Converting Resource ToReserve

8/8/2019 Converting Resource ToReserve

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Geolog y is not the problem . Becau se of inflation, taxation,and pol i t ics~m oreeserves are being reconverted touneconomic resources than there are n ew reserves createdby exploration and extraction technology.

The Problems of Converting Resourcesto ReservesPaul A. Bailly, Occidental Minerals Corp.

Assessments of future raw materials supply have beenpublished by the dozens in the last few years. They havevaried from prediction of immine nt du e shortages to state-ments that "even without technological improvement, theworld is not likely to be threatened with a physical short-age of raw materials until about the year 100,000,000A.D." W he n one analyzes all these forecasts, one can cometo the conclusion that each may be correct. The variationsdepend entirely on different assessments of mineral avail-ability measured with different geologic, technological,economic, and p olitical parameters.Resource Sem anticT o most of us, a resource is a thin g, a person, or an ac-tion which we can turn to, in time of need or emergency.To m ost mineral appraisers, however, th e same w ord indi-cates naturally-occurring mineral concentrations in suchform that economic extraction is currently or potentiallyfeasible. In this context, the term "resource" refers to botha known economic mineral co ncentration, i.e., a "reserve,"and an undiscovered deposit of unknown economics. Butthe common man's concept of resource, when it comes tominerals, includes only "reserves"; it does not include un-discovered deposits. Reserves are concentrations of a us-able mineral, or energy commodity, which can be eco-nomically and legally extracted at the time of determina-t ion. Reserves are t ruly ready for use and can be drawnupon to take care of a ne ed or an emergen cy; undiscov-ered deposits are not available for use.These different meanings of the word "resource" explainwhy apparently contradictory statements about future sup-ply of raw materials can all be correct. I n this presentation,when I refer to a "resource," I mean any thing, any per-son, any action which can be used to take care of a need.How ever, wh en it c0me.s to mineral resources an d m ineralreserves, 1 use th e definitions of the US Geological Surv eyan d the Bureau of M ines.Mineral-M aterials Resource BaseTable 1 classifies all components of our mineral mate-rials resource base. Immediately and economically avail-able mineral materials i r~clu de fro m the center leftward ) :exploitable demonstrated reserves; products recently pro-duced and available in the market; products in inventory,or in long-term stockpiles; and economically recoverablescrap.There are three main conversion routes available fortransforming uneconomic and/or undiscovered mineral re-

sources to usable reserves: First, mining and metallurgicalextraction technology research can result in inventions an d

developments that make demonstrated conditional re-sources economical. Second, used materials and productscan be converted into usable products through recyclingtechnology research that results in economical processes.Third, undiscovered mineral resources, whose existenceand economics must be demonstrated through discoveryand feasibility studies; the conversion process is mineralexploration.Undiscovered mineral resources include inferred min-eral resources in close proximity to known deposits; hypo-thetical mineral resources within known districts; andpurely speculative mineral resources in areas not knownto be mineralized.Forecasters who limit their investigations to existingscrap, mineral reserves, and mineral products can predictshortages for many commodities; other forecasters whodo not conceive of any great technological or economicdifficulty in using common rock such as granite an d basalt,and seawater, as a source base, can comfortably predictthat there won't be any physical shortages of raw mate-rials until the year 100,000,000 A.D.I will first discuss the conversion of undiscovered non-energy mineral resources to mineral reserves through ex-ploration resulting in mineral discoveries, and then ex-amine some aspects of economic and political availabilityaffecting the main metal commodities. I will conclude witha few comments on the potential supply of metals fromthe d eep oceans.What's N eeded For ConversionWhat are the main requirements for successful conver-sion of resou rces to reserves?The first absolute requirement is high-quality humanresources-individuals actively ded icated to discovery an dfully acquainted with the nature, uses, availability, andlimitations of all the othe r resources. T he key t o successfulex~ l ora t i ons the aualitv of human resources.I I ~ - -The next resource is land. It contains the deposits to bediscovered. But land is worthless unless both surface andsubsurface are accessible for exploration and legally avail-able for dev elopm ent and operations, in case of discovery.Obviously, any exploration project must be based on ahypothesis that mineral reserves may be found in the areaunder investigation. Essential components of such targethypotheses are the mineral-resource appraisals preparedby mineral scientists in industry and government. Mineralendowment evaluation, however, is a new discipline ingrowing demand for policy determination and for explora-tion planning. Like geology and exploration, it is both anart and a sclence. Most mineral-resource appraisals inte-

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Table 1-Mineral-Materials Resource Base

Waste ConsumableProductsMineral Resources

Undiscovered

SalesInventoryStockpileM w u m an dIndicatedReserves---- --- -- - - Inferred- Speculative% Resources Resources"FIecycIables"8 MunPoipalg wa*eA3 Resources-. Stockpilr ConditionalSubeconomicResources De c r e as i ng G e ol ~g i c ssurance >- - - -- -------- ----_ ----

"Common Rock"Sea WaterGraniteBasaltModified After W. PrattD. Brobst, 1973

grate two components : an extrapolation of all known re-sults of pre\.ious mineral production and mineral explora-tion activity, ant1 a theoretical estimatioll of minerals inexistence in the ground. Both are very hazardous fields.After all, reserves can be inventoried, but undiscoveredresources callnot; they can only be guessed at. To a largeextent, the guesses depend on subjective experiencc andjudgment and are subject to constant upgrading. Any suchappraisal is ill a constant dynamic state of flux, changingwith geological knowledge and econoniic coliditions.There are no once-and-for-all resource estimates.

We call usc three main methodologies in estimatingundiscovered resources: ( 1 the elemental distribution up-praisal; ( 2 ) he mineral distribution appraisal; and, (3 )the geological distribution appraisal. The first two havesome application in studies of large areas for policy de-termination. But since they rest oil mathematical formula-tions of current k~ ~o wl ed gebout the distrib~itioli f chem-ical elements (such as metals and nonmetals) or of the dis-tribution of s~ ec 'f ic minerals such as nickel silicates orIcopper sulfides, the first two methods provide quilntitativestatements tliat have no immediate application ill deciding\vhether a speciIic area is worthy of exploratioll or 11ot.

For the purpose of esploratioll planning, the only ap-praisal ~rlc>thotlo!ogj. f \ d u e is geological appraisal; itevaluates the fa\-orable characteristics of areas for the oc-cul-rence of specilic types of deposits ant1 shoultl be prc-ferably expressed it1 quantitative probabilistic ternls. Thisdiscover: -orlcnted approach is essentially that usccl by theUS Geolopical Survcv in its recent ~ublications.Thc de-gree of .~ccur,~cy)f such appraisals 2ecreases markedly aswe progl-c.,s fro111 appraisals of inferred rcscr \,es in theimmedia~c ic i l~ i ~yf know11 exploitable tleposits, then toevaluation of possible discoveries in large areas or districtswhere some r~iineraldeposits are known to occr~~.;illally,the accuracy is cxtrcmely poor when \ve appraisc largeareas where some favorable characteristics are known toexist, but \\here 110 deposits of the type sought is yetknown to exist. \Vc, should remind ourselves that most"provel~" mineral reserves of metals are known, a t best,withill a plu.; or nlinus mO( ;argin of error, arld that in-creasingly larger n~argil~sf error must 11e ;~ssiglledn thisorder to illfcl-red, l~ypothetical,an d speculative ~rrineralresources. Sul~ jec tive eologic appraisals are more valuabletlla11 ot1lc.r 'l~~pl-oacllesu cxplol-ziti011 planning ljccause

the methodological and conceptual tools to make such ap-praisals are exactly the same as those adopted in explora-tion planning, i.e., in trying to delineate areas that arehypothesized to contain possible ore deposits; this is whatexplorers call "targeting."I n recent years, many researchers have tried to combinematliematical and geological appraisal methods. Chemicalsurveys of areas considered favorable, for instance, haveIjeen interpreted through geostatistical inference fromknown metal distribution in well-explored control areas.This has also been done with geological parameters con-sidered favorab le to the occurrence of certain deposits.The ultimate purpose of such geostatistical studies andproljabilistic evaluations is, for a certain area, to determinethe probabil ity of finding a given economic deposit of cer-tain grade and tonnage. However, in the absence of com-plete knowledge of necessary and sufficient conditiolis forthe occulrence of ore deposits, it is impossible at presen tto reliably determine the relative merits of small areaswith this approach. Currently, our best tool is the subjec-tive geological judgment about the favorabil ity of specificareas Iby experienced appraisers and explorers.

Wh at controls the possibility of recognizing valid targetareas is:

First, the quality and quanti ty of geological, geo-chemical, and geophysical information available for vari-ous areas. This is basic regional and local geology, usuallysllown on maps. 111 general, US basic geological, geochein-ical, and geophysical regional information is very inconi-plete; actually, the US stands out among the developedcountries as one of the lcast adequate ly covered withgeological mapping. This must be remedied 11y illcreasedsystematic mapping efforts by the US Geological Surveya~iclhe state geological surveys.a Second, detailed knowledge of the characterist icsof ore deposits. Descriptive monographs of mining districtsare excellent for most pre-LVorld War I1 discoveries, butnonexistent or inadequate for latte r discoveries.a Third, knowledge of the geological environments in\\*hicll deposits of certain types and certain commoditiescan occur and the processes by which deposition can takeplace. Basic research on ol-c transportation and depositionshorlld result in a much bet ter understanding of the for-111ation of ore deposits and, consequelitly, 111 improvedc~xplora~ionargeting. This might also lead to new con-

28 JANUARY 1976 SOCIETY OF


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cepts about the possible occurrence of theoretically plaus-ible but yet unknown types of deposits. Research alongthese lines is neither well-funded nor adequately staffedin the US. We have had NASA, and we have talkedabout a NASA-type effort for the oceans. We also need aNASA-type effort for the mineral depths of the earth.In this country, mapping programs and economic geo-logic research efforts of the USGS, state geological sur-veys, universities, and industry should be considerably en-larged in order to improve the reliability of mineral re-source appraisals.The other resources needed for the conversion processare mineral detection technology, extraction technology,time, and money. A few words about detection technologyare now in order. It is essential to keep in mind that themost efficient and discriminant detection technique is ofno avail if the area chosen as a target is not mineralized.Exploration expenditures in the US average about 25%for land and overhead, 25% for nondestructive detectionsurveys, and 504; for destructive sampling and assaying ofexcavated rock cuttings, cores, and sludges. The main de-structive sampling technique is drilling. There is littledoubt that, in the future, drilling of geojogical targets notexpressed by geophysical and geochemical anomalies willincrease at a faster rate than drilling of geophysical-geo-chemical anomalies. Also, exploration based on geologicalconcepts will aim at deeper targets than are currentlysought. Geological extrapolation is the best remote sensingtool at our disposal.The delineation of new metallic reserves through ex-ploration will require a considerable increase in theamount of drilling, at a considerable increase in explora-tion costs with the currently available drilling and assay-

ing technology. Improvements and cost reduction in drill-ing and assaying for metals would contribute more to in-crease efficiency of the exploration dollar than any othertechnical factor. Presently, there is very little researchdone in the US and Canada on drilling for metal deposits,either in industry or the government agencies. Improvedmetal exploration drilling techniques and downhole analy-tical techniques should be a high priority item for re-search by the US Bureau of Mines.Exploration SequenceFig. 1 shows a generalized sequence of exploration ac-tivities that may lead to a mineral discovery. We startwith large areas under regional appraisals and progresstoward smaller and smaller areas containing a hypotheticaltarget, then a deposit. Please note that, at the first stage,certain areas can, on the basis of present knowledge, beeliminated as not having any potential for a given com-modity. However, one should keep in mind that such ap-praisals may be valid for deposits whose formation is rea-sonably well known (e.g., coal, gravel, phosphate, placerdeposits, etc.), but are highly risky for metal depositswhose origins are not as well known. Let's not forget thatwe can make the same mistake for metals as those petro-leum geologists who, 35 years ago, predicted the sedi-mentary Williston Basin would not contain any oil and gasfields; and those mineral appraisers who, 25 years ago,were willing to zone the area south of Tucson as nonmin-eral. As it is, the Williston Basin contains some petroleumand the area south of Tucson has turned out to be thelargest concentration of copper deposits in the US. Re-gional appraisals always include office studies and may in-clude field and airborne surveys; depending on commodity

RECONNAISSANCE TARGET EXPLORATION DEVELOPMENT/ \ / \ m

APPRAISALII

attractive atthis time

DETAILED DETAILEDSURFACE THREE-DIMENSIONAL

but not attractive at this timeat this time

I 1 - normal exploration sequence I If- - - - - - - ecycling after temporary rejection-@+ key exploration decisionsREGIONUNFAVORABLE

ECONOMIC"I :o"stT l

NOT A MINERALDEPOSITI

Fig. 1-The four main stages of "full-sequence" exploration.

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and count ry , a r eg iona l appra isa l p rogram may take a f ewweeks to a yea r and cos t a f ew thousand do l la r s to amill ion.Regional appraisa l leads to the def init ion of areaswor thy of de ta i led r econna issance , where in ta rge t a reasa re de l inea ted . These ta rge ts , o r exp lora t ion work ing hy-potheses , a r e born in the mind of the exp lore r .laws should preserve his exclusive r ight to investigate histarget conc ept if t he lan d is legally accessible . A de ta i leda rea r econna issance may take f rom s ix months to twoyea rs an d cos t f rom $20 ,000 to $ 1 mi ll ion . de pen ding oncommodi ty , cou l l t ry , and f ie ld me thod s .Then , we inves t iga te these ta rge t a reas . F i r s t , th roughsur face exp lora t ion to t ry and de te rmine the poss ib le ex-istence of a hypothe t ica l o re ta rge t ; second , th rough th ree -d imens iona l sampl ing techniques such a s d r i l l ing , p i t t ing ,a n d u n d e r g r o u n d w o r k i n g . T h e t i m e f o r t h e s e t w o s t a g e smay be on e yea r to five year s , an d the cos t f rom $ 100 ,000for a f ai lu re up to $5 mill ion for a successful program re-sult ing in discovery of a large deposit .W e s h o u l d b e a w a r e t h a t a n y a r e a t h a t w a s o n c e d e -scr ibed as a target area has some character is t ics favorableto the occur rence of ce r ta in depos i t s and , a s such , cannever 11e def inite ly e l iminated f rom explora tion considera-t ion. I t should remain available for explora tion recyclingf rom t ime to t ime . Many depos i t s d i scove re t l today ma>.become economica l ly ex t r ac tab le on ly yea r s hence ; anyuneconomic d iscove ry should r ema in ava i lab le fo r fu tureeconomic conve r s ion . For ins tance , many uneconomicuran ium depos i t s foun d in the la s t 20 yea r s a re jus t nowbecom ing econom ic reserves- thanks to the new tech-niqu e of so!ution m ining an d to high er uranium pr ices.I11 a comple te exp lora t ion sequence , 11 large region corn-pr i s ing seve ra l thousand squa re mi le s may be f i r s t ap-p r a i s ed a n d a success fu l p rogram n lay cncl up wi th on c ormore ta rge ts r eady for th ree -d imens iona l te s t ing , eachsuch target co ver ing f rom a f raction of a sq uar e mile formassive deposits , up to several square miles i l l the cast oflarge , tabular occurrcnces. From the lantl te1iul .e poil l t ofview, i t is a lways essentia l to remember this progressiona r td the need for r ecyc l ing . Land use po l ic ie s mus t a l lo \vaccess to large areas, availabil i ty of target areas to the i l l -vent or of th e targe t , a nd re turn to targ et arcas f ro111 t imc9to t ime ,

Availability for ConversionAt leas t f ive ma in f ac tor s de te rmine whe the r the con-version process can be achieved successfully. The exist-ence of tht: resource is se lf -evide nt; this c an 1)e la l~ ele t l sgeographic availabil i ty, which I have a lreatly discussetl .T he othe r four fac tors-extractabili ty, en\- iror iment, cn-ergy, an d economics-can be logically com bine d il l eco-nomic availability and political availabilit! . .Economic Availa'bilityEconomic ava i lab i l i ty and i t s counte rpa r t , economicscarc ity, were analyzed in great deta i l in the ear ly '50s.These theore t ica l economic s tud ie s led to the op t imis t icconclusion that economic availabil i ty of minerals displays ap r o n o u n c e d t r e n d t o w a r d c o n t i n u o u s i m p r o v e m e n t . T h i swas ex t r apola ted to ind ica te tha t the re was no lower eco-nomic l imit to the grades of mater ia ls that could 1)e eco-nomical ly r ecove red . Pr ice was the con t ro l l i~ ig ac tor . Ontha t bas i s , i t then became fa sh ionable to dcduc t tha t gco-logic availa l~il i tywas no t a f ac tor in r e source sca rc i ty , andtha t on ly economics contro lled . the ava ilab il i ty o f m i i ~ ~ r a lr e sources . Th e re was no l imit to g rowth .

This theore t ica l concept was fos te red by the obse rva t ionmade by Sam Lasky of the Bureau of Mines : fo r a f ewd o m e s t i c p o r p h y r y c o p p e r m i n e s h e i n v e s t i g a t e d a n dwi th in a na r row range of then economica l ly minablegrade , Lasky found tha t an a r i thme t ica l dec rease in g radewas a ssoc ia ted wi th a geometr ic inc rease in the tonnageof the r e se rves . This obse rva t ion became ma themat ica l lyexpressed as "Lasky's R ule" ( Gr ad e =K1 - Kg Log Tol l-n a g e ) . I t d i d n o t t a k e l o n g b e f o r e i t w a s a s s u m e d t h a ts imi la r tonnage -grade r e la t ionsh ips cou ld be ex tended tomany types of deposits over a wide range of grade, and toassume tha t Lasky ' s Rule a l so app l ied to undiscove reddepos i t s . Thus , Lasky ' s Rule was e r roneous ly used to sup-por t the concept of unlimited geological availabil i ty.Since tha t t ime , new knowledge and explora t ion r e su l t sh a v e t h r o w n g r e a t d o u b t a b o u t b o t h L a sk y' s R u l e a n d t h econcept of continuously improving economic availabil i ty.I t i s to Tom Lover ing ' s c red i t tha t he f i r s t po in ted ou tsom e of th e lim itation s of Lasky's R ule. First, lim itationo n t h e h i g h a n d l o w t o n n a g e s i d e s ; t h e n o n t h e h i g h a n dlow gra de s ides .I t is no w recognized t hat L asky's Rule is , within l imits ,usable in a restr ic ted, practica l range of values for somc

indiv idua l known mines and even for a f ew min i l lg d is -tr ic ts , but i t must be re jected as a universa l tool for thesta t is t ica l evaluation of mineral distr ibution over largera reas . For ins tance , s tudents o f porphyry coppe r depos i t sof North America recently came to the geological andmathemat ica l conc lus ion tha t the ava i lab le tonnage ofcop pe r in the lowcr -grade depos i t s does no t inc rease geo-me t r ica l ly wi th a dec rease in g rade . I t i s now accep tedtha t eac h comm odi ty and each t ype of depos i t has i t s ow11dis t r ibu t ion laws and tha t Lasky ' s Rule doesn ' t app ly toa n y d e p o s i t s b u t t h e m e d i u m - g r a d e p o r p h y r y c o p p e r de-pos it s fo r which i t was fo rm ula ted .Now, wi th r ega rd to economic sca rc i ty , the conc lus iontha t the re hasn 't been a nd the re i s un like ly to be a w arc i ty

of minerals in the economic sense is based on studies ofthe trends in mineral availabil i ty over a per iod of about acen tury . Ba rne t t and Morse , in the i r f amous s tudy "Sca rc -i ty and Growth , " publ i shed in 1963 , showed a pe r s i s ten tdec l ine dur in g the pe r iod 1870-1957 in the labor il lpu tpe r un i t o f mine ra l p roduced . This was t rue no t on ly ofmine ra ls in the aggrega te , bu t ind iv idua l ly a s we l l . F igs .2 . 3 . and 4 i l lustra te the results of this s tud v for min eral,fue ls , nonmeta ls , and me ta ls .Th e use of manp ower r equ i rem ent pe r un i t of ou tpu t asan availabil i ty indicator is based on thc theoretica l eco-nomic concept tha t th e p roduc t ion of a un i t of a givenprod uct requires inp ut of thr ee factors- land, la l~ or , nt1capita l . I f a scarc i ty of one factor develops, presumably agreate r inpu t of o ne or both of the o ther fac tors rvould 11crequi red to a l low produc t ion . His to r ica l t r ends dc inor l -s t r a te tha t the input o f labor has been dec l in ing r a the rthan inc reas ing . Wha t ' s d i s tu rb ing about these s tud ie s i stheir use of manpower as the sole measure of cconomicava ilab il i ty . Th e o the r tw o v i ta l inpu ts , a nd o the r f ac tor s .a re d is r ega rded : i . e . , c ap i ta l and land , p lus mine ra l -basedene rgy , the me ta ls used in machine ry a nd e qu ip i nc~ l t o rmine ra l p roduc t ion , the use o f wa te r , and the la i ld d is -t u r l ~ a n c e a u s ed b y m i n in g .I f a l l these inputs were calcula ted, assuming that somea d e q u a t e m e a s u r e c o u l d b e d e v e l o p e d f o r l ~ a l a n c i l l g orw e i g h i n g o n e a g a i n s t t h e o t h e r , w h a t ~ v o l ~ l d)c t l ie toll-elusion? I low, for example , does one b a l a n c c t h c 1939-1970 t lccrcasc of 7 2 ' ; i l l l a l ~ o r e q ll i re t l t o m i n e ;: toll o!'



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all mineral luels Ipetroleum and natural gas 1bituminous coalanthracite coal

Fig. 2-US mine ral fuels: labor cost per uni t of output, 187 0-195 7(after H. J. Barnett, 1973).copper, against an increase of 31% in the input of inani-mate energy? (T he total results may not be chang ed ifeverything were taken into consideration, but the con-clusion would b e far more conv incing if additional mea-sures would be used.) For copper, unlimited economicavailability was then assumed, based only on decreasinglabor input and on decl ining average copper grade (Fig.5 ) . Is this correct?I owe to the late Hugh Risser, mineral economist withthe USGS, some data h e conveyed to me. Before his deathin 197 4, he ha d started to invest igate in dep th the p rob-lem of eco nom ic availability. I'll show som e graph s heprepared which indicate that, for some commodities, theeconomic availability measured in manpower input hasstopped decreasing and, in some cases, actually startedincreasing in the 1970s. This is especially true for recov-erable copper metal (Fig. 6) , as opposed to manpowerinpu t pe r ton of cr ud e coppe r ore. However, th e trendcontinues to be improving for iron ore.Fig. 7 shows that manpower input started increasingfor all type s of coal operations in the US . These g raphsdemonstrate to me that historical observations should beextrapolated only very cautiously. We might expect that,in the future, the same reverse t rend may develop formost mineral commodities, thus adding another limitingfactor to geologic an d political availability.Actually, the problem is that this application of eco-nomic theory tells us tha t:

( 1 ) Th ere is no past eviden ce of a long-term t ren d ofecono mic scarcity of m inerals in ge neral.( 2 ) The long-term trend has been a decl ine in theinp ut of labor an d capital required to produce agiven m ineral.( 3 ) There have been temporary or short-term level-i n g ~ nd upturns of inputs , but they have notpersisted.( 4 ) Tendencies toward increased inputs have beeninterrupted by improved technology in discovery,production, processing, and utilization, and alsoby substitution of other materials for th e hig hercost increments of the initial commodity.

Where Economic Theory Goes WrongEconomic theory, as applied in the economic availabil-ity model, does not tell us many important things. I willnow list a few of them :(1) The decline in inputs of capital and labor areaccompanied by large increases in energy input

and horsepower of equipment.( 2 ) Decreasing grade is accompanied by increasing

rallo

+- sand and gravel

t ll nonmetals

t hosphate rock

Fig. 3-US nonm etals: labor cost per un it of output, 1880-1957(after H. J. Barnett, 1973).

t l l metals

t ron ore

Fig. 4-US metals: labor cost per uni t of output, 18 7b 1 95 7(after H. J. Barnett, 1973).

01910 1920 1930 1940 1950 1960 1970 1980

(From US Bureau of Mines data)Fig. 5-Average recovered grade of US copper ores.

problems of waste handling and disposal and dis-turbance of la nd areas.( 3 ) Much of the technoIogica1 progress comesthrough breakthroughs that occur at irregularand periodical intervals.( 4 ) Major mineral discoveries also appear intermit-tently, rather than at regular intervals.( 5 ) Th e timing of such technological breakthroughsand major discoveries cannot be predicted in ad-vance.

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(6 ) Economic evidence of an impending scarcity is alagging indicator; scarcity does not exist until themoment that demand firs t exceeds the reservesand production capacity.( 7 ) Slineral supply is generally elastic in the shortterm, up to the t ime that productive capacity isfully utilized; it is also elastic in the intermediateterm, up until production capacity equals thenlaxinlum producihility of known reserves; andsupply is also elastic in the long term, hut onlywhen allowance is made for t ime for the dis-covery of new reserves.

(8 ) Economic theory doesn't tell us that each dis-:.overv which makes minerals a\.ailablc for usereduces by an equal amount the potential forFuture discoveries.( 9 ) T h e tim e ~ e r i o drom initiation of search t h r o u ~ h0discovery and develop me nt of production ca pa-bility is great an d lengthening. W ith grow ing pro-duction, the period required to exhaust a givenrc,servc is shortening; i t is i ~ o t he ra te of dis-covery or the rate or prod~ic tion hat governs thel i~ n i tof pl-oducibility, hu t the relation of ava il-able known reserves to the rate of produc tion.Analysis of ec o~ io m ic vai1:tbility stu die s poi11 s to the,failings oi econonlic theory with regartl to energy, mate-rial, and time in puts. Le t us illustrate these points.With regard to carlerg!j n pu t, Table 2 shows n table pre-pared by Kellogg in 1973; i t indicates that for US copper,-.-.~~ .T.... ~.. .~~~--. ~ .-- - ---7

k. ! Iratio of 1 ..scale / '1 1 I

9 r- rude copper ore 1C.----3.4recoverable 1copper metal

crude iron oreusable iron ore

1 9 4 0 1910 1960 197"

Fig. &Man power input per ton of ore (afte r H. Risser, 1974).

strip mmes 1auger mlnes1 i all mones--

Fig.-7 Manp ower inp ut per ton of bituminous coal output (afte rH. Risser, 1974).

Fig. 8-Small copper bla st/le ach surface pro ject (197 4), nondis-counted cash flow after tax.

3 -

2 -

E '-m-0"0

g 1 ---E 2 -3-

4 -

in 1970 (wi th an ore grade of 0 .7% C u) , the to ta l energyconsumption to produce one pound of copper was ahout46.5 MJ 44,000 Btu) per lb. At that t ime, extrapolationsto low-grade ores of 0.2% Cu, and to average rock with10 0 ppm Cu, indicated that there was a n energetic l imitto com er avai lab il itv. This limit has beem e m ~h as iz ed \.L Lthe drastic increases in energy costs in the last two )cars.The National Academy of Sciences reached a tentativeconclusion in early 1975, based on mineralogy and energyrequirements , that i t was unreasonable to assume that anv

Wum;- -21% DtF-ROI

copper material with a grade of less than 0.15 copperw ou ld b e m in ed in t he f u t ~ r e . ~his definitely puts alimit on th e availability of new ly-mined co pper for gen-

8.8 ~ M M Iom0.35% Cu

- -erations 100 years from now .Many studies have been prepared of energy input invarious materials with the purpose of comparing theirenergy intensiveness. The figures below show that con-

0 0 - - 1 , 2 , 3 4 , 5 , 6 , 7I

If sdd: $0.5 mHImatter-tax cost, andO M War delaya W hkd p a r...Refurn: 11.4%DCF-ROl

b l a s t p r e c i p i t a t i o np l a n t

crete,-as a construction material delivered a t the construc-tion site, is considerably less energy-intensive than otherstructural materials such as s teel and aluminum. Suchstudies should be developed further and constantly up-dated, so that this input in economic availabili ty can beintegrated in any studies of the economic convertibilityof mineral resources into mineral reserves.I mentioned earlier that t im e was another factor notadequately taken into account in availability studies. Aslong as this country functions under a capitalistic systeni(o r what's left of i t ), new projects will have to promise ailacceptable return on investment before funds call be oh-ta ined an d commit ted.From this point of view, it is very enlightening to con-sider the effect of time delays on the profitability of sonicmining projects (Fig s. 8, 9, and 1 0 ) . Let's take, for in-stance, a small cop per project involving blasting of thcrock in place, followed by leaching in place and precipi-tation of cem ent copper (F ig. 8) . This is a hypotheticalmodeling example prepared more than a year ago. Thcinvestment of about half a million dollars during thc firstyear for land, exploration, dril l ing, an d preliminary metal-lurgical tests is followed by about $750,000 in the sccondyear for further metallurgical testing and feasibility study;and then, in the third year, by an investment of $3 mil-lion to implement a large in-place blast and the construc~tion of a leaching and precipitation setup. This operatio11

can produce cement copper at a declining rate f o r foul.years. The model deposit of 8 5 million tolls of 0 :35':



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Fig. 9-Medium-size underground zinc proj ect (197 3), nondis-counted cash flow after tax.copper would deliver a discounted cash flow return oninvestment after taxes of 21 %, according to this schedule.However , if reasons such as lack of smelter availability,or need for detailed ground water environmental study,caused a delay of one year at an after-tax cost of half amillion dollars, the return rate would come down to 11.4%>.It is doubtful that, with such a delay, any investor wouldput money into such a venture. This is a good example ofconversion of reserves into uneconomic resources. If thecopper depletion allowance were cancelled, the rate ofreturn would decrease from 21 % to 9%-another case ofreverse conversion. Increase taxes by 25% and this depositcan go into oblivion as a reserve.Fig. 9 gives another example. This model is a sizablezinc deposit, containing 29 million tons of 6% zinc ore ina flat-bedded deposit at a dept h of around 460 m (1500f t) , which can be extracted through underground miningand concentrated in a flotation mill. Such operation wouldsell zinc concentrates to ;I zinc smelter. After a seven-yearperiod a nd an investment of $34 million in surface ex-ploration and underground exploration, followed by feasi-bility study and equipment of a mine an d a mill, such adeposit , over a production life of 2 3 years, would deliver adiscounted cash flow return on investment of about 197;.However, if you insert before the expensive constructionprogram a two-year de1a.y at a half-million dollar after-taxcost for each year, the return is decreased to 17% and thepayout, a very important economic parameter to any in-vestor, is suddenly increased from 4.6 years after start ofproduction to 7.7 years after start of production. This de-lay might be acceptable to some investors. However, iffor reasons such as lack of smelter availability, environ-mental or other kind of shutdown, or great economic dif-ficulties in start-up, you insert after construction, beforeproduction starts, a one-year delay at an after-tax cost of$2 million, the return on investment is decreased to 14.7%and the payout is increased to 8 .9 years. These time effectsare drastic and more pronounced than one would guess.The cancellation of the depletion allowance would fu r-ther reduce the rate of return by 4%-transforming thesereserves into uneconomic and unprofitable resources. Ifprofits are not reasonably expected, then a project will notbe started. After all, profits are nothing but the costs ofassuring our future.The effect of time is less pronounced on large projects,as shown by the example in Fig. 10, where our model is a

3 i125 mflllbn toru-Q.8% Cu

22.000 tDll

I 1Fig. 10-Large copper open-pit proj ect (1974), nondiscounted cashflow after tax.medium-sized porphyry copper deposit amenable to open-pit mining and treatment in a flotation mill. Such a de-posit, according to this model, would require about fouryears of exploration, a fifth year for detailed feasibilitystudy, and then two well-filled years for construction, at atotal investment of over $170 million. Then, if productionstarts as planned, this deposit, for a production life of 17years at 22 ,000 tons per day of ore, would give a rate ofreturn of 17 % discounted cash flow return on investment.A two-year delay before feasibility study, for reasonswhich may be economic or environmental, means only asmall decrease in the rate of return. However, if you in-sert a delay of one year with cost of $5 million after tax,after the deposit has been equipped, then you seriouslyreduce the rate of return to 147; and considerably in-crease the payout from 5.0 years to 9.4 years. Cancellationof the depletion allowance would reduce the rate of returnby about 37 , , niaking such deposit uneconomic.Another aspect of time used in determining need fornew production and new discoveries is the estimate of"life of reserves." Table 3 shows that the apparent life ofreserves, as measured by total reserves divided by currentproduction rate, can indeed be a very misleading index.When actual production rates are taken into account, wefind that the combinat ion of five mines-A to E-with re-serves as shown on the second column and with produc-tion capability as shown on the third column, would pro-duce 18 units per year for the first four years; then 14units for the next six years; then 10 for the next 7 years;then 7 for 33 years, until final exhaustion. Thus, the actualproduction lifk is 50 years, at a rate varying between 7and 18 units, instead of an apparent life of reserves of 25years. If 18 units is a desirable production, then new de-posits must be found and opened up by the end of the4th year.I t is critical that realistic evaluat ion of productive capac-ity to exhaustion be inserted in any economic-mineralavailability studies. The US Bureau of Mines is to be com-mended for introducing such time factors as productivecapacity and lead time for construction, expansion, andstart-up in its copper availability studies published twoyears ago. Let's hope that the Bureau will extend this ap-proach to other industrial minerals.For those commodities where discoveries are needed tosatisfy future demand, then it is important to appreciatethe capital demands for achieving mineral discoveries andthe risks involved. Studies of the discoveries, and cost ofdiscoveries in dif ferent part s of the world, have indicatedthat over the last 20 years the efficiency of the exploration

M I N I N G E N GI N E E R S M I N I N G E N GI N E E R I N G 33


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Table 2-Energy Consum ption for Production of Table 3-Estimated Energy ConsumptionofCopper Material Delivered at Use Site(1970 and projected) (millions BTU per ton)Year BOOO? Distant(tow-made Fptnre1970, U S o n ) Baae Rock

Ore grade, % Cu 0.7 0.2Recovery of copper, % 0.0182. 80. 80.Tons of waste rock per ton ore 2.34 1.5Tons waste rock per ton copper 355. 0.5940.Tons tailings per ton copper 8300.145. 620. 12 500.Total tons waste cu ton oopper 500. 1580. 18:800.~nergy os*BmeBpar ton copper,MiIIions of Btu:For rnbing 25.1 93.8 1875.0For beneficiation 33.0For smelting + refine 127.2 2543,830.5 30.5 30.5Total energy 88.8 251.5 4449.3To@ wergv, Btu per Ib coppa 44,300. 185,800. 2,225,000.Equiv. Ib coal per Ib copper 3.5 10.1 178.

dollar (expressed i l l constant tlollars) has decreased Ilyabout two-thirds. Without breakthroughs ill detectiontechnology, this treild will continue.

The risks involved in exploration are also increasing, asdeposits are l~ecomingmore difficult to find, because ofcover of barren rock and/or increased depth. For instance,it is presently estimated that only lor: of the funds spentin Arizona for porphyry copper exploration are used ontargets which turn out to be deposits. In British Columbia,for the same type of deposit, the proportion used suc-cessfully is 6:'; ; whereas in Mexico, where less explorationhas taken place, the estimate is that 20C; of explorationfun ds art: used successfully. Th e cost of fa ilures is too of-ten forgotten ill lneasuring the economics of :] successfuluroiect.L ,For another type of dcposit, the small- to mediuin-size.high-gr,tde, massive sulfide deposit that is well-known illCanada, Australia, and other parts of thc ~v orl d, t is esti-mated that only I ( : of the exploration expendiiure is usedsuccessfully.With the increased capital denland for n c n mining op-erations, and in view of the cune nt capital shortage andreduced profitability of the mining industr!., will the avail-able risk funds for exploration be adequate for the US?This is 3 critical question l~ecause racticall). all esplora-tion funds for metals come out of earnings and not out ofnew equitv or debt.Political Availability of Mineral Resources

This topic has received much attention in the last twoyears. I11 the wake of OPEC's actions and of numerous ex-propriations and nationalizations ir~ nany countries, it ap-pears that the needed foreign supply \\rill have to comeinore through purchase from foreign producers thanthrough investinents l)y US industry for exploration andde\relopment in foreign countries.

The three inajor industrial areas of the Free World-theUS, Western Europe, and Japan-import 13 : , 75%, and90'; rcbpecti\rely of the industrial raw materials, otherthall fuels, which each consumes. Our position at presentis much more favorable than that of Western Europe orJapan anti can l ~ eonsidered in a separate context. How-ever, our favorable positioll is being eroded.Th c trend over the years 1950-1970 is shown in Table5 . At prcsent, our dependency on imports of rnetallic met-als varies from 15': for copper to 100": for chromium.Looking ;ct Table 5 , but updating the nurnbers for 1973,\ve find that our depeiidency has decreased for zinc, ti-

Aluminum 122co p er 89~teeT 45Paper 42Concrete 2(After COMRATE, 1973 and PCA. 1975)

tanium, and lead because in that year we imported only51% of our zinc needs, 33% of our titanium needs, and36 % for lead. However, our dependency on all other metalcommodities has worsened: as of 1973, it was 95% formanganese, 90% for aluminum, 18y i for iron (a doublingof dependency in three years), and 44r6 for tungsten. Thegeneral trend for most of these commodities is for an ab-solute increase in dependency, as measured in physicalvolume and dollars.

The political availability of imports varies considerabl),,us shown on Fig. 11 (borrowed from a 1974 study 11y theCouncil on International Economic Policy) . For copper.vanadium, iron ore, titanium, lead, tungsten, zinc, nickel,cobalt, platinum, chromite, and bauxite, a significant pro-portion of our imports comes from developed countries,including Canatla, that are trading partners with the US.However, especially for bauxite, cobalt, manganese, tin.alld chromite, we find a major part of our imports comefrom less-developed countries which do not have eithertlie same social, economic, and trading characteristics o rneeds as developed countries. In studying the fulfillmentof future US demand for these commodities, we must takeinto account the political climate, the potential for effec-ti\,e cartelization, and the likelihood of expropriation in theproducer-exporter countries. Such analysis-combiileclwith a study of ( a ) demand reduction, substitutabilityand recyclability; ( b ) geological availability of inferredreserves and hypothetical plus speculative mineral re-sources: and. i c ) currentlv noneconomic identified min-, \ ,era1 resources in the an tell us whether special ef-forts should be made toward attempting to iinprove oursupply position by increasing self-sufficiency.

A few comments about potential cartels are in order.Table 6 shows that the conditions necessary for the successof a carte l, such as OPEC, are not found to the degreethat they are found with respect to oil. When metallicminerals a re examined individually, some of thc condi-tions required for supply and price control are as follows.

Tab le 4--Hypothetical Example of Reserves andProductive CapacityOreMine Reserves Annual Appa"tMining Rote Life to Years

Apparent life of reserves: 457 i 8 = 25.3 yearsActual production would Last SO years:18 units per year for first 4 ye m, then14 units per year for next 8 years, then10 units per year for next 3 3 years,(After C. H. Burgess, 1974)



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C 0 -t! 'CI Q) CI $) C E Q)Q) C .- CItu s i= =I .-P Q) CI iu' 0 XUJ Q)P .- =I C CJ .-CI E0 C m z tu tuC m -u 0,0 0,=I

me

c- I- C 0zCanada other

US Production imports from developed countries imports from developing countries(Aiter CCIEP, 1974 Special Report on Critical Imported Materials)

I IFig. 11-US metal import dependence (19731, US production and imports as percent of total US demand.(1) Th ere must be a concentration of mineral re-

sources and producible reserves in exporting-pro-ducing countries.(2 ) Th e exporting-producing countries must have animportan t share of th e market.( 3 ) The commodity mus t be inelas tic to demand, andshow( 4 ) Limited recyclability, and(5) Limited substitutability.( 6 ) Another factor favoring cartelization is a sizablevalue added by processing, which means an im-provement in the local economy if processingtakes placo locally and willingness for importersto pay m ore for unprocessed raw materials .( 7 ) Another factor is whether or not processing in

the producing country is , or would be, an im-portant factor in achieving higher employmentlocally.Finally, shown on the right s ide, two extremely criticalrequirem ents for control:

(8) The exporting-producing countries must derive amajor part of their f inancial s trength from theproduction of the comm odity; an d(9 ) Market control can be used to satisfy specific in-ternational p01it:ical purposes of the exporting-producing countries.These factors have keen rated from low to high-i.e.,from 0 to 3 respectively. While these ratings are time-de-pendent, qualitative, anti subjective, they are of help in

analyzing each commodity. If there is a potential threat tosupp ly, bu t also significant geological ava ilability of do-mestic resources for conversion to reserves, the US shouldmake an effort to increase its exploration and production.But in the case of negligible g eologic availab ility of d o-mestic resources, special efforts should be made to reducedemand, to increase recycling and substitution and/or toimprov e our trading and importing positions.Availability Aspects For Certain Me talsCopper-US self-sufficiency in cop pe r, if desirable , canbe attained in the short term, barring reconversion of re-serves to resources throug h high-cost pollution abat em entmeasures. However, the small net imports from Peru andChile are not in any great jeopardy since effective cartel-ization for copper is very dubious. Long-term self-suffi-ciency can probably be reached through expansion ofproduction and through exploration in the US, but thiswould require the opening of known low-grade and/orhigh-cost deposits and discovery of many new domesticdeposits . The US and world resources are huge; economicconversion to reserves and new production should takeplace in due course, on a competitive basis, thus assuringan economic and secure supply to the importing coun-tries. Complete self-sufficiency does not appear eithernecessary or econom ically desirable.Iron-Ore is plentiful the world over an d effective car-telization unlikely. Our limited but increasing imports ofore from Venezuela and of products from Japan and theCommon Market countries do not appear endangered.Self-sufficiency could be attained in the US in the me-dium term, but does not appear to be reasonably desirable

MINING ENGINEERS MINING E NG INE E RING 35


10/11

in v iew of inc reasing economic an d s tab le pol it ica l av a i l -abi l i ty f rom deve loped countr ies and f rom marke t-econ-omy deve loping countr ies , such as Braz il .Lead-US self-suff iciency ha s be en increasing steadilythanks to discovery of the new hlissouri lead belt in themid-19 50s. Recycling has 11celi hig h for years an d iss lowly increas ing. Lead is mined in many col~ntr iesant1cartel izatio n is ver y unlik elv. I belie\-(- sclf-sufficiencym igh t be a t t a in a l~ le n the . long r uu , hu t n l a y lot 11ceconomicallv desiraSle in view of the high ;i x a i la l~ i l i tvoflead f rom ne ighbor ing countr ies .Tungsten-US de pen del lcy has tlecrc.aset1 sligh tly illth e last fe w vears. O ur identif ied n one tono mic res0urcc.sshould eventually respontl to extraction tec*hnology rc-search. 111 addi t ion , purp oseful explorat io i r for tungsten inthe US shou ld c onve r t hypo the t i c a l a nd spe c u la t ivc r e -sources in to rese rves . Such conversion cffort is very de-s i rable , s ince temporary ca r te l iza t ion is not unthinkableand supply f rom Bol iv ia , Peru , and Tha i lant l ca i rnot bcra ted as las tingly sccure .Zinc-occurs in man y couutr ies ant1 docs i ~ o t ppe ar tobe a m e na b le to ina r ke t c on t r o l bv e x~ or t e r s .Self-suffi-

I Iciency is increasing an(! will colltinuc. to iircrc*ase a s th ediscover ies of the ncn, mid-Tc nncssee z ir ic l~ e l t ~ ce ve l -ope d ant1 mo re do mestic discoxcries are matl( :. IIepe11-de nc y or1 Per11 (for som e ilnpor ts ok co ncen trates 1 ant1 onJa pa n i f o r m e ta l j is sign if ica~ it , mt does not suggcs t a l la t t e m p t at self-s uffici eilcy a t ail)- p1.ic.c. is j ustifi ed. Soshor t - te rm 01 . ong- te rm supply problems a rc ant ic ipa ted .Nickel-has be en sup plied to th e Fr ee iVorld 11y a fe wcorpora t ions based in deve loped countr ies . Wii i le domes-tic self-sufFicie:lcy is not possible in the short trrnl. huge,marginally economic resources in XIinilcsota descrvc!


11/11

Table 6-Main Factors Required for Control of Price and SupplyLimited Limited Value LaborMinerals Concentration Share of Inelasticity Recycl- Substitut- Added by Intensive Financial PoliticalMetallic of Supply the Market of Demand ability ability Processing Processing Strength Purpose

Copper 0Iron Ore 0Lead 0Tungsten 2Zinc 0Nickel 3Bauxite 1Manganese 0Tin 2Platinum 3Chromite 3Petroleum 2De ree of existence of these control factors3ery Low, 0; Low, 1; High, 2; Very High, (After3. Mason

but even a drastic increase would not make reserves out ofthe dom estic resources.Chromite, manganese, tin, and platinum supplies areth e most critical; the likelihood of develop ing successfulconversion of resources to reserves appears to be neithergeologically nor econoniically possible in the US. Forthese commodities, it seems that we will have to continueto rely on imports from traditional sources; we may en-hance our position by making special bilateral arrange-ment with the suppliers, or seeking a multilateral solutionin concert with other affected importing-consuming coun-tries.Availability Of Metal s From T he Deep OceansConsiderable exploration, mining, and metallurgical ex-traction research and development work has been done,mostly by US corporations, in the last 12 years. The USindustry is undoubtedly in a leading position with regardto economic developm ent of these nodules. Th e resourcesof co pper a re large; at least equivalent to those estim atedon land. They are enormous with regard to nickel, cobalt,and manganese; their geological availability is excellent,their economic availability has improved enough to con-sider feasibility studies and financing schemes. But theirpolitical availability is presently nonexistent. The deepoceans are a legal no-man's land without adequate legalprotection for the potential producers. With political as-surances of security of tenure, these deposits will becomecompetitively exploitable within the next decade. Suchinternational assurances may be forced b y actions of in-dividual countries.However, any new production will be limited by thecapability of any mining ship unit; 10,000 tpd is the larg-est nodule production unit contemplated at present. Itwould appear at this time that the most we can expect isa verv minor contribution to the SUDD~Vof coDDer an d a1 1sizabic: contribution to the supply 3 i cke l and cobal t .The m anganese content cannot be considered an economicresource at present. The ocean nodules give us an ex-cellent example of the combined effects of geological,econornic, and political availability on a possible futuresupply.ConclusionFor the whole planet. conversion of nonfuel resourcesto reserves is limited only by economic and political avail-ability problems. T here are no foreseeable geological avail-ability problems for cen turies . Because of c urre nt inflationand taxation, however, there are more reserves recon-verted to uneconomic resources than there are new re-serves created by exploration an d extraction research.

In the United States, limited geologic availability, asestimated at present, precludes the creation of adequatedomestic reserves for a few metal commodities-chromite,tin, platinum, and manganese. For the other metal com-modities, creation of needed new reserves can be achievedthro ugh exploration-if the economic climate is favorab le.That is a big "if" because such a favorable climate-freeof incap acitatin g uncertainties-depends on the avail-ability of lan d, of sta ble energy su pplies, of capital forhigh-risk exploration and for development, and on securityof investment recovery and of profit retention. In effect,the conversion of domestic mineral resources to reservesnee ded to assure the futu re growth an d freedom of ourcountry will occur when a solution is found to such prob-lems as land withdrawals, the energy shortage, the capi-tal shortage, inflation, and crippling taxation.ReferencesBarnett, Harold J. , 1973, "Energy, Resources, and Growth," Re-search Monograph 7381, Dept. of Economics, Washington University,St. Louis, Mo.' ourrelier, P., F. Callot, R. Diethrich and Hugon, J. P., Annales

de s Minzs, January 1975, pp. 1-68.3 US Council on International Economic Poli cy, 19 74, "Special Re-port: Critical lmported Materials," 49 pp.4 (US) National Academy of Sciences, National Research Council,Commission on Natural Resources, Committee on Mineral Resourcesand the Environment (COMRATE ), 1975, Mineral Resources and theEnvironment, 348 pp.:US Depxrtment of Interior, Bureau of Mines, Commodity DataSummaries, 1975, 193 pp.US Dept. of Interior, Bureau of Mines, "Minerals in the US Economy:Ten-Year Supply-Demand Profiles For Mineral and Fuel Commodities,"1975. 96 on., - -'Occidental Minerals Corporation, staff reports and evaluations, es-pecially contributions on cartels by M. A. Mason, vice-president; rate ofreturn computations by Ronald L. Haxby, senior staff mining engineer.C. Harry Burgess, private, 1974Hubert E. Risser, private, 1974

About the AuthorPau! A. Bail ly is president ofOccidental Minerals Corp. (6073West 44th Avenue, Wheat Ridge,Colorado 8C033), a subsidiary ofOccidental Petroleum Corp. Afterobtaining his MS in geologyfrom the University of Nancy,France, he pursued graduatestudies at Yale University, andreceived his Ph.D. i n geologyfro m Stanford University. Beforejoining Occidental, Dr. Baillyworked for Kennecott CopperCorp. and Bear Creek Mi ni ng Co.A member of several professionalsocieties, i nclud ing AIME, he hasalso served on various commit-tees of the National Academy ofSciences and the National Re-search Council. Dr. Bailly haswritten numerous articles on ge-ology, development, public landlaws, and is the author of thesection on "Minerals Explora-tion" in the SME Mining Engi-neering Handbook.

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Converting Resource ToReserve