & ! pr(it to be ga9$ by success mu/ be1 proportionally to ! exp5diture involv$1 v l>ge4 ,x is no case = calculat+ amortization & o!r ref9em5ts4 ,x is "o :]e sev]al hundr$s or ?\s&s ( p] c5t hop$ = on ! inve/m5t is ! only ju/ification4 ,,op9ions ,,& ,,valuations ,,^u ,,second-,,h& ,,data4 ,"s "o may come =w>d & deprecate ! b>e sugge/ion ( an eng9e]'s (f]+ an op9ion :5 he _c h prop] fir/-h& data4 ,b 9 ^! days we h to deal ) conditions z well z !ories ( pr(essional e?ics4 ,! gr[+ own]%ip ( m9es by companies1 t is by corporations compos$ ( _m individuals1 & ) _! /ocks (t5 dealt 9 on ! public ex*anges1 has result$ 9 hold]s ^: int]e/ is n l>ge en\gh to w>rant _! und]tak+ ! co/ ( exhau/ive exam9ations4 ,! sy/em has produc$ an increas+ class ( m9+ speculators & inve/ors :o are f9d+ & supply+ ! enorm\s sums requir$ to "w our m9es1--sums beyond ! rea* ( ! old-class s+le-h&$ m9+ m54 ,e ye> ! m9+ inve/ors ( ! new ord] are com+ m & m to ! eng9e] = advice1 & !y %\ld be enc\rag$1 because su* c\nsel c be giv5 )9 limits1 & ^! limits t5d to place ! indu/ry ^u a s\nd] foot+ ( own]%ip4 ,z 0 said be=e1 ! lamb c be 9 a measure protect$4 ,! eng9e]'s int]e/ is to protect him1 s t ! indu/ry :i* conc]ns 8 own life-"w may be 9 honorable repute1 & t capital may be readily =?com+ = its expansion4 ,moreov]1 by con/ant advice to ! inve/or z to :at con/itutes a prop]ly pres5t$ & manag$ project1 ! arrangem5t ( su* prop] pres5tation & managem5t w t5d to become an a priori function ( ! promot]4 ,sometimes ! eng9e] c make a %ort visit to ! m9e = data purposes1--m (t5 he _c4 ,9 ! =m] case1 he c resolve = himself an approximation ^u all ! factors be>+ on value1 except ! quality ( ! ore4 ,= ?is1 aside f inspection ( ! ore itself1 a look at ! plans is usually enlight5+4 ,a longitud9al section ( ! m9e %[+ a cont9u\s %ort5+ ( ! /opes ) ea* succe$+ level c>ries its own int]pretation4 ,9 ! ma91 ! curr5t record ( pa/ production & e/imates ( ! managem5t z to ore-res]ves1 etc41 c be accept$ 9 ratio to ! confid5ce t c be plac$ 9 ! m5 :o pres5t !m4 ,x !n becomes a case ( judgm5t ( m5 & ?+s1 & "h no rule applies4 ,advice mu/ (t5 be giv5 ^u data alone1 )\t inspection ( ! m9e4 ,mo/ m9+ data pres5t int]nal evid5ce z to cr$ibility4 ,! untru/wor?y & inexp]i5c$ betray !mselves 9 _! e writt5 production4 ,assum+ ! reliability ( data1 ! me?ods already discuss$ = weigh+ ! ultimate value ( ! prop]ty c be appli$4 ,x w\ld be possible to cite hundr$s ( examples ( valuation bas$ ^u second-h& data4 ,?ree w1 h[ev]1 suffici5tly illu/rate4 ,fir/1 ! ,r m9e at ,johannesburg4 ,) ! regul>ity ( ?is deposit1 ! developm5t done1 & a /udy ( ! work+s on ! neighbor+ m9es & 9 deep] gr\nd1 x is a n unfair assumption t ! reefs w ma9ta9 size & value ?r\gh\t ! area4 ,! managem5t is s\nd1 & all ! data are giv5 9 ! be/ mann]4 ,! life ( ! m9e is e/imat$ at six ye>s1 ) "s probabilities ( fur!r ore f l[-grade sections4 ,! annual e>n+s available = divid5ds are at ! rate ( ab\t #dej1jjj p] annum4 ,! capital is #ddj1jjj 9 #a %>es4 ,by ref]5ce to ! table on page #df x w be se5 t ! pres5t value ( #dej1jjj spread ov] six ye>s to return capital at ! end ( t p]iod1 & give #g divid5ds 9 ! meantime1 is #d4ec x #dej1jjj #b1jcf1ejj #ddj1jjj #d #abs4 #g;d4 p] %>e4 ,s t ?is m9e1 on ! assumption ( cont9uity ( values1 w pay ab\t #g & return ! price4 ,sev5 p] c5t is1 h[ev]1 n deem$ an adequate return = ! risks ( labor tr\bles1 faults1 dykes1 or poor pat*es4 ,on a #i basis1 ! m9e is wor? ab\t #d #ds4 p] %>e4 ,second1 ! ,g m9e 9 ,nevada4 ,x has a capital ( #aj1jjj1jjj 9 #a %>es1 /&+ 9 ! m>ket at #ej c5ts ea*4 ,! res]ves are #bej1jjj tons1 yield+ a pr(it = ye>ly division ( #g p] ton4 ,x has an annual capacity ( ab\t #ajj1jjj tons1 or #gjj1jjj net pr(it1 equal to #ad on ! m>ket value4 ,9 ord] to repay ! capital value ( #e1jjj1jjj & #h p] annum1 x w ne$ a life ( 7,table ,,iii7 #ac ye>s1 ( :i* #b-a_/b are visible4 ,! size ( ! ore-bodies indicates a yield ( ab\t #a1ajj tons p] foot ( dep?4 ,at an exhau/ion rate ( #ajj1jjj tons p] annum1 ! m9e w\ld ne$ to ext5d to a dep? ( ov] a ?\s& feet bel[ ! pres5t bottom4 ,!re is always a possibility ( f9d+ p>allel bodies or l>g] volumes 9 dep?1 b x w\ld be a sangu9e eng9e] inde$ :o w\ld recomm5d ! /ock1 ev5 ?\gh x pays an app>5t #ad4 ,?ird1 ! ,b m9e1 ) a capital ( #aj1jjj1jjj 9 #b1jjj1jjj %>es ( #e ea*4 ,! promot]s /ate t ! m9e is 9 ! slopes ( ! ,&es 9 ,p]u2 t !re are #f1jjj1jjj tons ( ore block$ out2 t two assays by ! assay]s ( ! ,bank ( ,engl& av]age #i copp]2 t ! copp] c be produc$ at five c5ts p] p\nd2 t !re is ?us a pr(it ( #aj1jjj1jjj 9 sight4 ,! evid5ces are :olly incompet5t4 ,x is a gamble on /atem5ts ( p]sons :o h n ! remote/ idea ( s\nd m9+4 ,,g5]al ,,conduct ,,( ,,exam9ation4 ,complete & exhau/ive exam9ation1 entail+ ext5sive sampl+1 assay+1 & metallurgical te/s1 is v exp5sive & requires "t4 ,an unfavorable report usually means to ! employ] absolute loss ( ! eng9e]'s fee & exp5ses4 ,x becomes !n ! initial duty ( ! latt] to det]m9e at once1 by ! g5]al conditions surr\nd+ ! prop]ty1 h[ f> ! exp5diture = exhau/ive exam9ation is w>rant$4 ,!re is usually nam$ a money valuation = ! prop]ty1 & ?us a peg is af=d$ ^u :i* to hang conclusions4 ,v (t5 collat]al factors ) a prelim9>y sampl+1 or inde$ no sampl+ at all1 w det]m9e ! :ole bus9ess4 ,9 fact1 x is becom+ v common to s5d y\ng] eng9e]s to report z to :e!r exhau/ive exam9ation by m exp5sive m5 is ju/ifi$4 ,9 ! c\rse ( su* prelim9>y inspection1 ! ore-bodies may prove to be too small to insure adequate yield on ! price1 ev5 assum+ cont9uity 9 dep? & repres5t$ value4 ,!y may be s difficult to m9e z to make co/s prohibitive1 or !y may %[ /rong signs ( pet]+ out4 ,! ore may pres5t visible metallurgical difficulties :i* make x unpr(itable 9 any ev5t4 ,a gold ore may conta9 copp] or ars5ic1 s z to deb> cyanidation1 :]e ?is process is ! only hope ( suffici5tly mod]ate co/s4 ,a lead ore may be an amorph\s comp\nd ) z9c1 & successful conc5tration or smelt+ )\t great p5alties may be preclud$4 ,a copp] ore may c>ry a great excess ( silica & be at ! same "t unconc5tratable1 & !re may be no base m9]al supply available = smelt+ mixture4 ,! m9e may be s small or s isolat$ t ! co/ ( equipm5t w nev] be ju/ifi$4 ,"s ( ^! conditions may be det]m9$ z unsurm\ntable1 assum+ a giv5 value = ! ore1 & may w>rant ! rejection ( ! m9e at ! price set4 ,x is a disagreeable ?+ to h a disappo9t$ promot] heap vitup]ation on an eng9e]'s head because he did n make an exhau/ive exam9ation4 ,al?\gh x is g5]ally desirable to d "s sampl+ to give assurance to bo? pur*as] & v5dor ( consci5ti\sness1 a little c\rage ( conviction1 :5 ?is is rightly & adequately gr\nd$1 usually br+s its own rew>d4 ,suppos+1 h[ev]1 t conditions are "r & t ! m9e is wor? ! price1 subject to confirmation ( values1 ! det]m9ation ( ^! _c be und]tak5 unless "t & money are available = ! "w4 ,z 0 said1 a sampl+ campaign is exp5sive1 & takes "t1 & no eng9e] has ! moral "r to und]take an exam9ation unless bo? facilities are af=d$4 ,curtailm5t is unju/1 bo? to himself & to 8 employ]4 ,h[ mu* "t & outlay are requir$ to prop]ly sample a m9e is obvi\sly a "q ( its size1 & ! "* ( its ore4 ,an eng9e] & "o pr9cipal assi/ant c conduct two sampl+ p>ties4 ,9 h>d rock x may be impossible to take m ?an five samples a day = ea* p>ty4 ,b1 9 av]age ore1 t5 samples = ea* is reasonable "w4 ,z ! numb] ( samples is dep5d5t ^u ! footage ( op5+s on ! deposit1 a r\gh approximation c be made 9 advance1 & a g5]al idea obta9$ z to ! "t requir$4 ,?is p]iod mu/ be insi/$ ^u4 ,,reports4 ,reports are to be read by ! layman1 & _! fir/ qualities %\ld be simplicity ( t]ms & def9it5ess ( conclusions4 ,reports are usually too long1 r ?an too %ort4 ,! ess5tial facts gov]n+ ! value ( a m9e c be express$ on "o %eet ( pap]4 ,x is always desirable1 h[ev]1 t ! gr\ndwork data & ! mann] ( _! det]m9ation %\ld be set out ) su* detail t any o!r eng9e] c\ld come to ! same conclusion if he accept$ ! facts z accurately det]m9$4 ,9 reg>d to ! detail$ =m ( reports1 ! writ]'s own pref]5ce is = a s+le page summ>iz+ ! ma9 factors1 & an assay plan1 r$uc$ to a longitud9al section :]e possible4 ,!n !re %\ld be add$1 = purposes ( record & = submission to o!r eng9e]s1 a set ( app5dices go+ into "s details z to ! hi/ory ( ! m9e1 its geology1 developm5t1 equipm5t1 metallurgy1 & managem5t4 ,a li/ ( samples %\ld be giv5 ) _! location1 & ! tonnages & values ( ea* sep>ate block4 ,a pres5tation %\ld be made ( ! probabilities ( ext5sion 9 dep?1 toge!r ) recomm5dations = work+ ! m9e4 ,,g5]al ,,summ>y4 ,! b$-rock value :i* atta*es to a m9e is ! pr(it to be won f prov$ ore & 9 :i* ! price ( metal is calculat$ at "s figure betwe5 basic & normal4 ,?is we may call ! ,a value4 ,beyond ?is !re is ! speculative value ( ! m9e4 ,if ! value ( ! probable ore be repres5t$ by ,x1 ! value ( ext5sion ( ! ore by ,y1 & a high] price = metal ?an ! price above assum$ repres5t$ by ,z1 !n if ! m9e be effici5tly manag$ ! value ( ! m9e is ,a ,x ,y ,z4 ,:at actual am\nts %\ld be atta*$ to ,x1 ,y1 ,z is a matt] ( judgm5t4 ,!re is no prescription = good judgm5t4 ,good judgm5t re/s ^u a prop] balanc+ ( evid5ce4 ,! am\nt ( risk 9 ,x1 ,y1 ,z is purely a "q ( h[ mu* ^! factors are requir$ to repres5t 9 money1--9 effect1 h[ mu* m ore mu/ be f\nd1 or h[ _m feet ! ore mu/ ext5d 9 dep?2 or 9 conv]tible t]ms1 :at life 9 ye>s ! m9e mu/ h1 or h[ high ! price ( metal mu/ be4 ,9 =m+ an op9ion :e!r ^! requirem5ts w be realiz$1 ,x1 ,y1 ,z mu/ be balanc$ 9 a scale ^: measur+ /&>ds are ! five geological weights & ! g5]al indu/rial outlook4 ,! wise eng9e] w put be=e 8 cli5ts ! scale1 ! weights1 & ! conclusion arriv$ at4 ,! %rewd inve/or w require to "k ^! ( 8 advis]4 ,,*apt] ,,vii4 ,developm5t ( ,m9es4 ,,entry ,,to ,,! ,,m9e2 ,,tunnels2 ,,v]tical1 ,,incl9$1 ,,& ,,comb9$ ,,%afts2 ,,location ,,& ,,numb] ,,( ,,%afts4 ,developm5t is conduct$ = two purposes3 fir/1 to se>* = ore2 & second1 to op5 av5ues = its extraction4 ,al?\gh bo? objects are always m or less 9 view1 ! fir/ pr$om9ates 9 ! e>ly life ( m9es1 ! prospect+ /age1 & ! second 9 its lat] life1 ! produc+ /age4 ,x is propos$ to discuss developm5t design$ to embrace ext5d$ production purposes fir/1 because developm5t dur+ ! prospect+ /age is gov]n$ by ! same pr9ciples1 b is temp]$ by ! great] degree ( unc]ta9ty z to ! future ( ! m9e1 & is1 !re=e1 ( a m tempor>y "*4 ,,entry ,,to ,,! ,,m9e4 ,!re are f\r me?ods ( entry3 by tunnel1 v]tical %aft1 incl9$ %aft1 or by a comb9ation ( ! la/ two1 t is1 by a %aft initially v]tical !n turn$ to an incl9e4 ,comb9$ %afts are l>gely a developm5t ( ! pa/ few ye>s to meet deep level conditions1 & h be5 r5d]$ possible only by skip-w9d+4 ,! angle 9 su* %afts 7,fig4 #b7 is n[ g5]ally made on a p>abolic curve1 & ! spe$ ( w9d+ is !n less dim9i%$ by ! b5d4 ,! eng9e]+ problems :i* pres5t !mselves "u entry may be divid$ into ^? (3-- #a4 ,me?od4 #b4 ,location4 #c4 ,%ape & size4 ,! resolution ( ^! que/ions dep5ds ^u !3-- a4 ,degree ( dip ( ! deposit4 b4 ,output ( ore to be provid$ =4 c4 ,dep? at :i* ! deposit is to be attack$4 d4 ,b\nd>ies ( ! prop]ty4 e4 ,surface topography4 f4 ,co/4 g4 ,op]at+ effici5cy4 h4 ,prospects ( ! m9e4 ,illu/ration3 ,fig4 #b4--,%[+ arrangem5t ( ! b5d 9 comb9$ %afts4 ,f ! po9t ( view ( entrance1 ! cop]ation ( a majority ( ^! factors p]mits ! division ( m9es into c]ta9 broad classes4 ,! type ( works dem&$ = mod]ate dep?s 7say v]tically #b1ejj to #c1jjj feet7 is v diff]5t f t requir$ = great dep?s4 ,to rea* great dep?s1 ! size ( %afts mu/ greatly exp&1 to provide = ext5d$ v5tilation1 pump+1 & w9d+ necessities4 ,moreov] incl9$ %afts ( a degree ( flatness possible = mod]ate dep?s become too long to be us$ economically f ! surface4 ,! va/ majority ( metal-m9+ %afts fall into ! fir/ class1 ^? ( mod]ate dep?s4 ,yet1 z "t goes on & ore-deposits are exhau/$ to l[] planes1 problems ( dep? w become m common4 ,"o ?+1 h[ev]1 _c be too mu* emphasiz$1 especially on m9es to be work$ f ! outcrop1 & t is1 t no eng9e] is w>rant$1 ow+ to ! speculation incid5tal to ext5sion 9 dep?1 9 initiat+ e>ly 9 ! m9e's c>e] %afts ( su* size or equipm5t z w\ld be available = great dep?s4 ,moreov]1 ! prop] location ( a %aft s z to "w economically ext5sion ( ! ore-bodies is a matt] ( no c]ta9ty1 & !re=e %afts ( speculative m9es are t5tative 9 any ev5t4 ,ano!r l9e ( division f an eng9e]+ view is br\ght ab\t by a comb9ation ( ?ree ( ! factors m5tion$4 ,?is is ! classification into outcrop & deep-level m9es4 ,! =m] are ^? f\nd$ ^u ore-deposits to be work$ f or close to ! surface4 ,! latt] are m9es bas$ ^u ! ext5sion 9 dep? ( ore-bodies f outcrop m9es4 ,su* projects are n s common 9 ,am]ica1 :]e ! law 9 mo/ di/ricts gives ! outcrop own] ! "r to foll[ ore beyond 8 side-l9es1 z 9 c\ntries :]e ! b\nd>ies are v]tical on all sides4 ,!y d1 h[ev]1 arise n alone 9 ! few ,am]ican sections :]e ! side-l9es are v]tical b\nd>ies1 b 9 o!r p>ts ow+ to ! pit* ( ore-bodies ?r\gh ! end l9es 7,fig4 #c74 ,m especially d su* problems arise 9 ,am]ica 9 effect1 :]e ! +ress que/ions h to be revis$ = m9es work$ out 9 ! upp] levels 7,fig4 #g74 ,illu/ration3 ,fig4 #c4--,longitud9al section %[+ deep level project aris+ f dip ( ore-body ?r\gh end-l9e4 ,if f a /&po9t ( entrance que/ions1 m9es are fir/ classifi$ into ^? ^: works are contemplat$ = mod]ate dep?s1 & ^? 9 :i* "w is contemplat$ = great dep?1 fur!r cl>ity 9 discussion c be ga9$ by subdivision into ! possible cases aris+ out ( ! factors ( location1 dip1 topography1 & b\nd>ies4 ,,m9es ,,( ,,mod]ate ,,dep?s4 ,case ,i4 ,deposits :]e topographic conditions p]mit ! alt]natives ( %aft or tunnel4 ,case ,,ii4 ,v]tical or horizontal deposits1 ! only practical means ( atta9+ :i* is by a v]tical %aft4 ,case ,,iii4 ,incl9$ deposits to be work$ f ne> ! surface4 ,!re are 9 su* in/ances ! alt]natives ( ei!r a v]tical or an incl9$ %aft4 ,case ,,iv4 ,incl9$ deposits :i* mu/ be attack$ 9 dep?1 t is1 deep-level projects4 ,!re are ! alt]natives ( a comp\nd %aft or ( a v]tical %aft1 & 9 "s cases ( an incl9e f ! surface4 ,,m9es ,,to ,,great ,,dep?s4 ,case ,v4 ,v]tical or horizontal deposits1 ! only way ( rea*+ :i* is by a v]tical %aft4 ,case ,,vi4 ,incl9$ deposits4 ,9 su* cases ! alt]natives are a v]tical or a comp\nd %aft4 ,,case ,i4--,al?\gh = logical arrangem5t tunnel entry has be5 giv5 fir/ place1 to save repetition x is propos$ to consid] x lat]4 ,) few exceptions1 tunnels are a tempor>y exp$i5t 9 ! m9e1 :i* mu/ soon] or lat] be op5$ by a %aft4 ,,case ,,ii4 ,,v]tical ,,or ,,horizontal ,,deposits4--,^! require no discussion z to mann] ( entry4 ,!re is no ju/ifiable alt]native to a v]tical %aft 7,fig4 #d74 ,illu/ration3 ,fig4 #d4--;,cross-sections %[+ entry to v]tical or horizontal deposits4 ,case ,,ii4 ,illu/ration3 ,fig4 #e4--;,cross-section %[+ alt]native %afts to incl9$ deposit to be work$ f surface4 ,case ,,iii4 ,,case ,,iii4 ,,incl9$ ,,deposits ,,:i* ,,are ,,int5d$ ,,to ,,be ,,work$ ,,f ,,! ,,outcrop1 ,,or ,,f ,,ne> ,,x 7,fig4 #e74--,! *oice ( incl9$ or v]tical %aft is dep5d5t ^u relative co/ ( con/ruction1 subsequ5t op]ation1 & ! useful life ( ! %aft1 & ^! matt]s are l>gely gov]n$ by ! degree ( dip4 ,assum+ a %aft ( ! same size 9 ei!r alt]native1 ! comp>ative co/ p] foot ( s9k+ is dep5d5t l>gely on ! break+ facilities ( ! rock "u ! diff]5t directions ( attack4 ,9 ?is1 ! angles ( ! b$d+ or jo9t planes to ! direction ( ! %aft outweigh o!r factors4 ,! %aft :i* takes ! greate/ advantage ( su* l9es ( break+ weakness w be ! *eape/ p] foot to s9k4 ,9 ,s\? ,african exp]i5ce1 :]e incl9$ %afts are sunk p>allel to ! b$d+ planes ( h>d qu>tzites1 ! co/ p] foot appe>s to be 9 favor ( ! incl9e4 ,on ! o!r h&1 s9k+ %afts across tight s*i/s seems to be m advantage\s ?an p>allel to ! b$d+ planes1 & incl9es foll[+ ! dip co/ m p] foot ?an v]tical %afts4 ,an incl9$ %aft requires m footage to rea* a giv5 po9t ( dep?1 & !re=e x w\ld entail a great] total exp5se ?an a v]tical %aft1 assum+ !y co/ ! same p] foot4 ,! excess am\nt w be repres5t$ by ! extra l5g?1 & ?is w dep5d ^u ! flatness ( ! dip4 ,) v]tical %afts1 h[ev]1 crosscuts to ! deposit are necess>y4 ,9 a comp>ative view1 !re=e1 ! co/ ( ! crosscuts mu/ be includ$ ) t ( ! v]tical %aft1 z !y w\ld be almo/ :olly sav$ 9 an incl9e foll[+ ne> ! ore4 ,! factor ( useful life = ! %aft ent]s 9 decid+ z to ! advisability ( v]tical %afts on incl9$ deposits1 f ! fact t at "s dep? "o ( two alt]natives has to be *os54 ,! v]tical %aft1 :5 x rea*es a po9t bel[ ! deposit :]e ! crosscuts are too long 7,c1 ,fig4 #e71 ei!r becomes useless1 or mu/ be turn$ on an incl9e at ! int]section ) ! ore 7,b74 ,! fir/ alt]native means ultimately a complete loss ( ! %aft = work+ purposes4 ,! latt] has ! disadvantage t ! b5d int]f]es slightly ) haulage4 ,! foll[+ table w indicate an hypo!tical extreme case1--n infrequ5tly met4 ,9 x a v]tical %aft #a1ejj feet 9 dep? is tak5 z cutt+ ! deposit at ! dep? ( #gej feet1 ! mo/ favor$ position s f> z aggregate l5g? ( crosscuts is conc]n$4 ,! co/ ( crosscutt+ is tak5 at #bj p] foot & t ( s9k+ ! v]tical %aft at #ge p] foot4 ,! incl9e is assum$ = two cases at #ge & #ajj p] foot respectively4 ,! /op+ height ^u ! ore betwe5 levels is c\nt$ at #abe feet4 ,dip ( ,dep? ( ,l5g? ( ,no4 ( ,crosscuts ,total ,l5g? ,deposit f ,v]tical ,incl9e ,requir$ f ( ,crosscuts1 ,horizontal ,%aft ,requir$ ,v ,%aft ,feet ---------------------------------------- ------------------------------ #hj #a1ejj #a1ebb #aa #hei #gj #a1ejj #a1eie #ab #a1iaa #fj #a1ejj #a1gcb #ac #c1bdg #ej #a1ejj #a1jeh #ae #e1chi #dj #a1ejj #b1ccd #ah #h1jch #cj #a1ejj #c1jjj #bc #af1bcg ,co/ ( ,co/ ,v]tical ,total ,co/ ,co/ ( ,incl9e,co/ ( ,incl9e ,crosscuts #bj ,%aft #ge ( ,v]tical #ge p] ,foot #ajj p] ,foot p] ,foot p] ,foot & ,crosscuts ---------------------------------------- ------------------------------ #ag1ahj #aab1ejj #abi1fhj #aad1aej #aeb1bjj #ch1bbj #aab1ejj #aej1gbj #aah1fbe #aei1ejj #fd1idj #aab1ejj #agg1ddj #abi1ijj #agb1bcj #ajg1ghj #aab1ejj #bbj1bhj #aad1hej #aie1hjj #agh1gfj #aab1ejj #bia1bfj #age1jej #bcc1djj #cbd1gdj #aab1ejj #dcg1bdj #bbe1jjj #cjj1jjj ,f ! above examples x w be se5 t ! co/ ( crosscuts put at ord9>y level int]vals rapidly outruns ! extra exp5se ( increas$ l5g? ( incl9es4 ,if1 h[ev]1 ! conditions are su* t crosscuts f a v]tical %aft are n necess>y at s frequ5t int]vals1 !n 9 proportion to ! decrease ! advantages sway to ! v]tical %aft4 ,mo/ situations :]e9 ! crosscuts c be avoid$ arise 9 m9es work$ out 9 ! upp] levels & fall "u ,case ,,iv1 t ( deep-level projects4 ,!re c be no d\bt t v]tical %afts are *eap] to op]ate ?an incl9es3 ! l5g? ( haul f a giv5 dep? is less2 mu* high] rope spe$ is possible1 & ?us ! haulage h\rs are less = ! same output2 ! we> & te> on ropes1 tracks1 or guides is n s great1 & pump+ is m economical :]e ! ,corni% ord] ( pump is us$4 ,on ! o!r h&1 ) a v]tical %aft mu/ be includ$ ! co/ ( op]at+ crosscuts4 ,on m9es :]e ! volume ( ore does n w>rant me*anical haulage1 ! co/ ( tramm+ ?r\gh ! extra di/ance involv$ is an exp5se :i* outweighs any extra op]at+ outlay 9 ! incl9$ %aft itself4 ,ev5 ) me*anical haulage 9 crosscuts1 x is d\btful if !re is any?+ 9 favor ( ! v]tical %aft on ?is score4 ,illu/ration3 ,fig4 #f4--;,cross-section %[+ auxili>y v]tical outlet4 ,9 deposits ( v flat dips1 "u #cj1 ! case arises :]e ! l5g? ( incl9e is s great t ! sav+ on haulage ?r\gh direct lift w>rants a v]tical %aft z an auxili>y outlet 9 addition to ! incl9e 7,fig4 #f74 ,9 su* a comb9ation ! crosscut "q is elim9at$4 ,! m9e is work$ above & bel[ ! int]section by incl9e1 & ! v]tical %aft becomes simply a m economical exit & an alt]native to secure increas$ output4 ,! ,nor? ,/> m9e at ,grass ,valley is an illu/ration 9 po9t4 ,su* a positive in/ance bord]s aga9 on ,case ,,iv1 deep-level projects4 ,9 conclusion1 x is ! writ]'s belief t :]e m9es are to be work$ f ne> ! surface1 co9cid5tally ) s9k+1 & :]e1 !re=e1 crosscuts f a v]tical %aft w\ld ne$ to be in/all$ frequ5tly1 incl9es are w>rant$ 9 all dips "u #ge & ov] #cj4 ,beyond #ge ! be/ alt]native is (t5 undet]m9able4 ,9 ! range "u #cj & ov] #ae1 al?\gh incl9es are prim>ily necess>y = actual deliv]y ( ore f levels1 !y c (t5 be ju/ifiably supplem5t$ by a v]tical %aft z a relief to a long haul4 ,9 dips ( less ?an #ae1 z 9 ^? ov] #ge1 ! advantages aga9 tr5d /rongly 9 favor ( ! v]tical %aft4 ,!re arise1 h[ev]1 9 m\nta9\s c\ntries1 topographic conditions su* z ! dip ( deposits into ! m\nta91 :i* preclude any alt]native on an incl9e at any angl$ dip4 ,,case ,,iv4 ,,incl9$ ,,deposits ,,:i* ,,mu/ ,,be ,,attack$ ,,9 ,,dep? 7,fig4 #g74--,!re are two pr9cipal conditions 9 :i* su* prop]ties exi/3 fir/1 m9es be+ op]at$1 or hav+ be5 previ\sly work$1 ^: me?od ( entry mu/ be revis$2 second1 ^? ^: ore-bodies to be attack$ d n outcrop )9 ! prop]ty4 ,! fir/ situation may occur 9 m9es ( inadequate %aft capacity or wrong location2 9 m9es ab&on$ & resurrect$2 9 m9es :]e a v]tical %aft has rea*$ its limit ( useful ext5sions1 hav+ pass$ ! place ( economical crosscutt+2 or 9 m9es 9 flat deposits ) incl9es ^: haul has become too long to be economical4 ,?ree alt]natives pres5t !mselves 9 su* cases3 a new incl9e f ! surface 7,a ,b ,f1 ,fig4 #g71 or a v]tical %aft comb9$ ) incl9e ext5sion 7,c ,d ,f71 or a simple v]tical %aft 7,h ,g74 ,a comp>ison c be fir/ made betwe5 ! simple incl9e & ! comb9$ %aft4 ,! con/ruction ( an incl9e f ! surface to ! ore-body w be m co/ly ?an a comb9$ %aft1 = until ! horizon ( ! ore is rea*$ 7at ,d7 no crosscuts are requir$ 9 ! v]tical section1 :ile ! incl9e mu/ be ( great] l5g? to rea* ! same horizon4 ,! case arises1 h[ev]1 :]e incl9es c be sunk ?r\gh old /opes1 & ?us m *eaply con/ruct$ ?an v]tical %afts ?r\gh solid rock2 & also ! case ( m\nta9\s topographic conditions m5tion$ above4 ,illu/ration3 ,fig4 #g4--;,cross-section ( incl9$ deposit :i* mu/ be attack$ 9 dep?4 ,f an op]at+ po9t ( view1 ! b5d 9 comb9$ %afts 7at ,d7 gives rise to a good deal ( we> & te> on ropes & ge>4 ,! possible spe$ ( w9d+ ?r\gh a comb9$ %aft is1 h[ev]1 great] ?an a simple incl9e1 = al?\gh haulage spe$ ?r\gh ! incl9e section 7,d ,f7 & ar\nd ! b5d ( ! comb9$ %aft is ab\t ! same z ?r\gh\t a simple incl9e 7,a ,f71 ! spe$ c be accel]at$ 9 ! v]tical portion 7,d ,c7 above t feasible did ! incl9e ext5d to ! surface4 ,!re is !re=e an advantage 9 ?is reg>d 9 ! comb9$ %aft4 ,! net advantages ( ! comb9$ ov] ! incl9$ %aft dep5d on ! comp>ative l5g? ( ! two alt]native r\tes f ! int]section 7,d7 to ! surface4 ,c]ta9ly x is n advisable to s9k a comb9$ %aft to cut a deposit at #cjj feet 9 dep? if a simple incl9e c be _h to ! surface4 ,on ! o!r h&1 a comb9$ %aft cutt+ ! deposit at #a1jjj feet w be m advisable ?an a simple incl9e #b1jjj feet long to rea* ! same po9t4 ,! matt] is "o = direct calculation 9 ea* special case4 ,9 g5]al1 !re are few in/ances ( really deep-level projects :]e a complete incl9e f ! surface is w>rant$4 ,9 mo/ situations ( ?is sort1 & 9 all ( ! second type 7:]e ! outcrop is outside ! prop]ty71 actual *oice usually lies betwe5 comb9$ %afts 7,c ,d ,f7 & entire v]tical %afts 7,h ,g74 ,! diff]5ce betwe5 a comb9$ %aft & a direct v]tical %aft c be r$uc$ to a comp>ison ( ! comb9$ %aft bel[ ! po9t ( int]section 7,d7 ) t portion ( a v]tical %aft :i* w\ld cov] ! same horizon4 ,! "q !n becomes id5tical ) t ( incl9$ v]sus v]ticals1 z /at$ 9 ,case ,,iii1 ) ! (fsett+ disadvantage ( ! b5d 9 ! comb9$ %aft4 ,if x is desir$ to rea* production at ! e>lie/ date1 ! l[] section ( a simple v]tical %aft mu/ h crosscuts to rea* ! ore ly+ above ! horizon ( its int]section 7,e74 ,if production does n press1 ! ore above ! int]section 7,,eb7 c be work$ by rises f ! horizon ( int]section 7,e74 ,9 ! use ( rises1 h[ev]1 !re foll[ ! difficulties ( v5tilation & l[]+ ! ore d[n to ! %aft1 :i* br+s exp5ses to mu* ! same ?+ z op]at+ ?r\gh crosscuts4 ,! advantages ( comb9$ ov] simple v]tical %afts are e>li] production1 sav+ ( ei!r rises or crosscuts1 & ! ultimate utility ( ! %aft to any dep?4 ,! disadvantages are ! co/ ( ! extra l5g? ( ! incl9$ section1 sl[] w9d+1 & great] we> & te> )9 ! incl9$ section & especially ar\nd ! b5d4 ,all ^! factors are ( v>iable import1 dep5d+ ^u ! dip4 ,on v /eep dips1--ov] #gj1--! net result is 9 favor ( ! simple v]tical %aft4 ,on o!r dips x is 9 favor ( ! comb9$ %aft4 ,,cases ,v ,,& ,,vi4 ,,m9es ,,to ,,be ,,work$ ,,to ,,great ,,dep?s1--,,ov] #c1jjj ,,feet4--,9 ,case ,v1 ) v]tical or horizontal deposits1 !re is obvi\sly no desirable alt]native to v]tical %afts4 ,9 ,case ,,vi1 ) incl9$ deposits1 !re are ! alt]natives ( a comb9$ or ( a simple v]tical %aft4 ,a v]tical %aft 9 locations 7,h1 ,fig4 #g7 su* z w\ld n necessitate ext5sion 9 dep? by an incl9e1 w\ld1 z 9 ,case ,,iv1 compel ei!r crosscuts to ! ore or incl9es up f ! horizon ( int]section 7,e74 ,ap>t f delay 9 com+ to production & ! consequ5t loss ( int]e/ on capital1 ! v5tilation problems ) ?is arrangem5t w\ld be appall+4 ,moreov]1 ! comb9$ %aft1 ent]+ ! deposit ne> its %all[e/ po9t1 (f]s ! possibility ( a sep>ate haulage sy/em on ! incl9$ & on ! v]tical sections1 & su* sep>ate haulage is usually advisable at great dep?s4 ,9 su* in/ances1 ! output to be h&l$ is l>ge1 = no m9e ( small output is likely to be contemplat$ at su* dep?4 ,sev]al mod]ate-siz$ incl9es f ! horizon ( int]section h be5 sugge/$ 7,,ef1 ,,dg1 ,,*1 ,fig4 #h7 to fe$ a l>ge prim>y %aft 7,,ab71 :i* ?us becomes ! trunk road4 ,?is program w\ld *eap5 lat]al haulage und]gr\nd1 z me*anical traction c be us$ 9 ! ma9 level1 7,,ec71 & horizontal haulage co/s c be r$uc$ on ! l[] levels4 ,moreov]1 sep>ate w9d+ eng9es on ! two sections increase ! capacity1 = ! effect is t ( two tra9s in/ead ( "o runn+ on a s+le track4 ,,%aft ,,location4--,al?\gh ! prime purpose 9 locat+ a %aft is obvi\sly to ga9 access to ! l>ge/ volume ( ore )9 ! %orte/ haulage di/ance1 o!r conditions also ent]1 su* z ! "* ( ! surface & ! rock to be int]sect$1 ! "t involv$ be=e rea*+ production1 & capital co/4 ,z %afts mu/ be> two relations to a deposit1--"o z to ! dip & ! o!r z to ! /rike1--!y may be consid]$ f ^! aspects4 ,v]tical %afts mu/ be on ! hang+-wall side ( ! outcrop if ! deposit dips at all4 ,9 any ev5t1 ! %aft %\ld be f> en\gh away to be out ( ! rea* ( creeps4 ,an incl9$ %aft may be sunk ei!r on ! ve91 9 :i* case a pill> ( ore mu/ be left to support ! %aft2 or1 in/ead1 x may be sunk a %ort di/ance 9 ! footwall1 & :]e necess>y ! excavation above c be support$ by fill+4 ,foll[+ ! ore has ! advantage ( prospect+ 9 s9k+1 & 9 _m cases ! s(tness ( ! gr\nd 9 ! region ( ! ve9 w>rants ?is proc$ure4 ,x has1 h[ev]1 ! disadvantage t a pill> ( ore is lock$ up until ! %aft is ready = ab&onm5t4 ,moreov]1 z ve9s or lodes are seldom ( ev5 dip1 an incl9$ %aft1 to h value z a prospect+ op5+1 or to take advantage ( break+ possibilities 9 ! lode1 w usually be crook$1 & an incl9e irregul> 9 detail adds greatly to ! co/ ( w9d+ & ma9t5ance4 ,^! tw9 disadvantages usually w>rant a /raight incl9e 9 ! footwall4 ,incl9es are n necess>ily ( ! same dip ?r\gh\t1 b = reasonably economical haulage *ange ( angle mu/ take place gradually4 ,illu/ration3 ,fig4 #h4--,longitud9al section %[+ %aft arrangem5t propos$ = v deep incl9$ deposits4 ,9 ! case ( deep-level projects on incl9$ deposits1 dem&+ comb9$ or v]tical %afts1 ! fir/ desid]atum is to locate ! v]tical section z f> f ! outcrop z possible1 & ?us secure ! mo/ ore above ! horizon ( int]section4 ,?is1 h[ev]1 z /at$ be=e1 w\ld involve ! co/ ( crosscuts or rises & w\ld cause delay 9 production1 toge!r ) ! accumulation ( capital *>ges4 ,h[ important ! increm5t ( int]e/ on capital may become dur+ ! p]iod ( op5+ ! m9e may be demon/rat$ by a concrete case4 ,= in/ance1 ! capital ( a company or ! co/ ( ! prop]ty is1 say1 #a1jjj1jjj1 & :]e op5+ ! m9e = production requires f\r ye>s1 ! aggregate sum ( accumulat$ comp\nd int]e/ at #e 7& mo/ op]ators want m f a m9+ inve/m5t7 w\ld be #baf1jjj4 ,"u su* circum/ances1 if a ye> or two c be sav$ 9 gett+ to production by ent]+ ! prop]ty at a high] horizon1 ! diff]5ce 9 accumulat$ int]e/ w m ?an repay ! inf9itesimal extra co/ ( w9d+ ?r\gh a comb9$ %aft ( some:at increas$ l5g? 9 ! incl9$ section4 ,! unkn[n "* ( ! ore 9 dep? is always a s\nd reason = rea*+ x z quickly & z *eaply z possible4 ,9 result1 su* %afts are usually be/ locat$ :5 ! v]tical section ent]s ! upp] portion ( ! deposit4 ,! objective 9 location ) reg>d to ! /rike ( ! ore-bodies is obvi\sly to h an equal l5g? ( lat]al ore-haul 9 e direction f ! %aft4 ,x is easi] to specify ?an to a*ieve ?is1 = 9 all speculative deposits ore-%oots are f\nd to pursue curi\s vag>ies z !y g d[n4 ,ore-bodies d n reoccur ) ! same locus z 9 ! upp] levels1 & g5]ally ! *ances to g wrong are m num]\s ?an ^? to g "r4 ,,numb] ,,( ,,%afts4--,! problem ( :e!r ! m9e is to be op5$ by "o or by two %afts ( c\rse influ5ces location4 ,9 metal m9es "u ,cases ,,ii & ,,iii 7outcrop prop]ties7 ! ore output requirem5ts are seldom beyond ! capacity ( "o %aft4 ,v5tilation & escape-ways are usually easily manag$ ?r\gh ! old /opes4 ,"u su* circum/ances1 ! conditions w>rant+ a second %aft are ! l5g? ( und]gr\nd haul & isolation ( ore-bodies or ve9s4 ,lat]al haulage und]gr\nd is necess>ily dis9tegrat$ by ! v>i\s levels1 & usually has to be done by h&4 ,by %ort5+ ?is di/ance ( tramm+ & by consolidation ( ! mat]ial f all levels at ! surface1 :]e me*anical haulage c be in/all$1 a second %aft is (t5 ju/ifi$4 ,!re is !re=e an economic limitation to ! radius ( a s+le %aft1 reg>dless ( ! ability ( ! %aft to h&le ! total output4 ,o!r que/ions also (t5 arise :i* are ( equal importance to haulage co/s4 ,sep>ate ore-%oots or ore-bodies or p>allel deposits necessitate1 if work$ f "o %aft1 con/ant levels ?r\gh unpayable gr\nd & extra haul z well1 or ore-bodies may dip away f ! orig9al %aft along ! /rike ( ! deposit & a long haulage ?r\gh dead levels mu/ foll[4 ,= in/ance1 levels & crosscuts co/ r\ghly "o-qu>t] z mu* p] foot z %afts4 ,!re=e f\r levels 9 b>r5 gr\nd1 to rea* a p>allel ve9 or isolat$ ore-body #a1jjj feet away1 w\ld pay = a %aft #a1jjj feet deep4 ,at a dep? ( #a1jjj feet1 at lea/ six levels might be necess>y4 ,! tramm+ ( ore by h& ?r\gh su* a di/ance w\ld co/ ab\t d\ble ! am\nt to hoi/ x ?r\gh a %aft & transport x me*anically to ! dress+ plant at surface4 ,! aggregate co/ & op]ation ( b>r5 levels !re=e soon pays = a second %aft4 ,if two or m %afts are 9 "q1 !y mu/ obvi\sly be set s z to be/ divide ! "w4 ,"u ,cases ,,iv1 ,v1 & ,,vi1--t is1 deep-level projects1--v5tilation & escape become mo/ important consid]ations4 ,ev5 :]e ! volume ( ore is )9 ! capacity ( a s+le %aft1 ano!r usually becomes a necessity = ^! reasons4 ,_! location is affect$ n only by ! locus ( ! ore1 b1 z said1 by ! "t requir$ to rea* x4 ,:]e two %afts are to be sunk to incl9$ deposits1 x is usual to set "o s z to int]sect ! deposit at a l[] po9t ?an ! o!r4 ,production c be />t$ f ! %all[]1 be=e ! second is entirely ready4 ,! ore above ! horizon ( int]section ( ! deep] %aft is ?us accessible f ! %all[] %aft1 & ! difficulty ( long rises or crosscuts f t deepe/ %aft does n arise4 ,,*apt] ,,viii4 ,developm5t ( ,m9es 7,cont9u$74 ,,%ape ,,& ,,size ,,( ,,%afts2 ,,spe$ ,,( ,,s9k+2 ,,tunnels4 ,,%ape ,,( ,,%afts4--,%afts may be r\nd or rectangul>499 ,r\nd v]tical %afts are l>gely appli$ to coal-m9es1 & "s eng9e]s h advocat$ _! usefulness to ! m9+ ( ! metals "u discussion4 ,_! great advantages lie 9 _! /ructural /r5g?1 9 ! l>ge am\nt ( free space = v5tilation1 & 9 ! fact t if wall$ ) /one1 brick1 concrete1 or /eel1 !y c be made wat]-tight s z to prev5t infl[ f wat]-be>+ /rata1 ev5 :5 "u great pressure4 ,! r\nd wall$ %afts h a long] life ?an timb]$ %afts4 ,all ^! advantages p]ta9 mu* m to m9+ coal or iron ?an metals1 = uns\nd1 wet gr\nd is (t5 ! accompanim5t ( coal-measures1 & seldom tr\bles metal-m9es4 ,v5tilation requirem5ts are also mu* great] 9 coal-m9es4 ,f a metal-m9]'s /&po9t1 r\nd %afts are comp>atively mu* m exp5sive ?an ! rectangul> timb]$ type49999 ,= a l>g] area mu/ be excavat$ = ! same useful space1 & if support is ne$$1 satisfactory wall+1 :i* ( necessity mu/ be brick1 /one1 concrete1 or /eel1 _c be *eaply accompli%$ "u ! conditions prevail+ 9 mo/ metal regions4 ,al?\gh su* %afts w\ld h a long] life1 ! duration ( timb]$ %afts is suffici5t = mo/ metal m9es4 ,x foll[s t1 z timb] is ! *eape/ & all ?+s consid]$ ! mo/ advantage\s means ( %aft support = ! comp>atively tempor>y "* ( metal m9es1 to get ! /ra9s appli$ to ! timb]s 9 ! be/ mann]1 & to use ! m9imum am\nt ( x consi/5t ) security1 & to lose ! lea/ work+ space1 ! %aft mu/ be con/ruct$ on rectangul> l9es4 ,footnote 993 ,octagonal %afts 7 sunk 9 ,mexico 9 =m] times4 ,at ea* face ( ! octagon 0 a :im run by mules1 & haul+ lea!r buckets4 ,footnote 99993 ,! economic situation is rapidly aris+ 9 a numb] ( localities t /eel beams c be usefully us$ in/ead ( timb]4 ,! same argum5ts apply to ?is type ( support t apply to timb]4 ,! v>iations 9 timb]$ %aft design arise f ! possible arrangem5t ( comp>tm5ts4 ,_m comb9ations c be imag9$1 ( :i* ,figures #i1 #aj1 #aa1 #ab1 #ac1 & #ad are examples4 ,illu/ration3 ,,fig4 #i4 ,,fig4 #aj4 ,,fig4 #aa4 ,,fig4 #ab4 ,,fig4 #ac4 ,,fig4 #ad4 ,! arrangem5t ( comp>tm5ts %[n 9 ,figures #i1 #aj1 #aa1 & #ac gives ! greate/ /r5g?4 ,x p]mits timb]+ to ! be/ advantage1 & avoids ! dang] und]gr\nd involv$ 9 cross+ "o comp>tm5t to rea* ano!r4 ,x is !re=e g5]ally adopt$4 ,any o!r arrangem5t w\ld obvi\sly be impossible 9 incl9$ or comb9$ %afts4 ,,size ,,( ,,%afts4--,9 consid]+ ! size ( %afts to be in/all$1 _m factors are involv$4 ,!y are 9 ! ma93-- a4 ,am\nt ( ore to be h&l$4 b4 ,w9d+ plant4 c4 ,vehicle ( transport4 d4 ,dep?4 e4 ,numb] ( m5 to be work$ und]gr\nd4 f4 ,am\nt ( wat]4 g4 ,v5tilation4 h4 ,"* ( ! gr\nd4 i4 ,capital outlay4 j4 ,op]at+ exp5se4 ,x is n to be assum$ t ^! factors h be5 /at$ 9 ! ord] ( relative importance4 ,m or less emphasis w be atta*$ to p>ticul> factors by diff]5t eng9e]s1 & "u diff]5t circum/ances4 ,x is n possible to sugge/ any arbitr>y /&>d = calculat+ _! relative weight1 & !y are s int]dep5d5t z to preclude sep>ate discussion4 ,! usual result is a compromise betwe5 ! dem&s ( all4 ,c]ta9 factors1 h[ev]1 dictate a m9imum position1 :i* may be consid]$ z a datum f :i* to />t consid]ation4 ,fir/1 a w9d+ eng9e1 9 ord] to "w ) any economy1 mu/ be balanc$1 t is1 a desc5d+ empty skip or cage mu/ assi/ 9 pull+ up a load$ "o4 ,!re=e1 except 9 m9es ( v small output1 at lea/ two comp>tm5ts mu/ be made = hoi/+ purposes4 ,wat] has to be pump$ f mo/ m9es1 escape-ways are necess>y1 toge!r ) room = wires & air-pipes1 s t at lea/ "o m comp>tm5t mu/ be provid$ = ^! objects4 ,we h ?us ?ree comp>tm5ts z a s\nd m9imum = any %aft :]e m ?an trivial output is requir$4 ,second1 !re is a c]ta9 m9imum size ( %aft excavation bel[ :i* !re is v little economy 9 actual rock-break+499 ,9 too conf9$ a space1 holes _c be plac$ to advantage = ! bla/1 m5 _c get r\nd exp$iti\sly1 & spoil _c be h&l$ readily4 ,! writ]'s own exp]i5ce leads him to believe t1 9 s f> z rock-break+ is conc]n$1 to s9k a %aft f\rte5 to sixte5 feet long by six to sev5 feet wide outside ! timb]s1 is z *eap z to drive any small] size )9 ! realm ( consid]ation1 & is m rapid4 ,?is size ( excavation p]mits ( ?ree comp>tm5ts1 ea* ab\t f\r to five feet inside ! timb]s4 ,footnote 993 ,notes on ! co/ ( %afts 9 v>i\s regions :i* h be5 p]sonally collect$ %[ a rem>kable decrease 9 ! co/ p] cubic foot ( mat]ial excavat$ ) increas$ size ( %aft4 ,v>iations 9 skill1 9 economic conditions1 & 9 me?od ( acc\nt+ make data reg>d+ diff]5t %afts ( d\btful value1 b ! foll[+ are ( int]e/3-- ,9 ,au/ralia1 eight %afts betwe5 #aj & #aa feet long by #d to #e feet wide co/ an av]age ( #a4bj p] cubic foot ( mat]ial excavat$4 ,six %afts #ac to #ad feet long by #d to #e feet wide co/ an av]age ( #j4ie p] cubic foot2 sev5 %afts #ad to #af feet long & #e to #g feet wide co/ an av]age ( #j4hb p] cubic foot4 ,9 ,s\? ,africa1 elev5 %afts #ah to #ai feet long by #g to #h feet wide co/ an av]age ( #j4hb p] cubic foot2 five %afts #ba to #be feet long by #h feet wide1 co/ #j4gd2 & sev5 %afts #bh feet by #h feet co/ #j4fj p] cubic foot4 ,! co/ ( timb]1 x is true1 is a factor ( ! size ( %aft1 b ! labor ( timb]+ does n increase 9 ! same ratio4 ,9 any ev5t1 ! co/ ( timb] is only ab\t #ae ( ! actual %aft co/1 ev5 9 localities ( extremely high prices4 ,?ird1 ?ree reasons are rapidly mak+ ! self-dump+ skip ! almo/ univ]sal %aft-vehicle1 in/ead ( ! old cage = c>s4 ,fir/1 !re is a great economy 9 labor = load+ into & dis*>g+ f a %aft2 second1 !re is m rapid despat* & dis*>ge & !re=e a l>g] numb] ( possible trips2 ?ird1 %aft-haulage is !n indep5d5t ( delays 9 arrival ( c>s at /ations1 :ile tramm+ c be done at any "t & %aft-haulage c be conc5trat$ into c]ta9 h\rs4 ,cages to c>ry m9e c>s & h&le ! same load z a skip mu/ ei!r be big en\gh to take two c>s1 :i* compels a mu* l>g] %aft ?an is necess>y ) skips1 or !y mu/ be d\ble-deck$1 :i* r5d]s load+ arrangem5ts und]gr\nd co/ly to in/all & exp5sive to "w4 ,= all ^! reasons1 cages c be ju/ifi$ only on metal m9es ( su* small tonnage t "t is no consid]ation & :]e ! sav+ ( m5 is n to be effect$4 ,9 comp>tm5ts ( ! m9imum size m5tion$ above 7f\r to five feet ei!r way7 a skip ) a capacity ( f two to five tons c be in/all$1 al?\gh f two to ?ree tons is ! pres5t rule4 ,light] loads ?an ?is involve m trips1 & ?us less h\rly capacity1 &1 on ! o!r h&1 heavi] loads require m co/ly eng9es4 ,?is matt] is fur!r discuss$ "u ,haulage ,appliances4 ,we h !re=e z ! economic m9imum a %aft ( ?ree comp>tm5ts 7,fig4 #i71 ea* f\r to five feet squ>e4 ,:5 ! maximum tonnage is want$ f su* a %aft at ! lea/ op]at+ co/1 x %\ld be equipp$ ) load+ b9s & skips4 ,! output capacity ( %afts ( ?is size & equipm5t w dep5d 9 a major degree ^u ! eng9e employ$1 & 9 a less degree ^u ! haul+ dep?4 ,! reason :y dep? is a subsidi>y factor is t ! rapidity ) :i* a load c be drawn is n :olly a factor ( dep?4 ,! "t consum$ 9 hoi/+ is p>tially exp5d$ 9 load+1 9 accel]ation & ret>dation ( ! eng9e1 & 9 dis*>ge ( ! load4 ,^! factors are con/ant = any dep?1 & extra di/ance is !re=e accompli%$ at full spe$ ( ! eng9e4 ,v]tical %afts w1 o!r ?+s be+ equal1 h great] capacity ?an incl9es1 z w9d+ w be mu* fa/] & l5g? ( haul less = same dep?4 ,s9ce eng9es h1 h[ev]1 a great tractive ability on incl9es1 by an increase 9 ! size ( skip x is usually possible p>tially to equalize matt]s4 ,!re=e ! size ( incl9es = ! same output ne$ n diff] mat]ially f v]tical %afts4 ,! maximum capacity ( a %aft ^: equipm5t is ( ! "* & size giv5 above1 w1 z /at$1 decrease some:at ) ext5sion 9 dep? ( ! haulage horizon4 ,at #ejj feet1 su* a %aft if v]tical c\ld produce #gj to #hj tons p] h\r com=tably ) an eng9e ^: w9d+ spe$ 0 #gjj feet p] m9ute4 ,z m5 & mat]ial o!r ?an ore h to be h&l$ 9 & out ( ! m9e1 & %aft-s9k+ has to be att5d$ to1 ! w9d+ eng9e _c be employ$ all ! "t on ore4 ,twelve h\rs ( actual daily ore-w9d+ are all t c be expect$ )\t auxili>y help4 ,?is repres5ts a capacity f su* a dep? ( #hjj to #a1jjj tons p] day4 ,a simil> %aft1 "u ord9>y work+ conditions1 ) an eng9e spe$ ( #b1jjj feet p] m9ute1 %\ld f1 say1 #c1jjj feet h a capacity ( ab\t #djj to #fjj tons daily4 ,x is desirable to inquire at :at /ages ! size ( %aft %\ld logically be enl>g$ 9 ord] to atta9 great] capacity4 ,a consid]able measure ( increase c be obta9$ by reliev+ ! ma9 hoi/+ eng9e ( all or "p ( its collat]al duties4 ,:]e ! pump+ ma*9]y is n elaborate1 x is (t5 possible to get a small s+le w9d+ comp>tm5t into ! gangway )\t mat]ially increas+ ! size ( ! %aft if ! haulage comp>tm5ts be made some:at n>r[] 7,fig4 #aj74 ,su* a comp>tm5t w\ld be op]at$ by an auxili>y eng9e = s9k+1 h&l+ tools & mat]ial1 & assi/+ 9 h&l+ m54 ,if ?is arrangem5t c be effect$1 ! productive "t ( ! ma9 eng9e c be exp&$ to ab\t tw5ty h\rs ) an addition ( ab\t two-?irds to ! output4 ,:]e ! exig5cies ( pump & gangway require m ?an two & "o-half feet ( %aft l5g?1 ! next /age ( expansion becomes f\r full-siz$ comp>tm5ts 7,fig4 #aa74 ,by ?us enl>g+ ! auxili>y w9d+ space1 "s assi/ance may be giv5 to ore-haulage 9 case ( necessity4 ,! m9e ^: output dem&s su* haulage provisions c usually /& ano!r foot ( wid? to ! %aft1 s t ! dim5sions come to ab\t #ba feet to #bb feet by #g feet to #h feet outside ! timb]s4 ,su* a %aft1 ) ?ree- to f\r-ton skips & an appropriate eng9e1 w h&le up to #bej tons p] h\r f a dep? ( #a1jjj feet4 ,! next logical /ep 9 advance is ! %aft ( five comp>tm5ts ) f\r full-siz$ haulage ways 7,fig4 #ac71 ea* ( great] size ?an 9 ! above in/ance4 ,9 ?is case1 ! auxili>y eng9e becomes a balanc$ "o1 & c be employ$ "p ( ! "t ^u ore-haulage4 ,su* a %aft w be ab\t #bf feet to #bh feet long by #h feet wide outside ! timb]s1 :5 provision is made = "o gangway4 ,! capacity ( su* %afts c be up to #d1jjj tons a day1 dep5d+ on ! dep? & eng9e4 ,:5 v l>ge quantities ( wat] are to be dealt ) & rod-driv5 pumps to be us$1 two pump+ comp>tm5ts are sometimes necess>y1 b o!r =ms ( pumps d n require m ?an "o comp>tm5t1--an additional reason = _! use4 ,= dep?s great] ?an #c1jjj feet1 o!r factors come into play4 ,v5tilation que/ions become ( m import4 ,! me*anical problems on eng9es & ropes become involv$1 & _! sum-effect is to dem& mu* increas$ size & a great] numb] ( comp>tm5ts4 ,! %afts at ,johannesburg int5d$ z outlets = work+s #e1jjj feet deep are z mu* z #df feet by #i feet outside timb]s4 ,x is n purpos$ to g into details z to s9k+ me?ods or timb]+4 ,:ile important matt]s1 !y w\ld unduly prolong ?is discussion4 ,besides1 a multitude ( treatises exi/ on ^! subjects & cov] all ! m9uti ( su* "w4 ,,spe$ ,,( ,,s9k+4--,m9es may be divid$ into two cases1--^? be+ develop$ only1 & ^? be+ op]at$ z well z develop$4 ,9 ! =m]1 ! entrance into production is usually dep5d5t ^u ! spe$ at :i* ! %aft is sunk4 ,until ! m9e is e>n+ pr(its1 !re is a loss ( int]e/ on ! capital involv$1 :i*1 9 n9ety-n9e in/ances out ( a hundr$1 w>rants any reasonable extra exp5diture to induce m rapid progress4 ,9 ! case ( m9es 9 op]ation1 ! volume ( ore available to treatm5t or valuation is g5]ally dep5d5t to a great degree ^u ! rapidity ( ! ext5sion ( work+s 9 dep?4 ,x w be demon/rat$ lat] t1 bo? f a f9ancial & a te*nical /&po9t1 ! maximum developm5t is ! "r "o & t unremitt+ ext5sion 9 dep? is n only ju/ifiable b necess>y4 ,spe$ "u special conditions or ov] %ort p]iods has a m romantic ?an practical int]e/1 outside ( its value z a /imulant to emulation4 ,! ?+ t c\nts is ! spe$ :i* c be ma9ta9$ ov] ! ye>4 ,rapidity ( s9k+ dep5ds ma9ly on3-- a4 ,:e!r ! %aft is or is n 9 use = op]at+ ! m9e4 b4 ,! break+ "* ( ! rock4 c4 ,! am\nt ( wat]4 ,! delays incid5t to g5]al c>ry+ ( ore & m5 are su* t ! use ( ! ma9 haulage eng9e = %aft-s9k+ is practically impossible1 except on m9es ) small tonnage output4 ,ev5 ) a sep>ate w9* or auxili>y w9d+-eng9e1 delays are unavoidable 9 a work+ %aft1 especially z x usually has m wat] to cont5d ) ?an "o n 9 use = op]at+ ! m9e4 ,! writ]'s own impression is t an av]age ( #dj feet p] mon? is ! maximum possibility = ye> 9 & out s9k+ "u su* conditions4 ,9 fact1 few go+ m9es manage m ?an #djj feet a ye>4 ,9 cases ( clean %aft-s9k+1 :]e e en]gy is b5t to spe$1 #aej feet p] mon? h be5 av]ag$ = _m mon?s4 ,special cases h occurr$ :]e z mu* z #bac feet h be5 a*iev$ 9 a s+le mon?4 ,) ord9>y conditions1 #a1bjj feet 9 a ye> is v good "w4 ,rock awkw>d to break1 & wat] especially1 l[]s ! rate ( progress v mat]ially4 ,fur!r ref]5ce to spe$ w be f\nd 9 ! *apt] on ,drill+ ,me?ods4 ,,tunnel ,,entry4--,! alt]native ( entry to a m9e by tunnel is usually n a "q ( topography altoge!r1 b1 l ev]y?+ else 9 m9+ sci5ce1 has to be temp]$ to meet ! capital available & ! exp5diture w>rant$ by ! value %[+4 ,9 ! initial prospect+ ( a m9e1 tunnels are occasionally ov]done by prospectors4 ,(t5 m w\ld be prov$ by a few incl9es4 ,z ! pione] has to rely ^u 8 "r arm = hoi/+ & dra9age1 ! tunnel (f]s great temptations1 ev5 :5 x is long & ga9s b little dep?4 ,at a m advanc$ /age ( developm5t1 ! sav+ ( capital outlay on hoi/+ & pump+ equipm5t1 at a "t :5 capital is co/ly to secure1 is (t5 suffici5t ju/ification = a tunnel entry4 ,b at ! /age :]e ! future work+ ( ore bel[ a tunnel-level mu/ be contemplat$1 o!r factors ent]4 ,= ore bel[ tunnel-level a %aft becomes necess>y1 & 9 cases :]e a tunnel ent]s a few hundr$ feet bel[ ! outcrop ! %aft %\ld v (t5 ext5d to ! surface1 because int]nal %afts1 w9d+ f tunnel-level1 require l>ge excavations to make room = ! transf] ( ore & = w9d+ ge>4 ,! latt] mu/ be op]at$ by transmitt$ p[]1 ei!r t ( /eam1 wat]1 electricity1 or air4 ,:]e p[] has to be g5]at$ on ! m9e1 ! sav+ by ! use ( direct /eam1 g5]at$ at ! w9d+ ge>1 is v consid]able4 ,moreov]1 ! co/ ( haulage ?r\gh a %aft = ! extra di/ance f tunnel-level to ! surface is (t5 less ?an ! co/ ( transf]r+ ! ore & remov+ x ?r\gh ! tunnel4 ,! load once on ! w9d+-eng9e1 ! consumption ( p[] is small = ! extra di/ance1 & ! sav+ ( labor is ( consequ5ce4 ,on ! o!r h&1 :]e dra9age problems arise1 !y usually outweigh all o!r consid]ations1 = :atev] ! horizon ent]$ by tunnel1 ! di/ance f t level to ! surface means a sav+ ( wat]-pumpage aga9/ s mu* head4 ,! accumulation ( su* con/ant exp5se ju/ifies a proportion$ capital outlay4 ,9 o!r words1 ! sav+ ( ?is extra pump+ w annually r$eem ! co/ ( a c]ta9 am\nt ( tunnel1 ev5 ?\gh x be us$ = dra9age only4 ,9 ord] to emphasize ! rapidity ) :i* su* a sav+ ( con/ant exp5se w ju/ify capital outlay1 "o may tabulate ! result ( calculations %[+ ! l5g? ( tunnel w>rant$ ) v>i\s hypo!tical factors ( quantity ( wat] & height ( lift elim9at$ f pump+4 ,9 ^! computations1 p[] is tak5 at ! l[ rate ( #fj p] horsep[]-ye>1 ! co/ ( tunnel+ at an av]age figure ( #bj p] foot1 & ! "t on ! basis ( a t5-ye> life = ! m9e4 ,feet ( ,tunnel ,paid = 9 #aj ,ye>s ) ,"u-m5tion$ ,conditions4 ,feet ( #ajj1jjj #bjj1jjj #cjj1jjj #ejj1jjj #a1jjj1jjj ,wat] ,lift ,gallons ,gallons ,gallons ,gallons ,gallons ,avoid$ p] ,diem p] ,diem p] ,diem p] ,diem p] ,diem ---------------------------------------- ---------------- #ajj #fjj #a1bjj #a1hjj #c1jjj #f1jjj #bjj #a1bjj #b1djj #c1fjj #f1jjj #ab1jjj #cjj #a1hjj #c1fjj #e1djj #i1jjj #ah1jjj #ejj #c1jjj #f1jjj #i1jjj #ae1jjj #cj1jjj #a1jjj #f1jjj #ab1jjj #ah1jjj #cj1jjj #fj1jjj ,! size ( tunnels :]e ore-extraction is involv$ dep5ds ^u ! daily tonnage output requir$1 & ! l5g? ( haul4 ,! smalle/ size t c be economically driv5 & manag$ is ab\t #f-a_/b feet by #f feet inside ! timb]s4 ,su* a tunnel1 ) s+le track = a l5g? ( #a1jjj feet1 ) "o turn-out1 p]mits h&l+ up to #ejj tons a day ) m5 & animals4 ,if ! di/ance be long] or ! tonnage great]1 a d\ble track is requir$1 :i* necessitates a tunnel at lea/ #h feet wide by #f-a_/b feet to #g feet high1 inside ! timb]s4 ,!re are tunnel projects ( a mu* m impressive ord] ?an ^? design$ to op]ate upp] levels ( m9es2 t is1 long crosscut tunnels design$ to dra9 & op]ate m9es at v consid]able dep?s1 su* z ! ,sutro tunnel at ,virg9ia ,city4 ,! advantage ( ^! tunnels is v great1 especially = dra9age1 & !y mu/ be con/ruct$ ( l>ge size & equipp$ ) appliances = me*anical haulage4 ,,*apt] ,,ix4 ,developm5t ( ,m9es 7,conclud$74 ,,subsidi>y ,,developm5t2--,,/ations2 ,,crosscuts2 ,,levels2 ,,int]val ,,betwe5 ,,levels2 ,,protection ,,( ,,levels2 ,,w9zes ,,& ,,rises4 ,,developm5t ,,9 ,,! ,,prospect+ ,,/age2 ,,drill+4 ,,subsidi>y ,,developm5t4 ,/ations1 crosscuts1 levels1 w9zes1 & rises foll[ aft] ! initial entry4 ,!y are all exp5sive1 & ! lea/ numb] t w answ] is ! ma9 desid]atum4 ,,/ations4--,z /ations are ! outlets ( ! levels to ! %aft1 _! size & con/ruction is a factor ( ! volume & "* ( ! "w at ! levels :i* !y are to s]ve4 ,if no timb] is to be h&l$1 & little ore1 & ?is on cages1 ! /ations ne$ be no l>g] ?an a good siz$ crosscut4 ,:]e timb] is to be let d[n1 !y mu/ be t5 to fifte5 feet high] ?an ! floor ( ! crosscut4 ,:]e load+ into skips is to be provid$ =1 b9s mu/ be cut und]nea? & suffici5t room be provid$ to %ift ! m9e c>s com=tably4 ,su* b9s are built ( f #ej to #ejj tons' capacity 9 ord] to conta9 "s res]ve = hoi/+ purposes1 & 9 _m cases sep>ate b9s mu/ be provid$ on opposite sides ( ! %aft = ore & wa/e4 ,x is a /rong argum5t 9 favor ( skips1 t ) ?is means ( haulage /orage capacity at ! /ations is possible1 & ! hoi/+ may !n g on indep5d5tly ( truck+ &1 z said be=e1 !re are no idle m5 at ! /ations4 ,illu/ration3 ,fig4 #ae4--;,cross-section ( /ation arrangem5t = skip-haulage 9 v]tical %aft4 ,illu/ration3 ,fig4 #af4--;,cross-section ( /ation arrangem5t = skip-haulage 9 v]tical %aft4 ,x is always desirable to conc5trate ! haulage to ! lea/ numb] ( levels1 = _m reasons4 ,among !m is t1 :]e haulage is conf9$ to few levels1 /orage-b9s are n requir$ at e /ation4 ,figures #ae1 #af1 #ag1 & #ah illu/rate v>i\s arrangem5ts ( load+ b9s4 ,,crosscuts4--,crosscuts are = two purposes1 = roadway connection ( levels to ! %aft or to o!r levels1 & = prospect+ purposes4 ,! numb] ( crosscuts = roadways c sometimes be decreas$ by mak+ ! connections ) ! %aft at e second or ev5 e ?ird level1 ?us n only sav+ 9 ! con/ruction co/ ( crosscuts & /ations1 b also 9 ! exp5ses ( scatt]$ tramm+4 ,! matt] becomes especially wor? consid]+ :]e ! quantity ( ore t c ?us be accumulat$ w>rants mule or me*anical haulage4 ,?is subject w be ref]r$ to lat] on4 ,illu/ration3 ,fig4 #ag4--;,arrangem5t ( load+ *utes 9 v]tical %aft4 ,on ! second purpose ( crosscuts1--t ( prospect+1--"o obs]vation m]its emphasis4 ,?is is1 t ! t5d5cy ( ore-fissures to be =m$ 9 p>allels w>rants m sy/ematic crosscutt+ into ! c\ntry rock ?an is done 9 _m m9es4 ,illu/ration3 ,fig4 #ah4--;,cross-section ( /ation arrangem5t = skip-haulage 9 incl9$ %aft4 ,,levels4 ,! ^w level is ano!r example ( m9]s' adaptations 9 nom5clature4 ,its use 9 ! s5se ( tunnels driv5 9 ! direction ( ! /rike ( ! deposit has bett]1 b less us$1 synonyms 9 ! words drifts or drives4 ,! t]m level is us$ by m9]s 9 two s5ses1 9 t x is sometimes appli$ to all op5+s on "o horizon1 crosscuts includ$4 ,levels are = ?ree purposes1--= a /op+ base2 = prospect+ ! deposit2 & = roadways4 ,z a prospect+ & a /op+ base x is desirable t ! level %\ld be driv5 on ! deposit2 z a roadway1 t x %\ld con/itute ! %orte/ di/ance betwe5 two po9ts & be 9 ! s\nde/ gr\nd4 ,on n>r[1 erratic deposits ! levels usually mu/ s]ve all ?ree purposes at once2 b 9 wid] & m regul> deposits levels are (t5 driv5 sep>ately = roadways f ! level :i* =ms ! /op+ base & prospect+ datum4 ,!re 0 a "t :5 m9es 7 work$ by driv+ ! level on ore & enl>g+ x top & bottom z f> z ! gr\nd w\ld /&1 !n driv+ ! next level #ae to #bj feet bel[1 & repeat+ ! op]ation4 ,?is int]val gradually exp&$1 b = "s reason #ajj feet 0 = ye>s assum$ to be ! prop] di/ance betwe5 levels4 ,scatt]$ ov] e m9+ camp on e>? are ?\s&s ( m9es op5$ on ?is empirical figure1 )\t consid]ation ( ! reasons = x or = any o!r di/ance4 ,! gov]n+ factors 9 det]m9+ ! v]tical int]val betwe5 levels are ! foll[+3-- a4 ,! regul>ity ( ! deposit4 b4 ,! effect ( ! me?od ( excavation ( w9zes & rises4 c4 ,! dip & ! me?od ( /op+4 ,,regul>ity ,,( ,,! ,,deposit4--,f a prospect+ po9t ( view ! m levels ! bett]1 & ! int]val !re=e mu/ be det]m9$ some:at by ! "* ( ! deposit4 ,9 erratic deposits !re is less risk ( miss+ ore ) frequ5t levels1 b x does n foll[ t e level ne$ be a ?r\gh roadway to ! %aft or ev5 a /op+ base4 ,9 su* deposits1 int]m$iate levels = prospect+ alone are bett] ?an complete levels1 ea* a roadway4 ,nor is x ess5tial1 ev5 :]e frequ5t levels are requir$ = a /op+ base1 t ea* %\ld be a ma9 haulage outlet to ! %aft4 ,9 "s m9es e ?ird level is us$ z a ma9 roadway1 ! ore be+ p\r$ f ! int]m$iate ones d[n to ! haulage l9e4 ,?us tramm+ & %aft "w1 z /at$ be=e1 c be conc5trat$4 ,,effect ,,( ,,me?od ,,( ,,excavat+ ,,w9zes ,,& ,,rises4--,) h& drill+ & hoi/+1 w9zes beyond a limit$ dep? become v co/ly to pull spoil out (1 & rises too high become difficult to v5tilate1 s t !re is 9 su* cases a limit to ! int]val desirable betwe5 levels1 b ^! difficulties l>gely disappe> :]e air-w9*es & air-drills are us$4 ,,! ,,dip ,,& ,,me?od ,,( ,,/op+4--,! me?od ( /op+ is l>gely dep5d5t ^u ! dip1 & indirectly ?us affects level int]vals4 ,9 dips "u t at :i* mat]ial w fl[ 9 ! /opes--ab\t #de to #ej--! int]val is greatly dep5d5t on ! me?od ( /ope-transport4 ,:]e ore is to be %ovel$ f /opes to ! roadway1 ! levels mu/ be comp>atively close toge!r4 ,:]e deposits are v flat1 "u #bj1 & walls fairly s\nd1 x is (t5 possible to use a sort ( long wall sy/em ( /op+ & to lay tracks 9 ! /opes ) self-act+ incl9es to ! levels4 ,9 su* in/ances1 ! int]val c be exp&$ to #bej or ev5 #djj feet4 ,9 dips betwe5 #bj & #de1 tracks are n (t5 possible1 & ei!r %ovel+ or bump+ tr\ghs99 are ! only help to transport4 ,) %ovel+1 int]vals ( #ajj feet9999 are mo/ common1 & ) tr\ghs ! di/ance c be exp&$ up to #aej or #age feet4 ,footnote 993 ,page #acf4 ,footnote 99993 ,int]vals giv5 are measur$ on ! dip4 ,9 dips ( ov] #dj to #ej1 dep5d+ on ! smoo?ness ( ! foot wall1 ! di/ance c aga9 be increas$1 z /ope-transport is greatly simplifi$1 s9ce ! /ope mat]ials fall out by gravity4 ,9 timb]$ /opes1 9 dips ov] ab\t #de1 int]vals ( #aej to #bjj feet are possible4 ,9 fill$ /opes int]vals ( ov] #aej feet pres5t difficulties 9 ! ma9t5ance ( ore-passes1 = ! we> & te> ( long] use (t5 breaks ! timb]s4 ,9 %r9kage-/opes1 :]e no passes are to be ma9ta9$ & few w9zes put ?r\gh1 ! int]val is sometimes rais$ to #bej feet4 ,! subject is fur!r discuss$ "u ,/op+4 ,ano!r factor be>+ on level int]vals is ! ne$$ insurance ( suffici5t po9ts ( /op+ attack to keep up a c]ta9 output4 ,?is mu/ p>ticul>ly influ5ce ! manag] ^: m9e has b little ore 9 res]ve4 ,illu/ration3 ,fig4 #ai4 ,,protection ,,( ,,levels4--,until rec5t ye>s1 timb]+ & occasional wall+ 0 ! only me?od = ! support ( ! ro(1 & = =m+ a plat=m = a /op+ base4 ,:]e ! rock requires no support sublevels c be us$ z a /op+ base1 & timb]+ = su* purpose avoid$ altoge!r 7,figs4 #ch1 #ci1 #db74 ,9 su* cases ! ma9 roadway c !n be driv5 on /raight l9es1 ei!r 9 ! walls or 9 ! ore1 & us$ entirely = haulage4 ,! subhead+ = a /op+ base is driv5 f> en\gh above or bel[ ! roadway 7dep5d+ on :e!r ov]h& or und]h& /op+ is to be us$7 to leave a support+ pill> :i* is p5etrat$ by %ort passes = ore4 ,9 ov]h& /opes1 ! ore is brok5 directly on ! floor ( an upp] sublevel2 & 9 und]h& /opes1 brok5 directly f ! bottom ( ! sublevel4 ,! me?od entails leav+ a pill> ( ore :i* c be recov]$ only ) difficulty 9 m9es :]e /ope-support is necess>y4 ,! "q ( its adoption is !n l>gely "o ( ! comp>ative co/ ( timb]+1 ! extra co/ ( ! sublevel1 & ! net value ( ! ore left4 ,9 bad swell+ ve9s1 or badly cru%+ walls1 :]e con/ant repair to timb]s w\ld be necess>y1 ! use ( a sublevel is a mo/ useful alt]native4 ,x is especially useful ) /opes to be left op5 or work$ by %r9kage-/op+ me?ods4 ,if ! haulage level1 h[ev]1 is to be ! /op+ base1 "s protection to ! roadway mu/ be provid$4 ,!re are ?ree sy/ems 9 use1--by wood /ulls or sets 7,figs4 #ai1 #cj1 #dc71 by dry-wall+ ) timb] caps 7,fig4 #ce71 & 9 "s localities by /eel sets4 ,/ulls are put up 9 v>i\s ways1 &1 z _! use entails ! lea/ difficulty 9 tak+ ! ore out f b5ea? ! level1 !y are mu* favor$1 b are applicable only 9 comp>atively n>r[ deposits4 ,,w9zes ,,& ,,rises4 ,^! two k9ds ( op5+s = connect+ two horizons 9 a m9e diff] only 9 _! mann] ( con/ruction4 ,a w9ze is sunk und]h&1 :ile a rise is put up ov]h&4 ,:5 ! connection betwe5 levels is complet$1 a m9] /&+ at ! bottom usually ref]s to ! op5+ z a rise1 & :5 he goes to ! top he calls x a w9ze4 ,?is confusion 9 t]ms makes x advisable to ref] to all su* complet$ op5+s z w9zes1 reg>dless ( h[ !y are con/ruct$4 ,9 actual "w1 ev5 disreg>d+ wat]1 x co/s on ! av]age ab\t #cj less to raise ?an to s9k su* op5+s1 = obvi\sly ! spoil runs out or is assi/$ by gravity 9 "o case1 & 9 ! o!r has to be %ovel$ & haul$ up4 ,moreov]1 x is easi] to foll[ ! ore 9 a rise ?an 9 a w9ze4 ,x usually happ5s1 h[ev]1 t 9 ord] to ga9 "t bo? ?+s are done1 & = prospect+ purposes s9k+ is necess>y4 ,! numb] ( w9zes requir$ dep5ds ^u ! me?od ( /op+ adopt$1 & is m5tion$ "u ,/op+4 ,aft] /op+1 ! numb] necess>y to be ma9ta9$ op5 dep5ds ^u ! necessities ( v5tilation1 ( escape1 & ( passageways = mat]ial to be us$ bel[4 ,:]e /opes are to be fill$ ) wa/e1 m w9zes mu/ be kept op5 ?an :5 o!r me?ods are us$1 & ^! w9zes mu/ be 9 suffici5t alignm5t to p]mit ! cont9u\s fl[ ( mat]ial d[n pa/ ! v>i\s levels4 ,9 ord] t ! w9zes %\ld deliv] timb] & fill+ to ! mo/ advantage\s po9ts1 !y %\ld1 9 dipp+ ore-bodies1 be z f> z possible on ! hang+ wall side4 ,,developm5t ,,9 ,,! ,,e>ly ,,prospect+ ,,/age4 ,! prime objects 9 ! prospect+ /age are to expose ! ore & to le>n reg>d+ ! ore-bodies some?+ ( _! size1 _! value1 metallurgical "*1 location1 dip1 /rike1 etc41--s mu* at lea/ z may be necess>y to det]m9e ! works mo/ suitable = _! extraction or values w>rant+ pur*ase4 ,9 outcrop m9es !re is "o rule1 & t is foll[ ! ore4 ,small tempor>y incl9es foll[+ ! deposit1 ev5 ?\gh !y are ev5tually useless2 are n9e times out ( t5 ju/ifi$4 ,9 prospect+ deep-level projects1 x is usually necess>y to lay\t "w :i* c be subsequ5tly us$ 9 op]at+ ! m9e1 because ! dep? involves works ( su* consid]able scale1 ev5 = prospect+1 t ! initial outlay does n w>rant any anticipation ( revision4 ,su* works h to be locat$ & design$ aft] a /udy ( ! g5]al geology z disclos$ 9 adjo9+ m9es4 ,practically ! only me?od ( supplem5t+ su* in=mation is by ! use ( *urn- & diamond-drills4 ,,drill+4--,*urn-drills are applicable only to comp>atively %all[ deposits ( l>ge volume4 ,!y h an advantage ov] ! diamond drill 9 expos+ a l>g] section & 9 _! application to loose mat]ial2 b inability to det]m9e ! exact horizon ( ! spoil does n l5d !m to n>r[ deposits1 & 9 any ev5t results are likely to be mislead+ f ! f9ely gr\nd /ate ( ! spoil4 ,!y are1 h[ev]1 ( v great value = prelim9>y prospect+ to %all[ horizons4 ,two facts 9 diamond-drill+ h to be borne 9 m9d3 ! indication ( values is liable to be mislead+1 & ! deflection ( ! drill is likely to c>ry x f> away f its anticipat$ de/9ation4 ,a diamond-drill secures a small section :i* is suffici5tly l>ge to reveal ! geology1 b ! values disclos$ 9 metal m9es mu/ be accept$ ) res]vations4 ,! core am\nts to b a little sample out ( possibly l>ge am\nts ( ore1 :i* is always ( v>iable "*1 & ! core is mo/ unlikely to repres5t ! av]age ( ! deposit4 ,two diamond-drill holes on ! ,oroya ,br[nhill m9e bo? pass$ ?r\gh ! ore-body4 ,"o app>5tly disclos$ unpayable values1 ! o!r seem+ly %[$ ore =ty feet 9 wid? assay+ #hj p] ton4 ,nei!r 0 "r4 ,on ! o!r h&1 ! pr$et]m9ation ( ! location ( ! ore-body ju/ifi$ exp5diture4 ,a rec5t exp]im5t at ,johannesburg ( plac+ a copp] w$ge 9 ! hole at a po9t above ! ore-body & deflect+ ! drill on re9troduc+ x1 0 successful 9 giv+ a second section ( ! ore at small exp5se4 ,! deflection ( diamond-drill holes f ! />t+ angle is almo/ univ]sal4 ,x (t5 am\nts to a consid]able w&]+ f ! int5d$ c\rse4 ,! am\nt ( su* deflection v>ies ) no seem+ rule1 b x is probable t x is especially affect$ by ! angle at :i* /ratification or lam9ation planes are incl9$ to ! direction ( ! hole4 ,a hole has be5 kn[n to w&] 9 a dep? ( #a1ejj feet m ?an #ejj feet f ! po9t int5d$4 ,v>i\s in/rum5ts h be5 devis$ = survey+ deep holes1 & !y %\ld be br\ght into use be=e works are laid out on ! basis ( diamond-drill results1 al?\gh none ( ! inv5tions are entirely satisfactory4 ,,*apt] ,x4 ,/op+4 ,,me?ods ,,( ,,ore-,,break+2 ,,und]h& ,,/opes2 ,,ov]h& ,,/opes2 ,,comb9$ ,,/ope4 ,,valu+ ,,ore ,,9 ,,c\rse ,,( ,,break+4 ,!re is a great deal ( confusion 9 ! application ( ! ^w /op+4 ,x is us$ n only specifically to mean ! actual ore-break+1 b also 9 a g5]al s5se to indicate all ! op]ations ( ore-break+1 support ( excavations1 & transportation betwe5 levels4 ,x is us$ fur!r z a n\n to designate ! hole left :5 ! ore is tak5 out4 ,worse /ill1 x is impossible to adh]e to m9]s' t]ms )\t employ+ x 9 e s5se1 tru/+ to luck & ! context to make ! mean+ cle>4 ,! conditions :i* gov]n ! me?od ( /op+ are 9 ! ma93-- a4 ,! dip4 b4 ,! wid? ( ! deposit4 c4 ,! "* ( ! walls4 d4 ,! co/ ( mat]ials4 e4 ,! "* ( ! ore4 ,e m9e1 & sometimes e /ope 9 a m9e1 is a problem special to itself4 ,any g5]al consid]ation mu/ !re=e be simply an inquiry into ! broad pr9ciples :i* gov]n ! adaptability ( special me?ods4 ,a logical arrangem5t ( discussion is difficult1 if n :olly impossible1 because ! factors are p>tially int]dep5d5t & ( v>y+ importance4 ,= discussion ! subject may be divid$ into3 #a4 ,me?ods ( ore-break+4 #b4 ,me?ods ( support+ excavation4 #c4 ,me?ods ( transport 9 /opes4 ,,me?ods ,,( ,,ore-,,break+4 ,! mann] ( actual ore-break+ is to drill & bla/ (f slices f ! block ( gr\nd "u attack4 ,z rock obvi\sly breaks easie/ :5 two sides are free1 t is1 :5 corn]s c be brok5 (f1 ! detail ( managem5t = bla/s is !re=e to set ! holes s z to pres]ve a corn] = ! next cut2 & z a consequ5ce ! face ( ! /ope %apes into a s]ies ( b5*es 7,fig4 #bb71--;inv]t$ b5*es 9 ! case ( ov]h& /opes 7,figs4 #bj1 #ba74 ,! size ( ^! b5*es w 9 a l>ge measure dep5d on ! dep? ( ! holes4 ,9 wide /opes ) ma*9e-drills !y v>y f #g to #aj feet2 9 n>r[ /opes ) h&-holes1 f two to ?ree feet4 ,illu/ration3 ,fig4 #bj4 ,! position ( ! m5 9 relation to ! work+ face gives rise to ! usual prim>y classification ( ! me?ods ( /op+4 ,!y are3-- #a4 ,und]h& /opes1 #b4 ,ov]h& /opes1 #c4 ,comb9$ /opes4 ,^! t]ms orig9at$ f ! direction ( ! drill-holes1 b ?is is no long] a logical basis ( di/9ction1 = und]h& holes 9 ov]h& /opes1--z 9 rill-/op+1--are us$ entirely 9 "s m9es 7,fig4 #ba74 ,illu/ration3 ,fig4 #ba4 ,,und]h& ,,/opes4--,und]h& /opes are ^? 9 :i* ! ore is brok5 d[nw>d f ! levels4 ,inasmu* z ?is me?od has ! advantage ( all[+ ! m9] to /rike 8 bl[s d[nw>d & to /& ^u ! ore :5 at "w1 x 0 almo/ univ]sal be=e ! inv5tion ( p[d]2 & 0 appli$ m g5]ally be=e ! inv5tion ( ma*9e-drills ?an s9ce4 ,x is nev] rightly introduc$ unless ! /ope is work$ back f w9zes ?r\gh :i* ! ore brok5 c be let d[n to ! level bel[1 z %[n 9 ,figures #bb & #bc4 ,illu/ration3 ,fig4 #bb4 ,?is sy/em c be advantage\sly appli$ only 9 ! r>e cases 9 :i* ! walls require little or no support1 & :]e v little or no wa/e requir+ sep>ation is brok5 ) ! ore 9 ! /opes4 ,to support ! walls 9 bad gr\nd 9 und]h& /opes w\ld be f> m co/ly ?an ) ov]h& /opes1 = squ>e-set timb]+ w\ld be mo/ difficult to introduce1 & to support ! walls ) wa/e & /ulls w\ld be ev5 m tr\blesome4 ,any wa/e brok5 mu/ ne$s be ?r[n up to ! level above or be /or$ ^u specially built /ages--aga9 a co/ly proce$+4 ,a fur!r drawback lies 9 ! fact t ! brok5 ore foll[s d[n ! face ( ! /ope1 & mu/ be %ovel$ (f ea* b5*4 ,x ?us all arrives at a s+le po9t1--! w9ze1--& mu/ be drawn f a s+le ore-pass into ! level4 ,?is usually results n only 9 m %ovel+ b 9 a conge/ion at ! passes n pres5t 9 ov]h& /op+1 = ) t me?od sev]al *utes are available = dis*>g+ ore into ! levels4 ,:]e ! walls require no support & no selection is desir$ 9 ! /opes1 ! advantage ( ! m5 /&+ on ! solid ore to "w1 & ( hav+ all d[n holes & !re=e drill$ wet1 gives ?is me?od a di/9ct place4 ,9 us+ ?is sy/em1 9 ord] to protect ! m51 a pill> is (t5 left "u ! level by driv+ a sublevel1 ! pill> be+ easily recov]able lat]4 ,! me?od ( sublevels is ( advantage l>gely 9 avoid+ ! timb]+ ( levels4 ,illu/ration3 ,fig4 #bc4--,longitud9al section ( an und]h& /ope4 ,,ov]h& ,,/opes4--,by f> ! greate/ bulk ( ore is brok5 ov]h&1 t is brok5 upw>d f "o level to ! next above4 ,!re are two g5]al =ms :i* su* /opes are giv51--horizontal & rill4 ,illu/ration3 ,fig4 #bd4--;,horizontal-cut ov]h& /ope--longitud9al section4 ,! horizontal flat-back or long-wall /ope1 z x is v>i\sly call$1 %[n 9 ,figure #bd1 is op]at$ by break+ ! ore 9 slices p>allel ) ! levels4 ,9 rill-/op+ ! ore is cut back f ! w9zes 9 su* a way t a pyramid-%ap$ room is creat$1 ) its apex 9 ! w9ze & its base at ! level 7,figs4 #be & #bf74 ,horizontal or flat-back$ /opes c be appli$ to almo/ any dip1 :ile rill-/op+ f9ds its mo/ advantage\s application :]e ! dip is su* t ! ore w run1 or :]e x c be made to run ) a little help4 ,! p>ticul> application ( ! two sy/ems is dep5d5t n only on ! dip b on ! me?od ( support+ ! excavation & ! ore4 ,) rill-/op+1 x is possible to cut ! break+ b5*es back horizontally f ! w9zes 7,fig4 #be71 or to /agg] ! cuts 9 su* a mann] z to take ! slices 9 a desc5d+ angle 7,figs4 #ba & #bf74 ,illu/ration3 ,fig4 #be4--,rill-cut ov]h& /ope--longitud9al section4 ,9 ! rill me?od ( incl9e cuts1 all ! drill-holes are d[n holes 7,fig4 #ba71 & c be drill$ wet1 :ile 9 horizontal cuts or flat-back$ /opes1 at lea/ "p ( ! holes mu/ be upp]s 7,fig4 #bj74 ,aside f ! easi] & *eap] drill+ & sett+ up ( ma*9es ) ?is k9d ( cut1 !re is no drill du/1--a great desid]atum 9 ^! days ( m9]s' ph?isis4 ,a fur!r advantage 9 ! rill cut arises 9 cases :]e horizontal jo9t+ planes run ?r\gh ! ore ( a sort f :i* unduly l>ge masses break away 9 flat-back /opes4 ,by ! desc5d+ cut ( ! rill me?od ^! calamities c be 9 a measure avoid$4 ,9 cases ( dips ov] #dj ! greate/ advantage 9 rill /op+ arises f ! possibility ( p\r+ fill+ or timb] into ! /ope f above ) less h&l+1 because ! ore & mat]ial w run d[n ! sides ( ! pyramid 7,figs4 #cb & #cd74 ,?us n only is !re less %ovel+ requir$1 b few] ore-passes & a less numb] ( prelim9>y w9zes are necess>y1 & a wid] level int]val is possible4 ,?is matt] w be gone into m fully lat]4 ,illu/ration3 ,fig4 #bf4--,rill-cut ov]h& /ope-longitud9al section4 ,,comb9$ ,,/opes4--,a comb9$ /ope is made by ! co9cid5t work+ ( ! und]h& & rill me?od 7,fig4 #bg74 ,?is ord] ( /ope has ! same limitations 9 g5]al z ! und]h& k9d4 ,= flat ve9s ) /rong walls1 x has a great sup]iority 9 t ! /ope is c>ri$ back m or less p>allel ) ! w9zes1 & ?us brok5 ore aft] bla/+ lies 9 a l9e on ! gradi5t ( ! /ope4 ,x is1 !re=e1 conv5i5tly plac$ = me*anical /ope haulage4 ,a fur!r advantage is ga9$ 9 t w9zes may be plac$ long di/ances ap>t1 & t m5 are n requir$1 ei!r :5 at "w or pass+ to & f x1 to be ev] f> f ! face1 & !y are ?us 9 ! safe/ gr\nd1 s t timb] & fill+ protection :i* may be o!rwise necess>y is n requir$4 ,?is me?od is l>gely us$ 9 ,s\? ,africa4 ,illu/ration3 ,fig4 #bg4--,longitud9al section ( a comb9$ /ope4 ,,m9imum ,,wid? ,,( ,,/opes4--,! m9imum /op+ wid? :i* c be consi/5tly brok5 ) h&-holes is ab\t #cj in*es1 & ?is only :]e !re is consid]able dip to ! ore4 ,?is space is s n>r[ t x is ( d\btful advantage 9 any case1 & #dj in*es is m common 9 n>r[ m9es1 especially :]e work$ ) :ite m54 ,:]e ma*9e-drills are us$ ab\t #d feet is ! m9imum wid? feasible4 ,,resu+4--,9 v n>r[ ve9s :]e a c]ta9 am\nt ( wall-rock mu/ be brok5 to give work+ space1 x pays "u "s circum/ances to advance ! /ope into ! wall-rock ahead ( ! ore1 ?us /ripp+ ! ore & enabl+ x to be brok5 sep>ately4 ,?is p]mits ( clean] selection ( ! ore2 b x is a problem to be work$ out 9 ea* case1 z to :e!r r\gh sort+ ( "s wa/e 9 ! /opes1 or fur!r sort+ at surface ) inevitable treatm5t ( "s wa/e rock1 is m economical ?an sep>ate /op+ cuts & inevitably wid] /opes4 ,,valu+ ,,ore ,,9 ,,c\rse ,,( ,,break+4--,!re are _m ores ^: payability c be det]m9$ by inspection1 b !re are _m ( :i* x _c4 ,cont9u\s assay+ is 9 ! latt] cases absolutely necess>y to avoid ! treatm5t ( valueless mat]ial4 ,9 su* in/ances1 sampl+ aft] ea* /op+-cut is ess5tial1 ! unpr(itable ore be+ brok5 d[n & us$ z wa/e4 ,:]e values fade into ! walls1 z 9 impregnation deposits1 ! wid? ( /opes dep5ds ^u ! limit ( payability4 ,9 ^! cases1 drill-holes are put into ! walls & ! drill+s assay$4 ,if ! ore is f\nd pr(itable1 ! holes are bla/$ out4 ,! gauge ( :at is pr(itable 9 su* situations is n dep5d5t simply ^u ! av]age total work+ co/s ( ! m9e1 = ore 9 t position c be said to co/ no?+ = developm5t "w & adm9i/ration2 moreov]1 x is usually m *eaply brok5 ?an ! av]age break+ co/1 m5 & ma*9es be+ already on ! spot4 ,,*apt] ,,xi4 ,me?ods ( ,support+ ,excavation4 ,,timb]+2 ,,fill+ ,,) ,,wa/e2 ,,fill+ ,,) ,,brok5 ,,ore2 ,,pill>s ,,( ,,ore2 ,,artificial ,,pill>s2 ,,cav+ ,,sy/em4 ,mo/ /opes require support to be giv5 to ! walls & (t5 to ! ore itself4 ,:]e !y d require support !re are five pr9cipal me?ods ( accompli%+ x4 ,! application ( any p>ticul> me?od dep5ds ^u ! dip1 wid? ( ore-body1 "* ( ! ore & walls1 & co/ ( mat]ials4 ,! v>i\s sy/ems are by3-- #a4 ,timb]+4 #b4 ,fill+ ) wa/e4 #c4 ,fill+ ) brok5 ore subsequ5tly )drawn4 #d4 ,pill>s ( ore4 #e4 ,artificial pill>s built ( timb]s & wa/e4 #f4 ,cav+4 ,,timb]+4--,at "o "t timb]+ 0 ! almo/ univ]sal means ( support 9 su* excavations1 b gradually v>i\s me?ods = ! economical application ( wa/e & ore itself h come =w>d1 until timb]+ is fa/ becom+ a second>y device4 ,aside f economy 9 work+ )\t x1 ! dang]s ( creeps1 or cru%+1 & ( fires are suffici5t inc5tives to d away ) wood z f> z possible4 ,!re are ?ree pr9cipal sy/ems ( timb] support to excavations1--by /ulls1 squ>e-sets1 & cribs4 ,/ulls are s]viceable only :]e ! deposit is s n>r[ t ! op5+ c be bridg$ by s+le timb]s betwe5 wall & wall 7,figs4 #bh & #dc74 ,?is sy/em c be appli$ to any dip & is mo/ useful 9 n>r[ deposits :]e ! walls are n too heavy4 ,/ulls 9 incl9$ deposits are usually set at a slightly high] angle ?an t p]p5dicul> to ! walls1 9 ord] t ! v]tical pressure ( ! hang+ wall w s]ve to tight5 !m 9 position4 ,! /ull sy/em c1 9 incl9$ deposits1 be fur!r /r5g!n$ by build+ wa/e pill>s aga9/ !m1 9 :i* case ! arrangem5t m]ges into ! sy/em ( artificial pill>s4 ,illu/ration3 ,fig4 #bh4--,longitud9al section ( /ull-support$ /ope4 ,illu/ration3 ,fig4 #bi4--,longitud9al section %[+ squ>e-set timb]+4 ,illu/ration3 ,fig4 #cj4--,squ>e-set timb]+ on incl9$ ore-body4 ,%[+ ultimate /ra9 on timb]s4 ,squ>e-sets 7,figs4 #bi & #cj71 t is1 trusses built 9 ! op5+ z ! ore is remov$1 are applicable to almo/ any dip or wid? ( ore1 b g5]ally are appli$ only 9 deposits too wide1 or to rock too heavy1 = /ulls4 ,su* trusses are usually con/ruct$ on v]tical & horizontal l9es1 & :ile dur+ actual ore-break+ ! /ra9s are p>tially v]tical1 ultimately1 h[ev]1 :5 ! weight ( ! walls beg9s to be felt1 ^! /ra9s1 except 9 v]tical deposits1 come at an angle to l9es ( /r5g? 9 ! trusses1 & !re=e timb] con/ructions ( ?is type pres5t little ultimate resi/ance 7,fig4 #cj74 ,squ>e-set timb]s are sometimes set to pres5t ! maximum resi/ance to ! direction ( /ra91 b ! difficulties ( plac+ !m 9 position & v>iations 9 ! direction ( /ra9 on v>i\s p>ts ( ! /ope d n (t5 comm5d ! me?od4 ,z a g5]al rule squ>e-sets on horizontal l9es answ] well en\gh = ! p]iod ( actual ore-break+4 ,! cru%+ or creeps is usually "s "t lat]2 & if ! cru%+ may damage ! :ole m9e1 _! use is fraught ) dang]4 ,ren=cem5t by build+ 9 wa/e is (t5 resort$ to4 ,:5 done fully1 x is difficult to see ! utility ( ! enclos$ timb]1 = entire wa/e-fill+ w\ld 9 mo/ cases be *eap] & equally effici5t4 ,illu/ration3 ,fig4 #ca4--;,cribs4 ,!re is always1 ) wood con/ructions1 z said be=e1 ! v p]t95t dang] ( subsequ5t cru%+ & ( subsid5ce 9 aft] ye>s1 & ! great risk ( fires4 ,bo? ^! disa/]s h co/ ,com/ock & ,brok5 ,hill m9es1 directly or indirectly1 millions ( doll>s1 & ! outlay on timb] & repairs "o way or ano!r w\ld h paid = ! fill+ sy/em t5 times ov]4 ,!re are cases :]e1 by virtue ( ! *eapness ( timb]1 squ>e-sett+ is ! mo/ economical me?od4 ,aga91 !re are in/ances :]e ! ore lies 9 su* a mann]--p>ticul>ly 9 lime/one replacem5ts--z to preclude o!r means ( support4 ,^! cases are be+ ye>ly m & m evad$ by ! +5uity ( eng9e]s 9 *>ge4 ,! au?or believes x soon w be recogniz$ t ! situation is r>e inde$ :]e complete squ>e-sett+ is necess>ily )\t an economical alt]native4 ,an objection is sometimes rais$ to fill+ 9 favor ( timb]1 9 t if x become desirable to re/ope ! walls = l[-grade ore left beh9d1 su* /opes c\ld only be ent]$ by draw+ ! fill+1 ) consequ5t dang] ( total collapse4 ,su* a cont+5cy c be provid$ = 9 l>ge ore-bodies by in/all+ an out] %ell ( sets ( timb] ar\nd ! p]iph]y ( ! /ope & fill+ ! inside ) wa/e4 ,if ! cru%+ possibilities are too great = ?is me?od !n1 ! subsequ5t recov]y ( ore is hopeless 9 any ev5t4 ,9 n>r[ ore-bodies ) cru%+ walls recov]y ( ore once left beh9d is n (t5 possible4 ,! ?ird sort ( timb] con/ructions are cribs1 a log-h\se sort ( /ructure usually fill$ ) wa/e1 & m fully discuss$ "u artificial pill>s 7,fig4 #ca74 ,! fur!r comp>ative m]its ( timb]+ ) o!r me?ods w be analyz$ z ! diff]5t sy/ems are describ$4 ,,fill+ ,,) ,,wa/e4--,! sy/em ( fill+ /ope-excavations completely ) wa/e 9 alt]nat+ progress ) ore-break+ is ( wide & increas+ly g5]al application 7,figs4 #cb1 #cc1 #cd1 #ce74 ,al?\gh a c]ta9 am\nt ( wa/e is ord9>ily available 9 ! /opes !mselves1 or f developm5t "w 9 ! m9e1 su* a supply mu/ usually be supplem5t$ f o!r directions4 ,treatm5t residues af=d ! easie/ & *eape/ h&l$ mat]ial4 ,qu>ri$ rock ranks next1 & 9 default ( any o!r easy supply1 mat]ials f crosscuts driv5 into ! /ope-walls are sometimes resort$ to4 ,9 work+ ! sy/em to ! be/ advantage1 ! w9zes ?r\gh ! block ( ore "u attack are kept 9 alignm5t ) simil> op5+s above1 9 ord] t fill+ may be p\r$ ?r\gh ! m9e f ! surface or any int]m$iate po9t4 ,w9zes to be us$ = fill+ %\ld be put on ! hang+-wall side ( ! area to be fill$1 = ! fill+ p\r$ d[n w !n rea* ! foot-wall side ( ! /opes ) a m9imum ( h&l+4 ,9 "s in/ances1 "o special w9ze is arrang$ = pass+ all fill+ f ! surface to a level above ! pr9cipal /op+ op]ations2 & x is !n di/ribut$ along ! levels into ! w9zes1 & ?us to ! op]at+ /opes1 by belt-conveyors4 ,illu/ration3 ,fig4 #cb4--,longitud9al section4 ,rill /ope fill$ ) wa/e4 ,illu/ration3 ,fig4 #cc4--,longitud9al section4 ,horizontal /ope fill$ ) wa/e4 ,illu/ration3 ,fig4 #cd4--,longitud9al section4 ,wa/e-fill$ /ope ) dry-wall+ ( levels & passes4 ,9 ?is sy/em ( /ope support ! ore is brok5 at int]vals alt]nat+ ) fill+4 ,if !re is dang] ( mu* loss f mix+ brok5 ore & fill+1 soll>s ( bo>ds or poles are laid on ! wa/e4 ,if ! ore is v ri*1 old canvas or c[hides are sometimes put "u ! bo>ds4 ,be=e ! fill+ int]val1 ! ore passes are built close to ! face above previ\s fill+ & _! tops cov]$ tempor>ily to prev5t _! be+ fill$ ) runn+ wa/e4 ,if ! walls are bad1 ! fill+ is kept close to ! face4 ,if ! unbrok5 ore requires support1 %ort /ulls set on ! wa/e 7z 9 ,fig4 #ci7 are usually suffici5t until ! next cut is tak5 (f1 :5 ! timb] c be recov]$4 ,if /ulls are insuffici5t1 cribs or bulkheads 7,fig4 #ca7 are also us$ & (t5 buri$ 9 ! fill+4 ,illu/ration3 ,fig4 #ce4--;,cross-section ( ,fig4 #cd on l9e ,a-,b4 ,bo? flat-back$ & rill-/ope me?ods ( break+ are employ$ 9 conjunction ) fill$ /opes4 ,! advantages ( ! rill-/opes are s pat5t z to make x difficult to und]/& :y !y are n univ]sally adopt$ :5 ! dip p]mits _! use at all4 ,9 rill-/opes 7,figs4 #cb & #cd7 ! wa/e fl[s to its de/9ation ) a m9imum ( h&l+4 ,w9zes & ore-passes are n requir$ ) ! same frequ5cy z 9 horizontal break+1 & ! brok5 ore always lies on ! slope t[>ds ! passes & is !re=e also easi] to %ovel4 ,9 flat-back$ /opes 7,fig4 #cc7 w9zes mu/ be put 9 e #ej feet or s1 :ile 9 rill-/opes !y c be d\ble ?is di/ance ap>t4 ,! sy/em is applicable by modification to almo/ any wid? ( ore4 ,x f9ds its mo/ economical field :]e ! dip ( ! /ope floor is ov] #de1 :5 wa/e & ore1 ) ! help ( ! rill1 w fl[ to _! de/9ation4 ,= dips f "u ab\t #de to ab\t #cj or #ce1 :]e ! wa/e & ore w n fl[ easily1 %ovel+ c be help$ by ! use ( ! rill sy/em & (t5 evad$ altoge!r1 if fl[ be assi/$ by a %eet-iron tr\gh describ$ 9 ! discussion ( /ope transport4 ,fur!r sav+ 9 %ovel+ c be ga9$ 9 ?is me?od1 by giv+ a /eep] pit* to ! fill+ w9zes & to ! ore-passes1 by />t+ !m f crosscuts 9 ! wall1 & by c>ry+ !m at great] angles ?an ! pit* ( ! ore 7,fig4 #cf74 ,^! artifices comb9$ h work$ out mo/ economically on sev]al m9es )9 ! writ]'s exp]i5ce1 ) ! dip z flat z #cj4 ,= v flat dips1 :]e fill+ is to be employ$1 rill-/op+ has no advantage ov] flat-back$ cuts1 & 9 su* cases x is (t5 advisable to assi/ /ope transport by tempor>y tracks & c>s :i* obvi\sly c\ld n be work$ on ! tortu\s cont\r ( a rill-/ope1 s t = dips "u #cj advantage lies ) flat-back$ ore-break+4 ,illu/ration3 ,fig4 #cf4--;,cross-section %[+ me?od ( /eep5+ w9zes & ore passes4 ,on v wide ore-bodies :]e ! support ( ! /&+ ore itself becomes a great problem1 ! fill+ sy/em c be appli$ by comb9+ x ) squ>e-sett+4 ,9 ?is case ! /opes are c>ri$ 9 panels laid out transv]sally to ! /rike z wide z ! /&+ /r5g? ( ! ore p]mits4 ,on bo? sides ( ea* panel a f5ce ( lagg$ squ>e-sets is c>ri$ up & ! area betwe5 is fill$ ) wa/e4 ,! panels are /op$ out alt]nately4 ,! application ( ?is me?od at ,brok5 ,hill w be describ$ lat]4 7,see pages #abj & ,figs4 #da & #db47 ,! same type ( wide ore-body c be manag$ also on ! fill+ sy/em by ! use ( frequ5t bulkheads to support ! ore 7,fig4 #ca74 ,comp>$ ) timb]+ me?ods1 fill+ has ! great advantage ( m effective support to ! m9e1 less dang] ( creeps1 & absolute fre$om f ! p]il ( fire4 ,! relative exp5se ( ! two sy/ems is det]m9$ by ! co/ ( mat]ials & labor4 ,two extreme cases illu/rate ! result ( ^! economic factors ) suffici5t cle>ness4 ,x is /at$ t ! co/ ( timb]+ /opes on ! ,le ,roi ,m9e by squ>e-sets is ab\t #ba c5ts p] ton ( ore excavat$4 ,9 ! ,ivanhoe m9e ( ,we/ ,au/ralia ! co/ ( fill+ /opes ) tail+s is ab\t #bb c5ts p] ton ( ore excavat$4 ,at ! =m] m9e ! av]age co/ ( timb] is "u #aj p] ,m bo>d-measure1 :ile at ! latt] its price w\ld be #ej p] ,m bo>d-measure2 al?\gh labor is ab\t ( ! same effici5cy & wage1 ! co/ 9 ! ,ivanhoe by squ>e-sett+ w\ld be ab\t #fe c5ts p] ton ( ore brok54 ,9 ! ,le ,roi1 on ! o!r h&1 no residues are available = fill+4 ,to qu>ry rock or drive crosscuts into ! walls might make ?is sy/em co/ #fe c5ts p] ton ( ore brok5 if appli$ to t m9e4 ,! comp>ative value ( ! fill+ me?od ) o!r sy/ems w be discuss$ lat]4 ,,fill+ ,,) ,,brok5 ,,ore ,,subsequ5tly ,,)drawn4--,?is ord] ( support is call$ by v>i\s names1 ! favorite be+ %r9kage-/op+4 ,! me?od is to break ! ore on to ! ro( ( ! level1 & by ?us fill+ ! /ope ) brok5 ore1 provide tempor>y support to ! walls & furni% /&+ floor ^u :i* to "w 9 mak+ ! next cut 7,figs4 #cg1 #ch1 & #ci47 ,z brok5 mat]ial occupies #cj to #dj m space ?an rock 9 situ1 9 ord] to provide work+ space at ! face1 ! brok5 ore mu/ be drawn f along ! level aft] ea* cut4 ,:5 ! area attack$ is completely brok5 ?r\gh f level to level1 ! /ope w be full ( loose brok5 ore1 :i* is !n entirely drawn (f4 ,a block to be attack$ by ?is me?od requires prelim9>y w9zes only at ! extremities ( ! /ope1--= entry & = v5tilation4 ,:]e x is desir$ to ma9ta9 ! w9zes aft] /op+1 !y mu/ ei!r be /rongly timb]$ & lagg$ on ! /ope side1 be driv5 9 ! walls1 or be protect$ by a pill> ( ore 7,fig4 #cg74 ,! settl+ ore & ! cru%+ aft] ! /ope is empty make x difficult to ma9ta9 timb]$ w9zes4 ,illu/ration3 ,fig4 #cg4--,longitud9al section ( /ope fill$ ) brok5 ore4 ,:]e x c be done )\t dang] to ! m9e1 ! empty /opes are all[$ to cave4 ,if su* cru%+ w\ld be dang]\s1 ei!r ! walls mu/ be held up by pill>s ( unbrok5 ore1 z 9 ! ,alaska ,treadwell1 :]e l>ge rib pill>s are left1 or ! op5 spaces mu/ be fill$ ) wa/e4 ,fill+ ! empty /ope is usually done by op5+ frequ5t passes along ! base ( ! fill$ /ope above1 & all[+ ! mat]ial ( ! upp] /ope to flood ! l[] "o4 ,?is program cont9u$ upw>ds ?r\gh ! m9e all[s ! :ole fill+ ( ! m9e to desc5d gradually & ?us requires repl5i%m5t only into ! top4 ,! old /opes 9 ! less critical & usually exhau/$ t]ritory ne>] ! surface are sometimes left )\t repl5i%+ _! fill+4 ,! weight ( brok5 ore /&+ at su* a high angle z to settle rapidly is v consid]able ^u ! level2 moreov]1 at ! mom5t :5 ! /ope is entirely drawn (f1 ! pressure ( ! walls z well is likely to be v great4 ,! roadways 9 ?is sy/em !re=e require m ?an usual protection4 ,?ree me?ods are us$3 7a7 timb]+2 7b7 driv+ a sublevel 9 ! ore above ! ma9 roadway z a /op+-base1 ?us leav+ a pill> ( ore ov] ! roadway 7,fig4 #ci72 7c7 by dry-wall+ ! levels1 z 9 ! ,baltic m9e1 ,mi*igan 7,figs4 #cd & #ce74 ,by ! use ( sublevels ! ma9 roadways are sometimes driv5 9 ! walls 7,fig4 #ch7 & 9 _m cases all timb]+ is sav$4 ,to recov] pill>s left bel[ sublevels is a r difficult task1 especially if ! old /ope above is cav$ or fill$4 ,! use ( pill>s 9 sub/itution = timb]1 if ! pill>s are to be lo/1 is simply a matt] ( economics z to :e!r ! lo/ ore w\ld repay ! co/ ( o!r devices4 ,illu/ration3 ,fig4 #ch4--;,cross-section ( %r9kage /ope4 ,frequ5t ore-*utes ?r\gh ! level timb]s1 or f ! sublevels1 are necess>y to prev5t lodgm5t ( brok5 ore betwe5 su* passes1 because x is usually too dang]\s = m5 to ent] ! empty+ /ope to %ovel out ! lodg$ remnants4 ,:]e ! ore-body is wide1 & 9 ord] t !re may be no lodgm5t ( ore1 ! timb]s ov] ! level are set s z to =m a tr\gh along ! level2 or :]e pill>s are left1 !y are made ,a-%ap$ betwe5 ! *utes1 z indicat$ 9 ,figure #cg4 ,illu/ration3 ,fig4 #ci4--;,cross-section ( %r9kage /ope4 ,! me?od ( break+ ! ore 9 conjunction ) ?is means ( support 9 comp>atively n>r[ deposits c be on ! rill1 9 ord] to h ! advantage ( d[n holes4 ,usually1 h[ev]1 flat-back or horizontal cuts are desirable1 z 9 su* an arrangem5t x is less tr\blesome to regulate ! draw+ ( ! ore s z to provide prop] head room4 ,:]e /opes are wide1 ore is sometimes cut ar*-%ap$ f wall to wall to assure its /&+4 ,:]e ?is me?od ( support is n ( avail1 %ort1 %>ply tap]+ /ulls are put 9 f ! brok5 ore to ! face 7,fig4 #ci74 ,:5 ! cut above ^! /ulls is tak5 out1 !y are pull$ up & are us$ aga94 ,?is me?od ( /op+ is only applicable :53-- #a4 ,! deposit dips ov] #fj1 & ?us brok5 mat]ial w freely settle d[nw>d to be drawn (f f ! bottom4 #b4 ,! ore is consi/5tly payable 9 "*4 ,no selection c be done 9 break+1 z all mat]ial brok5 mu/ be drawn (f toge!r4 #c4 ,! hang+ wall is /rong1 & w n cru% or spall (f wa/e into ! ore4 #d4 ,! ore-body is regul> 9 size1 else loose ore w lodge on ! foot wall4 ,/opes op5$ 9 ?is mann] :5 p>tially empty are too dang]\s = m5 to ent] = %ovel+ out remnants4 ,! advantages ( ?is sy/em ov] o!rs1 :]e x is applicable1 are3-- 7a7 ,a great] di/ance betwe5 levels c be op]at$ & few w9zes & rises are necess>y1 ?us a great sav+ ( developm5t "w c be effect$4 ,a /ope #hjj to #ajjj feet long c be op]at$ ) a w9ze at ei!r end & ) levels #bjj or #bbj feet ap>t4 7b7 ,!re is no %ovel+ 9 ! /opes at all4 7c7 ,no timb] is requir$4 ,z comp>$ ) timb]+ by /ull+1 x w apply to /opes too wide & walls too heavy = ?is me?od4 ,moreov]1 little /ag+ is requir$ = work+ ! face1 s9ce ore c be drawn f bel[ 9 su* a mann] z to all[ j ! "r head room4 7d7 ,comp>$ to ! sy/em ( fill+ ) wa/e1 co9cid5tally ) break+ 7second me?od71 x saves altoge!r 9 "s cases ! co/ ( fill+4 ,9 any ev5t1 x saves ! co/ ( ore-passes1 ( %ovel+ into !m1 & ( ! detail$ di/ribution ( ! fill+4 ,comp>$ ) o!r me?ods1 ! sy/em has ! foll[+ disadvantages1 t3 ,a4 ,! ore requires to be brok5 9 ! /opes to a degree ( f95ess :i* w prev5t block+ ( ! *utes at ! level4 ,:5 pieces too l>ge rea* ! *utes1 no?+ w op5 !m b bla/+1--to ! damage ( timb]s & *utes4 ,"s l>ge rocks are always liable to be buri$ 9 ! c\rse ( ore-break+4 ,b4 ,practically no su* p]fection ( walls exi/s1 b "s spall+ ( wa/e into ! ore w take place4 ,a cru%+ ( ! walls w\ld soon mean ! loss ( l>ge am\nts ( ore4 ,c4 ,!re is no possibility ( regulat+ ! mixture ( grade ( ore by v>y+ ! work+ po9ts4 ,x is mon?s aft] ! ore is brok5 be=e x c rea* ! levels4 ,d4 ,! break+ ( #fj m ore ?an imm$iate treatm5t dem&s results 9 ! inve/m5t ( a consid]able sum ( money4 ,an equilibrium is ultimately e/abli%$ 9 a m9e work$ on ?is sy/em :5 a c]ta9 numb] ( /opes full ( completely brok5 ore are available = entire )drawal1 & !re is no fur!r accumulation4 ,b1 9 any ev5t1 a consid]able am\nt ( brok5 ore mu/ be held 9 res]ve4 ,9 "o m9e work$ on ?is plan1 ) :i* ! writ] has _h exp]i5ce1 ! annual production is ab\t #bej1jjj tons & ! brok5 ore repres5ts an inve/m5t :i*1 at #e1 means an annual loss ( int]e/ am\nt+ to #g c5ts p] ton ( ore treat$4 ,e4 ,a m9e once />t$ on ! sy/em is mo/ difficult to alt]1 ow+ to ! lack ( frequ5t w9zes or passes4 ,especially is ?is s if ! only alt]native is fill+1 = an alt]ation to ! sy/em ( fill+ co9cid5t ) break+ f9ds ! m9e %ort ( fill+ w9zes4 ,z ! conditions ( walls & ore (t5 alt] ) dep?1 *ange ( sy/em may be necess>y & ! situation may become v emb>rass+4 ,f4 ,! re/op+ ( ! walls = l[]-grade ore at a lat] p]iod is impossible1 = ! walls ( ! /ope w be cru%$1 or1 if fill$ ) wa/e1 w usually cru% :5 x is drawn (f to s5d to a l[] /ope4 ,! sy/em has mu* to recomm5d x :]e conditions are favorable4 ,l all o!r alt]native me?ods ( m9+1 x requires ! mo/ c>eful /udy 9 ! light ( ! special conditions involv$4 ,9 _m m9es x c be us$ = "s /opes :]e n adaptable g5]ally4 ,x (t5 solves ! problem ( bl9d ore-bodies1 = !y c by ?is means be frequ5tly work$ ) an op5+ und]nea? only4 ,?us ! co/ ( driv+ a roadway ov]head is avoid$1 :i* w\ld be requir$ if timb] or co9cid5t fill+ 7 ! alt]natives4 ,9 su* cases v5tilation c be manag$ )\t an op5+ above1 by s direct+ ! curr5t ( air t x w rise ?r\gh a w9ze f ! level bel[1 fl[ along ! /ope & into ! level aga9 at ! fur!r end ( ! /ope ?r\gh ano!r w9ze4 ,illu/ration3 ,fig4 #dj4--,longitud9al section4 ,ore-pill> support 9 n>r[ /opes4 ,,support ,,by ,,pill>s ,,( ,,ore4--,z a me?od ( m9+ metals ( ! sort "u discussion1 ! use ( ore-pill>s except 9 conjunction ) "s o!r means ( support has no g5]al application4 ,to use !m )\t assi/ance implies walls suffici5tly /rong to hold betwe5 pill>s2 to leave !m p]man5tly any:]e implies t ! ore ab&on$ w\ld n repay ! labor & ! mat]ial ( a sub/itute4 ,!re are cases ( l>ge1 v l[-grade m9es :]e to ab&on "o-half ! ore z pill>s is m pr(itable ?an total extraction1 b ! m>g9 ( payability 9 su* ore mu/ be v1 v n>r[4 ,unpayable spots are always left z pill>s1 = obvi\s reasons4 ,p]man5t ore-pill>s z an adjunct to o!r me?ods ( support are 9 use4 ,su* are ! rib-pill>s 9 ! ,alaska ,treadwell1 ! =m ( :i* is indicat$ by ! upw>d ext5sion ( ! pill>s adjac5t to ! w9zes1 %[n 9 ,figure #cg4 ,always a c>eful balance mu/ be ca/ z to ! value ( ! ore left1 & z to ! co/ ( a sub/itute1 because e ore-pill> c be remov$ at "s outlay4 ,tempor>y pill>s are n unusual1 p>ticul>ly to protect roadways & %afts4 ,!y are1 :5 left = ^! purposes1 remov$ ultimately1 usually by beg9n+ at ! f>!r end & work+ back to ! f9al exit4 ,illu/ration3 ,fig4 #da4--;,horizontal plan at levels ( ,brok5 ,hill4 ,me?od ( alt]nate /opes & ore-pill>s4 ,illu/ration3 ,fig4 #db4--,longitud9al section ( ,figure #da4 ,a =m ( tempor>y ore-pill>s 9 v wide deposits is made use ( 9 conjunction ) bo? fill+ & timb]+ 7,figs4 #cg1 #ci1 #dj74 ,9 ! use ( tempor>y pill>s = ore-bodies #ajj to #bej feet wide at ,brok5 ,hill1 /opes are c>ri$ up at "r angles to ! /rike1 ea* fifty feet wide & cle> across ! ore-body 7,figs4 #da & #db74 ,a solid pill> ( ! same wid? is left 9 ! fir/ in/ance betwe5 adjac5t /opes1 & ! initial s]ies ( /opes are wall$ ) "o squ>e-set on ! sides z ! /ope is brok5 upw>d4 ,! room betwe5 ^! two l9es ( sets is fill$ ) wa/e alt]nat+ ) ore-break+ 9 ! usual fill+ me?od4 ,:5 ! ore f ! fir/ gr\p ( alt]nate /opes 7,,abc1 ,fig4 #db7 is completely remov$1 ! pill>s are /op$ out & replac$ ) wa/e4 ,! squ>e-sets ( ! fir/ set ( /opes ?us become ! b\nd>ies ( ! second set4 ,entry & v5tilation are obta9$ ?r\gh ^! l9es ( squ>e-sets1 & ! ore is pass$ out ( ! /opes ?r\gh !m4 ,illu/ration3 ,fig4 #dc4--;,cross-section ( /ull support ) wa/e ren=cem5t4 ,,artificial ,,pill>s4--,?is sy/em also implies a ro( s /rong z n to dem& cont9u\s support4 ,artificial pill>s are built 9 _m diff]5t ways4 ,! me?od mo/ curr5t 9 fairly n>r[ deposits is to ren=ce /ulls by pack+ wa/e above !m 7,figs4 #dc & #dd74 ,n only is x ?us possible to economize 9 /ulls by us+ ! wa/e :i* accumulates und]gr\nd1 b ! pr9ciple applies also to cases :]e ! /ulls alone are n suffici5t support1 & yet :]e complete fill+ or squ>e-sett+ is unnecess>y4 ,:5 ! conditions are propiti\s = ?is me?od1 x has ! comp>ative advantage ov] timb] sy/ems ( sav+ timb]1 & ov] fill+ sy/ems ( sav+ import$ fill+4 ,moreov]1 ^! con/ructions be+ pill>-%ap$ 7,fig4 #dd71 ! int]vals betwe5 !m provide outlets = brok5 ore1 & specially built passes are unnecess>y4 ,! me?od has two disadvantages z aga9/ ! squ>e-set or fill+ process1 9 t m /ag+ mu/ be provid$ f :i* to "w1 & 9 /opes ov] six feet ! erection ( ma*9e-drill columns is t$i\s & co/ly 9 "t & wages4 ,illu/ration3 ,fig4 #dd4--,longitud9al section ( /ull & wa/e pill>s4 ,9 wide deposits ( m>k$ly flat1 irregul> ore-bodies1 :]e a def9ite sy/em is difficult & :]e timb] is exp5sive1 cribs ( cord-wood or logs fill$ ) wa/e aft] ! ord] %[n 9 ,figure #ca1 (t5 make fairly s\nd pill>s4 ,!y w n la/ indef9itely & are be/ adapt$ to ! tempor>y support ( ! ore-ro( p5d+ fill+4 ,! increas$ difficulty 9 sett+ up ma*9e drills 9 su* /opes adds to ! break+ co/s1--(t5 en\gh to w>rant ano!r me?od ( support4 ,illu/ration3 ,fig4 #de4--,sublevel cav+ sy/em4 ,,cav+ ,,sy/ems4--,?is me?od1 ) v>iations1 has be5 appli$ to l>ge iron deposits1 to ! ,kimb]ley diamond m9es1 to "s copp] m9es1 b 9 g5]al x has little application to ! metal m9es "u consid]ation1 z few ore-bodies are ( suffici5tly l>ge horizontal area4 ,! sy/em is dep5d5t ^u a l>ge area ( loose or heavy gr\nd press+ directly on ! ore ) weight1 su* t if ! ore be cut into pill>s1 ^! w cru%4 ,! details ( ! sy/em v>y1 b 9 g5]al ! modus op]&i is to prep>e roadways ?r\gh ! ore1 & f ! roadways to put rises1 f :i* sublevels are driv5 close "u ! float+ mass ( wa/e & ore1--sometimes call$ ! matte 7,fig4 #de74 ,! pill>s betwe5 ^! sublevels are !n cut away until ! weight above cru%es !m d[n4 ,:5 all ! cru%$ ore :i* c be safely rea*$ is extract$1 retreat is made & ano!r s]ies ( subop5+s is !n driv5 close "u ! matte4 ,! pill> is r$uc$ until x cru%es & ! op]ation is repeat$4 ,ev5tually ! bottom /rata ( ! matte become l>gely ore1 & a sort ( equilibrium is rea*$ :5 !re is n mu* loss 9 ?is direction4 ,top slic+ is a v>iation ( ! above me?od by c>ry+ a horizontal /ope f ! rises imm$iately "u ! matte1 support+ ! float+ mat]ial ) timb]4 ,at ,kimb]ley ! sy/em is v>i$ 9 t gall]ies are run out to ! edge ( ! diamond-if]\s area & enl>g$ until ! pill> betwe5 cru%es4 ,9 ! cav+ me?ods1 betwe5 #dj & #ej ( ! ore is remov$ by ! prelim9>y op5+s1 & z !y are all head+s ( "s sort1 ! av]age co/ p] ton ( ?is p>ticul> ore is high] ?an by ord9>y /op+ me?ods4 ,on ! o!r h&1 ! rema9+ #ej to #fj ( ! ore co/s no?+ to break1 & ! av]age co/ is (t5 rem>kably l[4 ,z said1 ! sy/em implies bodies ( l>ge horizontal area4 ,!y mu/ />t ne> en\gh to ! surface t ! :ole sup]9cumb5t mass may cave & give cru%+ weight1 or ! imm$iately ov]hang+ ro( mu/ easily cave4 ,all ( ^! are conditions n (t5 met ) 9 m9es ( ! "* "u review4 ,,*apt] ,,xii4 ,me*anical ,equipm5t4 ,,conditions ,,be>+ ,,on ,,m9e ,,equipm5t2 ,,w9d+ ,,appliances2 ,,haulage ,,equipm5t ,,9 ,,%afts2 ,,lat]al ,,und]gr\nd ,,transport2 ,,transport ,,9 ,,/opes4 ,!re is no type ( me*anical eng9e]+ :i* pres5ts su* complexities 9 det]m9ation ( ! be/ equipm5t z does t ( m9+4 ,n only does ! economic side dom9ate ov] pure me*anics1 b ma*9es mu/ be in/all$ & op]at$ "u difficulties :i* arise f ! mo/ exceptional & conflict+ conditions1 none ( :i* c be entirely satisfi$4 ,compromise betwe5 capital outlay1 op]at+ effici5cy1 & conflict+ dem&s is ! key-note ( ! "w4 ,^! compromises are br\ght ab\t by influ5ces :i* lie outside ! que/ions ( me*anics ( individual ma*9es1 & are ma9ly z foll[s3-- #a4 ,cont9u\s *ange 9 horizon ( op]ations4 #b4 ,unc]ta9 life ( ! ent]prise4 #c4 ,c>e & pres]vation ( human life4 #d4 ,unequal adaptability ( p[] transmission m$iums4 #e4 ,orig9 ( p[]4 ,fir/4--,! dep? to be s]v$ & ! volume ( ore & wat] to be h&l$1 are n only unkn[n at ! initial equipm5t1 b !y are b\nd to *ange cont9u\sly 9 quantity1 location1 & horizon ) ! ext5sion ( ! work+s4 ,second4--,f ! m9e manag]'s po9t ( view1 :i* mu/ embrace t ( ! me*anical eng9e]1 fur!r difficulty pres5ts itself because ! life ( ! ent]prise is usually unkn[n1 & !re=e a manife/ necessity arises = an economic balance ( capital outlay & ( op]at+ effici5cy comm5surate ) ! prospects ( ! m9e4 ,moreov]1 ! initial capital is (t5 limit$1 & make%ifts = ?is reason alone mu/ be provid$4 ,9 net result1 no m9]al deposit ( speculative ultimate volume ( ore w>rants an initial equipm5t ( ! sort t w meet e ev5tuality1 or ( ! k9d t w give ev5 ! maximum effici5cy :i* a free *oice ( m9+ ma*9]y c\ld obta94 ,?ird4--,9 ! design & selection ( m9+ ma*9es1 ! safety ( human life1 ! pres]vation ( ! heal? ( workm5 "u conditions ( limit$ space & v5tilation1 toge!r ) reliability & conv5i5ce 9 in/all+ & work+ l>ge me*anical tools1 all dom9ate me*anical effici5cy4 ,= example1 compress$-air transmission ( p[] be/ meets ! requirem5ts ( drill+1 yet ! me*anical losses 9 ! g5]ation1 ! transmission1 & ! application ( compress$ air probably total1 f fir/ to la/1 #gj to #he4 ,f\r?4--,all ma*9es1 except ^? = %aft haulage1 mu/ be op]at$ by p[] transmitt$ f ! surface1 z obvi\sly p[] g5]ation und]gr\nd is impossible4 ,! conv]sion ( p[] into a transmission m$ium & its transmission are1 at ! outset1 b\nd to be ! occasions ( loss4 ,n only are ! v>i\s =ms ( transmission by /eam1 electricity1 compress$ air1 or rods1 ( diff]5t effici5cy1 b no "o sy/em l5ds itself to univ]sal or economical application to all k9ds ( m9+ ma*9es4 ,!re=e x is n uncommon to f9d ?ree or f\r diff]5t m$ia ( p[] transmission employ$ on ! same m9e4 ,to illu/rate3 f ! po9t ( view ( safety1 reliability1 control1 & 9 mo/ cases economy z well1 we may say t direct /eam is ! be/ motive =ce = w9d+-eng9es2 t = me*anical effici5cy & reliability1 rods con/itute ! be/ m$ia ( p[] transmission to pumps2 t1 consid]+ v5tilation & conv5i5ce1 compress$ air af=ds ! be/ m$ium = drills4 ,yet !re are o!r conditions z to "* ( ! "w1 volume ( wat] or ore1 & ! orig9 ( p[] :i* mu/ 9 special in/ances modify ea* & e "o ( ^! g5]alizations4 ,= example1 al?\gh pump+ wat] ) compress$ air is me*anically ! mo/ ineffici5t ( devices1 x (t5 becomes ! mo/ advantage\s1 because compress$ air may be ( necessity laid on = o!r purposes1 & ! extra p[] requir$ to op]ate a small pump may be ?us mo/ *eaply provid$4 ,fif?4--,fur!r limitations & modifications arise out ( ! orig9 ( p[]1 = ! s\rces ( p[] h an intimate be>+ on ! type ( ma*9e & m$ia ( transmission4 ,?is v circum/ance (t5 compels giv+ away effici5cy & conv5i5ce 9 "s ma*9es to ga9 m 9 o!rs4 ,?is is evid5t en\gh if ! pr9cipal orig9s ( p[] g5]ation be exam9$4 ,!y are 9 ! ma9 z foll[s3-- a4 ,wat]-p[] available at ! m9e4 b4 ,wat]-p[] available at a less di/ance ?an ?ree or f\r miles4 c4 ,wat]-p[] available "s miles away1 ?us necessitat+ electrical transmission 7or pur*as$ electrical p[]74 d4 ,/eam-p[] to be g5]at$ at ! m9e4 e4 ,gas-p[] to be g5]at$ at ! m9e4 a4 ,) wat]-p[] at ! m9e1 w9d+ eng9es c be op]at$ by direct hydraulic application ) a ga9 9 economy ov] direct /eam1 al?\gh ) ! sacrifice ( control & reliability4 ,rods = pumps c be driv5 directly ) wat]1 b ?is sup]iority 9 work+ economy means1 z discuss$ lat]1 a loss ( flexibility & increas$ total outlay ov] o!r =ms ( transmission to pumps4 ,z compress$ air mu/ be transmitt$ = drills1 ! compressor w\ld be op]at$ direct f wat]-:eels1 b ) less control 9 regul>ity ( pressure deliv]y4 b4 ,) wat]-p[] a %ort di/ance f ! m9e1 x w\ld normally be transmitt$ ei!r by compress$ air or by electricity4 ,compress$-air transmission w\ld bett] satisfy w9d+ & drill+ requirem5ts1 b w\ld %[ a great comp>ative loss 9 effici5cy ov] electricity :5 appli$ to pump+4 ,despite ! latt] drawback1 air transmission is a me?od gr[+ 9 favor1 especially 9 view ( ! advance made 9 effect+ compression by fall+ wat]4 c4 ,9 ! situation ( transmission too f> = us+ compress$ air1 !re is no alt]native b electricity4 ,9 ^! cases1 direct electric w9d+ is done1 b "u su* disadvantages t x requires a comp>atively v *eap p[] to take prec$5ce ov] a subsidi>y /eam plant = ?is purpose4 ,electric air-compressors "w "u ! mat]ial disadvantage ( con/ant spe$ on a v>iable load1 b ?is in/allation is also a "q ( economics4 ,! pump+ s]vice is well p]=m$ by direct electrical pumps4 d4 ,9 ?is in/ance1 w9d+ & air-compression are well accompli%$ by direct /eam applications2 b pump+ is beset ) :olly undesirable alt]natives1 among :i* x is difficult to *oose4 e4 ,) int]nal combu/ion eng9es1 gasol9e 7petrol7 motors h m ( a position 9 exp]im5tal ?an 9 sy/ematic m9+1 = _! application to w9d+ & pump+ & drill+ is fraught ) _m losses4 ,! eng9e mu/ be "u con/ant motion1 & t1 too1 ) v>iable loads4 ,:]e p[] f produc] gas is us$1 !re is a great] possibility ( in/all+ l>ge equipm5ts1 & x is g5]ally appli$ to ! w9d+ & less] units by conv]sion into compress$ air or electricity z an int]m$iate /age4 ,"o ?+ becomes c]ta9 f ^! examples cit$1 t ! "r in/allation = any p>ticul> portion ( ! m9e's equipm5t _c be det]m9$ )\t ref]5ce to all ! o!rs4 ,! :ole sy/em ( p[] g5]ation = surface "w1 z well z ! transmission und]gr\nd1 mu/ be =mulat$ ) reg>d to furni%+ ! be/ total result f all ! complicat$ prim>y & second>y motors1 ev5 at ! sacrifice ( "s memb]s4 ,ea* m9e is a unique problem1 & :ile x w\ld be easy to sket* an ideal plant1 !re is no m9e )9 ! writ]'s k ^u :i* ! ideal w\ld1 "u ! _m v>iable conditions1 be ! mo/ economical ( in/allation or ! mo/ effici5t ( op]ation4 ,! dom9ant feature ( ! task is an endeavor to f9d a compromise betwe5 effici5cy & capital outlay4 ,! result is a s]ies ( *oices betwe5 unsatisfy+ alt]natives1 a numb] ( :i* are usually f\nd to h be5 wrong ^u fur!r ext5sion ( ! m9e 9 dep?4 ,9 a g5]al way1 x may be /at$ t :]e p[] is g5]at$ on ! m9e1 economy 9 labor ( h&l+ fuel1 driv+ eng9es1 g5]ation & cond5s+ /eam :]e /eam is us$1 dem& a consolidat$ p[] plant = ! :ole m9e equipm5t4 ,! pr9cipal motors %\ld be driv5 direct by /eam or gas1 ) p[] di/ribution by electricity to all outly+ surface motors & sometimes to und]gr\nd motors1 & also to "s und]gr\nd motors by compress$ air4 ,mu* progress has be5 made 9 ! pa/ few ye>s 9 ! p]fection ( l>g] m9+ tools4 ,inh]5tly _m ( our devices are ( a wa/eful "*1 n only on acc\nt ( ! ne$ ( special =ms ( transmission1 b because !y are requir$ to op]ate "u greatly v>y+ loads4 ,z an outcome ( transmission losses & ( provid+ capacity to cope ) heavy peak loads1 _! effici5cy on ! basis ( actual foot-p\nds ( "w accompli%$ is v l[4 ,! adoption ( electric transmission 9 m9e "w1 :ile 9 c]ta9 phases b5eficial1 has n decreas$ ! p]plexity :i* arises f _m add$ alt]natives1 none ( :i* are z yet a complete or desirable answ] to any m9e problem4 ,:5 a satisfactory electric drill is inv5t$1 & a me?od is evolv$ ( apply+ electricity to w9d+-eng9es t w n involve su* abnormal losses due to high peak load !n we w h a solution to our mo/ difficult me*anical problems1 & electricity w des]ve ! univ]sal bless+ :i* x has receiv$ 9 o!r bran*es ( me*anical eng9e]+4 ,x is n int5d$ to discuss m9e equipm5t problems f ! ma*9]y /&po9t1--!re are ?\s&s ( diff]5t devices1--b f ! po9t ( view ( ! m9e adm9i/rator :o f9ds 9 ! manufactory ! v>i\s ma*9es :i* are applicable1 & ^: "w !n becomes t ( *oos+1 arrang+1 & op]at+ ^! tools4 ,! pr9cipal me*anical que/ions ( a m9e may be exam9$ "u ! foll[+ heads3-- #a4 ,%aft haulage4 #b4 ,lat]al und]gr\nd transport4 #c4 ,dra9age4 #d4 ,rock drill+4 #e4 ,work%ops4 #f4 ,improvem5ts 9 equipm5t4 ,,%aft ,,haulage4 ,,w9d+ ,,appliances4--,no device has yet be5 f\nd to displace ! s+le load pull$ up ! %aft by w9d+ a rope on a drum4 ,( driv+ me*anisms = drum motors ! alt]natives are ! /eam-eng9e1 ! electrical motor1 & infrequ5tly wat]-p[] or gas eng9es4 ,all ^! h to cope ) "o condition :i*1 on ! basis ( "w accompli%$1 gives !m a v l[ me*anical effici5cy4 ,?is difficulty is t ! load is int]mitt5t1 & x mu/ be />t$ & accel]at$ at ! po9t ( maximum weight1 & f t mom5t ! p[] requir$ dim9i%es to less ?an no?+ at ! end ( ! haul4 ,a l>ge numb] ( devices are 9 use to equalize p>tially ! inequalities ( ! load at diff]5t /ages ( ! lift4 ,! ma9 l9es ( progress 9 ?is direction h be53-- a4 ,! h&l+ ( two cages or skips ) "o eng9e or motor1 ! desc5d+ skip p>tially balanc+ ! asc5d+ "o4 b4 ,! use ( tail-ropes or balance weights to comp5sate ! increas+ weight ( ! desc5d+ rope4 c4 ,! use ( skips in/ead ( cages1 ?us p]mitt+ ( a great] p]c5tage ( pay+ load4 d4 ,! direct c\pl+ ( ! motor to ! drum %aft4 e4 ,! cone-%ap$ con/ruction ( drums1--?is latt] be+ n[ l>gely displac$ by ! use ( ! tail-rope4 ,! fir/ & ?ird ( ^! are absolutely ess5tial = any?+ l economy & spe$2 ! o!rs are ref9em5ts dep5d+ on ! "w to be accompli%$ & ! capital available4 ,/eam w9d+-eng9es require l>ge cyl9d]s to />t ! load1 b :5 once />t$ ! requisite p[] is mu* r$uc$ & ! load is too small = /eam economy4 ,! ?rottl+ ( ! eng9e = controll+ spe$ & rev]s+ ! eng9e at p]iodic /oppages militates aga9/ ! maximum expansion & cond5sation ( ! /eam & fur!r increases ! /eam consumption4 ,9 result1 ! be/ ( direct comp\nd cond5s+ eng9es consume f #fj to #ajj p\nds ( /eam p] horse-p[] h\r1 aga9/ a possible effici5cy ( su* an eng9e work+ "u con/ant load ( less ?an #af p\nds ( /eam p] horse-p[] h\r4 ,x is only )9 v rec5t ye>s t electrical motors h be5 appli$ to w9d+4 ,ev5 yet1 all ?+s consid]$1 ?is application is ( d\btful value except 9 localities ( extremely *eap electrical p[]4 ,! con/ant spe$ ( alt]nat+ curr5t motors at once places !m at a disadvantage = ?is "w ( high peak & int]mitt5t loads4 ,:ile cont9u\s-curr5t motors c be made to p>tially ov]come ?is drawback1 su* a curr5t1 :]e p[] is pur*as$ or transmitt$ a long di/ance1 is available only by conv]sion1 :i* fur!r increases ! losses4 ,h[ev]1 s*emes ( electrical w9d+ are 9 c\rse ( developm5t :i* bid fair1 by a sort ( /orage ( p[] 9 heavy fly-:eels or /orage batt]ies aft] ! peak load1 to r$uce ! total p[] consumption2 b ! v high fir/ co/ s f> prev5ts _! v g5]al adoption = metal m9+4 ,w9d+-eng9es driv5 by direct wat]- or gas-p[] are ( too r>e application to w>rant mu* discussion4 ,gasol9e driv5 hoi/s h a di/9ct place 9 prospect+ & e>ly-/age m9+1 especially 9 des]t c\ntries :]e transport & fuel conditions are on]\s1 = bo? ! ma*9es & _! fuel are easy ( transport4 ,z direct gas-eng9es entail con/ant motion ( ! eng9e at ! p[] dem& ( ! peak load1 !y are hopeless 9 me*anical effici5cy4 ,l all o!r motors 9 m9+1 ! size & arrangem5t ( ! motor & drum are dep5d5t ^u ! duty :i* !y w be call$ ^u to p]=m4 ,?is is prim>ily dep5d5t ^u ! dep? to be hoi/$ f1 ! volume ( ! ore1 & ! size ( ! load4 ,= %all[ dep?s & tonnages up to1 say1 #bjj tons daily1 ge>$ eng9es h a place on acc\nt ( _! l[ capital co/4 ,:]e great rope spe$ is n ess5tial !y are fully z economical z direct-c\pl$ eng9es4 ,) great dep?s & great] capacities1 spe$ becomes a mom5t\s factor1 & direct-c\pl$ eng9es are necess>y4 ,:]e ! dep? exce$s #c1jjj feet1 ano!r elem5t ent]s :i* has giv5 rise to mu* debate & exp]im5t2 t is1 ! great increase ( />t+ load due to ! increas$ l5g? & size ( ropes & ! drum space requir$ to hold x4 ,s f> ! mo/ advantage\s device seems to be ! ,:it+ hoi/1 a comb9ation ( d\ble drums & tail rope4 ,on m9es work$ f ne> ! surface1 :]e dep? is ga9$ by ! gradual exhau/ion ( ! ore1 ! only prud5t c\rse is to put 9 a new hoi/ p]iodically1 :5 ! dem& = increas$ w9d+ spe$ & p[] w>rants4 ,! lack ( economy 9 w9d+ ma*9es is greatly augm5t$ if !y are mu* ov]-siz$ = ! duty4 ,an eng9e in/all$ to h&le a giv5 tonnage to a dep? ( #c1jjj feet w h op]at$ ) m loss dur+ ! ye>s ! m9e is progress+ f ! surface to t dep? ?an sev]al int]m$iate-siz$ eng9es w\ld h co/4 ,on mo/ m9es ! unc]ta9ty ( ext5sion 9 dep? w\ld h>dly w>rant su* a prelim9>y equipm5t4 ,m m9es are equipp$ ) ov]-siz$ ?an ) "u-siz$ eng9es4 ,= %afts on go+ metal m9es :]e ! future is speculative1 an eng9e w suffice ^: size provides = an ext5sion 9 dep? ( #a1jjj feet beyond t rea*$ at ! "t ( its in/allation4 ,! co/ ( ! eng9e w dep5d m l>gely ^u ! w9d+ spe$ desir$ ?an ^u any o!r "o factor4 ,! prop] spe$ to be arrang$ is obvi\sly dep5d5t ^u ! dep? ( ! haulage1 = x is useless to h an eng9e able to w9d #c1jjj feet a m9ute on a %aft #ejj feet deep1 s9ce x c\ld nev] ev5 get "u way2 & besides1 ! relative op]at+ loss1 z said1 w\ld be enorm\s4 ,,haulage ,,equipm5t ,,9 ,,! ,,%aft4--,orig9ally1 mat]ial 0 hoi/$ ?r\gh %afts 9 buckets4 ,!n came ! cage = transport+ m9e c>s1 & 9 m rec5t ye>s ! skip has be5 develop$4 ,! aggr&iz$ bucket or kibble ( ! ,corni%man has practically disappe>$1 b ! cage /ill rema9s 9 _m m9es4 ,! advantages ( ! skip ov] ! cage are _m4 ,"s ( !m are3-- a4 ,x p]mits #be to #dj great] load ( mat]ial 9 proportion to ! dead weight ( ! vehicle4 b4 ,! load c be conf9$ )9 a small] horizontal space1 ?us ! area ( ! %aft ne$ n be s great = l>ge tonnages4 c4 ,load+ & dis*>g+ are m rapid1 & ! latt] is automatic1 ?us p]mitt+ m trips p] h\r & requir+ less labor4 d4 ,skips mu/ be load$ f b9s und]gr\nd1 & by provid+ 9 ! b9s /orage capacity1 %aft haulage is r5d]$ indep5d5t ( ! lat]al transport 9 ! m9e1 & !re are no delays to ! eng9e await+ loads4 ,! result is t ore-w9d+ c be conc5trat$ into few] h\rs1 & indirect economies 9 labor & p[] are ?us effect$4 e4 ,skips save ! "t ( ! m5 engag$ 9 ! lat]al haulage1 z !y h no delay wait+ = ! w9d+ eng9e4 ,loads equival5t to ^? f skips are obta9$ 9 "s m9es by d\ble-deck$ cages2 b1 aside f wa/e weight ( ! cage1 ?is arrangem5t necessitates ei!r /opp+ ! eng9e to load ! l[] deck1 or a d\ble-deck load+ /ation4 ,d\ble-deck load+ /ations are z co/ly to in/all & m exp5sive to "w ?an skip-load+ /ation ore-b9s4 ,cages are also con/ruct$ l>ge en\gh to take z _m z f\r trucks on "o deck4 ,?is entails a %aft comp>tm5t d\ble ! size requir$ = skips ( ! same capacity1 & ?us enorm\sly increases %aft co/ )\t ga9+ any?+4 ,altoge!r ! advantages ( ! skip are s c]ta9 & s important t x is difficult to see ! ju/ification = ! cage "u b a few conditions4 ,^! conditions are ^? :i* surr\nd m9es ( small output :]e rapidity ( haulage is no object1 :]e ! co/ ( /ation-b9s c ?us be evad$1 & ! conv5i5ce ( ! cage = ! m5 c /ill be pres]v$4 ,! easy *ange ( ! skip to ! cage = haul+ m5 removes ! la/ objection on l>g] m9es4 ,!re occurs also ! situation 9 :i* ore is brok5 "u contract at s mu* p] truck1 & :]e x is desirable to inspect ! cont5ts ( ! truck :5 dis*>g+ x1 b ev5 ?is objection to ! skip c be obviat$ by contract+ on a cubic-foot basis4 ,skips are con/ruct$ to c>ry loads ( f two to sev5 tons1 ! g5]al t5d5cy be+ t[>d l>g] loads e ye>4 ,"o ( ! mo/ feasible l9es ( improvem5t 9 w9d+ is 9 ! direction ( l>g] loads & less spe$1 = 9 ?is way ! sum total ( dead weight ( ! vehicle & rope to ! tonnage ( ore haul$ w be decreas$1 & ! effici5cy ( ! eng9e w be increas$ by a less high peak dem&1 because ( ?is less proportion ( dead weight & ! less ne$ ( high accel]ation4 ,,lat]al ,,und]gr\nd ,,transport4 ,inasmu* z ! majority ( metal m9es dip at consid]able angles1 ! useful life ( a roadway 9 a metal m9e is v %ort because p>ticul> horizons ( ore are soon exhau/$4 ,!re=e any me?od ( transport has to be calculat$ ^u a v quick r$emption ( ! capital laid out4 ,fur!rmore1 a roadway is limit$ 9 its daily traffic to ! product ( ! /opes :i* x s]ves4 ,,m5 ,,& ,,animals4--,"s means ( transport mu/ be provid$1 & ! basic equipm5t is light tracks ) pu%-c>s1 9 capacity f half a ton to a ton4 ,! latt] load is1 h[ev]1 too heavy to be pu%$ by "o man4 ,z b "o c> c be pu%$ at a "t1 h&-truck+ is bo? sl[ & exp5sive4 ,at av]age ,am]ican or ,au/ralian wages1 ! co/ works out betwe5 #be & #ce c5ts a ton p] mile4 ,an improvem5t ( gr[+ import :]e h&-truck+ is necess>y is ! ov]head mono-rail in/ead ( ! track4 ,if ! supply to any p>ticul> roadway is su* z to fully employ horses or mules1 ! numb] ( c>s p] trip c be increas$ up to sev5 or eight4 ,9 ?is case ! exp5se1 includ+ wages ( ! m5 & we>1 te>1 & c>e ( mules1 w "w out r\ghly at f #g to #aj c5ts p] ton mile4 ,manife/ly1 if ! ore-supply to a p>ticul> roadway is insuffici5t to keep a mule busy1 ! economy soon runs (f4 ,,me*anical ,,haulage4--,me*anical haulage is seldom applicable to metal m9es1 = mo/ metal deposits dip at consid]able angles1 & !re=e1 unlike mo/ coal-m9es1 ! horizon ( haulage mu/ frequ5tly *ange1 & !re are no ma9 art]ies along :i* haulage cont9ues ?r\gh ! life ( ! m9e4 ,any me*anical sy/em entails a good deal ( exp5se = in/allation1 & ! useful life ( any p>ticul> roadway1 z above said1 is v %ort4 ,moreov]1 ! crook$ roadways ( mo/ metal m9es pres5t difficulties ( negotiation n to be ov]look$4 ,9 ord] to use su* sy/ems x is necess>y to cond5se ! haulage to z few roadways z possible4 ,:]e ! tonnage on "o level is n suffici5t to w>rant o!r ?an m5 or animals1 x sometimes pays 7if ! dip is /eep en\gh7 to dump ev]y?+ ?r\gh w9zes f "o to two levels to a ma9 road bel[ :]e me*anical equipm5t c be advantage\sly provid$4 ,! co/ ( %aft-w9d+ ! extra dep? is inconsid]able comp>$ to o!r factors1 = ! extra v]tical di/ance ( haulage c be done at a co/ ( "o or two c5ts p] ton mile4 ,moreov]1 f su* an arrangem5t foll[s ! conc5tration ( %aft-b9s1 & ( %aft labor1 & w9d+ is accompli%$ )\t s mu* %ift+ z to horizon1 all ( :i* economies equalize ! extra di/ance ( ! lift4 ,!re are ?ree pr9cipal me?ods ( me*anical transport 9 use3-- #a4 ,cable-ways4 #b4 ,compress$-air locomotives4 #c4 ,electrical haulage4 ,cable-ways or endless ropes are exp5sive to in/all1 & to "w to ! be/ advantage require d\ble tracks & fairly /raight roads4 ,:ile !y are economical 9 op]ation & "w ) little dang] to op]atives1 ! limitations m5tion$ preclude !m f adoption 9 metal m9es1 except 9 v special circum/ances su* z ma9 crosscuts or adit tunnels1 :]e ! haulage is /raight & conc5trat$ f _m s\rces ( supply4 ,compress$-air locomotives are some:at heavy & cumb]some1 & !re=e require well-built tracks ) heavy rails1 b !y h v great advantages = metal m9e "w4 ,!y ne$ b a s+le track & are ( l[ initial co/ :]e compress$ air is already a requirem5t ( ! m9e4 ,no subsidi>y l9e equipm5t is ne$$1 & ?us !y are free to trav]se any road 9 ! m9e & c be readily %ift$ f "o level to ano!r4 ,_! me*anical effici5cy is n s l[ 9 ! long run z might appe> f ! l[ effici5cy ( pneumatic ma*9es g5]ally1 = by /orage ( compress$ air at ! *>g+ /ation a m ev5 rate ( en]gy consumption is possible ?an 9 ! con/ant cable & electrical p[] supply :i* mu/ be equal to ! maximum dem&1 :ile ! air-plant consumes b ! av]age dem&4 ,electrical haulage has ! advantage ( a mu* m compact locomotive & ! drawback ( m exp5sive track equipm5t1 due to ! necessity ( transmission wire1 etc4 ,x has ! fur!r disadvantages ( uselessness outside ! equipp$ haulage way & ( ! dang]s ( ! live wire 9 l[ & (t5 wet tunnels4 ,9 g5]al1 compress$-air locomotives possess _m attractions = metal m9e "w1 :]e air is 9 use 9 any ev5t & :]e any me*anical sy/em is at all ju/ifi$4 ,any ( ! me*anical sy/ems :]e tonnage is suffici5t 9 quantity to ju/ify _! employm5t w h&le mat]ial = f #a4e to #d c5ts p] ton mile4 ,,tracks4--,tracks = h&1 mule1 or rope haulage are usually built ) f #ab- to #af-p\nd rails1 b :5 compress$-air or electrical locomotives are to be us$1 less ?an #bd-p\nd rails are impossible4 ,z to tracks 9 g5]al1 x may be said t c>eful lay+ out ) ev5 grades & g5tle curves repays itself _m times ov] 9 _! subsequ5t op]ation4 ,fur!r c>e 9 repair & lubrication ( c>s w (t5 make a diff]5ce ( #ge 9 ! track resi/ance4 ,,transport ,,9 ,,/opes4--,ow+ to ! ev5 %ort] life ( individual /opes ?an levels1 ! actual transport ( ore or wa/e 9 !m is (t5 a function ( ! aborig9al %ovel plus gravity4 ,z %ovel+ is ! mo/ co/ly sy/em ( transport kn[n1 any means ( /op+ t decreases ! ne$ = x has m]it4 ,%r9kage-/op+ elim9ates x altoge!r4 ,9 ! o!r me?ods1 gravity helps 9 proportion to ! /eepness ( ! dip4 ,:5 ! und]lie becomes too flat = ! ore to run1 transport c sometimes be help$ by pit*+ ! ore-passes at a /eep] angle ?an ! dip 7,fig4 #cf74 ,9 "s cases ( flat deposits1 crosscuts into ! walls1 or ev5 levels "u ! ore-body1 are ju/ifiable4 ,! m num]\s ! ore-passes1 ! less ! lat]al %ovel+1 b z passes co/ money = con/ruction & = repair1 !re is a nice economic balance 9 _! frequ5cy4 ,me*anical haulage 9 /opes has be5 tri$ & f9ds a field "u "s conditions4 ,9 dips "u #be & possess+ fairly s\nd hang+-wall1 :]e long-wall or flat-back cuts are employ$1 tempor>y tracks c (t5 be laid 9 ! /opes & ! ore run 9 c>s to ! ma9 passes4 ,9 su* cases1 ! tracks are pu%$ up close to ! face aft] ea* cut4 ,fur!r self-act+ incl9es to l[] c>s to ! levels c sometimes be in/all$ to advantage4 ,?is arrangem5t also p]mits great] int]vals betwe5 levels & less numb] ( ore-passes4 ,= dips betwe5 #be & #ej :]e ! m9e is work$ )\t /ope support or ) occasional pill>s1 a v useful contrivance is ! %eet-iron tr\gh--ab\t eighte5 in*es wide & six in*es deep--made 9 sections t5 or twelve feet long & readily bolt$ toge!r4 ,9 dips #ce to #ej ?is tr\gh1 laid on ! foot-wall1 gives a suffici5tly smoo? surface = ! ore to run ^u4 ,:5 ! dip is flat1 ! tr\gh1 if hung f plugs 9 ! hang+-wall1 may be swung backw>d & =w>d4 ,! use ( ?is bump+-tr\gh saves mu* %ovel+4 ,= h&l+ fill+ or ore 9 flat runs x des]ves wid] adoption4 ,x is1 ( c\rse1 inapplicable 9 passes z a bump+-tr\gh1 b c be fix$ to give smoo? surface4 ,9 flat m9es x p]mits a wid] int]val betwe5 levels & !re=e saves developm5t "w4 ,! life ( ?is contrivance is %ort :5 us$ 9 op5 /opes1 ow+ to ! dang]s ( bomb>dm5t f bla/+4 ,9 dips /eep] ?an #ej mu* ( ! %ovel+ into passes c be sav$ by rill-/op+1 z describ$ on page #ajj4 ,:]e flat-back$ /opes are us$ 9 wide ore-bodies ) fill+1 tempor>y tracks laid on ! fill+ to ! ore-passes are useful1 = !y p]mit wid] int]vals betwe5 passes4 ,9 t und]gr\nd eng9e]'s p>adise1 ! ,witwat]sr&1 :]e ! /opes require nei!r timb] nor fill+1 ! long1 mod]ately pit*$ op5+s l5d !mselves p>ticul>ly to ! sw++ iron tr\ghs1 & ev5 endless wire ropes h be5 f\nd advantage\s 9 c]ta9 cases4 ,:]e ! ro( is heavy & close support is requir$1 & :]e ! deposits are v irregul> 9 %ape & dip1 !re is little hope ( me*anical assi/ance 9 /ope transport4 ,,*apt] ,,xiii4 ,me*anical ,equipm5t4 7,cont9u$74 ,,dra9age3 ,,controll+ ,,factors2 ,,volume ,,& ,,head ,,( ,,wat]2 ,,flexibility2 ,,reliability2 ,,p[] ,,conditions2 ,,me*anical ,,effici5cy2 ,,capital ,,outlay4 ,,sy/ems ,,( ,,dra9age1--,,/eam ,,pumps1 ,,compress$-,,air ,,pumps1 ,,electrical ,,pumps1 ,,rod-,,driv5 ,,pumps1 ,,bail+2 ,,comp>ative ,,value ,,( ,,v>i\s ,,sy/ems4 ,) ! exception ( dra9age tunnels--m fully describ$ 9 ,*apt] ,,viii--all dra9age mu/ be me*anical4 ,z ! bulk ( m9e wat] usually lies ne> ! surface1 sav+ 9 pump+ c sometimes be effect$ by leav+ a complete pill> ( ore "u "s ( ! upp] levels4 ,9 _m deposits1 h[ev]1 ! ore has too _m *annels to r5d] ?is ( mu* avail4 ,!re are six factors :i* ent] into a det]m9ation ( me*anical dra9age sy/ems = metal m9es3-- #a4 ,volume & head ( wat]4 #b4 ,flexibility to fluctuation 9 volume & head4 #c4 ,reliability4 #d4 ,capital co/4 #e4 ,! g5]al p[] conditions4 #f4 ,me*anical effici5cy4 ,9 ! dra9age appliances1 m ?an 9 any o!r feature ( ! equipm5t1 mu/ me*anical effici5cy be subord9at$ to ! o!r issues4 ,,flexibility4--,flexibility 9 plant is necess>y because volume & head ( wat] are fluctuat+ factors4 ,9 wet regions ! volume ( wat] usually increases = a c]ta9 di/ance ) ! ext5sion ( op5+s 9 dep?4 ,9 dry climates x g5]ally decreases ) ! d[nw>d ext5sion ( ! work+s aft] a c]ta9 dep?4 ,moreov]1 z dep? progresses1 ! wat] foll[s ! op5+s m or less & mu/ be pump$ aga9/ an ev] great] head4 ,9 mo/ cases ! volume v>ies ) ! seasons4 ,:at increase w occur1 f :at horizon x mu/ be lift$1 & :at ! fluctuations 9 volume are likely to be1 are all unkn[n at ! "t ( in/allation4 ,if a pump+ sy/em 7 to be laid out = a new m9e1 :i* w\ld p]adv5ture meet e possible cont+5cy1 ! capital outlay w\ld be enorm\s1 & ! op]at+ effici5cy w\ld be v l[ dur+ ! long p]iod 9 :i* x w\ld be work+ bel[ its capacity4 ,! "q ( flexibility does n arise s prom95tly 9 coal-m9es1 = ! m or less flat deposits give a fix$ factor ( dep?4 ,! fl[ is also m /eady1 & ! volume c be 9 a measure approximat$ f g5]al exp]i5ce4 ,,reliability4--,! factor ( reliability 0 at "o "t ( m importance ?an 9 ^! days ( high-class manufacture ( _m diff]5t pump+ sy/ems4 ,practically speak+1 ! only insurance f flood+ 9 any ev5t lies 9 ! provision ( a relief sy/em ( "s sort1--duplicate pumps1 or ! simple/ & mo/ usual ?+1 bail+ tanks4 ,only ,corni% & compress$-air pumps w "w ) any security :5 dr[n$1 & electrical pumps are easily ru9$4 ,,g5]al ,,p[] ,,conditions4--,! "q ( pump+ in/allation is mu* dep5d5t ^u ! p[] in/allation & o!r p[] requirem5ts ( ! m9e4 ,= in/ance1 :]e electrical p[] is pur*as$ or g5]at$ by wat]-p[]1 !n electrical pumps h e advantage4 ,or :]e a l>ge numb] ( subsidi>y motors c be economically driv5 f "o c5tral /eam- or gas-driv5 electrical g5]ation plant1 !y aga9 h a /rong call1--especially if ! am\nt ( wat] to be h&l$ is mod]ate4 ,:]e ! wat] is ( limit$ volume & compress$-air plant a necessity = ! m9e1 !n air-driv5 pumps may be ! mo/ advantage\s1 etc4 ,,me*anical ,,effici5cy4--,! me*anical effici5cy ( dra9age ma*9]y is v l>gely a "q ( me?od ( p[] application4 ,! actual pump c be built to almo/ ! same effici5cy = any p[] application1 & ) ! exception ( ! limit$ field ( bail+ ) tanks1 me*anical dra9age is a matt] ( pumps4 ,all pumps mu/ be set bel[ _! load1 b>r+ a few possible feet ( suction lift1 & !y are !re=e p]=ce und]gr\nd1 & 9 consequ5ce all p[] mu/ be transmitt$ f ! surface4 ,transmission itself means loss ( p[] v>y+ f #aj to #fj1 dep5d+ ^u ! m$ium us$4 ,x is !re=e ! *oice ( transmission m$ium t l>gely gov]ns ! me*anical effici5cy4 ,,sy/ems ,,( ,,dra9age4--,! ideal pump+ sy/em = metal m9es w\ld be "o :i* c\ld be built 9 units & c\ld be exp&$ or contract$ unit by unit ) ! fluctuation 9 volume2 :i* c\ld also be easily mov$ to meet ! diff]5ces ( lifts2 & 9 :i* ea* indep5d5t unit c\ld be ( ! highe/ me*anical effici5cy & w\ld require b little space = erection4 ,su* an ideal is unobta9able among any ( ! appliances ) :i* ! writ] is famili>4 ,! wide v>iations 9 ! orig9 ( p[]1 9 ! =m ( transmission1 & 9 ! me?od ( f9al application1 & ! _m comb9ations ( ^! factors1 meet ! dem&s = flexibility1 effici5cy1 capital co/1 & reliability 9 v>i\s degrees dep5d+ ^u ! environm5t ( ! m9e4 ,p[] n[adays is g5]at$ prim>ily ) /eam1 wat]1 & gas4 ,^! orig9s admit ! transmission ( p[] to ! pumps by direct /eam1 compress$ air1 electricity1 rods1 or hydraulic columns4 ,,direct ,,/eam-,,pumps4--,direct /eam has ! disadvantage ( radiat$ heat 9 ! work+s1 ( loss by ! radiation1 &1 worse /ill1 ( ! impracticability ( plac+ & op]at+ a highly effici5t /eam-eng9e und]gr\nd4 ,x is all b impossible to d]ive b5efit f ! vacuum1 z any =m ( surface cond5s] "h is impossible1 & !re c be no return ( ! hot s(t wat] to ! boil]s4 ,/eam-pumps fall into two classes1 rot>y & direct-act+2 ! =m] h ! great advantage ( p]mitt+ ! use ( /eam expansively & af=d+ "s field = effective use ( cond5sation1 b !y are m co/ly1 require mu* room1 & are n fool-pro(4 ,! direct-act+ pumps h all ! advantage ( compactness & ! disadvantage ( be+ ! mo/ ineffici5t ( pump+ ma*9es us$ 9 m9+4 ,tak+ ! /eam consumption ( a good surface /eam plant at #ae p\nds p] horse-p[] h\r1 ! effici5cy ( rot>y pumps ) well-insulat$ pipes is probably n ov] #ej1 & ( direct-act+ pumps f #dj d[n to #aj4 ,! advantage ( all /eam-pumps lies 9 ! l[ capital outlay1--h5ce _! conv5i5t application to exp]im5tal m9+ & tempor>y pump+ requirem5ts4 ,= f9al equipm5t !y af=d a great deal ( flexibility1 = if prop]ly con/ruct$ !y c be1 ) slight alt]ation1 mov$ f "o horizon to ano!r )\t loss ( relative effici5cy4 ,?us ! sy/em c be re>rang$ = an increas$ volume ( wat]1 by decreas+ ! lift & increas+ ! numb] ( pumps f diff]5t horizons4 ,,compress$-,,air ,,pumps4--,compress$-air transmission has an application simil> to direct /eam1 b x is ( /ill l[] me*anical effici5cy1 because ( ! great loss 9 compression4 ,x has ! sup]iority ( n heat+ ! work+s1 & !re is no difficulty z to ! disposal ( ! exhau/1 z ) /eam4 ,moreov]1 su* pumps w "w :5 dr[n$4 ,compress$ air has a di/9ct place = m9or pump+ units1 especially ^? remov$ f ! %aft1 = !y c be run z an adjunct to ! air-drill sy/em ( ! m9e1 & by ?is arrangem5t mu* capital outlay may be sav$4 ,! co/ ( ! extra p[] consum$ by su* an arrangem5t is less ?an ! av]age co/ ( compress$-air p[]1 because _m ( ! compressor *>ges h to be paid anyway4 ,:5 compress$ air is wat]-g5]at$1 !y h a field = p]man5t in/allations4 ,! effici5cy ( ev5 rot>y air-driv5 pumps1 bas$ on p[] deliv]$ into a good compressor1 is probably n ov] #be4 ,,electrical ,,pumps4--,electrical pumps h some:at less flexibility ?an /eam- or air-driv5 app>atus1 9 t ! spe$ ( ! pumps c be v>i$ only )9 small limits4 ,!y h ! same great advantage 9 ! easy reorganization ( ! sy/em to alt]$ conditions ( wat]-fl[4 ,electricity1 :5 /eam-g5]at$1 has ! h&icap ( ! losses ( two conv]sions1 ! actual pump effici5cy be+ ab\t #fj 9 well-con/ruct$ plants2 ! effici5cy is !re=e great] ?an direct /eam or compress$ air4 ,:]e ! m9e is op]at$ ) wat]-p[]1 pur*as$ electric curr5t1 or :]e !re is an in/allation ( electrical g5]at+ plant by /eam or gas = o!r purposes1 electrically driv5 pumps take prec$5ce ov] all o!rs on acc\nt ( _! comb9$ mod]ate capital outlay1 great flexibility1 & reasonable effici5cy4 ,9 late ye>s1 direct-c\pl$1 electric-driv5 c5trifugal pumps h ent]$ ! m9+ field1 b _! effici5cy1 despite mak]s' claims1 is l[4 ,:ile !y %[ comp>atively good results on l[ lifts ! slip increases ) ! lift4 ,9 heads ov] #bjj feet _! effici5cy is probably n #cj ( ! p[] deliv]$ to ! electrical g5]ator4 ,_! *ief attractions are small capital co/ & ! compact size :i* admits ( easy in/allation4 ,,rod-,,driv5 ,,pumps4--,pumps ( ! ,corni% type 9 v]tical %afts1 if op]at$ to full load & if driv5 by mod]n eng9es1 h an effici5cy mu* high] ?an any o!r sort ( in/allation1 & records ( #he to #ij are n unusual4 ,! highe/ effici5cy 9 ^! pumps yet obta9$ has be5 by driv+ ! pump ) rope transmission f a high-spe$ triple expansion eng9e1 & 9 ?is plant an actual consumption ( only #ag p\nds ( /eam p] horse-p[] h\r = actual wat] lift$ has be5 accompli%$4 ,to provide1 h[ev]1 = increase ( fl[ & *ange ( horizon1 rod-driv5 pumps mu/ be s ov]p[]$ at ! e>li] /age ( ! m9e t !y op]ate ) great loss4 ,( all pump+ sy/ems !y are ! mo/ exp5sive to provide4 ,!y h no place 9 crook$ op5+s & only "w 9 incl9es ) _m disadvantages4 ,9 g5]al _! lack ( flexibility is fa/ putt+ !m out ( ! metal m9]'s purview4 ,:]e ! pump+ dep? & volume ( wat] are approximately kn[n1 z is (t5 ! case 9 coal m9es1 ?is1 ! fa!r ( all pumps1 /ill holds its own4 ,,hydraulic ,,pumps4--,hydraulic pumps1 9 :i* a column ( wat] is us$ z ! transmission fluid f a surface pump to a correspond+ pump und]gr\nd has _h "s adoption 9 coal m9es1 b little 9 metal m9es4 ,!y h a c]ta9 am\nt ( flexibility b l[ effici5cy1 & are n likely to h mu* field aga9/ electrical pumps4 ,,bail+4--,bail+ des]ves to be m5tion$ among dra9age me?ods1 = "u c]ta9 conditions x is a mo/ useful sy/em1 & at all times a m9e %\ld be equipp$ ) tanks aga9/ accid5t to ! pumps4 ,:]e ! am\nt ( wat] is limit$1--up to1 say1 #ej1jjj gallons daily1--& :]e ! ore output ( ! m9e p]mits ! use ( ! w9d+-eng9e = "p ( ! "t on wat] haulage1 !re is 9 ! me?od an almo/ total sav+ ( capital outlay4 ,inasmu* z ! w9d+-eng9e1 ev5 :5 ! ore haulage is f9i%$ = ! day1 mu/ be "u /eam = h&l+ m5 9 em]g5cies1 & z ! labor ( /ok]s1 eng9e-driv]s1 %aft-m51 etc41 is !re=e necess>y1 ! co/ ( p[] consum$ by bail+ is n great1 despite ! l[ effici5cy ( w9d+-eng9es4 ,,comp>ison ,,( ,,v>i\s ,,sy/ems4--,if x is assum$ t flexibility1 reliability1 me*anical effici5cy1 & capital co/ c ea* be divid$ into f\r figures ( relative importance1--,a1 ,b1 ,c1 & ,d1 ) ,a repres5t+ ! mo/ desirable result1--x is possible to indicate r\ghly ! comp>ative values ( v>i\s pump+ sy/ems4 ,x is n pret5d$ t ! f\r degrees are ( equal import4 ,9 all cases ! factor ( g5]al p[] conditions on ! m9e may alt] ! relative positions4 ,direct,compress$ ,/eam- ,/eam ,air ,electricity,driv5,hydraulic,bail+ ,pumps ,rods ,columns ,tanks ---------------------------------------- ---------------------- ,flexibility4 ,a ,a ,b ,d ,b ,a ,reliability4 ,b ,b ,b ,a ,d ,a ,me*anical ,effici5cy4 ,c ,d ,b ,a ,c ,d ,capital ,co/ ,a ,b ,b ,d ,d -- ,z ea* m9e has its special environm5t1 x is impossible to =mulate any f9al conclusion on a subject s involv$4 ,! attempt w\ld lead to a discussion ( a ?\s& supposititi\s cases & hypo!tical rem$ies4 ,fur!r1 ! description alone ( pump+ ma*9es w\ld fill volumes1 & ! subject w nev] be exhau/$4 ,! eng9e] confront$ ) pump+ problems mu/ m>%al all ! alt]natives1 c\nt 8 money1 & apply ! te/s ( flexibility1 reliability1 effici5cy1 & co/1 *oose ! sy/em ( lea/ disadvantages1 & f9ally deprecate ! :ole affair1 = x is b a p>asite gr[? on ! m9e4 ,,*apt] ,,xiv4 ,me*anical ,equipm5t 7,conclud$74 ,,ma*9e ,,drill+3 ,,p[] ,,transmission2 ,,compress$ ,,air ,,vs4 ,,electricity2 ,,air ,,drills2 ,,ma*9e ,,vs4 ,,h& ,,drill+4 ,,"w-,,%ops4 ,,improvem5t ,,9 ,,equipm5t4 ,= ov] two hundr$ ye>s f ! introduction ( drill-holes = bla/+ by ,casp> ,we9del 9 ,hung>y1 to ! inv5tion ( ! fir/ practicable /eam p]cussion drill by ,j4 ,j4 ,cr\* ( ,philadelphia1 9 #ahdi1 all drill+ 0 done by h&4 ,s9ce ,cr\*'s "t a ho/ ( me*anical drills to be actuat$ by all sorts ( p[] h come =w>d1 & ev5 yet ! ma*9e-drill has n rea*$ a /age ( developm5t :]e x c displace h&-"w "u all conditions4 ,/eam-p[] 0 nev] adapt$ to und]gr\nd "w1 & a s]viceable drill = ?is purpose 0 n f\nd until compress$ air = transmission 0 demon/rat$ by ,dommeill] on ! ,mt4 ,c5is tunnel 9 #ahfa4 ,! ideal requirem5ts = a drill comb9e3-- a4 ,p[] transmission adapt$ to und]gr\nd conditions4 b4 ,lightness4 c4 ,simplicity ( con/ruction4 d4 ,/r5g?4 e4 ,rapidity & /r5g? ( bl[4 f4 ,ease ( erection4 g4 ,reliability4 h4 ,me*anical effici5cy4 i4 ,l[ capital co/4 ,no drill inv5t$ yet fills all ^! requirem5ts1 & all are a compromise on "s po9t4 ,,p[] ,,transmission2 ,,compress$ ,,air vs4 ,,electricity4--,! only transmissions adapt$ to und]gr\nd drill-"w are compress$ air & electricity1 & z yet an electric-driv5 drill has n be5 produc$ :i* meets z _m ( ! requirem5ts ( ! metal m9] z d compress$-air drills4 ,! latt]1 up to date1 h sup]iority 9 simplicity1 lightness1 ease ( erection1 reliability1 & /r5g? ov] electric ma*9es4 ,air has ano!r advantage 9 t x af=ds "s assi/ance to v5tilation1 b x has ! disadvantage ( rem>kably l[ me*anical effici5cy4 ,! actual "w p]=m$ by ! /&>d #c-c_/d-;in* air-drill probably does n am\nt to ov] two or ?ree horse-p[] aga9/ f fifte5 to eighte5 horse-p[] deliv]$ into ! compressor1 or me*anical effici5cy ( less ?an #be4 ,z electrical p[] c be deliv]$ to ! drill ) mu* less loss ?an compress$ air1 ! field = a m economical drill on ?is l9e is wide en\gh to create ev5tually ! prop] tool to apply x4 ,! mo/ satisfactory electric drill produc$ has be5 ! ,temple drill1 :i* is really an air-drill driv5 by a small electrically-driv5 compressor plac$ ne> ! drill itself4 ,b ev5 ?is has consid]able defici5cies 9 m9+ "w2 ! difficulties ( sett+ up1 especially = /op+ "w1 & ! m cumb]some app>atus to remove be=e bla/+ are s]i\s drawbacks4 ,x has defici5cies 9 reliability & great] complication ( ma*9]y ?an direct air4 ,,air-,,compression4--,! me?od ( air-compression s long accompli%$ only by p[]-driv5 pi/ons has n[ an alt]native 9 "s situations by ! use ( fall+ wat]4 ,?is latt] sy/em is a developm5t ( ! la/ twelve ye>s1 &1 due to ! l[ initial outlay & extremely l[ op]at+ co/s1 bids fair 9 ^? regions :]e wat] head is available n only to displace ! ma*9e compressor1 b also to ext5d ! application ( compress$ air to m9e motors g5]ally1 & to /ay 9 "s environm5ts ! encroa*m5t ( electricity into ! compress$-air field4 ,in/allations ( ?is sort 9 ! ,we/ ,koot5ay1 ,b4,c41 & at ! ,victoria copp] m9e1 ,mi*igan1 are giv+ results wor?y ( c>eful att5tion4 ,me*anical air-compressors are /eam-1 wat]-1 electrical-1 & gas-driv51 ! alt]native obvi\sly dep5d+ on ! s\rce & co/ ( p[]4 ,electrical- & gas- & wat]-driv5 compressors "w "u ! disadvantage ( con/ant spe$ motors & respond little to ! v>iation 9 load1 a p>tial rem$y = :i* lies 9 enl>g$ air-/orage capacity4 ,inasmu* z compress$ air1 s f> z our k goes at pres5t1 mu/ be provid$ = drills1 x =ms a conv5i5t transmission ( p[] to v>i\s motors und]gr\nd1 su* z small pumps1 w9*es1 or locomotives4 ,z /at$ 9 discuss+ ^? ma*9es1 x is n prim>ily a transmission ( ev5 mod]ate me*anical effici5cy = su* purposes2 b z aga9/ ! in/allation & op]ation ( indep5d5t transmission1 su* z /eam or electricity1 ! economic advantage (t5 comp5sates ! te*nical losses4 ,:]e su* motors are fix$1 z 9 pumps & w9*es1 a consid]able ga9 9 effici5cy c be obta9$ by reheat+4 ,x is n propos$ to ent] a discussion ( me*anical details ( air-compression1 m ?an to call att5tion to ! mo/ common del9qu5cy 9 ! in/allation ( su* plants4 ,?is defici5cy lies 9 insuffici5t compression capacity = ! ne$s ( ! m9e & consequ5t effective op]ation ( drills1 = ) "u #ge p\nds pressure ! drills decrease rem>kably 9 rapidity ( /roke & =ce ( ! bl[4 ,! consequ5t decrease 9 actual accompli%m5t is f> beyond ! ratio t might be expect$ on ! basis ( m]e diff]5ce ( pressure4 ,ano!r =m ( ! same *ronic ill lies 9 insuffici5t air-/orage capacity to provide = ma9t5ance ( pressure aga9/ mom5ts :5 all drills or motors 9 ! m9e syn*ronize 9 heavy dem& = air1 & ?us l[] ! pressure at c]ta9 p]iods4 ,,air-,,drills4--,air-drills are f a me*anical po9t ( view broadly ( two types1--! fir/1 9 :i* ! drill is ! pi/on ext5sion2 & ! second1 a m rec5t developm5t = m9+ "w1 9 :i* ! pi/on acts z a hamm] /rik+ ! head ( ! drill4 ,f an economic po9t ( view drills may be divid$ into ?ree classes4 ,fir/1 heavy drills1 weigh+ f #aej to #djj p\nds1 :i* require two m5 = _! op]ation2 second1 baby drills ( ! pi/on type1 weigh+ f #aaj to #aej p\nds1 requir+ "o man ) occasional assi/ance 9 sett+ up2 & ?ird1 v light drills almo/ :olly ( ! hamm] type4 ,?is type is built 9 two =ms3 a heavi] type = m\nt+ on columns1 weigh+ ab\t #hj p\nds2 & a type aft] ! ord] ( ! pneumatic rivet]1 weigh+ z l[ z #bj p\nds & work$ )\t m\nt+4 ,! weight & consequ5t mobility ( a drill1 aside f labor que/ions1 h a m>k$ effect on co/s1 = ! light] ! drill ! less difficulty & delay 9 erection1 & consequ5t less loss ( "t & less t5d5cy to drill holes f "o radius1 reg>dless ( po9t+ to take be/ advantage ( break+ planes4 ,moreov]1 small] diamet] & %ort] holes consume less explosives p] foot advanc$ or p] ton brok54 ,! be/ results 9 tonnage brok5 & explosive consum$1 if measur$ by ! foot ( drill-hole necess>y1 c be accompli%$ f h&-drill+ & ! light] ! ma*9e drill1 assum+ equal reliability1 ! ne>] x approximates ^! advantages4 ,! bl[1 & !re=e size & dep? ( hole & rapidity ( drill+1 are some:at dep5d5t ^u ! size ( cyl9d]s & l5g? ( /roke1 & !re=e ! heavi] types are bett] adapt$ to h>d gr\nd & to ! deep holes ( "s developm5t po9ts4 ,_! advantages ov] ! o!r classes lie *iefly 9 ?is ability to bore exce$+ly h>d mat]ial & 9 ! great] spe$ ( advance possible 9 developm5t "w2 b except = ^! two special purposes !y are n z economical p] foot advanc$ or p] ton ( ore brok5 z ! light] drills4 ,! second class1 :]e m5 c be induc$ to "w !m "o man p] drill1 saves 9 labor & ga9s 9 mobility4 ,_m te/s %[ great economy ( ! baby type ( pi/on drills 9 av]age gr\nd ov] ! heavi] ma*9es = /op+ & = mo/ lat]al developm5t4 ,all pi/on types are some:at cumb]some & ! heavi] types require at lea/ f\r feet ( head room4 ,! baby type c be op]at$ 9 less space ?an ?is1 b = n>r[ /opes !y d n l5d !mselves ) ! same facility z ! ?ird class4 ,! ?ird class ( drills is /ill 9 process ( developm5t1 b x bids fair to displace mu* ( ! occupation ( ! pi/on types ( drill4 ,aside f be+ a "o-man drill1 by its mobility x w app>5tly l>gely reproduce ! advantage ( h&-drill+ 9 ability to place %ort holes f ! mo/ advantage\s angles & = use 9 n>r[ places4 ,z comp>$ ) o!r drills x bids fair to require less "t = sett+ up & removal & = *ange ( bits2 to de/roy less /eel by breakages2 to dull ! bits less rapidly p] foot ( hole2 to be m economical ( p[]2 to require mu* less skill 9 op]ation1 = judgm5t is less call$ ^u 9 deliv]+ spe$2 & to evade difficulties ( fissur$ gr\nd1 etc4 ,& f9ally ! co/ is only "o-half1 initially & = sp>es4 ,its disadvantage s f> is a lack ( reliability due to lightness ( con/ruction1 b ?is is v rapidly be+ ov]come4 ,?is type1 h[ev]1 is limit$ 9 dep? ( hole possible1 =1 f lack ( positive rev]se movem5t1 !re is a t5d5cy = ! spoil to pack ar\nd ! bit1 & z a result ab\t f\r feet seems ! limit4 ,! p]=mance ( a ma*9e-drill "u %[ conditions may be any?+ up to t5 or twelve feet ( hole p] h\r on rock su* z compact granite2 b 9 und]gr\nd "w a l>ge proportion ( ! "t is lo/ 9 pick+ d[n loose ore1 sett+ up ma*9es1 removal = bla/+1 cle>+ away spoil1 mak+ adju/m5ts1 etc4 ,! am\nt ( lo/ "t is (t5 dep5d5t ^u ! wid? ( /ope or %aft & ! me?od ( /op+4 ,situations :i* require long drill columns or special scaffolds greatly acc5tuate ! loss ( "t4 ,fur!r1 ! difficulties 9 sett+ up reflect indirectly on effici5cy to a great] ext5t 9 t a l>g] proportion ( holes are drill$ f "o radius & ?us less adapt$ to ! be/ break+ results ?an :]e ! drill c easily be reset f v>i\s angles4 ,! usual duty ( a heavy drill p] eight-h\r %ift us+ two m5 is f #bj to #dj feet ( hole1 dep5d+ ^u ! rock1 facilities = sett+ up1 etc41 etc499 ,! light] drills h a less av]age duty1 av]ag+ f #ae to #be feet p] %ift4 ,footnote 993 ,ov] ! ye> #aijg 9 tw5ty-eight m9es compil$ f ,alaska to ,au/ralia1 an av]age ( #bc4e feet 0 drill$ p] eight-h\r %ift by ma*9es l>g] ?an ?ree-in* cyl9d]4 ,,ma*9e vs4 ,,h&-,,drill+4--,! advantages ( h&-drill+ ov] ma*9e-drill+ lie1 fir/1 9 ! total sav+ ( p[]1 ! abs5ce ( capital co/1 repairs1 depreciation1 etc41 on p[]1 compress] & drill plant2 second1 ! "t requir$ = sett+ up ma*9e-drills does n w>rant frequ5t bla/s1 s t a numb] ( holes on "o radius are a necessity1 & !re=e ma*9e-holes g5]ally _c be po9t$ to su* advantage z h&-holes4 ,h&-holes c be set to any angle1 & by ?us frequ5t bla/+ yield great] tonnage p] foot ( hole4 ,?ird1 a l>ge numb] ( comp>ative /ati/ics f ,am]ican1 ,s\? ,african1 & ,au/ralian m9es %[ a sav+ ( ab\t #be 9 explosives = ! same tonnage or foot ( advance by h&-holes ov] m$ium & heavy drill-holes4 ,! duty ( a skill$ :ite man1 s+le-h&$1 9 rock su* z is usually met bel[ ! zone ( oxidation1 is f #e to #g feet p] %ift1 dep5d+ on ! rock & ! man4 ,two m5 h&-drill+ w !re=e d f #a_/d to #b_/c ( ! same footage ( holes t c be done by two m5 ) a heavy ma*9e-drill1 & two m5 h&-drill+ w d f #a_/e to #a_/b ! footage ( two m5 ) two light drills4 ,! sav+ 9 labor ( f #ge to #cc by ma*9e-drill+ may or may n be made up by ! o!r co/s involv$ 9 ma*9e-"w4 ,! comp>ative value ( ma*9e- & h&-drill+ is n subject to sweep+ g5]alization4 ,a l>ge am\nt ( data f v>i\s p>ts ( ! _w1 ) skill$ :ite m51 %[s ma*9e-"w to co/ f half z mu* p] ton or foot advanc$ z h&-"w to #be m ?an h&work1 dep5d+ on ! situation1 type ( drill1 etc4 ,9 a g5]al way h&-"w c m ne>ly compete ) heavy ma*9es ?an light ones4 ,! situations :]e h&-"w c compete ) ev5 light ma*9es are 9 v n>r[ /opes :]e drills _c be po9t$ to advantage1 & :]e ! increas$ work+ space necess>y = ma*9e drills results 9 break+ m wa/e4 ,fur!r1 h&-drill+ c (t5 compete ) ma*9e-"w 9 wide /opes :]e long columns or plat=ms mu/ be us$ & !re=e !re is mu* delay 9 tak+ d[n1 rerection1 etc4 ,_m o!r factors ent] into a comp>ison1 h[ev]1 = ma*9e-drill+ produces a great] numb] ( deep] holes & p]mits l>g] bla/s & !re=e m rapid progress4 ,9 driv+ levels "u av]age conditions mon?ly footage is f two to ?ree times z great ) heavy ma*9es z by h&-drill+1 & by light] ma*9es a some:at less proportion ( great] spe$4 ,! great] spe$ obta9$ 9 developm5t "w1 ! great] tonnage obta9$ p] man 9 /op+1 ) consequ5t r$uction 9 ! numb] ( m5 employ$1 & 9 r$uction ( sup]9t5d5ce & g5]al *>ges are indirect advantages = ma*9e-drill+ n to be ov]look$4 ,! results obta9$ 9 ,s\? ,africa by h&-drill+ 9 %afts1 & its v g5]al adoption !re1 seem to indicate t bett] spe$ & m economical "w c be obta9$ 9 t way 9 v l>ge %afts ?an by ma*9e-drill+4 ,h[ f> special reasons !re apply to small] %afts or labor conditions else:]e h yet to be demon/rat$4 ,9 l>ge-dim5sion %afts dem&+ a l>ge numb] ( ma*9es1 ! h&l+ ( long ma*9e b>s & ma*9es g5]ally results 9 a great loss ( "t4 ,! l>ge *>ges 9 deep holes break ! walls v irregul>ly2 misfires cause m delay2 timb]+ is m difficult 9 ! face ( heavy bla/+ *>ges2 & ! l>g] am\nt ( spoil brok5 at "o "t delays r5ew$ drill+1 & altoge!r ! advantages seem to lie ) h&-drill+ 9 %afts ( l>ge horizontal section4 ,! rapid developm5t ( special drills = p>ticul> conditions has elim9at$ ! advantage ( h&-"w 9 _m situations dur+ ! pa/ t5 ye>s1 & ! inv5tion ( ! hamm] type ( drill bids fair to r5d] h&-drill+ a ?+ ( ! pa/4 ,"o g5]alization is possible1 & t is1 if drills are run on #dj-ej p\nds' pressure !y are no economy ov] h&-drill+4 ,,work%ops4 ,9 addition to ! ord9>y blacksmi?y1 :i* is a necessity1 ! mod]n t5d5cy has be5 to elaborate ! %ops on m9es to cov] ma*9e-"w1 patt]n-mak+ & f\ndry-"w1 9 ord] t delays may be m9imiz$ by quick repairs4 ,to provide1 h[ev]1 = su* cont+5cies a /aff ( m5 mu/ be kept l>g] ?an ! dem& ( av]age requirem5ts4 ,! result is an ef=t to provide jobs or to d "w extravagantly or unnecess>ily well4 ,9 g5]al1 x is an easy spot = fungi to />t gr[+ on ! adm9i/ration1 & if cu/om repair %ops are available at all1 m9e %ops c be easily ov]done4 ,a numb] ( ma*9es are n[ 9 use = %>p5+ drills4 ,ma*9e-%>p5+ is mu* *eap] ?an h&-"w1 al?\gh ! drills ?us %>p5$ are r less effici5t ow+ to ! difficulty ( temp]+ !m to ! same nicety2 h[ev]1 ! net results are 9 favor ( ! ma*9es4 ,,improvem5t ,,9 ,,equipm5t4 ,n only is e m9e a progressive indu/ry until ! bottom gives out1 b ! te*nology ( ! indu/ry is always progress+1 s t ! manag] is almo/ daily confront$ ) improvem5ts :i* c\ld be made 9 8 equipm5t t w\ld result 9 decreas+ exp5ses or increas+ metal recov]y4 ,!re is "o te/ to ! advisability ( su* alt]ations3 ,h[ long w x take to recov] ! capital outlay f ! sav+s effect$8 & ov] & above ?is recov]y ( capital !re mu/ be "s v consid]able ga94 ,! life ( m9es is at lea/ secur$ ov] ! p]iod expos$ 9 ! ore-res]ves1 & if ! propos$ alt]ation w %[ its recov]y & pr(it 9 t p]iod1 !n x is c]ta9ly ju/ifi$4 ,if x takes long] ?an ?is on ! av]age speculative ore-deposit1 x is a gamble on f9d+ fur!r ore4 ,z a matt] ( practical policy x w be f\nd t an improvem5t 9 equipm5t :i* requires m ?an ?ree or f\r ye>s to r$eem itself out ( sav+1 is usually a me*anical or metallurgical ref9em5t ! indulg5ce 9 :i* is v d\btful4 ,,*apt] ,,xv4 ,ratio ( ,output to ! ,m9e4 ,,det]m9ation ,,( ,,! ,,possible ,,maximum2 ,,limit+ ,,factors2 ,,co/ ,,( ,,equipm5t2 ,,life ,,( ,,! ,,m9e2 ,,me*anical ,,ineffici5cy ,,( ,,pat*work ,,plant2 ,,ov]production ,,( ,,base ,,metal2 ,,security ,,( ,,inve/m5t4 ,! output obta9able f a giv5 m9e is obvi\sly dep5d5t n only on ! size ( ! deposit1 b also on ! equipm5t provid$1--9 :i* equipm5t means ! :ole work+ appliances1 surface & und]gr\nd4 ,a r\gh & ready idea ( output possibilities ( incl9$ deposits c be secur$ by calculat+ ! tonnage available p] foot ( dep? f ! horizontal cross-section ( ! ore-bodies expos$ & assum+ an annual dep? ( exhau/ion1 or 9 horizontal deposits f an assumption ( a giv5 area ( exhau/ion4 ,few m9es1 at ! "t ( initial equipm5t1 are develop$ to an ext5t f :i* _! possibilities 9 production are evid5t1 = wise f9ance usually leads to ! erection ( "s equipm5t & production be=e developm5t has be5 advanc$ to a po9t t w>rants a l>ge or f9al in/allation4 ,moreov]1 ev5 7 ! full possibilities ( ! m9e kn[n1 ! limitations ( f9ance usually necessitate a less plant to />t ) ?an is f9ally contemplat$4 ,!re=e output & equipm5t are usually gr[+ possibilities dur+ ! e>ly life ( a m9e4 ,!re is no bett] in/ance 9 m9e eng9e]+ :]e pure !ory mu/ give way to practical necessities ( f9ance ?an 9 ! det]m9ation ( ! size ( equipm5t & !re=e output4 ,moreov]1 :]e f9ance ev5 is no ob/ruction1 !re are o!r limitations ( a v practical ord] :i* mu/ dom9ate ! "q ( ! size ( plant giv+ ! greate/ te*nical economy4 ,x is1 h[ev]1 useful to /ate ! !oretical consid]ations 9 det]m9+ ! ultimate volume ( output & !re=e ! size ( equipm5ts1 = ! !ory w s]ve to illum9ate ! practical limitations4 ,! discussion w also aga9 demon/rate t all eng9e]+ is a s]ies ( compromises ) natural & economic =ces4 ,,output ,,giv+ ,,lea/ ,,production ,,co/4--,z "o ( ! mo/ important objectives is to "w ! ore at ! lea/ co/ p] ton1 x is n difficult to demon/rate t ! m9imum work+ co/s c be obta9$ only by ! mo/ int5sive production4 ,to prove ?is1 x ne$ only be rememb]$ t ! work+ exp5ses ( a m9e are ( two sorts3 "o is a factor ( ! tonnage h&l$1 su* z /op+ & ore-dress+2 ! o!r is :olly or p>tially dep5d5t ^u "t4 ,a l>ge numb] ( items are ( ?is la/ ord]4 ,pump+ & head-(fice exp5ses are almo/ entirely *>ges indep5d5t ( ! tonnage h&l$4 ,sup]9t5d5ce & /aff sal>ies & ! l are 9 a l>ge proportion dep5d5t ^u "t4 ,_m o!r elem5ts ( exp5se1 su* z ! numb] ( eng9e-driv]s1 etc41 d n increase proportionately to increase 9 tonnage4 ,^! *>ges1 or ! "p ( !m dep5d5t ^u "t ap>t f tonnage1 may be t]m$ ! fix$ *>ges4 ,!re is ano!r fix$ *>ge m obscure yet no less c]ta94 ,ore /&+ 9 a m9e is l money 9 a bank draw+ no int]e/1 & ?is item ( int]e/ may be consid]$ a fix$ *>ge1 = if ! ore 7 realiz$ e>li]1 ?is loss c\ld be p>tially sav$4 ,?is subject is fur!r ref]r$ to "u ,amortization4 ,if1 !re=e1 ! "t requir$ to exhau/ ! m9e be prolong$ by ! failure to ma9ta9 ! maximum output1 ! total co/ ( work+ x w be great] by ! fix$ *>ges ov] su* an increas$ p]iod4 ,conv]sely1 by equipp+ on a l>g] scale1 ! m9e w be exhau/$ m quickly1 a sav+ 9 total co/ c be made1 & ! ultimate pr(it c be increas$ by an am\nt correspond+ to ! "t sav$ f ! ravages ( fix$ *>ges4 ,9 f9e1 ! work+ co/s may be r$uc$ by l>g] op]ations1 & !re=e ! value ( ! m9e increas$4 ,! problem 9 practice usually takes ! =m ( ! relative sup]iority ( m or ( few] units ( plant1 & x c be consid]$ 9 m detail if ! production be suppos$ to consi/ ( units av]ag+ say #ajj tons p] day ea*4 ,! advantage ( m units ov] less w be t ! extra ones c be produc$ free ( fix$ *>ges1 = ^! are an exp5se already involv$ 9 ! less] units4 ,?is extra production w also enjoy ! int]e/ :i* c be e>n$ ov] ! p]iod ( its e>li] production4 ,moreov]1 op]ations on a l>g] scale result 9 v>i\s m9or economies ?r\gh\t ! :ole production1 n entirely includ$ 9 ! type ( exp5diture m5tion$ z fix$ *>ges4 ,we may call ^! v>i\s advantages ! sav+ ( fix$ *>ges due to l>g]-scale op]ations4 ,! sav+ ( fix$ *>ges am\nts to v consid]able sums4 ,9 g5]al ! items ( work+ co/ alone1 m5tion$ above1 :i* d n increase proportionately to ! tonnage1 aggregate f #aj to #be ( ! total co/s4 ,:]e mu* pump+ is involv$1 ! p]c5tage w become ev5 great]4 ,! "q ( ! value ( ! m9e z affect$ by ! volume ( output becomes v prom95t 9 l[-grade m9es1 :]e1 if equipp$ = output on too small a scale1 no pr(its at all c\ld be e>n$1 & a suffici5t production is absolutely imp]ative = any ga94 ,!re are _m m9es 9 e c\ntry :i* ) "o-?ird ( _! pres5t rate ( production w\ld lose money4 ,t is1 ! fix$ *>ges1 if spread ov] small output1 w\ld be s great p] ton t ! pr(it w\ld be ext+ui%$ by !m4 ,9 ! !oretical view1 !re=e1 x w\ld appe> cle> t ! greate/ ultimate pr(it f a m9e c be secur$ only by ore extraction "u ! highe/ pressure4 ,z a coroll>y to ?is x foll[s t developm5t mu/ proce$ ) ! maximum spe$4 ,fur!r1 x foll[s t ! pres5t value ( a m9e is at lea/ p>tially a factor ( ! volume ( output contemplat$4 ,,factors ,,limit+ ,,! ,,output4 ,al?\gh ! above argum5t c be academically def5d$1 !re are1 z said at ! />t1 practical limitations to ! maximum int5sity ( production1 aris+ out ( _m o!r consid]ations to :i* weight mu/ be giv54 ,9 ! ma91 !re are five pr9cipal limitations3-- #a4 ,co/ ( equipm5t4 #b4 ,life ( ! m9e4 #c4 ,me*anical ineffici5cy ( pat*work plant4 #d4 ,ov]production ( base metal4 #e4 ,security ( inve/m5t4 ,,co/ ,,( ,,equipm5t4--,! sav+ ( fix$ *>ges c only be obta9$ by l>g] equipm5t1 :i* repres5ts an inve/m5t4 ,m9+ works1 %afts1 ma*9]y1 treatm5t plants1 & all ! p>aph]nalia co/ l>ge sums ( money4 ,!y become ei!r worn out or practically valueless ?r\gh ! exhau/ion ( ! m9es4 ,ev5 surface ma*9]y :5 9 good condition w seldom realize m ?an "o-t5? ( its exp5se if useless at its orig9al site4 ,all m9es are ephem]al2 !re=e virtually ! entire capital outlay ( su* works mu/ be r$eem$ dur+ ! life ( ! m9e1 & ! int]e/ on x mu/ also be recov]$4 ,! c]ta9 life1 ) ! exception ( banket & a few o!r types ( deposit1 is t %[n by ! ore 9 sight1 plus some?+ = ext5sion ( ! deposit beyond exposures4 ,s1 aga9/ ! sav+s to be made1 mu/ be set ! co/ ( obta9+ !m1 = obvi\sly x is ( no use inve/+ a doll> to save a total ( n9ety c5ts4 ,! economies by increas$ production are1 h[ev]1 ( su* an important "* t ! co/ ( almo/ any numb] ( add$ units 7)9 ! ability ( ! m9e to supply !m7 c be r$eem$ f ^! sav+s 9 a few ye>s4 ,= in/ance1 9 a ,cali=nian gold m9e :]e ! work+ exp5ses are #c & ! fix$ *>ges are at ! l[ rate ( #cj c5ts p] ton1 "o unit ( increas$ production w\ld %[ a sav+ ( ov] #aj1jjj p] annum f ! sav+ ( fix$ *>ges4 ,9 ab\t ?ree ye>s ?is sum w\ld repay ! co/ ( ! additional treatm5t equipm5t4 ,if fur!r %aft capacity 7 requir$1 ! p]iod w\ld be mu* ext5d$4 ,on a ,we/]n copp] m9e1 :]e ! co/s are #h & ! fix$ *>ges are #hj c5ts p] ton1 "o unit ( increas$ production w\ld effect a sav+ ( ! fix$ *>ges equal to ! co/ ( ! extra unit 9 ab\t ?ree ye>s4 ,t is1 ! total sum w\ld am\nt to #hj1jjj1 or en\gh to provide almo/ any type ( me*anical equipm5t = su* additional tonnage4 ,! fir/ result ( vigor\s developm5t is to increase ! ore 9 sight1--! visible life ( ! m9e4 ,:5 su* visible life has be5 s l5g!n$ t ! p]iod 9 :i* ! sav+ ( fix$ *>ges w equal ! am\nt involv$ 9 expansion ( equipm5t1 !n f ! /&po9t ( ?is limitation only is ! add$ in/allation ju/ifi$4 ,! equipm5t if exp&$ on ?is practice w gr[ ^u ! heels ( rapid developm5t until ! maximum production f ! m9e is rea*$1 & a k9d ( equilibrium e/abli%es itself4 ,conv]sely1 ?is argum5t leads to ! conclusion t1 reg>dless ( o!r consid]ations1 an equipm5t1 & !re=e output1 %\ld n be exp&$ beyond ! r$emption by way ( sav+ f fix$ *>ges ( ! visible or c]ta9 life ( ! m9e4 ,9 ^? m9es1 su* z at ! ,witwat]sr&1 :]e !re is a fairly s\nd assurance ( def9ite life1 x is possible to calculate at once ! size ( plant :i* by sav+ ( fix$ *>ges w be ev5tually ! mo/ economical1 b ev5 "h ! o!r limitations /ep 9 to vitiate su* policy ( managem5t1--*iefly ! limitation ?r\gh security ( inve/m5t4 ,,life ,,( ,,! ,,m9e4--,if c>ri$ to its logical extreme1 ! above program means a mo/ rapid exhau/ion ( ! m9e4 ,! maximum output w dep5d ev5tually ^u ! rapidity ) :i* developm5t "w may be ext5d$4 ,z levels & o!r subsidi>y developm5t op5+s c be prep>$ 9 incl9$ deposits mu* m quickly ?an ! %aft c be sunk1 ! critical po9t is ! %aft-s9k+4 ,z a %aft may by ex]tion be deep5$ at lea/ #djj feet a ye> on a go+ m9e1 ! provision ( an equipm5t to eat up ! ore-body at ?is rate ( s9k+ means v e>ly exhau/ion inde$4 ,9 fact1 _h su* a !ory ( production be5 put into practice by our =efa!rs1 ! m9+ pr(ession might f9d difficulty 9 obta9+ employm5t to-day4 ,su* rapid exhau/ion w\ld mean a depletion ( ! m9]al res\rces ( ! /ate at a pace :i* w\ld be al>m+4 ,,me*anical ,,ineffici5cy ,,( ,,pat*work ,,plant4--,m9e equipm5ts on speculative m9es 7! va/ majority7 are (t5 en\gh pat*work1 = !y usually gr[ f small beg9n+s2 b any s*eme ( expansion bas$ ^u ! above doctr9e w\ld ne$ to be modifi$ to ! ext5t t additions c\ld be 9 units l>ge 9 ratio to previ\s in/allations1 or _! pat*work "* w\ld be /ill fur!r acc5tuat$4 ,x w\ld be impossible to ma9ta9 me*anical effici5cy "u detail expansion4 ,,ov]production ,,( ,,base ,,metal4--,7 ?is int5sity ( production ( g5]al application to base metal m9es x w\ld flood ! m>kets1 &1 by an ov]production ( metal depress prices to a po9t :]e ! advantages ( su* l>ge-scale op]ations w\ld quickly vani%4 ,! !oretical solution 9 ?is situation w\ld be1 if metals fell bel[ normal prices1 let ! output be r$uc$1 or let ! products be /or$ until ! price recov]s4 ,f a practical po9t ( view ei!r alt]native is a policy difficult to face4 ,9 ! fir/ case1 r$uction ( output means an increase ( work+ exp5ses by ! spread ( fix$ *>ges ov] less tonnage1 & ?is 9 ! face ( r$uc$ metal prices4 ,x may be cont5d$1 h[ev]1 t a fall+ metal m>ket is usually ! accompanim5t ( a drop 9 all commodities1 :]e=e work+ co/s c be r$uc$ some:at 9 su* times ( depression1 !reby p>tially comp5sat+ ! o!r elem5ts mak+ = increas$ co/s4 ,falls 9 commodities are also ! accompanim5t ( h>d times4 ,consid]ation ( "o's workpeople & ! :olesale slaught] ( divid5ds to ! !n ne$y /ockhold]s1 result+ f a policy ( r$uc$ production1 are usually suffici5t det]r5ts to dim9i%$ output4 ,! second alt]native1 t ( /or+ metal1 means equally a loss ( divid5ds by ! inve/m5t ( a l>ge sum 9 unrealiz$ products1 & ! int]e/ on ?is sum4 ,! detrim5t to ! m>ket ( l>ge am\nts ( unsold metal r5d]s su* a c\rse n )\t fur!r disadvantages4 ,,security ,,( ,,inve/m5t4--,ano!r po9t ( view antagoni/ic to su* :olesale int5sity ( production1 & "o wor?y ( c>eful consid]ation1 is t ( ! inve/or 9 m9es4 ,! root-value ( m9+ /ocks is1 or %\ld be1 ! pr(it 9 sight4 ,if ! policy ( greate/ economy 9 production co/s be foll[$ z outl9$ above1 ! economic limit ( ore-res]ves gives an app>5tly v %ort life1 = ! ore 9 sight w nev] repres5t a life beyond ! "t requir$ to ju/ify m plant4 ,?us ! economic limit ( ore 9 res]ve w be a /ore equival5c+ a p]iod dur+ :i* additional equipm5t c be r$eem$ f ! sav+ ( fix$ *>ges1 or ?ree or f\r ye>s1 usually4 ,! inve/or has ! "r to say t he wants ! gu>antee ( long] life to 8 inve/m5t1--he w 9 effect pay insurance = x by a loss ( "s ultimate pr(it4 ,t ?is view1 contradictory to ! economics ( ! case1 is n simply academic1 c be obs]v$ by any "o :o /udies :at m9es are 9 be/ repute on any /ock ex*ange4 ,all eng9e]s mu/ wi% to h ! indu/ry "u !m 9 high repute4 ,! writ] kn[s ( sev]al m9es pay+ #bj on _! /ocks :i* yet /& l[] 9 price on acc\nt ( %ort ore-res]ves ?an m9es pay+ less annual returns4 ,! speculator1 :o is an elem5t n to be :olly disreg>d$1 wi%es a rise 9 8 m9+ /ock1 & if developm5t proce$s at a pace 9 advance ( production1 he w ga9 a legitimate rise ?r\gh ! increase 9 ore-res]ves4 ,! inve/or's & speculator's idea ( ! desirability ( a prov$ long life readily supports ! te*nical policy ( high-pressure developm5t "w1 b n ( expansion ( production1 = !y desire an increas+ ore-res]ve4 ,ev5 ! metal op]ator :o is afraid ( ov]production does n object to increas$ ore-res]ves4 ,on ! po9t ( maximum int5sity ( developm5t "w 9 a m9e all views co9cide4 ,! m9+ eng9e]1 if he takes a ,ma*iavellian view1 mu/ agree ) ! inve/or & ! metal deal]1 = ! eng9e] is a fix$ *>ge ! cont9uance ( :i* is important to 8 daily ne$s4 ,! net result ( all ^! limitations is !re=e an inv>iable compromise ^u "s output bel[ ! possible maximum4 ,! initial output to be contemplat$ is obvi\sly "o ^u :i* ! work+ co/s w be l[ en\gh to %[ a m>g9 ( pr(it4 ,! m$ium betwe5 ^! two extremes is det]m9able by a consid]ation ( ! limitations set out1--& ! ca% available4 ,:5 ! volume ( output is once det]m9$1 x mu/ be consid]$ z a factor 9 valuation1 z discuss$ "u ,amortization4 ,,*apt] ,,xvi4 ,adm9i/ration4 ,,labor ,,effici5cy2 ,,skill2 ,,intellig5ce2 ,,application ,,coord9ation2 ,,contract ,,"w2 ,,labor ,,unions2 ,,real ,,basis ,,( ,,wages4 ,! realization f a m9e ( ! pr(its e/imat$ f ! o!r factors 9 ! case is 9 ! end dep5d5t ^u ! managem5t4 ,good m9e managem5t is bas$ ^u ?ree elem5tals3 fir/1 s\nd eng9e]+2 second1 prop] cord9ation & effici5cy ( e human unit2 ?ird1 economy 9 ! pur*ase & consumption ( supplies4 ,! previ\s *apt]s h be5 devot$ to a m or less ext5d$ exposition ( economic eng9e]+4 ,:ile ! second & ?ird requirem5ts are equally important1 !y range 9 _m ways out ( ! eng9e]+ & into ! human field4 ,= ?is latt] reason no complete manual w ev] be publi%$ ^u ,h[ to become a ,good ,m9e ,manag]4 ,x is purpos$1 h[ev]1 to analyze "s features ( ^! second & ?ird fundam5tals1 especially 9 _! int]dep5d5t phases1 & next to consid] ! subject ( m9e /ati/ics1 = ! latt] are truly ! microscopes ?r\gh :i* ! compet5ce ( ! adm9i/ration mu/ be exam9$4 ,! human units 9 m9e organization c be divid$ into (fic]s & m54 ,! *oice ( m9e (fic]s is ! assembl+ ( specializ$ bra9s4 ,_! control1 /imulation1 & inspiration is ! ma9 "w ( ! adm9i/rative head4 ,success 9 ! selection & control ( /aff is ! index ( executive ability4 ,!re are no ma!matical1 me*anical1 or *emical =mulas = deal+ ) ! human m9d or human en]gies4 ,,labor4--,! :ole "q ( h&l+ labor c be r$uc$ to ! "o t]m effici5cy4 ,n only does ! actual labor outlay repres5t f #fj to #gj ( ! total und]gr\nd exp5ses1 b ! capacity or incapacity ( its units is responsible = wid] fluctuations 9 production co/s ?an ! b>e pr$om9ance 9 exp5diture might indicate4 ,! rema9+ exp5se is = supplies1 su* z dynamite1 timb]1 /eel1 p[]1 etc41 & ! economical application ( ^! mat]ials by ! workman has ! wide/ be>+ ^u _! consumption4 ,effici5cy ( ! mass is ! resultant ( t ( ea* individual "u a direction :i* cord9ates effectively all units4 ,! lack ( effectiv5ess 9 "o individual dim9i%es ! returns n simply f t man alone2 x l[]s ! results f numb]s ( m5 associat$ ) ! weak memb] ?r\gh ! delay+ & clogg+ ( _! "w1 & ( ! ma*9es op]at$ by !m4 ,cord9ation ( "w is a necess>y factor ( f9al effici5cy4 ,?is is a matt] ( organization & adm9i/ration4 ,! mo/ zeal\s /op+-gang 9 ! _w if associat$ ) half ! prop] numb] ( truck]s mu/ fail to get ! desir$ result4 ,effici5cy 9 ! s+le man is ! product ( ?ree factors1--skill1 intellig5ce1 & application4 ,a great proportion ( und]gr\nd "w 9 a m9e is ( a type :i* c be p]=m$ aft] a fa%ion by absolutely unskill$ & ev5 un9tellig5t m51 z witness ! break+-9 ( savages ( l[ av]age m5tality1 l ! ,s\? ,african ,kaffirs4 ,al?\gh mo/ duties c be p]=m$ by ?is crude/ ord] ( labor1 skill & intellig5ce c be appli$ to x ) su* economic results z to comp5sate = ! diff]5ce 9 wage4 ,! reason = ?is is t ! la/ fifty ye>s h se5 a sub/itution ( labor-sav+ ma*9es = muscle4 ,su* ma*9es displace hundr$s ( raw labor]s4 ,n only d !y initially co/ l>ge sums1 b !y require l>ge exp5diture = p[] & up-keep4 ,^! fix$ *>ges aga9/ ! ma*9e dem& t x %all be work$ at its maximum4 ,= int]e/1 p[]1 & up-keep g on 9 any ev5t1 & ! sav+ on crude labor displac$ is n s great b t x quickly disappe>s if ! ma*9e is run "u its capacity4 ,to get its greate/ effici5cy1 a high degree ( skill & intellig5ce is requir$4 ,nor are skill & intellig5ce alone applicable to labor-sav+ devices !mselves1 because drill+ & bla/+ rock & execut+ o!r works und]gr\nd are matt]s 9 :i* exp]i5ce & judgm5t 9 ! individual workman c\nt to ! highe/ degree4 ,h[ f> skill affects production co/s has _h a ?or\gh demon/ration 9 ,we/ ,au/ralia4 ,= a "t aft] ! op5+ ( ^? m9es only a small proportion ( exp]i5c$ m5 7 obta9able4 ,dur+ ?is p]iod ! rock brok5 p] man employ$ und]gr\nd did n exce$ ! rate ( #cjj tons a ye>4 ,9 ! l>ge m9es x has n[1 aft] "s eight ye>s1 atta9$ #fjj to #gjj tons4 ,h[ f> intellig5ce is a factor indisp5sable to skill c be well illu/rat$ by a comp>ison ( ! results obta9$ f work+ labor ( a l[ m5tal ord]1 su* z ,asiatics & negroes1 ) ^? a*iev$ by ,am]ican or ,au/ralian m9]s4 ,9 a g5]al way1 x may be /at$ ) confid5ce t ! :ite m9]s above m5tion$ c1 "u ! same physical conditions1 & ) f five to t5 times ! wage1 produce ! same economic result1--t is1 an equal or l[] co/ p] unit ( production4 ,mu* obs]vation & exp]i5ce 9 work+ ,asiatics & negroes z well z ,am]icans & ,au/ralians 9 m9es1 leads ! writ] to ! conclusion t1 av]ag+ actual results1 "o :ite man equals f two to ?ree ( ! color$ races1 ev5 9 ! simple/ =ms ( m9e "w su* z %ovel+ or tramm+4 ,9 ! mo/ highly skill$ bran*es1 su* z me*anics1 ! av]age ratio is z "o to sev51 or 9 extreme cases ev5 elev54 ,! "q is n entirely a comp>ison ( b>e effici5cy individually2 x is "o ( ! sum total ( results4 ,9 m9+ "w ! l[] races require a greatly increas$ am\nt ( direction1 & ?is excess ( sup]visors consi/s ( m5 n 9 !mselves directly productive4 ,!re is always1 too1 a wa/e ( supplies1 m accid5ts1 & m gr\nd to be kept op5 = accommodat+ increas$ /aff1 & ! ma9t5ance ( ^! op5+s mu/ be paid =4 ,!re is an add$ exp5se = h&l+ l>g] numb]s 9 & out ( ! m9e1 & ! l[] intellig5ce reacts 9 _m ways 9 lack ( cord9ation & inability to take initiative4 ,tak+ all divisions ( labor toge!r1 ! ratio ( effici5cy z measur$ 9 am\nt ( output works out f f\r to five color$ m5 z ! equival5t ( "o :ite man ( ! class /at$4 ,! ratio ( co/s1 = reasons already m5tion$1 & 9 o!r ?an quantity relation1 figures /ill m 9 favor ( ! high] intellig5ce4 ,! foll[+ comp>isons1 :i* l all m9e /ati/ics mu/ necess>ily be accept$ ) res]vation because ( "s dissimil>ity ( economic surr\nd+s1 are yet on suffici5tly common gr\nd to demon/rate ! ma9 issue1--t is1 ! be>+ ( inh]5t intellig5ce 9 ! workm5 & _! consequ5t skill4 ,f\r gr\ps ( gold m9es h be5 tak51 f ,india1 ,we/ ,au/ralia1 ,s\? ,africa1 & ,we/]n ,am]ica4 ,all ( ^? *os5 are ( ! same /op+ wid?1 #d to #e feet4 ,all are work+ 9 dep? & ) e labor-sav+ device available4 ,all dip at ab\t ! same angle & are !re=e 9 mu* ! same position z to h&l+ rock4 ,! o!r conditions are aga9/ ! :ite-mann$ m9es & 9 favor ( ! color$4 ,t is1 ! ,indian m9es h wat]-g5]at$ electric p[] & ,s\? ,africa has *eap] fuel ?an ei!r ! ,am]ican or ,au/ralian examples4 ,9 bo? ! :ite-mann$ gr\ps1 ! /opes are support$1 :ile 9 ! o!rs no support is requir$4 ,tons ( ,av]age ,tons ,mat]ial ,numb] ( ,m5 p] ,co/ p] ,gr\p ( ,m9es ,excavat$ ,employ$ ,man ,ton ( ov] ,p]iod--------------- p] ,mat]ial ,compil$#e;,color$ ,:ite ,annum ,brok5 ---------------------------------------- -------------------------- ,f\r ,kol> m9es#a #ifc1iej #ac1faa #cjb #fi4c #c4he ,six ,au/ralian m9es#b #a1jbg1gah -- #a1ecd #ffi4i #b4dg ,?ree ,witwat]sr& m9es#c #b1ifb1fdj #ac1efj #a1eie #aie4e #b4fh ,five ,am]ican m9es#d #a1jhi1ejj -- #a1ebd #gac4c #a4ib ,footnote #a3 ,indian wages av]age ab\t #bj c5ts p] day4 ,footnote #b3 ,:ite m5's wages av]age ab\t #c p] day4 ,footnote #c3 ,ab\t two-fif?s ( ! color$ work]s 7 negroes1 & ?ree-fif?s ,*9am54 ,negroes av]age ab\t #fj c5ts1 & ,*9am5 ab\t #de c5ts p] day1 includ+ keep4 ,footnote #d3 ,wages ab\t #c4ej4 ,tunnel entry 9 two m9es4 ,footnote #e3 ,includes rock brok5 9 developm5t "w4 ,9 ! case ( ! specifi$ ,african m9es1 ! :ite labor is employ$ almo/ :olly 9 positions ( actual or semi-sup]9t5d5ce1 su* z "o :ite man 9 *>ge ( two or ?ree drills4 ,9 ! ,indian case1 9 addition to ! :ite m5 :o are :olly 9 sup]9t5d5ce1 !re 7 ( ! natives enum]at$ "s #ajjj 9 positions ( semi-sup]9t5d5ce1 z contractors or headm51 work+-gang]s1 etc4 ,"o issue arises out ( ^! facts1 & t is t no eng9e] or inve/or 9 valu+ m9es is ju/ifi$ 9 anticipat+ l[] co/s 9 regions :]e *eap labor exi/s4 ,9 supplem5t to %e] skill & intellig5ce1 effici5cy c be ga9$ only by ! application ( ! man himself4 ,a few mon?s ago a m9e 9 ,cali=nia *ang$ manag]s4 ,! new head r$uc$ ! numb] employ$ "o-?ird )\t impair+ ! am\nt ( "w accompli%$4 ,?is 0 n ! result ( high] skill or intellig5ce 9 ! m51 b 9 ! manag]4 ,bett] application & cord9ation 7 secur$ f ! work+ =ce4 ,inspiration to increase ( ex]tion is creat$ less by driv+ ?an by recognition ( individual ef=t1 9 l>g] pay1 & by ext5d+ ju/ifiable hope ( promotion4 ,a great factor 9 ! pr(ici5cy ( ! m9e manag] is 8 ability to create an esprit-de-corps ?r\gh ! :ole /aff1 d[n to ! la/ tool boy4 ,fri5dly int]e/ 9 ! welf>e ( ! m5 & /imulation by competitions betwe5 v>i\s works & gr\ps all contribute to ?is end4 ,,contract ,,"w4--,! advantage bo? to employ] & employ$ ( piece "w ov] wage ne$s no argum5t4 ,9 a g5]al way1 contract "w honorably c>ri$ out puts a premium ^u individual ef=t1 & ?us makes = effici5cy4 ,!re are "s portions ( m9e "w :i* _c be contract$1 b ! developm5t1 /op+1 & truck+ c be l>gely manag$ 9 ?is way1 & ^! items cov] #fe to #ge ( ! total labor exp5diture und]gr\nd4 ,9 developm5t !re are two ways ( bas+ contracts1--! fir/ on ! footage ( holes drill$1 & ! second on ! footage ( head+ advanc$4 ,9 contract-/op+ !re are f\r me?ods dep5d+ on ! feet ( hole drill$1 on tonnage1 on cubic space1 & on squ>e area brok54 ,all ^! sy/ems h _! rightful application1 condition$ ^u ! class ( labor & "* ( ! deposit4 ,9 ! hole sy/em1 ! holes are po9t$ by "s m9e (ficial & are bla/$ by a special crew4 ,! m9] !re=e has little int]e/ 9 ! result ( ! break+4 ,if he is a skill$ :ite man1 ! h\rs :i* he has :]e9 to contemplate ! face usually enable him to place holes to bett] advantage ?an ! occasional visit+ =eman4 ,) color$ labor1 ! lack ( intellig5ce 9 plac+ holes & bla/+ usually ju/ifies contracts p] foot drill$4 ,!n ! holes are po9t$ & bla/$ by sup]9t5d+ m54 ,on developm5t "w ) ! foot-hole sy/em1 unless two work+ faces c be provid$ = ea* contract+ p>ty1 !y are likely to lose "t ?r\gh hav+ f9i%$ _! r\nd ( holes be=e ! end ( ! %ift4 ,z bla/+ mu/ be done outside ! contractor's %ifts1 x means t "o %ift p] day mu/ be set aside = ! purpose4 ,!re=e n ne>ly su* progress c be made z :]e work+ ! face ) ?ree %ifts4 ,= ^! reasons1 ! hole sy/em is n s advantage\s 9 developm5t z ! foot ( advance basis4 ,9 /op+1 ! hole sy/em has n only a wid]1 b a s\nd] application4 ,9 l>ge ore-bodies :]e !re are wa/e inclusions1 x has "o sup]iority ov] any sy/em ( excavation measurem5t1 namely1 t ! m9] has no int]e/ 9 break+ wa/e into ! ore4 ,! plan ( contract+ /opes by ! ton has ! disadvantage t ei!r ! ore produc$ by ea* contractor mu/ be weigh$ sep>ately1 or truck]s mu/ be tru/$ to c\nt correctly1 & to see t ! c>s are full4 ,moreov]1 trucks mu/ be inspect$ = wa/e1--a ?+ h>d to d und]gr\nd4 ,s great are ^! detail$ difficulties t _m m9es are s5d+ c>s to ! surface 9 cages :5 !y %\ld be equipp$ = b9-load+ & self-dump+ skips4 ,! me?od ( contract+ by ! cubic foot ( excavation saves all necessity = det]m9+ ! weight ( ! output ( ea* contractor4 ,moreov]1 he has no object 9 mix+ wa/e ) ! ore1 b>r+ ! break+ ( ! walls4 ,?is sy/em !re=e requires ! lea/ sup]9t5d5ce1 p]mits ! mod]n type ( hoi/+1 & !re=e leaves little ju/ification = ! survival ( ! tonnage basis4 ,:]e ve9s are n>r[1 /op+ "u contract by ! squ>e foot or fa?om measur$ p>allel to ! walls has an advantage4 ,! m9] has no object !n 9 break+ wall-rock1 & ! ?or\ghness ( ! ore-extraction is easily det]m9$ by inspection4 ,,bonus ,,sy/ems4--,by giv+ ca% bonuses = special accompli%m5t1 mu* ! same results c be obta9$ 9 "s dep>tm5ts z by contract+4 ,a bonus p] foot ( head+ ga9$ above a m9imum1 or an excess ( trucks tramm$ beyond a m9imum1 or prizes = ! l>ge/ am\nt done dur+ ! week or mon? 9 special works or 9 diff]5t %ifts1--all ^! h a useful application 9 creat+ effici5cy4 ,a high level ( results once e/abli%$ is easily ma9ta9$4 ,,labor ,,unions4--,!re is ano!r phase ( ! labor "q :i* mu/ be consid]$ & t is ! g5]al relations ( employ] & employ$4 ,9 ^! days ( l>gely corporate proprietor%ip1 ! own]s ( m9es are guid$ 9 _! relations ) labor by eng9e]s occupy+ executive positions4 ,on !m falls ! responsibility 9 su* matt]s1 & ! eng9e] becomes ?us a buff] betwe5 labor & capital4 ,z corporations h gr[n1 s likewise h ! labor unions4 ,9 g5]al1 !y are normal & prop] antidotes = unlimit$ capitali/ic organization4 ,labor unions usually pass ?r\gh two phases4 ,fir/1 ! in]tia ( ! unorganiz$ labor is too (t5 /irr$ only by demagogic means4 ,aft] organization ?r\gh ^! & o!r ag5cies1 ! lack ( balance 9 ! lead]s (t5 makes = inju/ice 9 dem&s1 & = viol5ce to obta9 !m & disreg>d ( agreem5ts ent]$ ^u4 ,z "t goes on1 m5 become educat$ 9 reg>d to ! rights ( _! employ]s1 & to ! reflection ( ^! rights 9 ultimate b5efit to labor itself4 ,!n ! m51 z well z ! intellig5t employ]1 endeavor to safegu>d bo? int]e/s4 ,:5 ?is /age arrives1 viol5ce disappe>s 9 favor ( negotiation on economic pr9ciples1 & ! unions a*ieve _! greate/ real ga9s4 ,giv5 a union ) lead]s :o c control ! memb]s1 & :o are dispos$ to approa* diff]5ces 9 a bus9ess _s1 !re are few s\nd] positions = ! employ]1 = agreem5ts honorably c>ri$ out dismiss ! con/ant h>assm5ts ( possible /rikes4 ,su* unions exi/ 9 doz5s ( trades 9 ?is c\ntry1 & !y are entitl$ to great] recognition4 ,! "t :5 ! employ] c\ld ride r\gh%od ov] 8 labor is disappe>+ ) ! doctr9e ( laissez faire1 on :i* x 0 f\nd$4 ,! soon] ! fact is recogniz$1 ! bett] = ! employ]4 ,! soon] "s m9]s' unions develop f ! fir/ into ! second /age1 ! m spe$ily w _! organizations secure g5]al respect & influ5ce499 ,footnote 993 ,"s ye>s ( exp]i5ce ) compulsory arbitration 9 ,au/ralia & ,new ,zeal& are conv9c+ t al?\gh ! law !re has _m defects1 /ill x is a /ep 9 ! "r direction1 & ! result has be5 ( almo/ unmix$ good to bo? sides4 ,"o ( its m9or1 yet really great1 b5efits has be5 a consid]able ext9ction ( ! p>asite :o lives by creat+ viol5ce4 ,! cry+ ne$ ( labor unions1 & ( "s employ]s z well1 is education on a fundam5tal ( economics too long disreg>d$ by all classes & especially by ! academic economi/4 ,:5 ! latt] ab&on ! !ory t wages are ! result ( supply & dem&1 & recognize t 9 ^! days ( int]national fl[ ( labor1 commodities & capital1 ! real controll+ factor 9 wages is effici5cy1 !n su* an educational campaign may become possible4 ,!n w ! employ] & employee f9d a common gr\nd on :i* ea* c b5efit4 ,!re lives no eng9e] :o has n se5 ins5sate dispute z to wages :]e ! real difficulty 0 ineffici5cy4 ,no adm9i/rator begrudges a division ) 8 m5 ( ! increas$ pr(it aris+ f increas$ effici5cy4 ,b e adm9i/rator begrudges ! wage level dem&$ by labor unions ^: policy is decreas$ effici5cy 9 ! false belief t !y are provid+ = m labor4 ,,*apt] ,,xvii4 ,adm9i/ration 7,cont9u$74 ,,acc\nts ,,& ,,te*nical ,,data ,,& ,,reports2 ,,work+ ,,co/s2 ,,division ,,( ,,exp5diture2 ,,inh]5t ,,limitations ,,9 ,,accuracy ,,( ,,work+ ,,co/s2 ,,work+ ,,co/ ,,%eets4 ,,g5]al ,,te*nical ,,data2 ,,labor1 ,,supplies1 ,,p[]1 ,,surveys1 ,,sampl+1 ,,& ,,assay+4 ,fir/ & =emo/1 m9e acc\nts are = guidance 9 ! di/ribution ( exp5diture & 9 ! collection ( rev5ue2 secondly1 !y are to det]m9e ! f9ancial progress ( ! ent]prise1 its pr(it or loss2 & ?irdly1 !y are to furni% /ati/ical data to assi/ ! managem5t 9 its int]m9able battle to r$uce exp5ses & increase rev5ue1 & to enable ! own] to det]m9e ! effici5cy ( 8 adm9i/rators4 ,bookkeep+ p] se is no "p ( ?is discussion4 ,! fundam5tal purpose ( t art is to cov] ! fir/ two objects1 &1 z su*1 does n diff] f its application to o!r comm]cial conc]ns4 ,9 addition to ^! acc\nt+ matt]s !re is a fur!r type ( adm9i/rative report ( equal importance--t is ! p]iodic /atem5ts z to ! physical condition ( ! prop]ty1 ! results ( exploration 9 ! m9e1 & ! condition ( ! equipm5t4 ,,acc\nts4 ,! special features ( m9e acc\nt+ reports :i* are a developm5t to meet ! ne$s ( ?is p>ticul> bus9ess are ! det]m9ation ( work+ co/s1 & ! f9al pres5tation ( ^! data 9 a =m available = comp>ative purposes4 ,! subject may be discuss$ "u3-- #a4 ,classes ( m9e exp5diture4 #b4 ,work+ co/s4 #c4 ,! dissection ( exp5ditures dep>tm5tally4 #d4 ,inh]5t limitations 9 ! accuracy ( work+ co/s4 #e4 ,work+ co/ %eets4 ,9 a wide view1 m9e exp5ditures fall into ?ree classes1 :i* maybe t]m$ ! fix$ *>ges1 proportional *>ges1 & susp5se *>ges or capital exp5diture4 ,fix$ *>ges are ^? :i*1 l pump+ & sup]9t5d5ce1 dep5d ^u "t r ?an tonnage & mat]ial h&l$4 ,!y are exp5ditures t w\ld n decrease relatively to output4 ,proportional *>ges are ^? :i*1 l ore-break+1 /op+1 support+ /opes1 & tramm+1 are a direct coeffici5t ( ! ore extract$4 ,susp5se *>ges are ^? :i* are an indirect factor ( ! co/ ( ! ore produc$1 su* z equipm5t & developm5t4 ,^! exp5ditures are prelim9>y to output1 & !y ?us repres5t a /orage ( exp5se to be *>g$ (f :5 ! ore is won4 ,?is outlay is (t5 call$ capital exp5diture4 ,su* a t]m1 ?\gh 9 common use1 is n /rictly correct1 = ! capital value vani%es :5 ! ore is extract$1 b 9 con=mity ) curr5t usage ! t]m capital exp5diture w be adopt$4 ,except = ! purpose ( special inquiry1 su* z outl9$ "u ! *apt] on ,ratio ( ,output1 fix$ *>ges are n cu/om>ily a special division 9 acc\nts4 ,9 a g5]al way1 su* exp5ditures1 comb9$ ) ! proportional *>ges1 are call$ rev5ue exp5diture1 z di/+ui%$ f ! capital1 or susp5se1 exp5ditures4 ,9 o!r words1 rev5ue exp5ditures are ^? involv$ 9 ! daily turnov] ( ! bus9ess & result+ 9 imm$iate returns4 ,! inh]5t diff]5ce 9 "* ( rev5ue & capital exp5ditures is responsible = mo/ ( ! difficulties 9 ! det]m9ation ( work+ co/s1 & mo/ ( ! discussion on ! subject4 ,,work+ ,,co/s4--,work+ co/s are a division ( exp5diture = "s unit1--! foot ( op5+1 ton ( ore1 a p\nd ( metal1 cubic y>d or fa?om ( mat]ial excavat$1 or "s o!r measure4 ,! co/s p] unit are usually d$uc$ = ea* mon? & ea* ye>4 ,!y are g5]ally det]m9$ = ea* ( ! diff]5t dep>tm5ts ( ! m9e or special works sep>ately4 ,fur!r1 ! v>i\s sorts ( exp5diture 9 ^! dep>tm5ts are likewise segregat$4 ,9 metal m9+ ! ton is ! univ]sal unit ( di/ribution = adm9i/rative purpose1 al?\gh ! p\nd ( metal is (t5 us$ to indicate f9al f9ancial results4 ,! object ( det]m9ation ( work+ co/s is fundam5tally = comp>ative purposes4 ,toge!r ) o!r te*nical data1 !y are ! n]ves ( ! adm9i/ration1 = by comp>ison ( detail$ & aggregate results ) o!r m9es & int]nally 9 ! same m9e1 ov] v>i\s p]iods & betwe5 diff]5t works1 a mo/ valuable *eck on effici5cy is possible4 ,fur!r1 !re is "o collat]al value 9 all /ati/ical data n to be ov]look$1 :i* is t ! k ( its exi/5ce induces 9 ! subord9ate /aff bo? solicitude & emulation4 ,! fact mu/ n be lo/ sight (1 h[ev]1 t ! wide v>iations 9 physical & economic environm5t are s likely to vitiate conclusions f comp>isons ( /ati/ics f two m9es or f two detail$ works on ! same m9e1 or ev5 f two diff]5t mon?s on ! same "w1 t ! greate/ c>e & discrim9ation are dem&$ 9 _! application4 ,moreov]1 ! inh]5t difficulties 9 segregat+ & divid+ ! acc\nts :i* und]lie su* data1 r5d] x mo/ desirable to (f] "s w>n+ reg>d+ ! limits to :i* segregation & division may be c>ri$ to advantage4 ,z work+ co/s are prim>ily = comp>isons1 9 ord] t !y may h value = ?is purpose !y mu/ include only su* items ( exp5diture z w regul>ly recur4 ,if ?is limitation 7 m g5]ally recogniz$1 a good deal ( dispute & polemics on ! subject might be sav$4 ,= ?is reason x is q impossible t all ! exp5diture on ! m9e %\ld be *>g$ into work+ co/s1 p>ticul>ly "s items t arise ?r\gh capital exp5diture4 ,,! ,,dissection ,,( ,,exp5ditures ,,dep>tm5tally4--,! f9al division 9 ! dissection ( ! m9e exp5diture is 9 ! ma93-- _/7#a7 ,g5]al ,exp5ses4 _/ ,ore-break+4 ,support+ ,/opes4 ,v>i\s ,rev5ue4 7#b7 ,ore ,extraction4 ,truck+ ,ore4 exp5ditures ,hoi/+4 = labor1 7#c7 ,pump+4 supplies1 p[]1 _/ ,%aft-s9k+4 repairs1 etc41 ,/ation-cutt+4 work$ out p] ,crosscutt+4 ton or foot _/7#d7 ,developm5t4 ,driv+4 advanc$ ,capital ,ris+4 ov] ea* or ,w9zes4 dep>tm5t4 ,susp5se4 ,diamond ,drill+4 _/ 7#e7 ,con/ruction & ,v>i\s ,works4 ,equipm5t4 _/ ,! detail$ dissection ( exp5ditures 9 ^! v>i\s dep>tm5ts ) view to det]m9e am\nt ( v>i\s sorts ( exp5diture ov] ! dep>tm5t1 or ov] "s special "w 9 t dep>tm5t1 is full ( unsolvable complications4 ,! allocation ( ! direct exp5diture ( labor & supplies appli$ to ! above divisions or special dep>tm5ts 9 !m1 is easily accompli%$1 b beyond ?is po9t two sorts ( difficulties imm$iately arise & (f] inf9ite field = op9ion & me?od4 ,! fir/ ( ^! difficulties arises f supplem5t>y dep>tm5ts on ! m9e1 su* z p[]1 repairs & ma9t5ance1 sampl+ & assay+4 ,^! dep>tm5ts mu/ be spread ov] ! divisions outl9$ above1 = su* *>ges are 9 "p or :ole a portion ( ! exp5se ( ^! divisions4 ,fur!r1 all ( ^! spread dep>tm5ts are appli$ to surface z well z to und]gr\nd works1 & mu/ be divid$ n only ov] ! above dep>tm5ts b also ov] ! surface dep>tm5ts1--n "u discussion "h4 ,! common me?od is to di/ribute p[] on a basis ( an approximation ( ! am\nt us$ 9 ea* dep>tm5t2 to di/ribute repairs & ma9t5ance1 ei!r on a basis ( %op returns1 or a di/ribution ov] all dep>tm5ts on ! basis ( ! labor employ$ 9 ^? dep>tm5ts1 on ! !ory t su* repairs arise 9 ?is proportion2 to di/ribute sampl+ & assay+ ov] ! actual po9ts to :i* !y relate at ! av]age co/ p] sample or assay4 ,g5]al exp5ses1 t is1 sup]9t5d5ce1 etc41 are (t5 n includ$ 9 ! f9al dep>tm5ts z above1 b are sometimes spread 9 an attempt to *>ge a proportion ( sup]9t5d5ce to ea* p>ticul> "w4 ,z1 h[ev]1 su* spread+ mu/ take place on ! basis ( ! relative exp5diture 9 ea* dep>tm5t1 ! result is ( little value1 = su* a basis does n truly repres5t ! proportion ( g5]al sup]9t5d5ce1 etc41 devot$ to ea* dep>tm5t4 ,if !y are di/ribut$ ov] all dep>tm5ts1 capital z well z rev5ue1 on ! basis ( total exp5diture1 !y inflate ! capital exp5diture dep>tm5ts aga9/ a day ( reckon+ :5 ^! *>ges come to be di/ribut$ ov] work+ co/s4 ,al?\gh x may be cont5d$ t ! capital dep>tm5ts also require sup]vision1 su* a practice is a favorite device = %[+ app>5tly l[ work+ co/s 9 ! rev5ue dep>tm5ts4 ,! mo/ c\rage\s way is n to di/ribute g5]al exp5ses at all1 b to *>ge !m sep>ately & directly to rev5ue acc\nts & ?us :olly into work+ co/s4 ,! second problem is to r$uce ! susp5se or capital *>ges to a f9al co/ p] ton1 & ?is is no simple matt]4 ,developm5t exp5ditures be> a relation to ! tonnage develop$ & n to t extract$ 9 any p>ticul> p]iod4 ,if x is desir$ to pres]ve any value = comp>ative purposes 9 ! m9+ co/s1 su* outlay mu/ be *>g$ out on ! basis ( ! tonnage develop$1 & su* portion ( ! ore z is extract$ mu/ be writt5 (f at ?is rate2 o!rwise "o mon? may see d\ble ! am\nt ( developm5t 9 progress :i* ano!r records1 & ! und]gr\nd co/s w\ld be swell$ or dim9i%$ !reby 9 a way to ru9 _! comp>ative value f mon? to mon?4 ,! ore develop$ _c be satisfactorily det]m9$ at %ort int]vals1 b x c be kn[n at lea/ annually1 & a price may be d$uc$ z to its co/ p] ton4 ,9 _m m9es a figure is arriv$ at by e/imat+ ore-res]ves at ! end ( ! ye>1 & ?is figure is us$ dur+ ! succe$+ ye> z a r$emption ( developm5t & z su* *>g$ to work+ co/s1 & ?us into rev5ue acc\nt 9 proportion to ! tonnage extract$4 ,?is matt] is fur!r elaborat$ 9 "s m9es1 9 t w9zes & rises are writt5 (f at "o rate1 levels & crosscuts at ano!r1 & %afts at "o /ill l[]1 on ! !ory t !y lo/ _! usefulness 9 ?is progression z ! ore is extract$4 ,?is c\rse1 h[ev]1 is a ref9em5t h>dly w>rant$4 ,plant & equipm5t con/itute ano!r susp5se acc\nt ev5 h>d] to *>ge up logically to tonnage co/s1 = x is 9 _m items dep5d5t ^u ! life ( ! m9e1 :i* is an unkn[n factor4 ,mo/ manag]s debit repairs & ma9t5ance directly to ! rev5ue acc\nt & leave ! r$uction ( ! con/ruction outlay to an annual depreciation on ! f9al balance %eet1 on ! !ory t ! plant is ma9ta9$ out ( co/s to its orig9al value4 ,?is subject w be discuss$ fur!r on4 ,,inh]5t ,,limitations ,,9 ,,accuracy ,,( ,,work+ ,,co/s4--,!re are ?ree types ( su* limitations :i* arise 9 ! det]m9ation ( co/s & r5d] too detail$ dissection ( su* co/s hopeless ( accuracy & ( little value = comp>ative purposes4 ,!y are1 fir/1 ! difficulty ( det]m9+ all ( ev5 direct exp5diture on any p>ticul> crosscut1 /ope1 haulage1 etc42 second1 ! level+ effect ( di/ribut+ ! spread exp5ditures1 su* z p[]1 repairs1 etc42 & ?ird1 ! difficulties aris+ out ( ! bord]l& ( v>i\s dep>tm5ts4 ,( ! fir/ ( ^! limitations ! in/ance may be cit$ t =em5 & timekeep]s c indicate v closely ! de/9ation ( labor exp5se1 & also t ( "s ( ! l>ge items ( supply1 su* z timb] & explosives1 b ! di/ribution ( m9or supplies1 su* z c&les1 drills1 picks1 & %ovels1 is impossible ( accurate k )\t an exp5se :olly unw>rant$ by ! in=mation ga9$4 ,to det]m9e at a p>ticul> crosscut ! exact am\nt ( /eel1 & ( tools consum$1 & ! co/ ( %>p5+ !m1 w\ld entail _! sep>ate & special deliv]y to ! same place ( attack & a f9al weigh+-up to le>n ! consumption4 ,( ! second sort ( limitations1 ! effect ( spread exp5diture1 ! in/ance may be giv5 t ! repairs & ma9t5ance are done by _m m5 at "w on timb]s1 tracks1 ma*9]y1 etc4 ,x is hopeless to try & tell h[ mu* ( _! "w %\ld be *>g$ specifically to detail$ po9ts4 ,9 ! di/ribution ( p[] may be tak5 ! in/ance ( air-drills4 ,al?\gh ! "w ^u :i* ! drill is employ$ c be kn[n1 ! p[] requir$ = compression usually comes f a common p[]-plant1 s t ! portion ( p[] debit$ to ! air compressor is an approximation4 ,! assumption ( an equal consumption ( air by all drills is a fur!r approximation4 ,9 practice1 !re=e1 _m exp5ses are di/ribut$ on ! !ory t !y arise 9 proportion to ! labor employ$1 or ! ma*9es us$ 9 ! v>i\s dep>tm5ts4 ,! net result is to level d[n exp5sive po9ts & level up inexp5sive ones4 ,! ?ird sort ( limitation ( acc\nt+ difficulty ref]r$ to1 arises 9 det]m9+ into :i* dep>tm5t are actually to be allocat$ ! *>ges :i* lie 9 ! bord]l& betwe5 v>i\s prim>y classes ( exp5diture4 ,= in/ance1 9 ore won f developm5t1--9 "s mon?s ?ree times z mu* developm5t may be 9 ore z 9 o!r mon?s4 ,if ! total exp5se ( developm5t "w :i* yields ore be *>g$ to /op+ acc\nt1 & if co/ be work$ out on ! total tonnage ( ore hoi/$1 !n ! /op+ co/ d$uc$ w be erratic1 & ! true figures w be obscur$4 ,on ! o!r h&1 if all developm5t is *>g$ to 'capital acc\nt' & ! /op+ co/ work$ out on all ore hoi/$1 x w include a fluctuat+ am\nt ( ore n actually paid = by ! rev5ue dep>tm5ts or *>g$ into co/s4 ,?is fluctuation ei!r way vitiates ! :ole comp>ative value ( ! /op+ co/s4 ,9 ! foll[+ sy/em a compromise is rea*$ by cr$it+ developm5t ) an am\nt repres5t+ ! ore won f developm5t at ! av]age co/ ( /op+1 & by *>g+ ?is am\nt into /op+4 ,a numb] ( su* que/ions arise :]e ! prop] division is simply a matt] ( op9ion4 ,! result ( all ^! limitations is t a po9t 9 detail is quickly rea*$ :]e no fur!r dissection ( exp5diture is ju/ifi$1 s9ce x becomes m]ely an approximation4 ,! writ]'s own impression is t )\t an unw>rantable numb] ( acc\ntants1 no manag] c tell ) any accuracy ! co/ ( any p>ticul> /ope1 or ( any p>ticul> developm5t head+4 ,!re=e1 aside f "s l>ge items1 su* detail$ /ati/ics1 if giv51 are to be tak5 ) great res]ve4 ,,work+ ,,co/ ,,%eets4--,!re are an inf9ite numb] ( =ms ( work+ co/ %eets1 practically e manag] hav+ a sy/em ( 8 own4 ,to be ( greate/ value1 su* %eets %\ld %[ on _! face ! me?od by :i* ! spread dep>tm5ts are h&l$1 & h[ rev5ue & susp5se dep>tm5ts are segregat$4 ,:5 too mu* detail is pres5t$1 x is b a wa/e ( acc\nt+ & consequ5t exp5se4 ,:]e to draw ! l9e 9 ?is reg>d is1 h[ev]1 a matt] ( great difficulty4 ,no co/ %eet is entirely satisfactory4 ,! app5d$ %eet is 9 use at a numb] ( m9es4 ,x is no m p]fect ?an _m o!rs4 ,x w be notic$ t ! effect ( ?is sy/em is to ?r[ ! g5]al exp5ses into ! rev5ue exp5ditures1 & z little z possible into ! susp5se acc\nt4 ,,g5]al ,,te*nical ,,data4 ,= ! purposes ( effici5t managem5t1 ! in=mation ga!r$ "u ?is head is ( equal1 if n sup]ior1 importance to t "u work+ co/s4 ,su* data fall g5]ally "u ! foll[+ heads3-- ,,labor4--,returns ( ! %ifts work$ 9 ! v>i\s dep>tm5ts = ea* day & = ! mon?2 work$ out on a mon?ly basis ( footage progress1 tonnage produc$ or tons h&l$ p] man2 also :]e possible ! footage ( holes drill$1 work$ out p] man & p] ma*9e4 ,,supplies4--,daily returns ( supplies us$2 ! pr9cipal items work$ out mon?ly 9 quantity p] foot ( progress1 or p] ton ( ore produc$4 ,,p[]4--,fuel1 lubricant1 etc41 consum$ 9 /eam production1 work$ out into units ( /eam produc$1 & ?is production allocat$ to ! v>i\s eng9es4 ,:]e electrical p[] is us$1 ! consumption ( ! v>i\s motors is set out4 ,,surveys4--,! ne$ ( accurate plans requires no discussion4 ,aside f ^!1 ! survey-(fice furni%es ! returns ( developm5t footage1 measurem5ts "u contracts1 & ! l4 ,,sampl+ ,,& ,,assay+4--,m9e sampl+ & assay+ fall "u two heads1--! det]m9ation ( ! value ( /&+ ore1 & ( products f ! m9e4 ,! sampl+ & assay+ on a go+ m9e call = ! same c>e & me?od z 9 cases ( valuation ( ! m9e = pur*ase1--! details ( :i* h be5 pres5t$ "u ,m9e ,valuation1--= ?r\gh x1 guidance mu/ n only be _h to ! value ( ! m9e & = reports to own]s1 b ! detail$ developm5t & ore extraction dep5d on an absolute k ( :]e ! values lie4 ,,*apt] ,,xviii4 ,,adm9i/ration 7,conclud$74 ,,adm9i/rative ,,reports4 ,9 addition to f9ancial returns %[+ ! mon?ly receipts1 exp5ditures1 & work+ co/s1 !re mu/ be 9 prop] adm9i/ration p]iodic reports f ! (fic]s ( ! m9e to ! own]s or directors z to ! physical progress ( ! ent]prise4 ,su* reports mu/ embrace details ( ore extraction1 metal cont5ts1 treatm5t recov]ies1 con/ruction ( equipm5t1 & ! results ( und]gr\nd developm5t4 ,! value ( m9es is s mu* affect$ by ! mon?ly or ev5 daily result ( exploration t reports ( su* "w are ne$$ v frequ5tly1--weekly or ev5 daily if critical "w is 9 progress4 ,^! reports mu/ %[ ! wid?1 l5g?1 & value ( ! ore disclos$4 ,! tangible result ( developm5t "w is ! tonnage & grade ( ore op5$ up4 ,h[ (t5 ?is /ock-tak+ %\ld take place is mu* dep5d5t ^u ! "* ( ! ore4 ,! result ( exploration 9 irregul> ore-bodies (t5 does n1 ov] %ort p]iods1 %[ any?+ tangible 9 def9ite measurable tonnage1 b at lea/ annually ! ore res]ve c be e/imat$4 ,9 m9es own$ by companies1 ! "q arises almo/ daily z to h[ mu* ( & h[ (t5 ! above in=mation %\ld be plac$ be=e /ockhold]s 7& !re=e ! public7 by ! directors4 ,9 a g5]al way1 any company ^: %>es are (f]$ on ! /ock ex*ange is indirectly invit+ ! public to become p>tn]s 9 ! bus9ess1 & ^! p>tn]s are entitl$ to all ! in=mation :i* affects ! value ( _! prop]ty & are entitl$ to x promptly4 ,moreov]1 m9+ is a bus9ess :]e competition is s obscure & s mu* a matt] ( indiff]5ce1 t suppression ( important facts 9 docum5ts = public circulation has no ju/ification4 ,on ! o!r h&1 bo? ! te*nical progress ( ! indu/ry & its position 9 public e/eem dem& ! fulle/ disclosure & greate/ c>e 9 prep>ation ( reports4 ,mo/ /ockhold]s' ignorance ( m9+ te*nology & ( details ( _! p>ticul> m9e dem&s a great deal ( c>e & discretion 9 ! prep>ation ( ^! public reports t !y may n be misl$4 ,developm5t results may mean little or mu*1 dep5d+ ^u ! location ( ! "w done 9 relation to ! ore-bodies1 etc41 & ?is %\ld be cle>ly set =?4 ,! be/ opportunity ( cle>1 well-balanc$ /atem5ts lies 9 ! prep>ation ( ! annual report & acc\nts4 ,su* reports are ( ?ree p>ts3-- #a4 ,! pr(it & loss acc\nt1 or ! rev5ue acc\nt4 #b4 ,! balance %eet2 t is1 ! assets & liabilities /atem5t4 #c4 ,! reports ( ! directors1 manag]1 & consult+ eng9e]4 ,! fir/ two items are l>gely matt]s ( bookkeep+4 ,!y or ! report %\ld %[ ! work+ co/s p] ton = ! ye>4 ,:at mu/ be "h includ$ 9 co/s is easi] ( det]m9ation ?an 9 ! detail$ mon?ly co/ %eets ( ! adm9i/ration2 = at ! annual review1 x is n difficult to assess ! am\nt *>geable to developm5t4 ,equipm5t exp5diture1 h[ev]1 pres5ts an annual difficulty1 =1 z said1 ! di/ribution ( ?is item is a factor ( ! life ( ! m9e1 & t is unkn[n4 ,if su* a plant has be5 paid = out ( ! e>n+s1 !re is no object 9 c>ry+ x on ! company's books z an asset1 & mo/ well-conduct$ companies write x (f at once4 ,on ! o!r h&1 :]e ! plant is paid = out ( capital provid$ = ! purpose1 ev5 to write (f depreciation means t a correspond+ sum ( ca% mu/ be held 9 ! company's treasury 9 ord] to balance ! acc\nts1--9 o!r words1 depreciation 9 su* an in/ance becomes a return ( capital4 ,! "q !n is "o ( policy 9 ! company's f9ance1 & 9 nei!r case is x a matt] :i* c be br\ght into work+ co/s & leave !m any value = comp>ative purposes4 ,inde$1 ! true co/ ( work+ ! ore f any m9e c only be told :5 ! m9e is exhau/$2 !n ! divid5ds c be subtract$ f ! capital sunk & metal sold1 & ! diff]5ce divid$ ov] ! total tonnage produc$4 ,! ?ird section ( ! report af=ds wide scope = ! be/ ef=ts ( ! adm9i/ration4 ,?is portion ( ! report falls into ?ree divisions3 7a7 ! con/ruction & equipm5t "w ( ! ye>1 7b7 ! ore extraction & treatm5t1 & 7c7 ! results ( developm5t "w4 ,! fir/ requires a /atem5t ( ! plant con/ruct$1 its object & accompli%m5t2 ! second a disclosure ( tonnage produc$1 values1 metallurgical & me*anical effici5cy4 ,! ?ird is ( ! utmo/ importance to ! /ockhold]1 & is ! "o mo/ (t5 disreg>d$ & obscur$4 ,^u ?is h+es ! value ( ! prop]ty4 ,!re is no reason :y1 ) plans & simplicity ( t]ms1 su* reports _c be pres5t$ 9 a mann] f :i* ! novice c judge ( ! intr9sic position ( ! prop]ty4 ,a /atem5t ( ! tonnage ( ore-res]ves & _! value1 or ( ! numb] ( ye>s' supply ( ! curr5t output1 toge!r ) details ( ore disclos$ 9 developm5t "w1 & ! work+ co/s1 give ! gr\nd data ^u :i* any /ockhold] :o takes int]e/ 9 8 inve/m5t may judge = himself4 ,failure to provide su* data w "s day be und]/ood by ! inve/+ public z a prima facie index ( ei!r incapacity or villa9y4 ,by ! insi/5ce ( ! _m eng9e]s 9 adm9i/ration ( m9es ^u ! publication ( su* data1 & by ! insi/5ce ( o!r eng9e]s ^u su* data = _! cli5ts be=e inve/m5t1 & by ! exposure ( ! del9qu5ts 9 ! press1 a m practicable protection ( inve/ors c be rea*$ ?an by ye>s ( academic discussion4 ,,*apt] ,,xix4 ,! ,am\nt ( ,risk 9 ,m9+ ,inve/m5ts4 ,,risk ,,9 ,,valuation ,,( ,,m9es2 ,,9 ,,m9es ,,z ,,comp>$ ,,) ,,o!r ,,comm]cial ,,ent]prises4 ,f ! con/ant reit]ation ( ! risks & difficulties involv$ 9 e /ep ( m9+ ent]prise f ! valuation ( ! m9e to its adm9i/ration z a go+ conc]n1 ! impression may be ga9$ t ! :ole bus9ess is "o great gamble2 9 o!r words1 t ! po9t :]eat c]ta9ties /op & conjecture /eps 9 is s vital z to r5d] ! :ole highly speculative4 ,f> f d5y+ t m9+ is1 9 comp>ison ) bett]-class gov]nm5t bonds1 a speculative type ( inve/m5t1 x is desirable to av[ & emphasize ! fact4 ,b x is none ! less well to inquire :at degree ( haz>d ent]s 9 & h[ x comp>es ) t 9 o!r =ms ( indu/rial ent]prise4 ,m9+ bus9ess1 f an inve/m5t view1 is ( two sorts1--prospect+ v5tures & develop$ m9es2 t is1 m9es :]e little or no ore is expos$1 & m9es :]e a def9ite quantity ( ore is measurable or c be reasonably anticipat$4 ,! great haz>ds & likewise ! ,aladd9 caves ( m9+ are ma9ly conf9$ to ! fir/ class4 ,al?\gh all m9es mu/ pass ?r\gh ! prospect+ /age1 ! great indu/ry ( metal production is bas$ on develop$ m9es1 & x is ^! :i* %\ld come into ! purview ( ! non-pr(essional inve/or4 ,! fir/ class %\ld be res]v$ inv>iably = speculators1 & a speculator may be def9$ z "o :o haz>ds all to ga9 mu*4 ,x is ) m9+ z an inve/m5t1 h[ev]1 t ?is discussion is conc]n$4 ,,risk ,,9 ,,valuation ,,( ,,m9es4--,assum+ a compet5t collection ( data & effici5t managem5t ( ! prop]ty1 ! risks 9 valu+ are f /ep to /ep3-- #a4 ,! risk ( cont9uity 9 metal cont5ts beyond sample faces4 #b4 ,! risk ( cont9uity 9 volume ?r\gh ! blocks e/imat$4 #c4 ,! risk ( successful metallurgical treatm5t4 #d4 ,! risk ( metal prices1 9 all b gold4 #e4 ,! risk ( prop]ly e/imat+ co/s4 #f4 ,! risk ( ext5sion ( ! ore beyond exposures4 #g4 ,! risk ( managem5t4 ,z to ! cont9uity ( values & volumes ?r\gh ! e/imat$ area1 ! exp]i5ce ( hundr$s ( eng9e]s 9 hundr$s ( m9es has %[n t :5 ! e/imates are bas$ on prop]ly secur$ data = prov$ ore1 "h at lea/ !re is absolutely no haz>d4 ,metallurgical treatm5t1 if det]m9$ by pa/ exp]i5ce on ! ore itself1 c>ries no *ance2 & :]e det]m9$ by exp]im5t1 ! risk is elim9at$ if ! "w be suffici5tly exhau/ive4 ,! risk ( metal price is simply a "q ( h[ cons]vative a figure is us$ 9 e/imat+4 ,x c be elim9at$ if a price l[ en\gh be tak54 ,risk ( ext5sion 9 dep? or beyond exposures _c be avoid$4 ,x c be r$uc$ 9 proportion to ! di/ance assum$4 ,obvi\sly1 if no ext5sion is c\nt$1 !re is no?+ *anc$4 ,! risk ( prop] appreciation ( co/s is negligible :]e exp]i5ce 9 ! di/rict exi/s4 ,o!rwise1 x c be elim9at$ if a suffici5tly l>ge all[ance is tak54 ,! risk ( failure to secure good managem5t c be elim9at$ if prov$ m5 are *os54 ,!re is1 !re=e1 a basic value to e m9e4 ,! prov$ ore tak5 on kn[n metallurgical gr\nds1 "u kn[n conditions ( co/s on m9imum prices ( metals1 has a value z c]ta9 z t ( money 9 "o's own vault4 ,?is is ! value previ\sly ref]r$ to z ! ,a value4 ,if ! price 7& int]e/ on x p5d+ recov]y7 falls )9 ?is am\nt1 !re is no "q t ! m9e is wor? ! price4 ,:at ! risk is 9 m9+ is simply :at am\nt ! price ( ! inve/m5t dem&s %all be won f ext5sion ( ! deposit beyond kn[n exposures1 or :at high] price ( metal mu/ be realiz$ ?an t calculat$ 9 ! ,a value4 ,! dem&s on ?is ,x1 ,y portion ( ! m9e c be conv]t$ into tons ( ore1 life ( production1 or high] prices1 & ^! c be weigh$ ) ! geological weights & ! indu/rial outlook4 ,,m9es ,,comp>$ ,,to ,,o!r ,,comm]cial ,,ent]prises4--,! pr(its f a m9+ v5ture ov] & above ! b$-rock value ,a1 t is1 ! return to be d]iv$ f m ext5sive ore-recov]y & a high] price ( metal1 may be comp>$ to ! value includ$ 9 o!r =ms ( comm]cial ent]prise = good-w4 ,su* =ms ( ent]prise are valu$ on a basis ( ! am\nt :i* w replace ! net assets plus 7or m9us7 an am\nt = good-w1 t is1 ! e>n+ capacity4 ,?is good-w is a speculation ( v>y+ risk dep5d+ on ! "* ( ! ent]prise4 ,= natural monopolies1 l "s railways & wat]works1 ! risk is less & = %oe factories m4 ,ev5 natural monopolies are subject to ! risks ( antagoni/ic legislation & indu/rial /orms4 ,b1 elim9at+ ?is class ( ent]prise1 ! speculative value ( a good-w involves a great] risk ?an prospective value 9 m9es1 if prop]ly measur$2 because ! dang]s ( competition & indu/rial /orms d n ent] to su* a degree1 nor is ! future s dep5d5t ^u ! human g5ius ( ! f\nd] or manag]4 ,m9+ has rea*$ su* a /age ( developm5t z a sci5ce t managem5t proce$s ^u comp>atively well-kn[n l9es4 ,x is subject to kn[n *ecks ?r\gh ! opportunity ( comp>isons by :i* effici5cy c be det]m9$ 9 a mann] m op5 = ! inve/or to le>n ?an 9 any o!r =m ( indu/ry4 ,:ile 9 m9+ an e/imate ( a c]ta9 m9imum ( ext5sion 9 dep?1 z indicat$ by collat]al factors1 may occasionally fall %ort1 x w1 9 n9e cases out ( t51 be exce$$4 ,if inve/m5t 9 m9es be spread ov] t5 cases1 simil>ly valu$ z to m9imum ( ext5sion1 ! risk has be5 virtually elim9at$4 ,! indu/ry1 if r$uc$ to ! above basis = f9ancial guidance1 is a m pr(itable bus9ess & is "o ( less haz>ds ?an competitive =ms ( comm]cial ent]prises4 ,9 view ( :at has be5 said be=e1 x may be unnecess>y to ref] aga9 to ! subject1 b ! con/ant reit]ation by wiseacres t ! weak po9t 9 m9+ inve/m5ts lies 9 _! %ort life & possible loss ( capital1 w>rants a repetition t ! ,a1 ,b1 ,c ( prop] inve/m5t 9 m9es is to be assur$1 by ! ,a value1 ( a return ( ! :ole or major portion ( ! capital4 ,! risk ( int]e/ & pr(it may be def]r$ to ! ,x1 ,y value1 & 9 su* case x is on a plane ) good-w4 ,x %\ld be said at once to t class :o want l>ge returns on inve/m5t )\t inve/igation z to m]its1 or assurance z to ! managem5t ( ! bus9ess1 t !re is no field 9 ?is _w = ! employm5t ( _! money at ov] #d4 ,un=tunately = ! reputation ( ! m9+ indu/ry1 & metal m9es especially1 ! bus9ess is (t5 n conduct$ or valu$ on l9es :i* h be5 outl9$ 9 ^! *apt]s4 ,!re is (t5 ! desire to sell /ocks beyond _! value4 ,!re is always ! possibility t ext5sion 9 dep? w reveal a glori\s ,eldorado4 ,x occasionally does1 & ! report e*oes r\nd ! _w = ye>s1 toge!r ) tributes to ! great judgm5t ( ! exploit]s4 ,! volume ( s\nd allures undue numb]s ( ! v5turesome1 untra9$1 & ill-advis$ public to ! bus9ess1 toge!r ) a mob ( camp-foll[]s ^: objective is to exploit ! ignorant by prey+ on _! gambl+ in/9cts4 ,?us a consid]able section ( metal m9+ indu/ry is 9 ! h&s ( ^! classes1 & a cl\d ( disrepute hangs ev] 9 ! horizon4 ,!re has be5 a great educational campaign 9 progress dur+ ! pa/ few ye>s ?r\gh ! te*nical tra9+ ( m5 = conduct ( ! indu/ry1 by ! example ( reputable companies 9 regul>ly publi%+ ! ess5tial facts ^u :i* ! value ( _! m9es is bas$1 & ?r\gh und]/&able nonte*nical discussion 9 & by "s sections ( ! f9ancial & g5]al press4 ,! real inve/or is be+ educat$ to di/+ui% betwe5 reputable conc]ns & ! c\nt]s ( game/]s4 ,moreov]1 ye>ly1 m5 ( te*nical k are tak+ a /rong] & m influ5tial "p 9 m9+ f9ance & 9 ! direction ( m9+ & exploration companies4 ,! net result ( ^! =ces w be to put m9+ on a bett] plane4 ,,*apt] ,,xx4 ,! ,"*1 ,tra9+1 & ,obligations ( ! ,m9+ ,eng9e]+ ,pr(ession4 ,9 a discussion ( "s problems ( metal m9+ f ! po9t ( view ( ! direction ( m9+ op]ations x may n be amiss to discuss ! "* ( ! m9+ eng9e]+ pr(ession 9 its be>+s on tra9+ & practice1 & its relations to ! public4 ,! mo/ dom9ant *>act]i/ic ( ! m9+ eng9e]+ pr(ession is ! va/ prepond]ance ( ! comm]cial ov] ! te*nical 9 ! daily "w ( ! eng9e]4 ,= ye>s a gradual evolution has be5 9 progress alt]+ ! l>g] dem&s on ?is bran* ( ! eng9e]+ pr(ession f advisory to executive "w4 ,! m9+ eng9e] is no long] ! te*nician :o concocts reports & blue pr9ts4 ,x is dem&$ ( him t he devise ! f9ance1 con/ruct & manage ! works :i* he advises4 ,! dem&s ( su* executive "w are l>gely comm]cial2 al?\gh ! comm]cial exp]i5ce & executive ability ?us become "o pi] 9 ! f\ndation ( tra9+1 ! bridge no less requires two pi]s1 & ! second is bas$ on te*nical k4 ,f> f be+ deprecat$1 ^! comm]cial phases _c be too /rongly emphasiz$4 ,on ! o!r h&1 ,i am f> f cont5d+ t our vocation is a bus9ess r ?an a pr(ession4 ,= _m ye>s aft] ! dawn ( mod]n eng9e]+1 ! memb]s ( our pr(ession 7 m5 :o rose ?r\gh ! ranks ( workm51 & z a result1 we are to ?is day 9 ! public m9d a sort ( sup]ior artisan1 = to _m ! eng9e-driv] is equally an eng9e] ) ! design] ( ! eng9e1 yet _! real relation is b z ! h& to ! bra94 ,at a lat] p]iod ! recruits ent]$ by appr5tice%ip to ^? m5 :o _h e/abli%$ _! intellectual sup]iority to _! fell[-work]s4 ,^! m5 7 ne>ly always employ$ 9 an advisory way--subjective to ! executive head4 ,dur+ ! la/ few decades1 ! advance ( sci5ce & ! complication ( indu/ry h dem&$ a :olly broad] basis ( sci5tific & g5]al tra9+ = its lead]s4 ,executive heads are dem&$ :o h te*nical tra9+4 ,?is has result$ 9 ! e/abli%m5t ( special te*nical colleges1 & compell$ a place = eng9e]+ 9 ! great univ]sities4 ,! high intellig5ce dem&$ by ! vocation itself1 & ! revolution 9 tra9+ caus$ by ! /r5g!n+ ( its f\ndations 9 g5]al education1 has f9ally1 beyond all "q1 rais$ ! "w ( application ( sci5ce to indu/ry to ! dignity ( a pr(ession on a p> ) ! law1 m$ic9e1 & sci5ce4 ,x dem&s ( its memb]s equally high m5tal atta9m5ts1--& a m rigor\s tra9+ & exp]i5ce4 ,despite all ?is1 indu/ry is conduct$ = comm]cial purposes1 & leaves no room = ! haughty intellectual sup]iority assum$ by "s pr(essions ov] bus9ess call+s4 ,!re is n[ dem&$ ( ! m9+ speciali/ a wide k ( c]ta9 bran*es ( civil1 me*anical1 electrical1 & *emical eng9e]+1 geology1 economics1 ! humanities1 & :at n2 & 9 addition to all ?is1 eng9e]+ s5se1 executive ability1 bus9ess exp]i5ce1 & f9ancial insight4 ,eng9e]+ s5se is t f9e bl5d ( hone/y1 +5uity1 & intuition :i* is a m5tal end[m5t ap>t f k & exp]i5ce4 ,its possession is ! te/ ( ! real eng9e]4 ,x di/+ui%es eng9e]+ z a pr(ession f eng9e]+ z a trade4 ,x is ?is s5se t elevates ! possessor to ! pr(ession :i* is1 ( all o!rs1 ! mo/ difficult & ! mo/ compreh5sive4 ,f9ancial insight c only come by exp]i5ce 9 ! comm]cial _w4 ,likewise mu/ come ! exp]i5ce 9 te*nical "w :i* gives balance to !oretical tra9+4 ,executive ability is t capacity to cord9ate & comm& ! be/ results f o!r m51--x is a natural end[m5t4 :i* c be cultivat$ only 9 actual use4 ,! practice ( m9e eng9e]+ be+ s l>ge a mixture ( bus9ess1 x foll[s t ! :ole ( ! tra9+ ( ?is pr(ession _c be _h 9 s*ools & univ]sities4 ,! comm]cial & executive side ( ! "w _c be taught2 x mu/ be absorb$ by actual p>ticipation 9 ! indu/ry4 ,nor is x impossible to rise to great em95ce 9 ! pr(ession )\t univ]sity tra9+1 z witness "s ( our greate/ eng9e]s4 ,! univ]sity c d mu*2 x c give a broad basis ( k & m5tal tra9+1 & c inculcate moral feel+1 :i* entitles m5 to lead _! fell[s4 ,x c tea* ! te*nical fundam5tals ( ! multifold sci5ces :i* ! eng9e] %\ld "k & mu/ apply4 ,b aft] ! univ]sity mu/ come a s*ool+ 9 m5 & ?+s equally ?or\gh & m ardu\s4 ,9 ?is pr$om9at+ dem& = comm]cial qualifications ov] ! te*nical ones1 ! m9+ pr(ession has diff]5tiat$ to a great degree f its bro!r eng9e]+ bran*es4 ,t ?is is true w be mo/ app>5t if we exam9e ! c\rse ?r\gh :i* eng9e]+ projects m>*1 & ! dem&s ( ea* /age on _! road to completion4 ,! life ( all eng9e]+ projects 9 a g5]al way may be divid$ into five phases399-- ,footnote 993 ,^! phases d n necess>ily proce$ /ep by /ep4 ,= an exp&+ works especially1 all ( !m may be 9 process at ! same "t1 b if ea* item be consid]$ to itself1 ?is is ! usual progress1 or %\ld be :5 prop]ly eng9e]$4 #a4 ,det]m9ation ( ! value ( ! project4 #b4 ,det]m9ation ( ! me?od ( attack4 #c4 ,! detail$ del9eation ( me?od1 means1 & tools4 #d4 ,! execution ( ! works4 #e4 ,! op]ation ( ! complet$ works4 ,^! v>i\s /ages ( ! resolution ( an eng9e]+ project require 9 ea* m or less ( e quality ( intellect1 tra9+1 & "*4 ,at ! diff]5t /ages1 c]ta9 ( ^! qualities are 9 pr$om9ant dem&3 9 ! fir/ /age1 f9ancial insight2 9 ! second1 eng9e]+ s5se2 9 ! ?ird1 tra9+ & exp]i5ce2 9 ! f\r? & fif?1 executive ability4 ,a c]ta9 am\nt ( compass ov] ! project dur+ ! :ole five /ages is requir$ by all bran*es ( ! eng9e]+ pr(ession1--h>bor1 canal1 railway1 wat]works1 bridge1 me*anical1 electrical1 etc42 b 9 none ( !m s completely & 9 su* con/ant comb9ation is ?is dem&$ z 9 m9+4 ,! det]m9ation ( ! comm]cial value ( projects is a great] section ( ! m9+ eng9e]'s occupation ?an ( ! o!r eng9e]+ bran*es4 ,m9es are op]at$ only to e>n imm$iate pr(its4 ,no "q ( public utility ent]s1 s t all m9+ projects h by ?is necessity to be f ! fir/ weigh$ f a pr(it po9t ( view alone4 ,! det]m9ation ( ?is "q is "o :i* dem&s su* an am\nt ( te*nical k & exp]i5ce t ^? :o are n exp]ts _c ent] ! field1--!re=e ! s]vice ( ! eng9e] is always dem&$ 9 _! satisfactory solution4 ,moreov]1 unlike mo/ o!r eng9e]+ projects1 m9es h a faculty ( *ang+ own]s sev]al times dur+ _! c>e]1 s t e "o has to survive a p]iodic revaluation4 ,f ! o!r bran*es ( eng9e]+1 ! electrical eng9e] is ! mo/ (t5 call$ ^u to weigh ! probabilities ( f9ancial success ( ! ent]prise1 b usually 8 pres5ce 9 ?is capacity is call$ ^u only at ! initial /age1 = electrical ent]prises seldom *ange h&s4 ,! me*anical & *emical bran*es are usually call$ ^u = purely te*nical s]vice on ! dem& ( ! op]ator1 :o decides ! f9ancial problems = himself1 or ^u works =m+ b units 9 und]tak+s :]e ! op9ion on ! f9ancial advisability is compass$ by "s o!r bran* ( ! eng9e]+ pr(ession4 ,! o!r eng9e]+ bran*es1 ev5 less (t51 are call$ 9 = f9ancial advice1 & 9 ^? bran*es involv+ works ( public utility ! pr(it-&-loss phase sc>cely ent]s at all4 ,giv5 t ! project has be5 det]m9$ ^u1 & t ! ent]prise has ent]$ ^u ! second /age1 t ( det]m9ation ( me?od ( attack1 ! imm$iate comm]cial result limits ! m9+ eng9e]'s e plan & design to a great] degree ?an x does ! o!r eng9e]+ speciali/s4 ,! "q ( capital & pr(it dogs 8 e foot/ep1 = all m9es are ephem]al2 ! life ( any giv5 m9e is %ort4 ,metal m9es h inde$ ! %orte/ lives ( any4 ,:ile "s exceptional ones may produce ?r\gh "o g5]ation1 "u ! /ress ( mod]n me?ods a mu* l>g] proportion ext5d only ov] a decade or two4 ,b ( m p]t95t =ce is ! fact t z ! c]ta9 life ( a metal m9e c be positively kn[n 9 mo/ cases b a %ort p]iod beyond ! actual "t requir$ to exhau/ ! ore 9 sight1 n ev5 a decade ( life to ! ent]prise is available = ! e/imates ( ! m9+ eng9e]4 ,m9+ works are ( no value :5 ! m9e is exhau/$2 ! capital inve/$ mu/ be recov]$ 9 v %ort p]iods1 & !re=e all m9+ works mu/ be ( ! mo/ tempor>y "* t w answ]4 ,! m9+ eng9e] _c erect a works t w la/ z long z possible2 x is to la/ z long z ! m9e only1 &1 9 lay+ x out1 =efront 9 8 m9d mu/ be ! "q1 ,c its co/ be r$eem$ 9 ! p]iod ( use ( :i* ,i am c]ta9 x w f9d employm5t8 ,if n1 w "s *eap] device1 :i* gives less effici5cy1 d8 ,! h>bor eng9e]1 ! railway eng9e]1 ! me*anical eng9e]1 build z solidly z !y c1 = ! dem& = ! "w w exi/ till aft] _! mat]ials are worn out1 h[ev] s\ndly !y con/ruct4 ,our eng9e] c\s9s c1 9 a great] degree by /udy & inve/igation1 m>%al 9 advance ! factors ) :i* !y h to deal4 ,! m9+ eng9e]'s works1 on ! o!r h&1 dep5d at all times on _m elem5ts :i*1 f ! nature ( ?+s1 mu/ rema9 unkn[n4 ,no m9e is laid b>e to /udy & resolve 9 advance4 ,we h to deal ) conditions buri$ 9 ! e>?4 ,especially 9 metal m9es we _c "k1 :5 our works are initiat$1 :at ! size1 m9]alization1 or surr\nd+s ( ! ore-bodies w be4 ,we mu/ plunge into !m & le>n1--& rep5t4 ,n only is ! useful life ( our m9+ works indet]m9ate1 b ! v "* ( !m is unc]ta9 9 advance4 ,all our works mu/ be 9 a way d\bly t5tative1 = !y are subject to con/ant alt]ations z !y proce$4 ,n only does ?is apply to our initial plans1 b to our daily am5dm5t ( !m z we proce$ into ! unkn[n4 ,m9+ eng9e]+ is1 !re=e1 nev] end$ ) ! initial det]m9ation ( a me?od4 ,x is call$ ^u daily to replan & reconceive1 co9cid5tally ) ! daily progress ( ! con/ructions & op]ation4 ,we>y ) disappo9tm5t 9 8 wise/ conception1 _m a m9+ eng9e] looks jeal\sly ^u 8 happi] eng9e]+ c\s91 :o1 :5 he designs a bridge1 c "k its size1 its /ra9s1 & its co/1 & c wa% 8 h&s ( x f9ally :5 ! contractor /eps 9 to its con/ruction4 ,&1 above all1 x is no conc]n ( 8 :e!r x w pay4 ,did he />t to build a bridge ov] a wat]1 ! wid? or dep? or bottom ( :i* he c\ld n "k 9 advance1 & require to get its co/ back 9 t5 ye>s1 ) a pr(it1 8 w\ld be a task ( simil> h>assm5ts4 ,z said be=e1 x is becom+ m g5]al e ye> to employ ! m9+ eng9e] z ! executive head 9 ! op]ation ( m9+ eng9e]+ projects1 t is1 9 ! f\r? & fif? /ages ( ! ent]prise4 ,he is becom+ ! =eman1 manag]1 & presid5t ( ! company1 or z x may be cont5d$ by "s1 ! executive head is com+ to h te*nical qualifications4 ,ei!r way1 9 no bran* ( ent]prise f\nd$ on eng9e]+ is ! op]ative head ( necessity s mu* a te*nical director4 ,n only is ?is caus$ by ! necessity ( executive k be=e valuations c be prop]ly done1 b ! incorporation ( ! executive "w ) ! te*nical has be5 br\ght ab\t by sev]al o!r =ces4 ,we h a type ( works :i*1 by reason ( ! new conditions & con/ant revisions :i* arise f pu%+ into ! unkn[n co9cid5tally ) op]at+1 dem&s an intimate cont9u\s daily employm5t ( eng9e]+ s5se & design ?r\gh ! :ole hi/ory ( ! ent]prise4 ,^! works are ( !mselves ( a "* :i* requires a con/ant vigilant eye on f9ancial outcome4 ,! advances 9 metallurgy1 & ! decreas$ co/ ( production by l>g] capacities1 require ye>ly l>g]1 m complicat$1 & m co/ly plants4 ,?us1 l>g] & l>g] capitals are requir$1 & ent]prise is pass+ f ! h&s ( ! individual to ! f9ancially /rong] corporation4 ,?is alt]$ position z to ! works & f9ance has made ke5] dem&s1 bo? te*nically & 9 an adm9i/rative way1 = ! highly tra9$ man4 ,9 ! e>ly /ages ( ,am]ican m9+1 ) ! mod]ate dem& on capital & ! simpl] =ms ( eng9e]+ involv$1 m9+ 0 l>gely a matt] ( individual ent]prise & own]%ip4 ,^! own]s 7 m5 to :om exp]i5ce _h br\ght "s ( ! ne$ful te*nical qualifications4 ,!y usually held ! re9s ( bus9ess managem5t 9 _! own h&s & employ$ ! eng9e] subjectively1 :5 !y employ$ him at all4 ,!y 7 also1 z a rule1 di/+ui%$ by _! contempt = univ]sity-tra9$ eng9e]s4 ,! gradually increas+ employm5t ( ! eng9e] z comb9$ executive & te*nical head1 0 l>gely ( ,am]ican developm5t4 ,_m ,engli% & ,european m9es /ill ma9ta9 ! two sep>ate bureaus1 ! te*nical & ! f9ancial4 ,su* organization is op5 to mu* objection f ! po9t ( view ( ! own]'s int]e/s1 & /ill m f t ( ! eng9e]4 ,9 su* an organization ! latt] is always subord9ate to ! f9ancial control1--h5ce ! lea/ paid & lea/ respect$4 ,:5 two bureaus exi/1 ! te*nical lacks t balance ( comm]cial purpose :i* x %\ld h4 ,! ambition ( ! !oretical eng9e]1 divorc$ f comm]cial result1 is complete te*nical nicety ( works & l[ production co/s )\t ! reg>d = capital outlay :i* ! comm]cial exp]i5ce & tempor>y "* ( m9+ con/ructions dem&4 ,on ! o!r h&1 ! purely f9ancial bureau usually begrudges ! capital outlay :i* s\nd eng9e]+ may w>rant4 ,! result is an adm9i/ration t is n comp>able to ! s+le head ) bo? qualifications & an ev5 balance 9 bo? sph]es4 ,9 ,am]ica1 we /ill h a relic ( ?is =m ( adm9i/ration 9 ! consult+ m9+ eng9e]1 b b>r+ 8 functions z a valu] ( m9es1 he is disappe>+ 9 connection ) ! indu/ry1 9 favor ( ! manag]1 or ! presid5t ( ! company1 :o has adm9i/rative control4 ,! m9+ eng9e]'s field ( employm5t is !re=e n only wid] by ?is g5]al inclusion ( adm9i/rative "w1 b "o ( m responsibility4 ,:ile he mu/ conduct all five phases ( eng9e]+ projects co9cid5tally1 ! o!r bran*es ( ! pr(ession are m or less conf9$ to "o phase or ano!r4 ,!y c draw %>p] limitations ( _! engagem5ts or specialization & conf9e !mselves to m purely te*nical "w4 ,! civil eng9e] may con/ruct railway or h>bor works2 ! me*anical eng9e] may design & build eng9es2 ! naval ar*itect may build %ips2 b giv5 t he design$ to d ! "w 9 ! mo/ effectual mann]1 x is no conc]n ( 8 :e!r !y subsequ5tly e>n divid5ds4 ,he does n h to op]ate !m1 to f9d ! income1 to fe$ ! mill1 or sell ! product4 ,! pr(it & loss does n h\nd 8 foot/eps aft] 8 con/ruction is complete4 ,al?\gh x is desirable to emphasize ! comm]cial side ( ! practice ( ! m9+ eng9e]'s pr(ession1 !re are o!r sides ( no less mom5t4 ,!re is ! "r ( e r$-blood$ man to be assur$ t 8 "w w be a daily satisfaction to himself2 t x is a "w :i* is contribut+ to ! welf>e & advance ( 8 c\ntry2 & t x w build = him a position ( dignity & consequ5ce among 8 fell[s4 ,!re are ! moral & public obligations ^u ! pr(ession4 ,!re are to-day ! dem&s ^u ! eng9e]s :i* are ! dem&s ^u _! positions z lead]s ( a great indu/ry4 ,9 an indu/ry t l5ds itself s mu* to speculation & *ican]y1 !re is ! duty ( e eng9e] to dim9i% ! opportunity ( ! vulture s f> z is possible4 ,:]e he c ent] ^! li/s has be5 sugge/$ 9 ! previ\s pages4 ,fur!r ?an to ! inve/or 9 m9es1 he has a duty to 8 bro!rs 9 ! pr(ession4 ,9 no pr(ession does competition ent] s obscurely1 nor 9 no o!r are m5 ( a pr(ession ?r[n into su* t]ms ( intimacy 9 pr(essional "w4 ,f ^! causes !re has aris5 a fre$om ( disclosure ( te*nical results & a comrad]y ( memb]s great] ?an t 9 any o!r pr(ession4 ,no pr(ession is s subject to ! caprici\sness ( =tune1 & he ^: position is assur$ to-day is n assur$ to-morr[ unless x be c\pl$ ) a consid]ation ( ^? memb]s n s =tunate4 ,especially is !re an obligation to ! y\ng] memb]s t !y may h opportunity ( tra9+ & a "r />t 9 ! "w4 ,! v ess5ce ( ! pr(ession is t x calls ^u its memb]s to direct m54 ,!y are ! (fic]s 9 ! great indu/rial army4 ,f ! nature ( ?+s1 metal m9es d n1 l our cities & settlem5ts1 lie 9 ^? regions cov]$ deep 9 ri* soils4 ,our m9es mu/ be f\nd 9 ! m\nta9s & des]ts :]e rocks are expos$ to se>*4 ,?us !y lie away f ! c5t]s ( com=t & culture1--!y are ! outpo/s ( civilization4 ,! eng9e] is an (fic] on outpo/ duty1 & 9 ^! places he is ! camp lead]4 ,by 8 position z a lead] 9 ! community he has a *iefta9%ip t c>ries a responsibility besides m]e m9e managem5t4 ,8 is ! responsibility ( example 9 fair deal+ & good gov]nm5t 9 ! community4 ,9 b few ( its greate/ works does ! p]sonality ( its real creator rea* ! e>s ( ! _w2 ! real eng9e] does n adv]tise himself4 ,b ! eng9e]+ pr(ession g5]ally rises ye>ly 9 dignity & importance z ! re/ ( ! _w le>ns m ( :]e ! real bra9s ( indu/rial progress are4 ,! "t w come :5 p w ask1 n :o paid = a ?+1 b :o built x4 ,to ! eng9e] falls ! "w ( creat+ f ! dry bones ( sci5tific fact ! liv+ body ( indu/ry4 ,x is he ^: intellect & direction br+ to ! _w ! com=ts & necessities ( daily ne$4 ,unlike ! doctor1 8 is n ! con/ant /ruggle to save ! weak4 ,unlike ! soldi]1 de/ruction is n 8 prime function4 ,unlike ! lawy]1 qu>rels are n 8 daily bread4 ,eng9e]+ is ! pr(ession ( creation & ( con/ruction1 ( /imulation ( human ef=t & accompli%m5t4 ,,index4 ,acc\nts4 ,adm9i/ration4 ,adm9i/rative reports4 ,air-compression4 -drills4 ,alt]ation1 second>y4 ,alt]native %afts to incl9$ deposit4 ,amortization ( capital & int]e/4 ,animals = und]gr\nd transport4 ,annual dem& = base metals4 report4 ,artificial pill>s4 ,assay foot4 in*4 ( samples4 plans4 ,assay+4 ,a value ( m9e4 ,av]ages1 calculation4 ,bail+4 ,balance %eet4 ,basic price4 value ( m9e4 ,b5*es4 ,b5d 9 comb9$ %afts4 ,b9s4 ,block$-out ore4 ,blocks4 ,bonanzas1 orig94 ,bonus sy/ems1 ( "w4 ,break+ ore4 ,brok5 ,hill1 levels4 ore-pill>s4 ,bump+-tr\gh4 ,cable-ways4 ,cages4 ,calculation ( av]ages4 ( quantities ( ore4 ,capital exp5diture4 ,cav+ sy/ems4 ,*urn-drills4 ,*utes1 load+1 9 v]tical %aft4 ,classification ( ore 9 sight4 ,comb9$ %aft4 /opes4 ,comm]cial value ( projects1 det]m9ation4 ,comp>tm5ts = %aft4 ,compress$-air locomotives4 -air pumps4 vs4 electricity = drills4 ,cont5t1 av]age metal1 det]m9+4 metal1 diff]5ces4 ,contract "w4 ,copp]1 annual dem&4 deposits4 ores1 enri*m5t4 ,co/ ( entry into m9e4 ( equipm5t4 production4 p] foot ( s9k+4 work+4 ,cribs4 ,crosscuts4 ,cross-section ( incl9$ deposit :i* mu/ be attack$ 9 dep?4 %[+ auxili>y v]tical outlet4 ,cr\*1 ,j4 ,j4 ,cubic feet p] ton ( ore4 foot cont5ts ( block4 ,deep-level m9es4 ,dem& = metals4 ,dep>tm5tal dissection ( exp5ditures4 ,deposits1 9 situ4 ore1 classes4 regul>ity4 size4 /ructure4 ,dep? ( exhau/ion4 ,det]m9ation ( av]age metal cont5ts ( ore4 ,developm5t 9 e>ly prospect+ /age4 9 neighbor+ m9es4 ( m9es4 ,diamond-drill+4 ,dilut+ n>r[ samples to a /op+ wid?4 ,dip4 ,direct-act+ /eam-pumps4 ,di/ribution ( values4 ,divid5d1 annual1 pres5t value4 ,dommeil]4 ,d[n holes4 ,dra9age4 comp>ison ( diff]5t sy/ems4 sy/ems4 ,drifts4 ,drill1 requirem5ts4 ,drill+4 ,drives4 ,dry wall+ ) timb] caps4 ,effici5cy1 factors (4 ( mass4 ,electrical haulage4 pumps4 ,electricity = drills4 ,eng9e1 size = w9d+ appliances4 ,eng9e]1 m9+1 z executive4 ,eng9e]+ projects1 phases (4 ,enri*m5t4 at cross-ve9s4 ,entry1 to m9e4 to v]tical or horizontal deposits4 ,equipm5t1 co/4 improvem5ts4 me*anical4 ,erosion4 ,error1 p]c5tage 9 e/imates f sampl+4 ,escape4 ,exam9ation ( m9+ prop]ty4 ,excavation1 support+4 ,exhau/ion1 dep?4 ,exp5ditures1 dep>tm5tal dissection4 m9e4 ,ext5sion 9 dep?4 ,factor ( safety 9 calculat+ av]ages ( samples4 ,fill+4 sy/em comb9$ ) squ>e-sett+4 ) brok5 ore subsequ5tly )drawn4 wa/e4 ,fissure ve9s4 ,fissur+4 dep?4 ,fix$ *>ges4 ,flat-back /ope4 ,flexibility 9 dra9age sy/em4 ,floors4 ,fold+4 ,foot-drill$ sy/em ( contract "w4 -hole sy/em ( contract "w4 ( advance sy/em ( contract "w4 value4 ,fraud1 precautions aga9/ 9 sampl+4 ,g5]al exp5ses4 ,gold deposits4 deposits1 alt]ation4 enri*m5t4 ,hamm] type ( drill4 ,h&-drill+4 -truck+4 ,haulage1 electrical4 equipm5t 9 %aft4 me*anical4 ,hole sy/em ( contract "w4 ,horizons ( ore-deposits4 ,horizontal deposits1 entry4 /ope4 fill$ ) wa/e4 ,hydraulic pumps4 ,impregnation deposits4 ,in*1 assay4 ,incl9$ deposits to be work$ f outcrop or ne> x4 deposits :i* mu/ be attack$ 9 dep?4 %aft4 ,incl9es4 capacity4 ,infiltration type ( deposits4 ,intellig5ce z factor ( skill4 ,int]e/ calculations 9 m9e valuation4 ,int]vals1 level4 ,inwood's tables4 ,iron hat4 lea*+4 ,ivanhoe m9e1 ,we/ ,au/ralia4 ,kibble4 ,labor1 g5]al te*nical data4 h&l+4 unions4 ,lat]al und]gr\nd transport4 ,le ,roi m9e4 ,lead1 annual dem&4 deposits4 enri*+4 prices1 #ahhd-aijh4 -z9c ores1 enri*m5t4 ,l5ses4 ,levels4 int]vals4 ( ,brok5 ,hill4 protection4 ,life1 9 sight4 ( m9e4 ,locomotives1 compress$-air4 ,lode m9es1 valuation4 ,lodes4 ,long-wall /ope4 ,ma*9e-drill1 p]=mance4 drill+4 vs4 h&-drill+4 ,managem5t1 m9e4 ,matte4 ,me*anical effici5cy ( dra9age ma*9]y4 equipm5t4 ,m5 = und]gr\nd transport4 ,metal cont5t1 det]m9+4 cont5ts1 diff]5ces4 dem& =4 m9e1 value4 price4 ,m9es comp>$ to o!r comm]cial ent]prises4 equipm5t4 exp5ditures4 ,m9es--cont9u$4 life (4 metal1 value (4 ( mod]ate dep?s4 to be work$ to great dep?s4 valuation4 ,m9+ eng9e]+ pr(ession4 ,mt4 ,c5is tunnel4 ,morgan gold m9e4 ,normal price4 ,obligations ( eng9e]+ pr(ession4 ,op5+s1 position 9 relation to second>y alt]ation4 ,ore1 av]age wid? 9 block4 block$-out4 -bodies4 %apes4 -break+1 me?ods4 calculation ( quantities (4 -*utes 9 %r9kage-/op+4 -deposits1 classes4 det]m9ation ( av]age metal cont5ts4 develop$4 develop+4 expectant4 9 sight4 sight1 classification4 -pill>s4 support 9 n>r[ /opes4 -%oots4 weight ( a cubic foot4 wid? = "o sample4 ,orig9 ( deposit4 ,outcrop m9es4 ,output1 factors limit+4 giv+ lea/ production co/4 maximum1 det]m9ation4 ,ov]h& /apes4 ,ov]production ( base metal4 ,oxidation4 ,pat*work plant1 me*anical ineffici5cy (4 ,pay areas1 =mation4 ,pill>s1 artificial4 ,positive ore4 value ( metal m9e4 ,possible ore4 ,p[] conditions4 g5]al te*nical data4 s\rces4 transmission4 ,prelim9>y inspection4 ,previ\s yield4 ,price ( metals4 ,probable ore4 ,produc+ /age ( m9e4 ,production1 co/4 ,pr(it & loss acc\nt4 factors det]m9+4 9 sight4 ,proportional *>ges4 ,prospect+ /age ( m9e4 ,prospective ore4 value4 ,protection ( levels4 ,prov$ ore4 ,pump+ sy/ems4 ,pumps1 compress$-air4 electrical4 hydraulic4 rod-driv54 ,ratio ( output to m9e4 ,recov]able p]c5tage ( gross assay value4 ,recov]y ( ore4 ,rectangul> %aft4 ,r$emption ( capital & int]e/4 ,r$uction ( output4 ,regul>ity ( deposit4 ,reliability ( dra9age sy/em4 ,replacem5t4 ,reports4 adm9i/rative4 ,resu+4 ,rev5ue acc\nt4 ,rill-cut ov]h& /ope4 me?od ( incl9e cuts4 -/opes4 fill$ ) wa/e4 -/op+4 ,rises4 ,risk 9 m9+ inve/m5ts4 9 valuation ( m9es4 ,roadways1 protect+ 9 %r9kage-/op+4 ,rod-driv5 pumps4 ,rot>y /eam-pumps4 ,r\nd v]tical %afts4 ,runs ( value4 te/-treatm5t4 ,safety1 factor (1 9 calculat+ av]ages ( samples4 ,sample1 assay (4 av]age value4 n>r[1 dilut+ to a /op+ wid?4 sections4 tak+1 physical details4 mann] ( tak+4 ,sampl+4 accuracy4 p]c5tage ( error 9 e/imates f4 precautions aga9/ fraud4 ,sav+ ( fix$ *>ges4 ,second>y alt]ation4 enri*m5t4 ,security ( inve/m5t4 ,self-dump+ skip4 ,sets4 ,%afts4 arrangem5t = v deep incl9$ %afts4 comp>tm5ts4 diff]5t dep?s4 haulage4 location4 numb]4 output capacity4 %ape4 size4 ,%r9kage-/ope4 -/op+4 advantages4 disadvantages4 :5 applicable4 ,silv] deposits4 deposits1 enri*m5t4 prices4 ,s9k+1 spe$4 ,size ( deposit4 ,skill1 effect on production co/4 ,skips4 balanc$4 haulage 9 v]tical %aft4 ,soll>s4 ,solubility ( m9]als4 ,specific volume ( ores4 ,speculative values ( metal m9e4 value ( m9e4 ,spelt]1 annual dem&4 ,squ>e-set4 -set timb]+4 ,/ations4 arrangem5t = skip haulage 9 v]tical %aft4 ,/eam-pumps1 direct4 ,/eep5+ w9zes & ore passes4 ,/ope fill$ ) brok5 ore4 m9imum wid?4 ,/op+4 contract sy/ems4 ,/or+ metal4 ,/ructural "* ( deposit4 ,/ructure ( deposit4 ,/ull & wa/e pill>s4 support ) wa/e ren=cem5t4 -support$ /ope4 ,/ulls4 wood4 ,subhead+4 ,sublevel cav+ sy/em4 ,subsidi>y developm5t4 ,sup]ficial enri*m5t4 ,supplies1 g5]al te*nical data4 ,support by pill>s ( ore4 ,support+ excavation4 ,surveys4 ,susp5se *>ges4 ,te/ p>cels4 sections4 -treatm5t runs4 ,timb]1 co/4 ,timb]$ %aft design4 ,timb]+4 ,t91 annual dem&4 deposits4 ore1 migration & enri*m5t4 ,tools4 ,top slic+4 ,tracks4 ,transport 9 /opes4 ,tunnel entry4 feet paid = 9 #aj ye>s4 size4 ,und]h& /opes4 ,upp]s4 ,valuation1 m9e4 ( lode m9es4 m9es1 risk 94 m9es ) little or no ore 9 sight4 on second-h& data4 ,value1 av]age1 ( samples4 discrepancy betwe5 e/imat$ & actual4 di/ribution4 ( ext5sion 9 dep?1 e/imat+4 positive1 ( metal m9e4 pres5t1 ( an annual divid5d4 ( #a or #a1 payable 9 -- ye>s4 runs (4 speculative1 ( metal m9e4 ,valu+ ore 9 c\rse ( break+4 ,v5tilation4 ,v]tical deposits1 entry4 int]val betwe5 levels4 %afts4 capacity4 ,volume1 specific1 ( ores4 ,wa/e-fill$ /ope4 ,wat]-p[]4 ,weight p] cubic foot ( ore4 ,we9del1 ,casp>4 ,:it+ hoi/4 ,wid? ( ore = "o sample4 ,w9d+ appliances4 ,w9zes4 9 %r9kage-/op+4 to be us$ = fill+4 ,work+ co/4 inh]5t limitations 9 accuracy (4 %eets4 ,work%ops4 ,yield1 previ\s4 ,ye>s ( life requir$ to yield -- int]e/4 ,z9c deposits4 lea*+4