No. 9044 
 
 

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Bureau of Mines Information Circular/1985 
 
 Molybdenum Availability- 
 Market Economy Countries 
 
 A Minerals Availability Appraisal 
 
 By C. M. Palencia 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 
 7® 
 
 V/NES 75TH A*»^ 
 
Information Circular 9044 
 
 Molybdenum Availability- 
 Market Economy Countries 
 
 A Minerals Availability Appraisal 
 
 By C. M. Palencia 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 Donald Paul Hodel, Secretary 
 
 BUREAU OF MINES 
 Robert C. Horton, Director 
 
As the Nation's principal conservation agency, the Department of the 
 Interior has responsibility for most of our nationally owned public lands 
 and natural resources. This includes fostering the wisest use of our land 
 and water resources, protecting our fish and wildlife, preserving the 
 environmental and cultural values of our national parks and historical 
 places, and providing for the enjoyment of life through outdoor recreation. 
 The Department assesses our energy and mineral resources and works to 
 assure that their development is in the best interests of all our people. The 
 Department also has a major responsibility for American Indian reserva- 
 tion communities and for people who live in island territories under U.S. 
 administration. 
 
 
 Library of Congress Cataloging in Publication Data 
 
 Palencia, Cesar M. 
 
 Molybdenum availability — market economy countries. 
 
 (Bureau of Mines information circular; 9044) 
 
 Bibliography: p. 21 
 
 Supt. of Docs, no.: I 28.27: 
 
 1. Molybdenum industry 2. Molybdenum mines and mining. I. United States. Bureau of Mines. FJ. Tide. 
 IE. Series: Information circular (United States. Bureau of Mines); 9044. 
 
 TN295:U4~ 
 
 HD9539.M62 
 
 622 s 
 
 338.2 '74646 
 
 85-600115 
 
 For sale by the Superintendent of Documents, U.S. Government Printing Office 
 Washington, DC 20402 
 
Ill 
 
 PREFACE 
 
 The Bureau of Mines is assessing the worldwide availability of critical minerals, ex- 
 clusive of the energy fuel minerals. The Bureau identifies, collects, compiles, and evaluates 
 specific information on producing, developing, and explored mines and deposits, including 
 the processing plants that convert raw minerals to marketable products. The objectives 
 are to classify domestic and foreign resources in order to identify by cost evaluation those 
 that are reserves, and to prepare analyses of the availability of these minerals at different 
 times and conditions. 
 
 This report on the availability of molybdenum is part of a continuing series of reports 
 that analyze the availability of critical minerals from domestic and foreign sources. Analyses 
 of other minerals are currently in progress. Questions about these reports should be ad- 
 dressed to Chief, Division of Minerals Availability, Bureau of Mines, 2401 E St., NW., 
 Washington DC 20241. 
 
 
 
CONTENTS 
 
 Page Page 
 
 Preface iii Other processing 10 
 
 Abstract 1 Deposit evaluation procedure 10 
 
 Introduction 2 Assumptions 10 
 
 Molybdenum products and uses 2 Cost estimation 12 
 
 Marketing- and pricing structure 3 Operating costs 12 
 
 World production, consumption, and trade 4 Capital costs 13 
 
 U.S. production, consumption, and trade 5 Molybdenum availability 14 
 
 Geology 6 Evaluation methodology 14 
 
 Mineralogy 6 Total availability 14 
 
 Resources 7 Annual availability 16 
 
 Primary molybdenum resources 8 Byproduct molybdenum total availability 17 
 
 Byproduct molybdenum resources 9 Conclusions 20 
 
 Mining and processing technology 9 References 21 
 
 Mining methods 9 Appendix. -Deposit descriptions for primary 
 
 Beneficiation 9 molybdenum 23 
 
 ILLUSTRATIONS 
 
 1. Molybdenum consumption according to industrial use, market economy countries, 1983 2 
 
 2. Molybdenum deposit locations, market economy countries , 7 
 
 3. Minerals Availability program evaluation workflow 11 
 
 4. Mineral resource classification categories 11 
 
 5. Total molybdenum available from primary deposits, market economy countries 15 
 
 6. Total molybdenum available from producing mines at a 0-pct DCFROR, market economy countries 15 
 
 7. Total molybdenum potentially available in the United States and Canada from producing mines and nonpro- 
 ducing deposits 16 
 
 8. Potential annual production of molybdenum from producing mines and nonproducing deposits at various 
 
 cost ranges, market economy countries 17 
 
 9. Potential annual production of molybdenum from developing and explored deposits at various cost ranges, market 
 economy countries 18 
 
 10. Total available molybdenum byproducts from copper deposits, market economy countries 18 
 
 11. Potential annual capacity of molybdenum byproducts at selected copper prices, market economy countries . . 19 
 
 TABLES 
 
 1. Comparative prices of molybdenum products 3 
 
 2. Molybdenum production from market economy and centrally planned economy countries 4 
 
 3. Molybdenum consumption from production in market economy countries 4 
 
 4. U.S. import duties on molybdenum materials 5 
 
 5. U.S. salient molybdenum concentrate statistics 5 
 
 6. U.S. molybdenum exports as reported by producers 5 
 
 7. Physical and chemical properties of principal molybdenum minerals 6 
 
 8. Primary molybdenum deposits and in situ demonstrated resources, market economy countries, January 1983 8 
 
 9. Byproduct molybdenum deposits and in situ demonstrated resources, market economy countries, January 1983 8 
 
 10. Byproduct commodity prices, market economy countries, January 1983 12 
 
 11. Estimated cost of mining and milling operations from primary producers in the United States and Canada, 
 January 1983 13 
 
 12. Estimated mine and mill operating costs for primary molybdenum producers in the United States and Canada, 
 January 1983 13 
 
 13. Estimated capital costs for developing and explored molybdenum deposits, market economy countries, 
 January 1983 14 
 
 14. Molybdenum potentially available from primary producing, developing, and explored deposits in market 
 economy countries at selected 1983 prices, at a 15-pct DCFROR 14 
 
 'olybdenum potentially available within the United States and Canada, at a 15-pct DCFROR 16 
 
 16. Potential 1983 molybdenum production capacities from primary molybdenum mines and deposits in market 
 economy countries, at a 15-pct DCFROR 17 
 
 17. Total molvbdenum byproduct potentially available in market economy countries at selected copper production costs, 
 
 at a 15-pct DCFROR 19 
 
 18. Annual U.S. molybdenum byproduct capacity and demonstrated resources of recoverable molybdenum from 
 evaluated U.S. copper operations at selected copper prices, at a 15-pct DCFROR 19 
 
VI 
 
 CONTENTS— Continued 
 
 TABLES— Continued 
 
 Page 
 
 19. Molybdenum byproduct potential annual production for 1983 and 1991 from market economy countries, at a 
 15-pct DCFROR 19 
 
 20. Estimated total 1983 molybdenum capacity from primary and byproduct producers in market economy 
 countries 20 
 
 
 
 UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 
 
 op 
 
 degree Fahrenheit 
 
 mm 
 
 millimeter 
 
 h 
 
 hour 
 
 mt 
 
 metric ton 
 
 in 
 
 inch 
 
 mt/d 
 
 metric ton per day 
 
 km 
 
 kilometer 
 
 mt/yr 
 
 metric ton per year 
 
 lb 
 
 pound 
 
 pet 
 
 percent 
 
 Ib/yr 
 
 pound per year 
 
 ppm 
 
 part per million 
 
 m 
 
 meter 
 
 yr 
 
 year 
 
MOLYBDENUM AVAILABILITY— MARKET ECONOMY COUNTRIES 
 
 A Minerals Availability Appraisal 
 
 By C. M. Palencia 1 
 
 ABSTRACT 
 
 The Bureau of Mines evaluated the potential availability of molybdenum resources 
 from 88 mines and deposits that account for more than 90 pet of the demonstrated resource 
 base in market economy countries (MEC's). For each property, tonnage-cost relationships 
 were developed that indicate the molybdenum potentially available at different average 
 production costs, including a 15-pct rate of return on invested capital. From the 23 MEC 
 primary deposits, 2.5 billion lb Mo was determined to be potentially available at a price 
 of S4/lb, rising to 4.7 billion lb Mo at $8/lb. 
 
 Copper price-molybdenum tonnage relationships were developed for those mines and 
 deposits from which molybdenum can be recovered as a byproduct of copper production. 
 This analysis showed that another 3.4 billion lb Mo is potentially available based on a cop- 
 per price of $0.75/lb. rising to 4.3 billion lb Mo at $1.00/lb. 
 
 The United States has been the world's largest molybdenum supplier since 1924. Its 
 remaining resources are sufficient to meet the domestic demand of 57 million lb/yr Mo 
 (averaged for a 10-yr period) through the end of the century. Production from primary 
 domestic mines was suspended during most of 1983 because of oversupply of materials. 
 A major concern is the cheap molybdenum byproducts from foreign copper operations 
 in which employment and the need for hard currency override economics in meeting pro- 
 duction goals. 
 
 PhysicaJ scientist (mining engineer). Minerals Availability Field Office, Bureau of Mines, Denver, CO. 
 
INTRODUCTION 
 
 This study provides analyses of the resources, engineer- 
 ing, economics, and other factors that influence the availabili- 
 ty of molybdenum. Production costs, including mining and 
 beneficiation, were determined for each property. Since some 
 producers market molybdenite concentrate as a final product 
 at the minesite, no attempt was made to analyze factors af- 
 fecting the availability beyond that point. 
 
 The molybdenum resources located in the Soviet Union, 
 China, and other centrally planned economy countries 
 (CPEC's) were not analyzed in this study. Inasmuch as it is 
 
 difficult to collect quantitative resource information and pro- 
 duction cost estimates from these countries, reliable and 
 definitive estimates could not be developed. 
 
 Domestic deposits were evaluated by personnel of the 
 Bureau's Field Operations Centers, and foreign data collec- 
 tion and cost estimation were performed under contract by 
 Pincock, Allen and Holt Inc., Tucson, AZ; personnel of the 
 Bureau's Minerals Availability Field Office, Denver, CO, 
 evaluated the data and performed the economic evaluation 
 analyses. 
 
 MOLYBDENUM PRODUCTS AND USES 
 
 A rare metallic element, molybdenum is gaining import- 
 ance in industrial applications. In a pure state, molybdenum 
 is a lustrous gray metal with a melting temperature of 4,730° 
 F. The word molybdenum came from the ancient Greek word 
 Molybdos, which means "leadlike," a name applied to all 
 minerals that were soft and leadlike in character, probably 
 minerals such as molybdenite, galena, and graphite. In 1778, 
 Karl Wilhelm Scheele differentiated molybdenite from the 
 other soft minerals. Four years later, J. J. Hjelm isolated the 
 metal as a new element now known as molybdenum ("moly" 
 for short). 
 
 It took more than a century to find a use for the new 
 element. The French first applied molybdenum to toughen 
 steel used in armor plates. Later the Germans improved the 
 
 technology by using molybdenum as an alloying element with 
 other metals. Further research found more applications for 
 molybdenum including lubricants, paints, pigments, fertilizer 
 additives, chemical catalysts, vitamin supplements, flame 
 retardants, smoke suppressants, refractory metals, and 
 semiconductor applications. 
 
 In spite of these diverse uses, 83 pet of molybdenum con- 
 sumption is for alloying uses. In some stainless steels, 
 molybdenum tends to minimize surface and intergranular cor- 
 rosion. Figure 1 shows an approximate percentage consump- 
 tion in market economy countries (MEC's) according to use 
 for 1983 (l) 2 . 
 
 2 Italicized numbers in parentheses refer to items in the list of references 
 preceding the appendix. 
 
 KEY 
 Alloying uses 
 
 Super and special alloys 
 3 pet 
 
 Molybdenum metal 
 Other uses/ 6 pet 
 
 pet 
 Figure 1— Molybdenum consumption according to industrial use, market economy countries, 1983. 
 
Basically, nonintegrated mine operations (mostly small 
 and byproduct producers) sell molybdenum in concentrate 
 form to independent companies for roasting. The major por- 
 tion of the total concentrate production is roasted to technical- 
 grade molybdenum trioxide (MoOj), the intermediate 
 marketable material from which almost all molybdenum prod- 
 ucts are made; a small portion of the concentrate is used 
 
 directly in mineral form (MoS,). Any technical-grade oxide 
 not directly used in the industry is further processed into 
 another marketable form; i.e.. high-purity MoO, and fer- 
 romolybdenum. The high-purity MoO, in turn is converted 
 either into chemical form (as pure salts), metal form, or alloy 
 form (as master alloys for high-temperature metals). 
 
 MARKETING AND PRICING STRUCTURE 
 
 There are two price structures in molybdenum markets, 
 the producers' price and the dealers* price. Molybdenum 
 marketed directly by producers is sold at the producers' price. 
 Normally, this accounts for about 90 pet of total molybdenum 
 production. The remainder is sold at a dealers' price in the 
 open market: this often commands a premium in times of 
 tight supply hut sells at a discount in times of plenty. In 1979. 
 when molybdenum demand was high and supply was tight. 
 the dealers' price went up to more than twice the producers' 
 price. However, when demand softened from mid- 1980 
 through 1981. the dealers' price went down to as much as 
 S3/lb below the producers' price. Table 1 provides price com- 
 parisons for the various forms of molvbdenum from 1975 to 
 1983. 
 
 Molybdenum on the domestic market is almost all sold 
 in processed forms: i.e.. oxides, ferro molybdenum, and am- 
 monium and sodium molybdate. Molybdenite (molybdenum 
 sulfide in concentrate), if any. is sold in very small quantities 
 for special uses such as lubricants. However, because of pro- 
 tective tariffs on processed molybdenum products, the 
 molybdenum market overseas, especially in Western Euro- 
 pean countries, is mostly in the form of molybdenite concen- 
 trates. While the United Kingdom, France, Italy, and West 
 Germany, for example, have no tariffs on molybdenite, they 
 impose 25 pet. 9 pet, 7.5 pet, and 7 pet tariffs, respectively, 
 on ferromolybdenum (2). 
 
 With the exception of 1977, molybdenum consumption 
 in MEC's exceeded its production from 1974 through 1979. 
 Consumption started declining in 1980 owing to the effects 
 of the recession. In 1974. consumption exceeded production 
 by about 42 million lb Mo. To offset demand requirements, 
 the General Services Administration (GSA) released 35 
 million lb from the U.S. Government Stockpile (3). With 
 strong demand continuing in September 1976 the GSA re- 
 
 leased all the remaining molybdenum concentrate from the 
 Stockpile (4). The continued increase in consumption in 1978 
 and 1979. which far exceeded production, forced a drawdown 
 from producers' inventories. This expanded industrial de- 
 mand, combined with the supply shortage situation caused 
 by labor strikes in Canada and reduced molybdenum 
 byproduct recovery from copper production, resulted in an 
 artificially high price in 1979 and early 1980, especially in 
 the international market. A self-imposed, anti-inflationary 
 measure instituted by the major domestic producers during 
 these years kept domestic molybdenum prices well below 
 those of exported products. (See table 1.) As production in- 
 creased and consumption dropped in late 1980, the supply- 
 demand picture took a reverse trend. 
 
 During the first quarter of 1981, while producers held 
 the prices for technical molybdic oxides and ferromolybdenum 
 at $9.70 to $9.35 and $10.60 to $10.25 per pound of contained 
 molybdenum, respectively, dealers were selling the metal for 
 about $1.25/lb lower. The price gap widened to about $3/lb 
 in the last quarter (5). This price difference caused the pro- 
 ducers to follow the downward trend, and in December 1981 
 Codelco (the Government-owned Chilean copper producer) 
 posted a price per pound of $5.55 for oxide and $6.55 for fer- 
 romolybdenum. In early 1982, a wide difference in prices 
 existed between individual producers. While Climax held to 
 its published price of $8.75 for canned oxide, $9.90 for fer- 
 romolybdenum, and $8.80 for briquettes, Codelco posted 
 prices of $5.52 for oxide, $6.57 for ferromolybdenum, and 
 $5.61 for briquettes. At the same time, Duval and Noranda 
 quoted export prices of $7.00 for oxides, $8.10 for fer- 
 romolybdenum, and $7.11 for briquettes. Dealers' prices for 
 this period ranged from $4.80 to $5.15 for oxide and $5.15 
 to $5.50 for ferromolybdenum. In September 1982, Climax 
 firmed the price at $5.85 for oxide, $6.75 for fer- 
 
 Table 1.— Comparative prices of molybdenum products 
 
 (Dollars per pound of contained molybdenum) 
 
 Concentrates 
 
 Technical-grade oxide 
 
 Ferromolybdenum 
 
 Year Byproduct Climax Climax' Dealers 
 
 1975 $ 2.20- S2.62 $2.62 $2.90 $2.90- $2.95 
 
 1976 2.85- 3.20 2.70 3.54 3.30- 3.35 
 
 1977 3.85- 4.01 4.01 4.31 3.60- 3.75 
 
 1978 4.50- 5.15 4.95 5.30 9.00- 9.50 
 
 1979 25 00 27.00 8.84 9.80 26.00-28.00 
 
 1980 7.50 9.00 9.20 9.70 6.95- 7.45 
 
 1981 5.80 7.90 7.90 8.50 6.65- 6.25 
 
 1982 3.10 3.50 7.90 8.50 4.30- 4.60 
 
 1983 3.3Q 3.60 (J) (j) 3.75- 4.05 
 
 The Climax oxide prices shown are for domestic consumption. The oxide export prices were as follows 
 
 1980 . . . .$21.50-522.49 1982 . . . .511.15-513.23 
 
 1981 . . . .$18.50-519.29 1983 ... .5 8.65-513.23 
 'Suspended 
 
 Source Metals Week, various years. 
 
 Climax 
 lump 
 
 Dealers' 
 export 
 
 $3.44 
 
 $3.45- 
 
 $3.50 
 
 4.10 
 
 3.80- 
 
 3.90 
 
 4.99 
 
 5.40- 
 
 5.80 
 
 6.10 
 
 9.75- 
 
 10.00 
 
 6.68 
 
 29.00- 
 
 29.50 
 
 9.90 
 
 8.60- 
 
 9.30 
 
 9.40 
 
 7.30- 
 
 8.00 
 
 9.40 
 
 5.35- 
 
 5.55 
 
 P) 
 
 4.45- 
 
 4.55 
 
romolybdenum, and $5.96 for briquettes. Simultaneously, 
 Codelco lowered its price for oxide to $4.50/lb, while the 
 dealers sold the material for as low as $2.50/lb (6). 
 
 In December 1982, the average dealers' price for oxide 
 slipped to $2.47/lb Mo. Low price, compounded by high in- 
 ventory and sluggish demand for the metal, caused primary 
 producers to stop mine production for most of 1983; the only 
 
 new molybdenite supply at the time came from byproduct 
 producers. This limited supply of molybdenite induced the 
 drawdown of inventories and eventually resulted in an up- 
 turn of price. Although there was no reported producers' price 
 in 1983, dealers' price for oxide ranged from $3.75/lb to 
 $4.05/lb Mo for most of the year (1). 
 
 WORLD PRODUCTION, CONSUMPTION, AND TRADE 
 
 Since the reopening of the Climax Mine in 1924, the 
 United States has maintained its position as the world's 
 largest molybdenum producer. A net exporter, the United 
 States supplies not only MEC's, but also CPEC's. 
 Molybdenum production in MEC's over the last 10 yr aver- 
 aged 178 million lb, with the United States accounting for 
 63 pet of the total, or 114 million lb/yr (table 2). Consump- 
 tion from MEC production over the last 10 yr averaged 148 
 million lb/yr with the United States using 57 million lb/yr 
 (table 3). This indicates that more than half of U.S. produc- 
 tion is exported, as is a large portion of the production from 
 Canada and Chile. 
 
 China, the U.S.S.R., and other CPEC's, as shown in table 
 2, produced an estimated 34 million lb in 1982. Nevertheless, 
 these countries as a whole are net importers of molybdenum. 
 
 As a block these countries imported an average of 17 million 
 lb/yr from 1974 through 1982 (table 3). 
 
 International trade is primarily limited to molybdenite, 
 especially in Western European countries because of protec- 
 tive tafiffs imposed on processed molybdenum forms. In order 
 to directly enter the European market, AMAX Inc. (the U.S.'s 
 largest producer) established processing plants in the 
 Netherlands, England, and Italy. 
 
 Although molybdenum enters international trade in the 
 form of molybdenite concentrate and various primary prod- 
 ucts, prices are based on the molybdenum content of the prod- 
 uct. Normally, molybdenite is marketed at a minimum grade 
 of 90 pet MoS 2 ; however, molybdenum produced as a 
 byproduct may be marketed at a lower MoS 2 grade. 
 
 To protect domestic molybdenum producers, the United 
 
 
 Table 2.— Molybdenum production from market economy and centrally planned economy countries 
 
 (Million pounds of contained molybdenum) 
 
 Country 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 
 
 MEC's: 
 
 United States 112 106 113 122 132 144 151 140 83 34 
 
 Canada 29 32 31 33 31 25 26 31 31 23 
 
 Chile 21 23 24 24 29 30 30 34 44 33 
 
 Mexico ' 1 1 1 ' ' 1 1 11 13 
 
 Peru 1 1 1 1 2 3 6 7 7 6 
 
 Total 
 
 CPEC's: 
 
 China 
 
 U.S.S.R 
 
 Others 
 
 Total 2 
 
 Grand total 183 182 193 205 220 229 240 241 210 143 
 
 p Prelimary. 
 "Less than 170,000 lb. 
 
 2 Bulgaria, Mongolia, Niger , North Korea, Romania, Turkey, and Yugoslavia are believed to have molybdenum production, but no quantitative out- 
 put information is available. 
 Sources: Engineering and Mining Journal and Bureau of Mines Mineral Industry Surveys, various years. 
 
 163 
 
 162 
 
 169 
 
 180 
 
 194 
 
 202 
 
 213 
 
 213 
 
 176 
 
 109 
 
 
 
 20 
 
 
 
 
 
 20 
 
 
 
 3 
 
 20 
 
 1 
 
 3 
 
 21 
 
 1 
 
 4 
 21 
 
 1 
 
 4 
 22 
 
 1 
 
 4 
 
 22 
 
 1 
 
 4 
 
 23 
 
 1 
 
 4 
 
 24 
 
 6 
 
 4 
 
 24 
 
 6 
 
 20 
 
 20 
 
 24 
 
 25 
 
 26 
 
 27 
 
 27 
 
 28 
 
 34 
 
 34 
 
 Table 3.— Molybdenum consumption from production in market economy countries 
 
 (Million pounds of contained molybdenum) 
 
 1974 1975 1976 1977 1978 1979 1980 1981~ 
 
 MEC's: 
 
 United States 75 55 57 60 69 71 60 58 
 
 Western Europe" 78 66 70 70 72 75 65 57 
 
 Japan 27 21 25 24 25 25 28 26 
 
 Subtotal 
 
 CPEC's 6 
 
 Other 
 
 Subtotal 
 
 Total 207 168 177 182 200 205 182 170 
 
 e estimated. P preliminary. 
 
 'Production data include both Government and private shipment and releases from inventory stockpile. 
 
 Source: Engineering and Mining Journal, various years. 
 
 1982 
 
 1983 
 
 34 
 
 30 
 
 55 
 
 53 
 
 26 
 
 24 
 
 180 
 
 142 
 
 152 
 
 154 
 
 166 
 
 171 
 
 153 
 
 141 
 
 115 
 
 107 
 
 14 
 13 
 
 15 
 11 
 
 15 
 10 
 
 17 
 11 
 
 22 
 12 
 
 22 
 12 
 
 18 
 11 
 
 18 
 11 
 
 15 
 9 
 
 18 
 8 
 
 27 
 
 26 
 
 25 
 
 28 
 
 34 
 
 34 
 
 29 
 
 29 
 
 24 
 
 26 
 
 139 
 
 133 
 
States also imposed a restrictive tariff schedule on most 
 molybdenum products, especially those coming from coun- 
 tries not having a most-favored-nation (MFN) status. In 1979, 
 a multilateral trade negotiation, known as the Tokyo Round, 
 adopted new tariff agreements that placed most countries 
 under the MFN status and gave them a much lower tariff 
 rate. The agreement called for the phasing down of tariff 
 rates for MFN countries over a 7-yr period ending in 1987 
 (7). This two-tiered tariff schedule is shown in table 4. 
 
 Table 4.— U.S. Import duties on molybdenum materials 
 
 (Percent ad valorem, except where Indicated) 
 
 
 Most-favored-nation (MFN) 
 
 Non-MFN: 
 
 Material 
 
 Jan. 1, 1983 
 
 Jan. 1, 1987 
 
 Jan. 1983 
 
 Ore and concentrate, c/lb. . 
 
 10.5 
 
 9.0 
 
 35.0 
 
 Material In chief value 
 
 
 
 
 molybdenum . . . . «/lb . . 
 
 8.0 
 
 6.0 
 
 50.0 
 
 Plus pet ad valorem . . 
 
 2.5 
 
 1.9 
 
 5.0 
 
 Ferromolybdenum 
 
 5.9 
 
 4.5 
 
 31.5 
 
 Molybdenum: 
 
 
 
 
 Waste and scrap 
 
 8.3 
 
 6.0 
 
 50.0 
 
 Wrought 
 
 9.6 
 
 6.6 
 
 60.0 
 
 Unwrought c/lb.. 
 
 8.1 
 
 6.3 
 
 50.0 
 
 Plus pet ad valorem 
 
 2.5 
 
 1.9 
 
 15.0 
 
 Molybdenum chemicals: 
 
 
 
 
 Ammonium molybdate 
 
 5.3 
 
 4.3 
 
 29.0 
 
 Calcium molybdate . . 
 
 4.8 
 
 4.7 
 
 24.5 
 
 Molybdenum 
 
 
 
 
 compounds 
 
 3.7 
 
 3.2 
 
 20.5 
 
 Potassium molybdate 
 
 3.4 
 
 3.0 
 
 23.0 
 
 Sodium molybdate . . . 
 
 4.4 
 
 3.7 
 
 25.5 
 
 Mixtures of inorganic 
 
 
 
 
 compounds, chief 
 
 
 
 
 value molybdenum . 
 
 3.2 
 
 2.8 
 
 18.0 
 
 Molybdenum orange . 
 
 5.0 
 
 5.0 
 
 25.0 
 
 Source: Blossom (7). 
 
 
 
 
 U.S. PRODUCTION, CONSUMPTION, AND TRADE 
 
 Table 5 shows production, shipments, and stocks of 
 molybdenum in concentrate for U.S. producers. Shipments 
 alone may not represent the actual mine production volume, 
 since some molybdenum produced in a specific year may be 
 shipped or released from the mine stockpile. The shipment 
 statistics shown may be a little confusing; while the export 
 figures are actual concentrate shipments to foreign countries, 
 the domestic shipments of concentrate may not to used for 
 domestic consumption per se. Domestic shipments, in part, 
 represent deliveries of concentrate to intermediate processors 
 or converters, who in turn may export finished molybdenum 
 products. In addition, domestic consumption is not always 
 the difference between the domestic production and foreign 
 exports, since producers normally keep or release inventories 
 
 depending on the status of supply and demand prevailing at 
 the time. Total U.S. exports of molybdenum in all forms are 
 shown in table 6. 
 
 U.S. export destinations vary from year to year, though 
 the major importing countries are the Netherlands, Japan, 
 Belgian-Luxembourg, and the Federal Republic of Germany. 
 Most of the concentrate exported is converted to oxides and 
 reshipped to other countries, including CPEC's. 
 
 Imports account for 2 to 5 pet of domestic U.S. consump- 
 tion. The majority of imports are in the form of concentrate, 
 primarily from Canada. Other sources of U.S. imports include 
 China, a supplier of ammonium molybdate, Japan, Peru, and 
 Western European countries. 
 
 Table 5.— U.S. salient molybdenum concentrate statistics 
 
 (Thousand pounds of contained molybdenum) 
 
 Hem 1974 1975 1976 1977 1978 1979 1980 
 
 Production 112,011 105,980 113,233 122,408 131,843 143,967 150,686 
 
 Shipments': 
 
 Domestic 3 78,198 68,552 83,592 95,308 99,511 107,099 114,285 
 
 Export 39,965 36,618 30,935 29,666 31,183 36,405 35,026 
 
 Stocks, mine and 
 
 plant 18,659 10,680 9,390 9,161 8,980 9,520 18,101 
 
 As reported by producers. 
 'Part of domestic shipment is exported in molybdenum product forms. 
 
 1981 
 
 1982 
 
 1983 
 
 139,900 
 
 86,182 
 32,734 
 
 35,548 
 
 83,050 
 
 55,918 
 21,870 
 
 35,527 
 
 33,951 
 
 39,822 
 9,341 
 
 36,407 
 
 Table 6.— U.S. molybdenum exports as reported by producers 
 
 (Thousand pounds of contained molybdenum) 
 
 Item 
 
 1974 
 
 1975 
 
 1976 
 
 1977 
 
 1978 
 
 1979 
 
 1980 
 
 1981 
 
 1982 
 
 1983 
 
 Molybdenite 
 
 concentrate 
 Molybdic oxide 
 Others 
 
 39,985 
 
 35,949 
 
 2,921 
 
 36,618 
 
 31,210 
 
 1.874 
 
 30,935 
 
 29,644 
 
 2,152 
 
 29,666 
 
 31,529 
 
 1,803 
 
 31,183 
 
 33,258 
 
 2,095 
 
 36,405 
 
 33,920 
 
 1,853 
 
 35,026 
 
 33,167 
 
 2,390 
 
 32,734 
 
 19,072 
 
 932 
 
 21,870 
 
 22,938 
 
 437 
 
 9,341 
 
 18,847 
 
 839 
 
 Total 
 
 . 78,835 
 
 69,702 
 
 62,731 
 
 62,998 
 
 66,536 
 
 72,178 
 
 70,583 
 
 52,738 
 
 45,245 
 
 29,027 
 
GEOLOGY 
 
 Molybdenum deposits are classified into five genetic 
 types: (1) primary porphyry or disseminated deposits, in- 
 cluding stockworks and breccia pipes in which metallic 
 sulfides are dispersed through relatively large volumes of 
 altered and fractured rocks; (2) contact metamorphic zones 
 and tactite bodies of silicated limestone adjacent to intrusive 
 granitic rocks; (3) quartz veins; (4) pegmatites and aplite 
 dikes; and (5) bedded deposits in sedimentary rocks (8). 
 
 The first three genetic types are determined to be 
 hydrothermal in origin. As such, nearly all resources in the 
 world fall under these types. The remaining two types cur- 
 rently do not possess any economic importance. Molybdenum 
 from these types are recovered only when it interferes in the 
 metallurgical recovery of the primary product (8). 
 
 Primary porphyry deposits, the major source of 
 molybdenite, occur as small disseminated grains in veins and 
 veinlets of hydrothermally altered igneous rocks. The 
 mineralization normally is associated with intrusions along 
 fault intersections. Generally, the intrusive rocks are siliceous 
 with composition ranging from granodiorite to granite. 
 
 The average mineral concentration in the resources iden- 
 tified for this study ranges from 0.1 to 0.5 pet MoS 2 . The 
 major known deposits of this type are the Endako and Boss 
 Mountain Mines of Canada, and the Climax, Henderson, and 
 Mount Tolman deposits of the United States. 
 
 Copper-molybdenum porphyry deposits are somewhat 
 similar in origin to that of primary molybdenum porphyry 
 deposits. The deposits are related to silicic intrusions and 
 hydrothermal alteration. Molybdenite concentrations are 
 much lower, ranging from 0.015 to 0.1 pet MoS 2 , and 
 therefore can only be economically recovered as a byproduct 
 (9). 
 
 In contact-metamorphic and tactite deposits, molybdenite 
 is widely distributed along the contact between granitic in- 
 trusives and lime-rich sedimentary rocks. In many places, the 
 size, shape, and occurrence of the ore bodies indicate that 
 the mineralization was controlled by preore fracturing of the 
 lime-rich host rock. The molybdenite is usually associated with 
 scheelite, bismuthite, and copper sulfides. The deposits are 
 generally small, but contain relatively high molybdenite con- 
 centration, up to 0.6 pet MoS 2 . The only domestic molybdenite 
 production from this type of depost was a byproduct from 
 the Pine Creek tungsten mine in California (10). 
 
 Molybdenite also occurs in fissure or quartz vein deposits. 
 
 The vein filling is mainly quartz and molybdenite with minor 
 amounts of pyrite, chalcopyrite, and chlorite and varies in 
 size from a fraction of an inch to several feet. The mineral 
 concentration also varies widely, and most of the molybdenite 
 is fairly fine grained and appears to be concentrated along 
 vein walls or joints and seams. The Questa surface mine in 
 New Mexico is the only deposit known to have produced ap- 
 preciable amounts of molybdenite from this type of deposit. 
 
 Pegmatite and aplite dike deposits are igneous rocks that 
 were formed by magmatic fluid filling dikes with rock com- 
 position similar to that of the associated pluton. Molybdenite 
 generally occurs in coarse crystalline structure, forming large 
 rosettes and aggregates of flakes, which are valued as a 
 mineral specimen rather than as a source of molybdenum. 
 Mineralization normally occurs in small pods that give no 
 leads to other pods and limit mining to single pods. Very few 
 deposits of this type have been developed. Known deposits 
 include the Val d'Or and Preissac deposits of Quebec, Canada 
 (8). 
 
 Molybdenite is also found in bedded sedimentary rocks 
 like coal and shale, though the concentrations are too low 
 to be of economic importance. In some lignitic sandstone 
 deposits of Montana, the Dakotas, and Utah, the mineral ap- 
 proaches economic concentrations. Some molybdenite 
 minerals are also associated with bedded uranium in Arizona, 
 Wyoming, South Dakota, New Mexico, and Utah. In such 
 deposits, when the mineral reaches a high level of concen- 
 tration, it becomes necessary to separate the molybdenite as 
 it interferes with uranium recovery (9). 
 
 MINERALOGY 
 
 Molybdenum has not been found free or as a native metal 
 in a natural environment. Even as a compound, it is relatively 
 scarce, comprising only about 1.0 to 1.5 ppm concentration 
 in the continental crust. This concentration is evenly 
 distributed throughout igneous rocks, though higher concen- 
 trations have been noted in basalt rocks. 
 
 Molybdenite (MoS 2 ) and, to a minor extent, wulfenite 
 (PbMo0 4 ), powellite [Ca(Mo,W)0 4 ], and ferrimolybdite 
 [Fe 2 (Mo0 4 ) 3 .8H 2 0], are the most important minerals of 
 molybdenum. Table 7 summarizes the physical and chemical 
 properties of these principal minerals. Powellite and fer- 
 
 Table 7.— Physical and chemical properties of principal molybdenum minerals (10) 
 
 Properties 
 
 Composition 
 
 Mo pet . 
 
 Crystal system 
 
 Cleavage 
 
 Sp.gr 
 
 Color 
 
 Tenacity 
 
 Luster 
 
 Fracture 
 
 Hardness' 
 
 Streak 
 
 Molybdenite 
 
 Wulfenite 
 
 Powellite 
 
 Ferrimolybdite 
 
 MoS 2 
 
 60.0 
 
 Hexagonal 
 
 Perfect in 1 direction 
 
 4.6-4.7 
 
 Lead-gray 
 
 Flexible 
 Metallic 
 
 None 
 
 1-1.5 
 
 Bluish gray on paper, 
 greenish on porcelain 
 or glazed paper. 
 
 PbMo0 4 
 
 26.1 
 
 Tetragonal 
 
 Perfect in 4 directions . . 
 
 6.5-7.0 
 
 Grayish-white through 
 
 yellow to orange and 
 
 orange red. 
 
 Brittle 
 
 Adamantine or resinous 
 
 Uneven 
 
 3 
 
 White 
 
 Ca(Mo,W)0, 
 
 39-48 
 
 Tetragonal 
 
 Indistinct 
 
 4.3 
 
 Straw yellow to dirty 
 white. 
 
 NA 
 
 Subadamatine, pearly, or 
 greasy. 
 
 Uneven 
 
 3.5-4 
 
 White 
 
 Fe 2 (Mo0 4 ) 3 .8H 2 0. 
 
 39. 
 
 Orthorombic. 
 
 NA. 
 
 2.99-4.5. 
 
 Sulfur yellow. 
 
 Powdery. 
 Silky to earthy. 
 
 None. 
 
 1.5. 
 
 Pale yellow. 
 
 NA Not available. 
 ■Mohs scale. 
 
rimolybdite. which are products of oxidation from other 
 minerals, have widespread occurrences, though it is unlike- 
 ly that they will become major sources of molybdenum. 
 
 Molybdenite is the most common mineral of molybdenum. 
 The mineral is lead-gray with a metallic sheen that 
 characteristically occurs in thin, tabular, hexagonal plates. 
 and is disseminated in fine specks. The plates have an emi- 
 nent basal cleavage, and are soft and flexible but not elastic. 
 Molybdenite is commonly mistaken for graphite because of 
 its similarity in structure and softness. It frequently occurs 
 in pneumatolytie contact deposits associated with cassiterite, 
 scheelite. wolframite, fluorite. etc. 
 
 Wulfenite. a lead molybdate. is a heavy mineral with a 
 resinous or adamantine luster. The mineral occurs in a well- 
 formed crystal structure, commonly square tabular, but 
 sometimes extremely thin. It displays a very smooth cleavage 
 with red. orange, yellow, gray, and white colors. Wulfenite 
 is of secondary origin, being found in lead and zinc deposits 
 in the oxidation zone (11). 
 
 Powellite, a calcium molybdate with calcium tungsten, 
 is formed through the oxidation of molybdenite. The mineral 
 is powdery and exhibits a tetragonal crystal structure with 
 variable colors, including dirty white, straw yellow, greenish 
 yellow, pale green, blue, and brown. Powellite is isomorphous 
 and often associated with scheelite. This association helps in 
 the identification of powellite because it fluoresces a golden 
 yelllow color under ultraviolet light (11). 
 
 Ferrimolybdite, long known as "molybdite," is a hydrous 
 ferric molybdate. The mineral is commonly impure and most 
 often is intimately associated with limonite. The mineral is 
 soft with a distinctive canary yellow color. It occurs commonly 
 in small amounts as an oxidation product of molybdenite. 
 
 Other molybdenum minerals include chillagite, ilseman- 
 nite, koechlinite, lingrenite, achrematite, belonisite, eosite, 
 and jordisite (12). 
 
 RESOURCES 
 
 A total of 88 primary and byproduct properties in MEC's 
 were evaluated to determine potential reserve-resources, 
 grade, mine capacity, and costs of production. The 23 primary 
 properties consisted of 9 producing mines and 14 undeveloped 
 deposits. The 65 secondary properties (in which molybdenum 
 is produced as a byproduct of copper production) consisted 
 of 34 producing and 31 undeveloped deposits. Deposit loca- 
 tions are shown in figure 2. Discussion of the geology of in- 
 dividual primary deposits is included in the appendix. 
 
 MEC primary molybdenum properties have approximate- 
 ly 5,018 million mt of in situ ore, containing 9.6 billion lb of 
 recoverable molybdenum and are all located in North America 
 (table 8). Nearly 84 pet of the recoverable molybdenum would 
 be from U.S. deposits, with Canada and Mexico accounting 
 for 13 pet and 3 pet, respectively. 
 
 20 
 
 Btaftw 
 
 23 <•.<■:-. 
 
 24 Copp.' *» 
 23 !#• -o -.- 
 2* W»>t» 
 
 27 ««!.>» 
 
 2 -,<« •}«'-, »**>—. ■ 
 
 IS. »■ Mi l M»^~? v 
 
 30 •».»» CkMd 
 I ' w ■ 
 
 It -.w .... 
 
 » :• .•< C4*i 
 
 33 l'i«^ lo*ro* 
 
 34 *>.-4..»«* 
 V! - -c. 
 
 M lit l-—y. 
 
 KEr 
 
 37 B a C Sptirig 
 38. Tonopo* 
 
 39 OvMtd 
 
 40 T««>Bvti., 
 
 41 UiMf.i o»« 
 42- CfP'ol 6>3dod 
 
 43 Owe*. %■».« 
 
 44 P...0 van., 
 43. He, 
 
 47 Copp*. "07 
 
 48 CM 
 
 '< 3«« Uonu.1 
 90 V«to4 Hill. 
 31 3.1... 8.11 
 
 • I 
 
 33 »-. -. 
 
 v. Ha 
 
 M - In Km 
 
 33 Cypru. Pimo 
 
 36 Lo Condod 
 
 37 C**mobODi 
 
 38 O00O.P. 
 
 39 C.r.o Colorado 
 60 Uiehiquilloy 
 «l El Aggilo 
 
 82 *«ti.M 
 
 83 To..off«otho 
 
 84 CuoiOft. 
 86 3o.to t*,%ri 
 84 .■ • m 
 67 Toqvopolo 
 
 8ft C."o Colofooo 
 89 Ow«oroda Bionco 
 
 70 Ct.ogulco.not. 
 
 71 [ki»Mi 
 
 72 El lolvMor 
 
 73. 80)0 Lo Alumpr.i 
 
 74. Andocollo 
 
 73 Lo. P.lomb... 
 
 76 El Pochon 
 
 77 Po.orMllo Sur 
 
 78 Lo. Bronc. 
 
 79 Andlna 
 
 80 El T.ni.nt. 
 
 61 So. Ch..m.rt 
 
 62 Soiftdok 
 
 63 Block Mountain 
 
 64 Sipolar 
 83 So.oi 
 88 OK T.dl 
 67 Yond..ra 
 88 >.-.-■. 
 
 LEGENO 
 8 Primary molybdenum 
 • Byproduct molybdenum 
 
 Figure 2. — Molybdenum deposit locations, market economy countries. 
 
Table 8.— Primary molybdenum deposits and in situ demonstrated resources, market economy countries, January 1983 
 
 Country and 
 deposit name 
 
 Owner 
 
 Status' 
 
 Type 2 
 
 Demonstrated 
 
 resources, 
 
 10" mt 
 
 Grade 
 pet Mo 
 
 Recoverable 
 
 Mo in cone, 
 
 10 6 mt 
 
 Estimated 
 
 ore capacity 
 
 10 3 mt/yr 
 
 Canada: 
 Adanac 
 
 Ajax Deposit . . 
 Boss Mountain 
 
 Endako 
 
 Glacier Gulch . 
 
 Kitsault 
 
 Mt. Thomlinson 
 
 Red Bird 
 
 Trout Lake 
 
 Subtotal 
 
 Mexico: 
 
 Cumobabi 
 
 Opodepe 
 
 Subtotal 
 
 United States: 
 
 Big Ben Deposit . 
 Buckingham 
 
 Deposit 
 
 B&C Spring 
 
 Climax Mines . . . 
 Hall (Tonopah) 
 
 Mine 
 
 Henderson Mines 
 Mt. Emmons 
 
 Mt. Tolman 
 
 Quartz Hill 
 
 Questa Mines . . . 
 Thompson Creek 
 White Cloud 
 
 Subtotal 
 Total . . . 
 
 Adanac Mining & 
 
 Explorations Co 
 
 Newmont Mining Corp 
 
 Noranda Mines Ltd 
 
 Placer Development Co 
 
 AMAX Inc 
 
 . . Do 
 
 Kidd Creek Mines Ltd 
 
 Phelps Dodge Corp. of Canada 
 Newmont, 55 pet; ESSO, 45 pet 
 
 Minera Cumobabi S.A. de C.V. . 
 Compania Minera Fresnillo, S.A. 
 
 AMAX Inc. 
 
 Rocky Mt. Energy 
 Sharon Steel 
 AMAX Inc 
 
 Anaconda Co 
 
 AMAX Inc 
 
 ..do 
 
 Colville Confederated Tribe . . . 
 Pacific Coast Molybdenum Co. 
 
 Molycorp 
 
 Cyprus Mine Corp. 
 
 ASARCO 
 
 201 
 
 179 
 4 
 
 187 
 18 
 
 104 
 41 
 81 
 49 
 
 5,018 
 
 0.059 
 .073 
 .141 
 .095 
 .210 
 .112 
 .072 
 .071 
 .115 
 
 .109 
 
 229 
 
 205 
 
 9 
 
 305 
 
 57 
 232 
 
 44 
 102 
 
 85 
 
 9,628 
 
 4,760 
 8,750 
 857 
 10,320 
 1,050 
 3,810 
 2,493 
 3,500 
 2,600 
 
 
 864 
 
 .084 
 
 1,268 
 
 38,140 
 
 s 
 
 17 
 
 .250 
 
 67 
 
 7,000 
 
 s 
 
 162 
 
 .100 
 
 241 
 
 7,000 
 
 
 179 
 
 .114 
 
 308 
 
 14,000 
 
 s 
 
 107 
 
 .096 
 
 187 
 
 5,350 
 
 s 
 
 217 
 
 .057 
 
 224 
 
 7,000 
 
 s 
 
 34 
 
 .080 
 
 47 
 
 2,198 
 
 c 
 
 375 
 
 .210 
 
 1,397 
 
 17,123 
 
 s 
 
 143 
 
 .096 
 
 303 
 
 7,000 
 
 u 
 
 223 
 
 .251 
 
 999 
 
 9,710 
 
 u 
 
 115 
 
 .323 
 
 678 
 
 6,602 
 
 s 
 
 900 
 
 .060 
 
 953 
 
 19,050 
 
 s 
 
 1,362 
 
 .082 
 
 2,112 
 
 19,591 
 
 u 
 
 95 
 
 .186 
 
 395 
 
 5,877 
 
 s 
 
 175 
 
 .112 
 
 389 
 
 8,051 
 
 s 
 
 229 
 
 .081 
 
 368 
 
 7,938 
 
 
 3,975 
 
 .109 
 
 8,052 
 
 115,510 
 
 167,650 
 
 Producer; D Developing; E Explored. 
 Surface; U Underground; C Combined. 
 
 The resource from byproduct properties as estimated at 
 30,535 million mt of ore, with recoverable molybdenum 
 estimated at 6.8 billion lb (table 9). 
 
 Primary Molybdenum Resources 
 
 The United States has an estimated 8.0 billion lb of 
 recoverable molybdenum from 12 primary mines. Five of 
 these mines -Climax, Henderson, Thompson Creek, Hall, and 
 Questa -were evaluated as producers, and one mine, Quartz 
 Hill, was evaluated as developing property. The remaining 
 six deposits have been explored but have no immediate plans 
 
 for development. The present capacity from producing 
 primary domestic deposits was estimated at 153 million lb/yr 
 Mo; an additional capacity of 40 million lb/yr will be added 
 when Quartz Hill starts production. 
 
 Canada accounts for 1.3 billion lb of recoverable 
 molybdenum from nine primary deposits. Current produc- 
 tion comes from three mines with an installed capacity 
 estimated at 23 million lb/yr. 
 
 Mexico has two primary molybdenum deposits (a pro- 
 ducer and a nonproducer), with total recoverable molybdenum 
 estimated at 308 million lb. Molybdenum production from 
 Cumobabi, the producing mine, is estimated at 2.7 million 
 lb/yr, though a capacity expansion is being planned. 
 
 Table 9.— Byproduct molybdenum deposits and in situ demonstrated resources, market economy countries, January 1983 
 
 Country 
 
 Argentina 
 
 Canada 
 
 Chile 
 
 Fiji 
 
 Iran 
 
 Mexico 
 
 Pakistan 
 
 Panama 
 
 Papua New Guinea 
 
 Peru 
 
 Philippines 
 
 United States .... 
 
 Total 
 
 Demonstrated 
 
 Av feed grade, 
 
 pet 
 
 Recoverable 
 
 Estimated ore 
 
 capacity, 10 3 mt/yr 
 
 resources, 
 
 Cu 
 
 Mo 
 
 Mo in cone, 
 
 Producer 
 
 Nonproducers 
 
 10 6 mt 
 
 
 
 10 6 lb 
 
 
 
 1,279 
 
 0.73 
 
 0.014 
 
 244 
 
 
 
 37,569 
 
 3,250 
 
 .40 
 
 .033 
 
 873 
 
 73,918 
 
 61,836 
 
 11,050 
 
 1.32 
 
 .060 
 
 2,935 
 
 74,443 
 
 60,116 
 
 813 
 
 .49 
 
 .014 
 
 73 
 
 
 
 14,200 
 
 414 
 
 1.13 
 
 .030 
 
 117 
 
 13,200 
 
 
 
 1,200 
 
 .67 
 
 .020 
 
 317 
 
 25,200 
 
 
 
 348 
 
 .43 
 
 .006 
 
 14 
 
 
 
 3,500 
 
 1,380 
 
 .73 
 
 .009 
 
 172 
 
 
 
 27,000 
 
 791 
 
 .81 
 
 .015 
 
 136 
 
 
 
 34,312 
 
 2,841 
 
 .87 
 
 .021 
 
 705 
 
 33,840 
 
 14,805 
 
 879 
 
 .50 
 
 .002 
 
 25 
 
 22,600 
 
 
 
 6,290 
 
 .62 
 
 .019 
 
 1,153 
 
 268,538 
 
 35,331 
 
 30,535 
 
 .89 
 
 .034 
 
 6,764 
 
 511,739 
 
 288,669 
 
Byproduct Molybdenum Resources 
 
 The 21 U.S. copper properties analyzed for this report 
 have the capability to produce a total of 1.2 billion lb Mo from 
 demonstrated resources. Of these deposits. 14 were evaluated 
 as producers, though many are presently temporarily shut 
 down. These 14 producing mines have the capacity to pro- 
 duce an estimated 47 million lb/yr Mo. 
 
 Canada has recoverable molybdenum estimated at 873 
 million lb from 13 copper deposits. At present, copper pro- 
 ducers contribute about 21 million lb/yr Mo from 6 mines. 
 
 The La Caridad copper mine in Mexico has a recoverable 
 molybdenum resource estimated at 317 million lb. Current 
 capacity is estimated at 10.1 million lb/yr. 
 
 All molybdenum production in Chile is a byproduct of cop- 
 per operations, with Chuquicamata and El Teniente account- 
 ing for more than S2 pet of the total. Chile has an estimated 
 2.9 billion lb Mo recoverable from 10 copper properties. 5 
 of which are producing. At present, the five producing mines 
 have a total installed capacity estimated at 45 million lb/yr 
 Mo. Actual capacity may vary depending on the grade and 
 recovery at the time. For example, in 1982. one major mine 
 not only improved the mill recovery but also encountered a 
 high-grade molybdenum ore body, causing a large increase 
 in molybdenum output in that particular year. 
 
 Molybenum resources in Peru come from eight copper 
 deposits. Current production comes from four copper opera- 
 tions, with Cuajone and Toquepala accounting for more than 
 98 pet of the total. Demonstrated resources for the eight prop- 
 erties evaluated is estimated at 2.8 billion mt of ore and 705 
 million lb Mo (recoverable). The installed capacity from the 
 four producing mines is estimated at 9.0 million lb/yr. 
 
 Iran has a single source of molybdenum, the Sar 
 Cheshmeh copper mine. The mine has an estimated reserve 
 of 414 million mt ore. containing approximately 117 million 
 lb Mo (recoverable). The installed capacity of the mine is 
 estimated at 4.0 million lb/yr. 
 
 Production of molybdenum in the Philippines comes from 
 three small copper operations: Sipalay. Basay, and Black 
 Mountain Mines. The total demonstrated resource from these 
 mines is estimated at 879 millions mt containing a total of 
 25 million lb Mo (recoverable). The present installed capaci- 
 ty is approximately 1.0 million lb/yr. 
 
 Among countries with nonproducing deposits. Argentina 
 accounts for the largest molybdenum in situ resources with 
 1.279 million mt ore from Bajo la Alumbrera, Paramillo Sur, 
 and El Pachon deposits. The recoverable resource from these 
 deposits is estimated at 244 million lb Mo, all of which would 
 be recovered as a byproduct of copper operations. Fiji has 
 one copper deposit, the Namosi. with in situ reserves 
 estimated at 813 million mt ore. An estimated 73 million lb 
 Mo is potentially recoverable. Pakistan also has one proper- 
 ty, the Saindak Copper deposit, which contains an estimated 
 14.3 million lb Mo (recoverable). 
 
 One copper deposit in Panama contains molybdenum, the 
 Cerro Colorado. An estimated 172 million lb Mo is potential- 
 ly recoverable. Development of this deposit has been delayed 
 because of the slumping copper market. Papua New Guinea 
 has two deposits, the OK Tedi and Yanderra, from which 
 about 137 million lb Mo is potentially recoverable. OK Tedi 
 started initial production for gold in 1984. However, produc- 
 tion of copper and molvbdenum is not scheduled to start un- 
 til 1987. 
 
 MINING AND PROCESSING TECHNOLOGY 
 
 MINING METHODS 
 
 Ore deposits are mined by either underground or open 
 pit methods. The selection of a mining method for a given 
 deposit is more or less controlled by the grade, size, shape, 
 and attitude of the ore body. Normally, the ideal choice is 
 the one that gives safe working conditions and yields the 
 greatest economic profit. Since primary molybdenum deposits 
 occur as low-grade, high-tonnage porphyry deposits, low-cost 
 underground block-caving and open-bit operations are the 
 most commonly used methods to extract the ore economically. 
 
 Currently, of the nine primarily molybdenum producers, 
 two use underground block-caving methods (Henderson and 
 Questa), five use open-pit methods (Endako, Kitsault, 
 Cumobabi. Thompson Creek, and Hall), and two use combined 
 methods (Climax and Boss Mountain). Of the byproduct 
 operations, six are mined by underground block-caving 
 methods and the rest by open pit. 
 
 BENEFICIATION 
 
 To separate the molybdenite from the gangue minerals, the 
 ore is crushed and ground to a size where the mineral is 
 liberated. The size requirement is controlled by the ore 
 characteristics, economics, and available processing 
 technology. Molybdenite is a relatively easily flotable mineral, 
 so concentration always involves crushing and grinding to 
 release the mineral, followed by floatation. Crushing of 
 molybdenite ore. as practiced by primary molybdenum pro- 
 
 ducers, consists of primary, secondary, and tertiary crushing 
 systems. Semiautogenous crushing is practiced at the 
 Henderson and Thompson mines where run-of-mine ore is 
 crushed through the primary stage only to take advantage 
 of the grinding effect of the rock size. 
 
 After crushing, the ore is fed to ball mills which are in 
 closed circuit with classifiers. Most of the flotation reagents 
 are added at the grinding stage. Final grinding is monitored 
 closely to avoid the production of fines. 
 
 Molybdenite flotation practices are very similar for all 
 operations. The only noticeable difference is in the equipment 
 sizes, where newer plants employ much larger, more efficient 
 equipment than old plants. 
 
 In normal flotation practice, the pulp is pumped through 
 banks of rougher cells, to produce a rougher concentrate. This 
 is then reground in closed circuit with a classifier and routed 
 to the cleaner section. Generally three to four cleaner stages 
 are required before a final concentrate is produced. The grade 
 of the final concentrate is about 54 pet Mo (90 pet MoS 2 ). 
 
 In the Cu-Mo flotation process, the rougher cells are 
 designed to handle bulk flotation at the highest overall 
 recovery of copper and molybdenite minerals at the coarsest 
 grind possible. A much stronger collector such as xanthate 
 is used for bulk flotation in the rougher cells, and a more selec- 
 tive reagent is used in the cleaner cells. A nonselective frother 
 is also used in the rougher cells, methylisobutyl carbinol 
 (MIBC) being the most popular. 
 
 Copper-molybdenum separation varies from one plant to 
 another, especially in the use of chemical reagents. However, 
 the most commonly used technique to recover molybdenite 
 
10 
 
 from copper is the sodium hydrosulfide-sodium sulfide proc- 
 ess. In this process, sodium hydrosulfide or sodium sulfide 
 is added to the copper-molybdenite concentrate in a flotation 
 procedure to depress the copper and ion sulfide minerals and 
 allow the molybdenite to float (13). Sometimes cooking or 
 steaming is done ahead of the rougher flotation circuit to 
 reduce sulfide consumption. Although the hydrosulfide proc- 
 ess can treat all Cu-Mo concentrate separations, the 
 economics of the process may vary. This is mainly because 
 of varying concentrate composition, especially in terms of 
 mineral contaminants. The presence of contaminants such 
 as talc, coal, and sulfur alter the entire process. 
 
 OTHER PROCESSING 
 
 Molybdenite concentrate (90 to 95 pet MoS 2 ) is processed 
 in roasters to produce technical-grade Mo0 3 . Roasting is nor- 
 mally performed in four- zone multiple-hearth roasters, where 
 molybdenite is converted to technical-grade Mo0 3 
 exothermically. 
 
 The first zone is for preheating, final drying, and burning 
 of residual flotation oils. Temperature increases exothermical- 
 ly in the second zone, where the molybdenite is converted 
 to Mo0 2 with a minor amount transformed to M0O3. In the 
 
 third zone, both the remaining sulfide and dioxide are con- 
 verted to M0O3. In the fourth zone, with about 95 pet of the 
 molybdenite already oxidized, an exothermic reaction can no 
 longer be sustained. Hence, supplemental heat is supplied to 
 complete the removal of sulfur to a content of less than 0.1 
 pet. 
 
 The product, technical-grade Mo0 3 , contains about 88 to 
 98 pet Mo0 3 . About 0.1 pet of the plant feed is lost in the dust. 
 
 Ferromolybdenum production begins by blending a 
 charge consisting of Mo0 3 , ferrosilicon, and iron oxide to at- 
 tain a homogenous mixture. A starter mix composed of 
 magnesium, aluminum, potassium nitrate, and iron oxide is 
 sprinkled over the charge and ignited; it readily ignites and 
 starts the exothermic reaction. The reaction generates heat 
 high enough to initiate the ignition of the actual charge. The 
 resulting molten bath attains a temperature of 3,300° to 
 3,500° F in the final stage of the reaction. This is allowed 
 to cool for at least 16 h. At this time, a metallic fer- 
 romolybdenum button is formed, and subsequently quenched. 
 
 The metallic button is allowed to cool for another 24 h, 
 before the slag is separated from the ferromolybdenum metal. 
 Following the smelting and cooling the ferromolybdenum 
 metal is normally broken to minus 8-in size before it is crushed 
 and screened to different sizes and specifications (11*). 
 
 DEPOSIT EVALUATION PROCEDURE 
 
 Illustrated in figure 3 is the flow of the Bureau's Minerals 
 Availability program (MAP) evaluation process, from deposit 
 identification to the development of availability curves. This 
 flowsheet shows the various evaluation stages used in this 
 study to assess the availability of molybdenum from individual 
 properties. After a deposit was identified for analysis, an 
 economic evaluation of the property was performed. Optimal 
 mining and concentrating rates and other production 
 parameters were chosen using current engineering principles. 
 Startup dates for developing deposits were based on an- 
 nounced company plans. For explored deposits, a near-term 
 development schedule (5 to 10 yr) was developed. Planned 
 expansions for operating mines were included when known. 
 
 Information on average grades, ore tonnages, and dif- 
 ferent physical characteristics affecting production was ob- 
 tained from various sources, including Bureau of Mines and 
 U.S. Geological Survey publications, professional journals, 
 State and industry publications, company annual reports, 10K 
 reports and prospectuses filed with the Securities and Ex- 
 change Commission, private companies, and estimates made 
 by Bureau personnel. Much of the foreign data was collected 
 through a Bureau contract with Pincock, Allen and Holt Inc., 
 of Tucson, AZ. 
 
 Selection of deposits was limited to known deposits that 
 have significant demonstrated reserves or resources. 
 Reserves are material that can be mined, processed, and 
 marketed at a profit under prevailing economic and 
 technological conditions. Resources are concentrations of 
 naturally occurring solid, liquid, or gaseous materials in the 
 earth's crust in such form that economic extraction of a com- 
 modity is currently or potentially feasible (15). 
 
 For the deposits analyzed, tonnage estimates were made 
 at the demonstrated resource level based on the mineral 
 resource-reserve classification system developed jointly by 
 the Bureau of Mines and the U.S. Geological Survey (15). The 
 demonstrated resource category includes measured plus in- 
 
 dicated tonnages (fig. 4). Generally, reserve and resource ton- 
 nage and grade calculations presented in this report were 
 computed from specific measurements, samples, or produc- 
 tion data, and from estimations made on geologic evidence. 
 The deposits included in the analysis had to meet the 
 following criteria: 
 
 1. Producing properties accounting for at least 85 pet 
 of the molybdenum production from each significant produc- 
 ing country. 
 
 2. Developing and explored deposits where the 
 demonstrated molybdenum reserve-resource quantity was 
 equivalent to at least the lower limits of the reserve-resource 
 quantity of the producing deposits. 
 
 3. Past-producing deposits where the remaining 
 demonstrated molybdenum reserve-resource quantity was 
 equivalent to at least the lower limits of the reserve-resource 
 quantity of the producing deposits. 
 
 ASSUMPTIONS 
 
 The objective of the engineering-economic analysis for 
 each deposit was to determine the total cost necessary to pro- 
 duce a specified level of output from the deposit. Total cost, 
 also called commodity or incentive price, is defined as the 
 average total cost of production for the deposit. In this study, 
 profit computed at a 15-pct discounted-cash-flow rate of 
 return (DCFROR) was included in the total cost. Total cost, 
 then, is the minimum molybdenum price (in constant dollars) 
 at which a firm would be willing to develop its property; at 
 this price, the firm would recover its investment and make 
 a 15-pct profit. 
 
 Determinations of the quantity of molybdenum that could 
 be produced and the cost required to achieve this production 
 were based on the following assumptions: 
 
 1. Each operation will produce at full planned operating 
 
Identification 
 
 and 
 
 selection 
 
 of deposits 
 
 Tonnage 
 
 and 
 
 grade 
 
 determination 
 
 Engineering 
 
 and 
 
 cost 
 
 evaluation 
 
 Deposit 
 
 report 
 
 preparation 
 
 Mineral 
 
 Industries 
 
 Location 
 
 System 
 
 (MILS) 
 
 data 
 
 MAP 
 
 computer 
 
 data 
 
 base 
 
 MAP 
 
 permanent 
 
 deposit 
 
 files 
 
 Taxes, 
 royalties, 
 
 cost 
 indexes, 
 prices, etc. 
 
 Data 
 selection 
 
 and 
 validation 
 
 Economic 
 analysis 
 
 Data 
 
 Availability 
 curves 
 
 Analytical 
 reports 
 
 u 
 
 11 
 
 Variable 
 
 and 
 
 parameter 
 
 adjustments 
 
 Sensitivity 
 analysis 
 
 Data 
 
 Availability 
 curves 
 
 Analytical 
 reports 
 
 y 
 
 Figure 3.— Minerals Availability program evaluation workflow. 
 
 Cumulative 
 production 
 
 ECONOMIC 
 
 MARGINALLY 
 ECONOMIC 
 
 SUBECONOMIC 
 
 IDENTIFIED RESOURCES 
 
 UNDISCOVERED RESOURCES 
 
 
 
 Demonstrated 
 
 Inferred 
 
 Probability range 
 
 Measured 
 
 Indicated 
 
 (C 
 
 Hypothetical 
 
 Speculative 
 
 
 
 
 
 
 Res 
 
 erve 
 
 Inferred 
 
 
 
 ba 
 
 se 
 
 reserve 
 base 
 
 1 
 
 
 
 
 r 
 
 1 
 
 
 
 
 Other 
 occurrences 
 
 Includes nonconventional and low-grade materials 
 
 Figure 4. — Mineral resource classification categories. 
 
12 
 
 Table 10.— Byproduct commodity prices, market economy 
 countries, January 1983 
 
 Price, $/lb 
 
 Tungsten $3.24 
 
 Tin 5.53 
 
 Copper .78 
 
 Molybdenum 1 3.45 
 
 'Produced as a byproduct of copper production. 
 
 capacity throughout its life (capacities were based on 1983 
 and/or 1984 company plans or engineering judgments). 
 
 2. Competition and demand conditions are assumed such 
 that each operation will be able to sell all its output at its 
 total production cost. This condition implies that the level 
 of molybdenum demand will support the highest cost deposit, 
 or that existing Government subsidies will equal the dif- 
 ference between the market price and the total cost for each 
 submarginal deposit. 
 
 3. All byproducts will be sold at the prices shown on table 
 10. 
 
 4. Production costs are for concentrates sold f.o.b. mine; 
 i.e., no transportation or roasting costs are included. 
 
 Time lags involved in filing environmental impact 
 statements and receiving necessary permits, financing, etc., 
 were not included in the analysis. Existing laws and regula- 
 tions, environmental, political, legal, or other constraints may 
 limit production from some of the deposits included in this 
 study. 
 
 The byproduct prices used in this study (table 10) were 
 based on 1983 averages. Because the study was conducted 
 using constant 1983 dollars, no escalation of either costs or 
 prices was included. 
 
 COST ESTIMATION 
 
 When possible, actual company cost data were used. If 
 these data were not available, the required capital and 
 operating costs were estimated by standardized costing 
 techniques. 
 
 In some cases costs were estimated from a costing system 
 prepared for the Bureau (16). This system is designed to 
 prepare capital and operating cost estimates and is based on 
 an average of the costs for existing mining operations in the 
 United States and Canada. Correct use of this costing system 
 will produce reliable estimates, which historically have fallen 
 within 25 pet of actual costs. 
 
 Individually deposit cost data were used to perform an 
 economic analysis for each property. Capital and operating 
 costs for developing and explored deposits were adjusted to 
 average 1983 dollars. Mine and mill capital costs incurred 
 prior to 1983 by producing mines (and some developing and 
 explored deposits) were adjusted to average 1983 using the 
 remaining book value of the investments. 
 
 Capital expenditures were calculated for exploration, ac- 
 quisition, development, and mine and mill plant and equip- 
 ment. Capital expenditures for mining and processing 
 facilities include the costs of mobile and stationary equipment, 
 construction, engineering, infrastructure, and working 
 capital. Infrastructure includes, among other things, the costs 
 of the water system, power system, fire protection, roads, 
 port facilities, construction of necessary rail facilities, and, 
 in remote areas, construction of town and housing facilities. 
 Working capital is a revolving cash fund for such operating 
 expenses as labor, insurance, supplies, and taxes. 
 
 Mine and mill operating costs were also calculated for 
 each deposit. The total operating cost is a combination of 
 direct and indirect costs. Direct operating costs include direct 
 and maintenance labor, materials, payroll overhead, and 
 utilities. Indirect operating costs include administrative costs, 
 facilities maintenance and supplies, research, and technical 
 and clerical labor. Other costs not included in operating costs 
 but used in the analysis include deferred expenses, deprecia- 
 tion, insurance, interest payments (if applicable), and taxes. 
 
 The Bureau previously developed a Supply Analysis 
 Model (SAM) to perform an economic analysis which presents 
 the result as the primary commodity price (total production 
 cost) needed to provide a stipulated rate of return (17). The 
 DCFROR, used in this study, is most commonly defined as 
 the rate of return that makes the present worth of cash flows 
 from an investment equal to the present worth of all after- 
 tax investments (18). For this study, a 15-pct DCFROR was 
 considered necessary to cover the opportunity cost of capital 
 plus risk. For some Government-owned operations, a 15-pct 
 DCFROR may not be required for continued production. 
 However, for comparison purposes, each deposit was ana- 
 lyzed at this DCFROR. 
 
 For producing mines, analysis was also performed at a 
 0-pct DCFROR, which is roughly equivalent to a breakeven 
 production cost. In the short run, a mine may continue to 
 produce at molybdenum prices even below this cost in an- 
 ticipation of improved market conditions. 
 
 
 OPERATING COSTS 
 
 The average total capital and operating costs calculated 
 for each of the deposits analyzed include mining, concen- 
 trating, and capital recovery, taxes, and profit. These costs 
 often vary greatly, depending on such factors as size of opera- 
 tion, mining method, deposit location, stripping ratio, depth 
 of ore body, grade of molybdenum and byproducts, process- 
 ing losses, energy and labor costs, and applicable tax 
 structure. 
 
 The operating costs presented in this section are based 
 on mining ore and concentrating the ore over the life of the 
 operation. Capital costs for deposits not producing at the time 
 of the study reflect the total investment required to develop 
 a mine, construct all facilities, and begin production. Capital 
 costs for producing mines have less effect because some of 
 the mines have been producing for many years and a large 
 portion of the initial cost has been depreciated. 
 
 Weighted average cost data for all primary mines 
 evaluated in the United States and Canada are shown in table 
 11 on a per-ton-of-ore basis and in table 12 on a per-pound- 
 of-molybdenum basis. To maintain confidentiality, cost data 
 on the two Mexican deposits are withheld. The U.S. produc- 
 ing mines consist of two underground, two surface, and one 
 combined (underground-surface) operation; the Canadian 
 mines includes two surface mines and one combined 
 operation. 
 
 The average operating cost on a per-ton-of-ore basis for 
 producing U.S. mines (table 11) is more than twice that of 
 the Canadian mines. This is attributed to the high stripping 
 ratio of U.S. surface mines (3:5:1.0) and the fact that about 
 50 pet of the U.S. tonnage is from underground operations. 
 In nonproducing mines, the projected cost of U.S. mining is 
 less than half that of the Canadian operations. This is because 
 
13 
 
 Table 11.— Estimated cost of mining and milling operations from 
 
 primary producers in the United States and Canada, 
 
 January 1983 
 
 
 
 Prod 
 
 ucers 
 
 Nonprod 
 
 ucers 
 
 
 United 
 
 Canada 
 
 United 
 
 Canada 
 
 
 
 States 
 
 
 States 
 
 
 Number of 
 
 
 
 
 
 
 deposits . 
 
 
 5 
 
 3 
 
 7 
 
 6 
 
 Total annual 
 
 ore 
 
 
 
 
 
 capacity. . 
 
 10'mt. . 
 
 47.781 
 
 14.987 
 
 67.730 
 
 23.153 
 
 Av feed 
 
 
 
 
 
 
 grade . .pet Mo. . 
 
 0.1696 
 
 0.092 
 
 0.100 
 
 0.073 
 
 Av operating 
 
 cost. 
 
 
 
 
 
 S/mt ore: 
 
 
 
 
 
 
 Mine . . 
 
 
 7.03 
 
 $2.79 
 
 $2.87 
 
 $6.78 
 
 Mill . 
 
 
 3.14 
 
 $2.83 
 
 S3.40 
 
 $2.78 
 
 
 
 
 six of the seven projected U.S. mines would use surface 
 methods, whereas four of the six projected Canadian mines 
 would be underground. Comparing U.S. mines, the producers 
 show a much higher mining cost than the nonproducers. This 
 is due to the higher stripping ratio experienced by producers 
 and the higher percentage of ore produced by underground 
 methods. 
 
 The per-ton cost for beneficiation reflects small dif- 
 ferences between U.S. and Canadian operations. The five pro- 
 ducing U.S. mines averaged S3.14/mt ore. while the three 
 Canadian mines averaged S2.83/mt. The added cost of 
 byproduct recovery made the U.S. operations slightly higher 
 than Canadian mines, which produce no byproducts. 
 
 When costs are converted from dollars per metric ton 
 of ore to cents per pound of molybdenum contained in con- 
 centrate, the average operating cost for producing U.S. mines 
 -2.16/lb for mining and S0.99/lb for milling. 
 Operating costs for Canadian mines average $3.3S71b, $1.54/lb 
 for mining and S1.84/lb for milling. On a cost per metric ton 
 of ore basis, mine operating costs for producing U.S. mines 
 are 2.5 times greater than for Canadian producing mines. 
 However, owing to the much higher ore grade of the mines. 
 costs on a per pound basis are only 1.4 times higher. For mill- 
 ing. U.S. mines have a cost advantage over Canadian mines 
 owing to a higher ore grade (0.1696 pet compare with 0.092 
 pet) and economies of scale of the larger U.S. milling opera- 
 tions. The annual capacity of the five U.S. milling operations 
 in 1983 averaged 9.6 million mt ore. while the three Cana- 
 dian mines averaged only 5.0 million mt. The difference in 
 mill operating costs between U.S. producing and nonproduc- 
 ing mines is due primarily to the much lower grade (0.09 pet 
 compared with 0.1696 pet) of the nonproducing deposits. 
 
 Taxes for producing mines in the United States and 
 Canada are nearly equal, averaging SO.lO/lb in the United 
 States and S0.11/lb in Canada. Taxes are greater for non- 
 producers because, in most cases, the revenues required to 
 
 Table 12.— Estimated mine and mill operating costs' for primary 
 
 molybdenum procuers in the United States and Canada, 
 
 January 1983 
 
 (Dollars per pounds molybdenum contained in concentrate) 
 
 Producers Nonproducers 
 
 Cost United r^«-«j«> United „ . . 
 States' Canada States' Canada 
 
 Operating cost: 
 
 Mine $2.16 $1.54 $1.43 $4.30 
 
 Mill .99 1.84 2.52 2.27 
 
 Total 3.15 3.38 3^91 (f57 
 
 Taxes 10 .11 .17 .12 
 
 Capital recovery 52 .60 .96 1.77 
 
 Byproduct credit (-.30) (-.00) (-.25) (-.09) 
 
 Breakeven cost' ... 3.47 4.09 4.83 8.37 
 
 Total cost 3 4.28 5.62 9.03 27.26 
 
 'Costs based on total annual capacity for molybdenum in concentrate 
 as shown below: 
 
 Number Mo in cone, 
 of mines 10" Ib/yr 
 
 Producers: 
 
 United States 
 Canada 
 
 Nonproducers: 
 United States 
 Canada 
 
 161 
 25 
 
 133 
 33 
 
 'Mine and mill cost, plus taxes and capital 
 recovery, less byproduct credits (as shown). 
 'Breakeven cost plus profit at a 15-pct DCFROR. 
 
 cover the higher production costs (incl ding recovery of 
 capital) are greater. 
 
 The capital recovery cost reflects the complete recovery 
 of all capital investments allocated on a per-pound-of- 
 production basis over the life of the mine. This cost averaged 
 $0.52/lb for U.S. producers and $0.60/lb for Canadian. Costs 
 for nonproducing deposits are much higher (particularly in 
 Canada), since none of the capital cost has been depreciated, 
 as it has for producing mines. 
 
 Byproduct credits (W0 3 , Sn, and Cu) provide an added 
 benefit to U.S. producers, averaging $0.30/lb Mo. Canadian 
 producing mines, on the other hand, produce no byproducts. 
 
 Producing U.S. mines average $3.47/lb, while Canadian 
 producers average $0.62/lb higher at $4.09/lb. Total costs of 
 nonproducing U.S. deposits are more than double those of 
 producing mines; in Canada the nonproducer total cost is 
 nearly triple the producer total cost. 
 
 Breakeven cost reflects the cost of production at which 
 the mines would break even and cover all production costs 
 after credit for byproducts. Total cost includes net cost plus 
 profit at 15-pct DCFROR. Total costs are much higher for 
 nonproducers because greater revenues are required to pro- 
 vide profit on the larger capital investment. 
 
 CAPITAL COSTS 
 
 To estimate the capital costs for explored and develop- 
 ing properties, exploration, acquistion, development, mine 
 and mill plant and equipment, and infrastructure costs were 
 calculated. Capital costs beyond beneficiation, such as for 
 roasting, were not included in the analyses. A total of 14 prop- 
 erties, 9 surface and 5 underground, were evaluated for this 
 section. Capital costs according to mine type and ore capaci- 
 ty are shown in table 13. All costs were adjusted to January 
 1983 dollars. Actual cost for individual deposits may vary 
 greatly depending on required infrastructure, exploration and 
 
 development works, size of operation, characteristic of the 
 orebody, and complexity of the ore. 
 
 The average capital cost of nine surface mining opera- 
 tions was estimated at $269 million, or $18.92 per pound of 
 annual molybdenum capacity. This compares with an average 
 cost of five underground operations of $286 million, 
 representing $19.60 per pound of annual capacity. 
 
 In both surface and underground operations, cost per 
 pound of annual capacity was lower for the larger mines, 
 representing some economies of scale. However, most of the 
 
14 
 
 Table 13.— Estimated capital costs for developing and explored molybdenum deposits, market economy countries, January 1983 
 
 (Thousand dollars) 
 
 Number 
 
 of 
 mines 
 
 Av 
 capacity, 
 mt/d ore 
 
 Acquisition, 
 exploration, 
 development 
 
 Mine 
 
 Mill 
 
 Infra- 
 structure 
 
 Total 
 cost 
 
 Capital cost, 
 
 per lb 
 
 annual capacity 
 
 Surface: 
 
 < 10,000 2 
 
 10,001 to 20,000 4 
 
 >20,000 3 
 
 Total or average . . . 
 
 Underground: 
 
 < 10,000 
 
 > 10,000 
 
 Total or average 5 
 
 8,141 
 
 $23,000 
 
 $30,830 
 
 $41,400 
 
 $44,030 
 
 $139,260 
 
 $35.80 
 
 17,221 
 
 17,320 
 
 33,300 
 
 97,560 
 
 25,990 
 
 174,170 
 
 17.57 
 
 43,840 
 
 54,150 
 
 103,670 
 
 292,960 
 
 42,250 
 
 493,030 
 
 16.31 
 
 9 
 
 23,067 
 
 $31,490 
 
 $55,933 
 
 $143,973 
 
 $37,423 
 
 $268,819 
 
 $18.92 
 
 3 
 2 
 
 5,066 
 25,200 
 
 $19,230 
 195,100 
 
 $19,850 
 60,170 
 
 $38,950 
 103,610 
 
 $38,150 
 97,790 
 
 $116,180 
 456,670 
 
 $26.39 
 18.23 
 
 15,133 
 
 $107,165 
 
 $40,010 
 
 $71,280 
 
 $67,970 
 
 $286,425 
 
 $19.60 
 
 capital cost differential was due to higher proportional costs 
 for exploration and development and infrastructure in the 
 smaller mines; for example, infrastructure costs for the 
 
 smallest group (less than 10,000 mt/d ore) of surface opera- 
 tions were actually higher than total such costs for the largest 
 (greater than 20,000 mt/d ore) surface mines. 
 
 MOLYBDENUM AVAILABILITY 
 
 EVALUATION METHODOLOGY 
 
 After cost and resource data were determined for each 
 deposit, total and annual resource availability curves were 
 constructed to illustrate molybdenum availability. These 
 curves are discontinuous functions relating the total cost (as 
 defined in the "Assumptions" section) for a deposit to its level 
 of production. The total or annual quantity of molybdenum 
 from each deposit was accumulated from lowest to highest 
 total cost to show molybdenum availability. 
 
 A total resource availability curve is not an ordinary sup- 
 ply curve because it does not consider the time parameter 
 and is not the industry's marginal cost curved. Rather, a total 
 resource availability curve is an aggregate of the total pro- 
 duction potential at a stipulated cost that covers full produc- 
 tion costs. 
 
 For the engineering analysis, it was necessary to deter- 
 mine a development schedule for each property. For produc- 
 ing mines, expansions considered to have a high probability 
 of occurring were included. For nonproducing deposits, the 
 time required for development depends upon the exploration, 
 extent of preproduction development, plant construction, and 
 infrastructure requirements. Annual resource availability 
 curves are disaggregations of total resource curves to an an- 
 nual production basis. Compared with total availability 
 curves, annual availability curves more closely resemble true 
 supply curves since they show annual production; but they 
 also indicate average total cost of production rather than 
 marginal cost. 
 
 Separate annual availability curves were constructed for 
 producing mines and nonproducing (developing and explored) 
 deposits. Annual curves for producing mines show the 
 molybdenum capacity of existing mines and planned expan- 
 sions when known. Annual curves for most nonproducing 
 deposits are not related to any given year, since the startup 
 year is uncertain. They do, however, show required lead times 
 before production can begin and indicate potential annual pro- 
 duction capabilities. 
 
 TOTAL AVAILABILITY 
 
 At the demonstrated resource level potential recoverable 
 molybdenum from primary mines was estimated at 9.6 billion 
 
 lb, with an additional 6.6 billion lb available from primary 
 copper mines. 
 
 With 15-pct DCFROR on invested capital, a total of 8.9 
 billion lb would be available from the primary deposits at pro- 
 duction costs ranging from $3.20/lb to $14/lb Mo (figure 5 
 and table 14). The remaining 712,000 lb would have a pro- 
 duction cost exceeding $14/lb. In January 1983, dealers were 
 selling the metal for $2.47/lb, a price well below the produc- 
 tion cost of primary producers. Analyses indicated that vir- 
 tually the only supply source that could provide molybdenum 
 at this price would be byproduct producers, especially from 
 the foreign copper operations. 
 
 At a price of $10/lb, approximately equivalent to the 1980 
 selling price, the available resource would be 7.9 billion lb. 
 However, at $4.50/lb, the 1982 selling price, the available 
 resource drops to 2.5 billion lb. When dealers were selling 
 the metal at $2.47/lb, analyses indicated that only one primary 
 mine could cover production costs (DCFROR, breakeven cost) 
 (fig. 6). Costs reflected in figure 6 include capital recovery; 
 hence these costs should not be interpreted as cash cost 
 equivalents. 
 
 Producing mines account for 43 pet of the tonnage poten- 
 tially recoverable from primary properties, while deposits 
 under development account for 22 pet; explored deposits, hav- 
 ing no specific plans for development, account for the remain- 
 ing 35 pet. 
 
 The weighted-average cost of production for producing 
 mines (including a 15-pct DCFROR) is estimated to be 
 $4.46/lb Mo; nearly 2.5 billion lb is available at a molybdenum 
 price of $4/lb. At $6/lb, the available molybdenum from pro- 
 Table 14.— Molybdenum potentially available from primary pro- 
 ducing, developing, and explored deposits in market economy 
 countries at selected 1983 prices, at a 15-pct DCFROR 
 (Million pounds of contained molybdenum) 
 
 T .... Producing Developing and 
 
 lotai cost vip mines explored deposits Total' 
 
 Under $4.00 2,463 2,463 
 
 $ 4.01 to $ 6.00 1,002 1,002 
 
 $ 6.01 to $ 8.00 630 610 1,240 
 
 $ 8.01 to $10.00 3,200 3,200 
 
 $10.01 to $14.00 1,009 1,009 
 
 Above $14.00 712 712 
 
 Total 1 4,096 5,531 9,626 
 
 'Totals may not add owing to independent rounding. 
 
15 
 
 -69- 
 
 ro 
 
 CD 
 
 c 
 o 
 
 "3 
 
 o 
 o 
 
 < 
 h- 
 
 o 
 
 12 3 4 5 6 7 8 
 
 TOTAL RECOVERABLE MOLYBDENUM, I0 9 lb 
 Figure 5. —Total molybdenum available from primary deposits, market economy countries. 
 
 10 
 
 6.00 
 
 00 
 CD 
 
 c 
 o 
 
 CO 
 
 o 
 o 
 
 O 
 
 1.0 1.5 2.0 2.5 3.0 
 
 TOTAL RECOVERABLE MOLYBDENUM, I0 9 lb 
 Figure 6. —Total molybdenum available from producing minesat a 0-pct DCFROR, market economy countries. 
 
 4.5 
 
16 
 
 during mines increases by 1.0 billion lb. At these prices no 
 tonnage is available from the nonproducers. However, at 
 $8/lb, an additional 1.2 billion lb would be available, nearly 
 half of which would be from deposits not currently produc- 
 ing. At prices exceeding $8/lb, an additional resource of 4.9 
 billion lb is potentially available, entirely from nonproduc- 
 ing deposits. 
 
 The total potential availability of primary molybdenum 
 from properties within Canada and the United States con- 
 stitutes 97 pet of the total resource. Shown in figure 7 are 
 curves illustrating the molybdenum availability of each coun- 
 try. These data are grouped in various price categories in 
 table 15. At a price under $4/lb and a 15-pct DCFROR, the 
 United States has a potential available resource of 2.4 billion 
 
 Table 15.— Molybdenum potentially available' within the United 
 States and Canada, at a 15-pct DCFROR 
 
 (Million pounds or recovered molybdenum) 
 
 Tota 'cost, United Canada T , 
 $/lb States 
 
 Under $4.00 2,396 2,396 
 
 $ 4.01 to $ 6.00 697 305 1,002 
 
 $ 6.01 to $ 8.00 757 241 998 
 
 $ 8.01 to $10.00 3,200 3,200 
 
 $10.01 to $14.00 952 57 1,009 
 
 Above $14.00 48 664 712 
 
 Total' 8,050 1,267 9,317 
 
 'Includes both producers and nonproducers. 
 
 lb, enough to supply current domestic requirements for at 
 least 40 yr. A price of $6/lb would bring an additional resource 
 of 697 million lb from U.S. deposits for a total of 3.1 billion 
 lb. At the same price, Canada could produce a total of 305 
 million lb. At a price exceeding $8/lb, U.S. deposits could pro- 
 duce an additional 4.2 million lb, while Canada could mine 
 an additional 721 million lb. 
 
 ANNUAL AVAILABILITY 
 
 The estimated molybdenum production capacities for the 
 deposits analyzed are shown in table 16. At full capacity 
 levels, a total production of 337 million lb is available from 
 the market economy countries- 179 million lb from the pro- 
 ducing mines and 158 million lb from nonproducers. All pro- 
 duction capacity from operating mines would be available at 
 a cost of $8/lb or less, while explored deposits could only con- 
 tribute 25 million lb at that price. Additional production 
 capacities would be available at costs ranging up to $14/lb, 
 all from developing and explored deposits. 
 
 Figure 8 shows potential annual molybdenum production 
 at various cost ranges for producing mines and nonproduc- 
 ing deposits. The large increase in production from 1983 to 
 1984 for producing mines occurs because many mines were 
 shut down in 1983 and were assumed to be reopened in 1984. 
 The production from 1984 to 2000 for these mines represents 
 molybdenum output potential at full-capacity levels of pro- 
 
 30 
 
 CO 
 O 
 o 
 
 _l 
 
 I 
 
 25- 
 
 20- 
 
 15- 
 
 10- 
 
 5- 
 
 -Canada 
 
 / 
 
 / 
 
 / 
 
 ■United States 
 
 -L 
 
 -L 
 
 J_ 
 
 RECOVERABLE MOLYBDENUM, I0 9 lb 
 Figure 7. —Total molybdenum potentially available in the United States and Canada from producing mines and 
 nonproducing deposits. 
 
17 
 
 350 
 
 1989 
 
 1991 
 
 1993 
 
 1995 
 
 1997 
 
 1999 
 
 2001 
 
 Figure 8.— Potential annual production of molybdenum from producing mines and nonproducing deposits at various cost ranges, 
 
 market economy countries. 
 
 Table 16. — Potential 1983 molybdenum production capacities 
 
 from primary molybdenum mines and deposits in market 
 
 economy countries, at a 15-pct DCFROR 
 
 (Million pounds of contained molybdenum) 
 
 Total cost S/lb Producng Developing and ~~ 
 
 mines explored deposits Total 1 
 
 Under $3.50 44 44 
 
 S 3.51 to S 4.75 74 74 
 
 S 4.76 to S 6.00 34 34 
 
 S 6.01 to $ 8.00 27 25 52 
 
 S 8.01 to S 9.00 62 62 
 
 S 9.01 to S12 00 40 40 
 
 S12.01 to S14.00 
 
 Above $14.00 31 31 
 
 Total 179 158 337 
 
 Installed capacities for producing mines and projected capacities for 
 developing and explored deposits. 
 
 duction. The fact that the curves for producing mines do not 
 decrease indicates that these mines have sufficient reserves 
 to produce at full capacity until sometime after the year 2000. 
 At a cost of S3.50/lb with 15-pct DCFROR, an annual pro- 
 duction of 44 million lb would be economically available from 
 producing mines. At S4.75/lb, production would increase to 
 a total of 118 million lb/yr; while at S8, all producing mines 
 could economically operate. 
 
 Because startup dates for developing and explored 
 deposits were not known, construction of annual availabili- 
 ty curves for them were based on the assumption that 
 preproduction would begin in year "N" (fig. 9). These curves 
 indicate that several years would be required from the year 
 development begins before any production could occur. 
 
 Although an additional 133 million lb/yr Mo could be produced 
 from these deposits, a price exceeding $8/lb would be re- 
 quired. Therefore, for most of these deposits, production in 
 the near future appears unlikely. 
 
 BYPRODUCT MOLYBDENUM TOTAL 
 AVAILABILITY 
 
 A significant portion of molybdenum production is as a 
 byproduct of copper; production from this source has been 
 increasing in recent years. A total of 65 copper deposits were 
 analyzed for molybdenum production, 34 producers and 31 
 nonproducers. A total of 14 domestic copper operations were 
 evaluated as producers, some of which are temporarily closed. 
 
 As shown in figure 10, the total byproduct availability 
 from all minas evaluated amounts to approximately 6.6 billion 
 lb Mo at a price up to $3.80/lb Cu, with producers account- 
 ing for over 65 pet of the total. As shown in table 17, a total 
 of 1,435 million lb Mo could be economically mined at a cop- 
 per price under $0.50/lb, with an additional 1,986 million lb 
 available at prices up to $0.75/lb. At higher copper prices (ex- 
 ceeding $2.25/lb) a total of 6,608 million lb Mo is potentially 
 available, two-thirds of which would be from producing mines. 
 
 Annual availability from all mines evaluated amounts to 
 an annual capacity of 47.1 million lb Mo. Table 18 shows the 
 U.S. molybdenum capacity from operating or temporarily 
 shut down copper mines for 1983. At a copper price of 
 $0.75/Ib the domestic molybdenum producers can supply 22.3 
 million lb Mo from two copper mines. An additional capacity 
 of 6. 1 million lb can be generated at a copper price of $1 ,00/lb. 
 The remaining capacity requires a copper price gre »ter than 
 
18 
 
 80 
 
 70 
 
 io E 60 
 O 
 
 ^ 50 
 
 UJ 
 
 Q 
 
 Q 40 
 
 30 
 
 UJ 
 
 _l 
 CD 
 < 
 
 a: 
 
 UJ 
 
 ui 
 or 
 
 10 
 
 N Year preproduction 
 development begins 
 
 N+2 
 
 N+4 
 
 N+6 
 
 N+12 
 
 N+14 
 
 N + 16 
 
 N+18 
 
 Figure 
 market 
 
 N+8 N+IO 
 
 YEAR 
 9.— Potential annual production of molybdenum from developing and explored deposits at various cost ranges, 
 economy countries. 
 
 o 
 
 ro 
 oo 
 o> 
 
 o 
 
 ~3 
 
 g |.50 
 
 
 2 3 4 5 6 
 
 TOTAL RECOVERABLE MOLYBDENUM, I0 9 lb 
 Figure 10.— Total available molybdenum byproducts from copper deposits, market economy countries. 
 
19 
 
 $1.00/lb to be economically extractable. At copper prices 
 above Sl.OO/lb molybdenum production is questionable since 
 many of these mines are now shut down. It is likely that many 
 of these mines will remain closed owing to the availability 
 of cheaper byproduct molybdenum from copper operations 
 in foreign countries. 
 
 Table 17.— Total molydenum byproduct potentially available in 
 
 market economy countries at selected copper production costs, 
 
 at a 15-pct DCFROR 
 
 (Million pounds of molybdenum) 
 
 ^ •«. Producing Developing and 
 
 Copper price. S/lb 3 , ; ." ,. _ , 
 
 mines explored deposits Total 
 
 Under $0.50 1.005 430 1.435 
 
 S0.51 to S0.75 1.810 176 1.986 
 
 S0.76toS1.00 760 136 896 
 
 S1.01 to S1.50 706 443 1,149 
 
 S1.51 to S2.25 137 715 852 
 
 Above S2.25 290 290 
 
 Total 4.418 2.190 6,608 
 
 Table 18.— Annual U.S. byproduct molybdenum capacity and 
 
 total demonstrated resources of recoverable molydenum from 
 
 evaluated U.S. copper operations at selected copper prices, at 
 
 a 15-pct DCFROR 
 
 (Million pounds of molybdenum) 
 
 _ __. Annual Total 
 
 Copper price. S/lb capacity. 1983 resources 
 
 Under S0.75 22.3 294.4 
 
 $0.76 to S1.00 6.1 131.7 
 
 $1.01 to $1.50 16.2 495.9 
 
 Above $1.50 2^5 7.6 
 
 Total 47.1 929.6 
 
 Estimated annual production capacities for byproduct 
 molybdenum from primary copper deposits are shown in table 
 19. Capacities, as shown, were estimated at full designed 
 capacity for the years 1983 and 1991. A total production 
 capacity of 109 million lb was estimated for 1983 from pro- 
 ducing mines, with the United States contributing 47 million 
 lb. As shown, there are planned capacity increases in pro- 
 ducing mines of over 25 pet by 1991. In addition, deposits 
 not now producing have the potential to add nearly 70 million 
 lb/Mo, although for most deposits, much higher copper prices 
 would be required. 
 
 Since copper price influences molybdenum production, 
 potential annual molybdenum capacity was analyzed on the 
 basis of copper price (fig. 11). As shown, at a copper price 
 of $0.50/lb, annual production capacity in 1983 was estimated 
 at 25 million lb from seven properties. As these mines ex- 
 pand molybdenum production capabilities, capacity could ap- 
 proach 50 million lb/yr. At a copper price of $l/lb, produc- 
 tion capacity for 1983 increases to 64.0 million lb. At the same 
 
 Table 19.— Molybdenum byproduct potential annual production 
 
 for 1983 and 1991 from market economy countries, at a 15-pct 
 
 DCFROR 
 
 (Million pounds of contained molybdenum) 
 
 
 1983 capacity: 
 Producing 
 
 
 1991 capacity 
 
 
 Copper price 
 
 Producin 
 
 g Nonproducing 
 
 
 $/lb 
 
 mines 
 
 mines 
 
 deposits 
 
 Total 
 
 Under $0.75 
 
 51.7 
 
 74.2 
 
 20.4 
 
 94.6 
 
 $0.75 to $1.00 . . . 
 
 12.4 
 
 26.0 
 
 0.0 
 
 26.0 
 
 $1.00 to $1.50 . . . 
 
 34.6 
 
 30.4 
 
 21.6 
 
 52.0 
 
 $1.50 to $2.25 . . . 
 
 10.5 
 
 8.7 
 
 27.6 
 
 36.3 
 
 Total 
 
 109.2 
 
 139.3 
 
 69.6 
 
 208.9 
 
 225 
 
 zz: - 
 
 to 
 o 
 
 UJ 
 Q 
 
 CD 
 
 o 
 
 I75 - 
 
 I50- 
 
 I25 - 
 
 UJ ICO 
 
 CD 
 
 < 
 or 
 
 UJ 
 UJ 
 
 or 
 
 200I 
 
 Figure 11. — Potential annual capacity of molybdenum byproducts at selected copper prices, market economy 
 countries. 
 
20 
 
 price, 124.8 million lb/yr capacity would be available from 
 28 properties in 1991, 80 pet of which would be from mines 
 currently producing. As shown, molybdenum as a byproduct 
 of copper production could exceed 200 million lb/yr. However, 
 prices well above $1.00/lb would be required. 
 
 Table 20 shows the 1983 estimated installed molybdenum 
 capacity on a country basis for producing mines. Among 
 primary producers, the United States accounts for 153 million 
 lb/yr or 85 pet of the total capacity, while Canada and Mex- 
 ico hold 13 pet and 2 pet, respectively. In byproduct produc- 
 tion, the United States has the capacity to produce 47 million 
 lb/yr, 34 pet of the total. Chile has a production capacity of 
 45 million lb/yr, with Canada following at 21 million lb/yr. 
 The remaining capacity is divided between four countries: 
 Mexico, Peru, Iran, and the Philippines. 
 
 As shown in the table, the installed capacity far exceeds 
 the MEC production, which has averaged 178 million lb/yr 
 over the last 10 yr. In addition, private inventories estimated 
 at 200 million lb in 1983 have contributed to the oversupply 
 
 Table 20.— Estimated total 1983 molybdenum capacity from 
 primary and byproduct producers in market economy countries 
 
 (Million pounds of molybdenum) 
 
 Country Primary Byproduct Total 
 
 United States 153 47 200 
 
 Canada 23 21 44 
 
 Mexico 3 10 13 
 
 Chile 45 45 
 
 Peru 9 9 
 
 Iran 4 4 
 
 Philippines 1 1 
 
 Total 179 137 316 
 
 of molybdenum (19). As a result, there is little likelihood for 
 explored primary deposits to be developed in the foreseeable 
 future. It is more likely that planned expansions by byproduct 
 producers will continue to affect primary production and, as 
 a result of continued overcapacity conditions, molybdenum 
 price will tend to remain low. 
 
 CONCLUSIONS 
 
 The United States has about 8.1 billion lb Mo 
 (recoverable) from primary deposits and 1.2 billion lb as a 
 byproduct of copper production. This constitutes 84 pet of 
 all recoverable primary resources located in the MEC'S, and 
 17 pet of the recoverable byproduct resource. The current 
 U.S. production capacity is estimated at 153 million lb from 
 primary producers and 47 million lb from byproduct pro- 
 ducers, a total of 200 million lb/yr. This capacity is well above 
 the domestic consumption requirement, which has a 10-yr 
 average of about 57 million lb/yr. Disregarding economics, 
 available U.S. resources could supply current domestic de- 
 mand at this level for at least 160 yr. Assuming production 
 at the average rate over the last 10 yr (about 114 million 
 lb/yr), U.S. resources could last for over 80 yr. 
 
 Applying profitability at a 15-pct DCFROR on invested 
 capital and a price of $4/lb Mo, 2.5 billion lb of Mo could be 
 recovered from MEC primary mines. If the molybdenum 
 price were to increase to $6/lb, an additional 1 billion lb would 
 be available. There are also large resources (5.5 billion lb Mo) 
 potentially available from primary deposits that are not now 
 producing; however, prices exceeding $14/lb would be 
 required. 
 
 With such a large resource base located within the ter- 
 ritorial boundaries of the United States, molybdenum 
 
 availability is well assured regardless of international trade 
 disruption. However, most of these resources can only be pro- 
 duced at prices higher than those prevailing today (1983). 
 
 As major international molybdenum suppliers, primary 
 U.S. producers are threatened by foreign byproduct pro- 
 ducers. As new foreign byproduct production capacity comes 
 on-stream, large quantities of molybdenum will be available 
 to the international market. In effect this could dislocate some 
 primary suppliers, which require higher molybdenum prices 
 in order to profitably operate. In recent years, primary mines 
 have cut back production, and in 1983 production at all 
 primary U.S. mines was halted. Unless market conditions 
 significantly improve, the outlook for these primary pro- 
 ducers is bleak. 
 
 Byproduct production is less sensitive to molybdenum 
 price changes since the operation is more dependent on cop- 
 per price. In addition, many of the byproduct properties are 
 located in countries where employment and the need for 
 foreign currency are the primary concerns rather than pro- 
 fitability. Even under continued poor economic conditions, 
 molybdenum production from these sources will continue to 
 be available. Furthermore, the production from these coun- 
 tries is expected to increase, owing to planned copper mine 
 expansions and new mine developments. 
 
21 
 
 REFERENCES 
 
 1. Billhorn. W. W. Molybdenum-A Year for Pruning Mine Out- 
 put and Inventories. Eng. and Min. J., v. 185. No. 3. Mar. 1984, p. 53. 
 
 2. Engineering and Mining Journal. Molybdenum Metal and 
 Mineral Market. V. 166, No. 3, Mar. 1965. pp. 3-18. 
 
 3. Gouseland. P. Molybdenum-Suppliers Race To Catch Up With 
 Demand. Eng. and Min". J., v. 176, No. 3, Mar. 1975, p. 103. 
 
 4. Goth, J. W. Molybdenum-Strong Demand Fosters New Pros- 
 pects. Eng. and Min.'j.. v. 178. No. 3. Mar. 1977, p. 88. 
 
 5. Distler. \V. F. Molybdenum Outlook Remains Good as New 
 Mine Properties Are Sought. Eng. and Min. J., v. 181, No. 3, Mar. 
 1980. pp. 99-100. 
 
 6. BUIhorn. \V. W. Molybdenum-Highest Inventory Ever; Demand 
 Hits New Low. Eng. and Min. J., v. 184, No. 3, Mar. 1983, pp. 70-71. 
 
 7. Blossom. J. W. Molvbdenum. Ch. in BuMines Minerals Year- 
 book 1982. v. 1. pp. 609-618. 
 
 8. Kummer. J. T. Molvbdenum. BuMines Minerals Commodity 
 Profile. 1979. 23 pp. 
 
 9. Ferrara. T. Molybdenum Geology. The ID Miner, Coll. Mines 
 and Earth Resour.. Univ. ID. 1981, pp. 5-6. 
 
 10. Mclnnis, W. Molybdenum, A Materials Survey. BuMines IC 
 77S4. 1957. 75 pp. 
 
 11. Dana. E. S. A Textbook of Mineralogy. Wiley, 4th ed., 1982, 
 pp. 773-774. 
 
 12. Hicks, C. Molybdenum Occurrences in Arizona. AZ Dep. 
 Miner. Resour.. Miner. Rep. 3. 1979. pp. 1-35. 
 
 13. Shirley. J. F. State of the Art, By-product Molybdenite 
 Recovery. Pres. at the Molybdenum in Transition Symp., Tucson, 
 AZ. Sept. 1981: reprinted courtesy of Mountain States Mineral Enter- 
 prises Inc.. available upon request from BuMines Minerals Availabili- 
 ty Field Office. Denver. CO. 
 
 14. Rust. D. H. Ferromolybdenum Plant. Tech. Paper in Mineral 
 Processing Division. Pres. at AZ Sec. AIME. Spring Meeting, Tuc- 
 son. AZ. May 15. 1975. Duval Sierrita Corp., 1975, 72 pp. 
 
 15. U.S. Geological Survey and U.S. Bureau of Mines. Principles 
 of a Resource/Reserve Classification for Minerals. U.S. Geol. Surv. 
 Circ. 831. 1980. 5 pp. 
 
 16. Clement. G. K., Jr.. R. L. Miller, P. A. Seibert, L. Avery, and 
 H. Bennett. Capital and Operating Cost Estimating System Manual 
 for Mining and Beneficiation of Metallic and Nonmetallic Minerals 
 Except Fossil Fuels in the United States and Canada. BuMines Spec. 
 Publ.. 1980. 149 pp.: also available as: 
 
 STRAAM Engineers Inc. Capital and Operating Cost 
 Estimating System Handbook - Mining and Beneficiation of Metallic 
 and Nonmetallic Minerals Except Fossil Fuels in the United States 
 and Canada (contract JO255026). BuMines OFR 10-78, 1977, 382 
 PP 
 
 17. Davidoff, R. L. Supply Analysis Model (SAM): A Minerals 
 Availability System Methodology. BuMines IC 8820, 1979, 45 pp. 
 
 18. Stermoie. F. J. Economic Evaluation and Investment Deci- 
 sion Methods. Investment Evaluation Corp., Golden, CO, 2d ed., 
 1974. 443 pp. 
 
 19. Sutulov, A. Chilean Expert Sees Better Molybdenum Outlook 
 in 1984. Eng. and Min. J., v. 185, No. 3, Mar. 1984, p. 22. 
 
 20. U.S. Forest Service (Dep. Agriculture) and others. Final 
 Development Concept Analysis Document. AK Region Rep. 150, 
 Aug. 1983, 176 pp. 
 
 21. Mining Magazine. Go Ahead for Alaskan Moly Mines. V. 144, 
 No. 5. May 1981. p. 359. 
 
 22. Tweto, O., and P. K. Sims. Precambrian Ancestry of the Col- 
 orado Mineral Belt. Geol. Soc. America Bull., v. 74, 1963, pp. 
 991-1014. 
 
 Julin. D. E.. K. E. Smith. E. L. Ohmert, and others. Climax 
 Caving System. Ch. 12 in SME Mining Engineering Handbook. Soc. 
 Min. Eng. AIME. 1973. v 1. pp. 12-188 to 12-198. 
 
 24. Wallace. S. R.. N. K. Muncaster, and others. Multiple Intru- 
 sion and Mineralization at Climax, CO. Ch. in Ore Deposits of the 
 United States. 1933-1967. AMIE. Maple Press Co., York, PA v. 2 
 1968. pp. 606-640. 
 
 2-5 AMAX Corp. 10K Report. 1988, pp. 6-7. 
 
 26 Mining Magazine. Henderson on Stream. V. 136, No. 1 , Jan. 
 
 27 The Henderson Project. V. 133, No. 2, Aug. 1975, 
 
 pp. 90-96. 
 
 28. Sharp, J. E. A Molybdenum Mineralized Breccia Pipe Com- 
 plex, Redwell Basin, Colorado. Econ. Geol., v. 73, May 1978, pp. 
 369-382. 
 
 29. Lyle, D. AMAX Delays Project Indefinitely. Rocky Mountain 
 News, Denver, CO, Feb. 4, 1984, pp. 93, 96. 
 
 30. Pay Dirt. Questa-The Newest Moly Mine. No .50, Nov. 1983, 
 pp. 1M-31M. 
 
 31. Schmidt, E. A. Geology of Thompson Creek Molybdenum 
 Deposit- An Update. Pers. at the 86th Annu. Conv., NW Min. Assoc, 
 Spokane WA, Dec. 4-6, 1980; available upon request from Western 
 Field Operations Center, BuMines, Spokane, WA. 
 
 32. U.S. Forest Service (Dep. Agriculture). Thompson Creek 
 Molybdenum Project, Custer County, ID. Final Environmental Im- 
 pact Statement. Cyprus Mines Corp., Oct. 1980, pp. B2-B3. 
 
 33. Cavanaugh, P. The Geology of the Little Boulder Creek 
 Molybdenum Deposit, Custer County, ID. M.S. Thesis, Univ. MT, 
 1979, 100 pp. 
 
 34. Olmore, S. D. Geology of the Big Ben Molybdenum Deposit 
 Near Neihart, Montana. Pres. at the 85th Annu. Conv., NW Min. 
 Assoc, Spokane, WA, Dec. 6-8, 1979; abstract available upon re- 
 quest from Western Field Operations Center, BuMines, Spokane, 
 WA. 
 
 35. Weed, W. H. Geology of Little Belt Mountains, Mont. Sec. 
 in Twentieth Annual Report of the U.S. Geological Survey, 1898-99. 
 Part III: Precious Metal Mining Districts. U.S. Geol. Surv., 1900, 
 pp. 271-459. 
 
 36. Kirkemo, H. H., C. A. Anderson, and S. C. Creasey. Investiga- 
 tions of Molybdenum Deposits in the Conterminous United States, 
 1942-60. U.S. Geol. Surv. Bull. 1182E, 1965, 90 pp. 
 
 37. Creasey, S. C, and E. A. Scholz. Big Ben Molybdenum 
 Deposit. Neihart Mining District, Cascade County, Mont. U.S. Geol. 
 Surv. Strategic Miner. Prelim. Rep., Open File Rep. 45-2, 1944, 29 
 pp.; available upon request from Western Field Operations Center, 
 BuMines, Spokane, WA. 
 
 38. Wright, W. A. Molybdenite Mineralization at the Hall Pro- 
 perty, Nye County, Nev. Geol. Soc. America Abs., v. 8, No. 6, 1900, 
 pp. 1176-1177. 
 
 39. Krai, V. E. Mineral Resources of Nye County, Nevada. Univ. 
 NV, Geol. and Min. Ser. 50, v. 45, No. 3, 1951, pp. 159-160. 
 
 40. Engineering and Mining Journal. Anaconda Plans Nevada's 
 Largest Mining Investment in 50 Years. V. 181, No. 2, Feb. 1980, 
 p. 9. 
 
 41. Anaconda's Nevada Moly Project To Go on 
 
 Stream in Fall 1981. V. 181, No. 3, Mar. 1980, pp. 39-41. 
 
 42. Tingley, J., and P. Smith. Mineral Industry of Shoshone- 
 Eureka Resource Area, Battle Mountain District, Nevada. NV. Bur. 
 Mines and Geol., Open File Rep. 83-3, 1983, 104 pp. 
 
 43. Engineering and Mining Journal. Moly Market Will Deter- 
 min Start-Up of Mount Hope. V. 184, No. 4, Apr. 1983, p. 31. 
 
 44. Utterback, W. C. Geology of Mt. Tolman Deposit. AMAX 
 Corp., private company rep., 1980, pp. 2-8. 
 
 45. World Mining. Mt. Tolman Reserves Increased to 900,000,000 
 Tons. V. 33, Feb. 1980, p. 37. 
 
 46. Mining Journal (London). Mount Tolman Investment Sought. 
 V. 300, No. 7711, June 3, 1983, p. 379. 
 
 47. Kimura, E. T., G D. Bysouth, and A. D. Drummond. Endako. 
 Paper 44 in Porphyry Deposits of the Canadian Cordillera; Part D- 
 Porphyry Molybdenum Deposits of the Calc-Alkalic Suite. Can. Inst. 
 Min. and Metal!., spec. v. 15, 1976, pp. 444-454. 
 
 48. Soregaroli, A. E. Geology and Genesis of the Boss Mountain 
 Molybdenum Deposit, British Columbia. Econ. Geol., v. 70, 1975, 
 pp. 4-14. 
 
 49. Noranda Corp. Annua) Report. Dec. 1981, p. 19. 
 
 50. Devitt, J. C. Reopening an Open Pit Molybdenum Mine- 
 KitsauJt Project. Paper in Open Pit Mining Session. Pres. at the 1980 
 Am. Min. Congr. Conv., San Francisco, CA, Sept. 21-29, 1980, VI 
 pp.; preprint available from American Mining Congress. 
 
 51. Bright, M. J., and D. C. Jonson. Glacier Gulch ( Yorky Har- 
 dy). Paper 45 in Porphyry Deposits of the Canadian Cordillera; Part 
 
22 
 
 D- Porphyry Molybdenum Deposits of the Calc-AlkaJic Suite. Can. 
 Inst. Min. and Metall., spec. v. 15, 1976, pp. 455-461. 
 
 52. Costin, C. P. An Economic Analysis of the Ajax Molybdenum 
 Deposit -British Columbia, Canada. M.S. Thesis 1630, CO Sch. 
 Mines, Golden, CO, Mar. 11, 1975, 92 pp. 
 
 53. Christopher, P A., W. H. White and J. E. Harakal. Age of 
 Molybdenum and Tungsten Mineralization in Northern British Col- 
 umbia. Can. J. Earth Sci., v. 9, 1972, pp. 1727-1734. 
 
 54. White, W. H., D. R. Stewart, and M. W. Ganster. Adanac 
 (Ruby Creek). Paper 47 in Porphyry Deposits of the Canadian Cor- 
 dillera; Part D- Porphyry /Molybdenum Deposits of the Calc-Alkalic 
 Suite. Can. Inst. Min. and Metall., spec. v. 15, 1976, pp. 476-483. 
 
 55. Adanac Mining and Exploration Ltd. Annual Directors' 
 Report to the Shareholders. Jan. 1982, 3 pp. 
 
 56. Diment, W. D. The Redbird Molybdenum Deposit. Craigmont 
 Mines Ltd., Merritt, BC, May 1980, 11 pp. 
 
 57. Brown, S. A. Characteristics of Canadian Cordilleran 
 Molybdenum Deposits. Paper 42 in Porphyry Deposits of the Cana- 
 dian Cordillera; Part D- Porphyry Molybdenum Deposits of the Calc- 
 Alkalic Suite. Can. Inst. Min. and Metall., spec. v. 15, 1976, pp. 
 417-431. 
 
 58. Boyle, C. H., and C. H. B. Leitch. Geology of Trout Lake 
 Molybdenum Deposit, B.C. CIM Bull., v. 76, 849, Jan. 1983, pp. 
 115-124. 
 
 59. Pazour, D. Mexico Joins Moly League: Cumobabi Now Min- 
 ing Ore. World Min., v. 33, July 1980, pp. 44-49. 
 
 60. Leon, F. L., and C. P. Miller. Geology of the Creston 
 Molybdenum-Copper Deposit, Opodepe, Sonora, Mexico. Pres. at Int. 
 Meeting, Cordillerian Sec., Geol. Soc. America, Hermosillo, Sonora, 
 Mexico, Mar. 25-27, 1981, 16 pp.; available upon request from 
 Minerals Availability Field Office, BuMines, Denver, CO. 
 
23 
 
 APPENDIX.— DEPOSIT DESCRIPTIONS 
 FOR PRIMARY MOLYBDENUM 
 
 UNITED STATES 
 Alaska 
 
 Quartz Hill 
 
 The Quartz Hill deposit is located on a knoll bounded by 
 the Wilson Arm-Smeaton Bay Fjords on the north and the 
 Boca de Quadra fjord on the south. It lies within a transi- 
 tional zone between the Wrangell-Revillagigedo Belt 
 metamorphic complex to the west and the massive Coast 
 Range Batholith rocks to the east. The deposit is situated 
 approximately at N55° 24'05" latitude and W130° 29'00" 
 longitude. 
 
 Metavolcanic and metasedimentary rocks of Mesozoic 
 and/or Paleozoic age are the oldest rocks exposed in the area. 
 The Coast Range rocks vary in composition from diorite, 
 quartz diorite. and granodiorite to quartz monzonite. These 
 quartz-and sodium-rich monzonites are the sources and 
 primary hosts for the molybdenum mineralization. The main 
 mass of the Quartz Hill stock is a textured porphyritic quartz 
 monzonite (20).' 
 
 U.S. Borax and Chemical Co. began exploration work on 
 the Coast Range intrusive complex in 1971. Several years 
 of both bedrock and geochemical sampling indicated the 
 presence of molybdenum in the area and resulted in the 
 discovery of the Quartz Hill deposit Initial core drilling made 
 in 1974-75 confirmed Quartz Hill as a molybdenum deposit. 
 By the end of 1978, a total of 280 shallow and deep drill holes 
 delineated at least 635 million mt of ore at 0.09 pet Mo. As 
 of 1981, 70.492 m of core drilling were completed, delineating 
 a total of 1.36 billion mt ore at an average grade of 0.081 
 pet Mo. 
 
 The deposit, as planned, will be mined by open-pit 
 methods. Mine development will consist of removing 11.8 
 million mt ore and waste rock during the first year and pro- 
 cessing approximately 9.9 million mt ore. The pit will have 
 an ultimate length of 3.38 km. a width of 2.09 km, and an 
 average depth of 488 m. Based upon a mining rate of 54,420 
 mt/d, the mine could produce 40 million lb of contained 
 molybdenum in concentrate per year for about 70 yr (21). 
 
 Colorado 
 
 Colorado accounts for about 22 pet of all known domestic 
 resources, in terms of recoverable metal. The three major 
 ore bodies are Climax, Henderson, and Mount Emmons. At 
 present, these deposits contain about 3.1 billion lb of 
 recoverable molybdenum, with Climax and Henderson hav- 
 ing a combined annual capacity estimated at more than 100 
 million lb of Mo. 
 
 All three deposits are located in the same geologic prov- 
 ince, the Colorado mineral belt. Climax and Henderson are 
 located close to major Tertiary faults, the Mosquito fault and 
 the Berthoud Pass fault, respectively (22). The ores are 
 associated with composite intrusives of nearly identical age 
 and composition. Multiple intrusions and mineralizations are 
 characteristics of the deposits. 
 
 1 Italicized numbers in parentheses refer to items in the list of references 
 preceding the appendix. 
 
 Climax 
 
 The Climax molybdenum mine is in the Robinson min- 
 ing district, on the boundary between Lake and Summit 
 Counties, at about N39° 22'09" latitude and VV106 10'17" 
 longitude. The deposit was first discovered in 1879 and all 
 early work was directed towards gold, but after several years 
 of fruitless exploration, the owner sold the property. The new 
 owner dug an exploratory tunnel into the Bartlett Mountain 
 hoping to intercept gold veins, until it was determined the 
 mountain contained the element molybdenum. 
 
 The Climax ore body was formed by a massive Tertiary 
 stockwork in Precambrian granite and schist. The well- 
 mineralized, quartz-porphyry stockwork is a component of 
 the intrusive complex known as the Climax Group (28). 
 
 The ore body has an elliptical shape with a radius of 550 
 m at the outer section and 340 m at the central barren core. 
 The ore deposit appears arcuate with a vertical height of 
 about 425 m in its greatest dimensions. The final depth has 
 not yet been reached. 
 
 Molybdenite occurs in three distinct, but overlapping ore 
 bodies. The molybdenite is finely crystalline and intimately 
 intergrown in, or enclosed by, quartz. The deposit also con- 
 tains tungsten (as huebnerite) and tin (as cassiterite) in 
 recoverable quantities. Other minor minerals are monazite, 
 galena, and sphalerite. 
 
 In 1916 during a tungsten shortage, the American Metal 
 Co. began to explore and develop the property; as substitute 
 for tungsten, molybdenum demand improved. The Climax 
 Molybdenum Co. was formed to operate the property. 
 
 A 227 mt/d mill began production in February 1918, but 
 was forced to close in March 1919 owing to declining demand. 
 The mill remained closed until August 1924 when increas- 
 ing demand for the metal led to its reopening at a capacity 
 of 363 mt/d (21+). Since then, production has increased to the 
 current combined capacity of 54,420 mt/d from two mines, 
 an underground block-caving operation and an open-pit opera- 
 tion developed in 1973. 
 
 Though it is one deposit, reserves are classed in two 
 separate categories, underground and surface. The full ex- 
 tent of mineralization at Climax is not fully defined. As of 
 January 1983, the underground operation had an in situ 
 reserve of 244.0 million mt ore, and the open-pit operation 
 had reserves of 130.6 mt (25). 
 
 Henderson 
 
 The Henderson Mine lies in the Urad mining district in 
 Clear Creek County. The deposit has location coordinates of 
 N39° 46'09" and W105° 50'29". 
 
 The Henderson ore body is near the western edge of the 
 Colorado mineral belt. The molybdenite stockwork ore body 
 is associated with a rhyolitic subvolcanic center commonly 
 referred to as the Red Mountain complex. The complex con- 
 sists of a number of chemically and mineralogically related 
 intrusive rocks. The primary units of concern are the Urad 
 Porphyry, Primos Porphyry, and the Henderson Granite. 
 
 Molybdenum mineralization occurs as veinlets, as 
 coatings on joints, and as disseminations. Veinlet 
 molybdenite, typically 2 to 25 mm thick, accounts for the ma- 
 jority of the ore. It is fine grained and mixed with gangue 
 mineral, primarily quartz, pyrite, fluorite, sericite, and 
 
24 
 
 potassium feldspar. The lower part of the ore body, especially 
 the Henderson Granite, contains a different type of 
 molybdenite veinlets which are generally larger and contain 
 different gangue mineral associations. The veinlets imply 
 replacements rather than open space filling (22). 
 
 In plan, the ore body is elliptical in shape, about 915 m 
 in the long axis and 700 m in the short. The thickness varies 
 from 120 to 240 m, but depths to the south and east are still 
 unknown. 
 
 The Red Mountain area was first prospected in the late 
 1800's because of the red rocks produced from iron staining. 
 With the absence of gold and silver, little activity occurred 
 until 1914, when the Primos Chemical Co. acquired the prop- 
 erty and began developing the Urad mine for molybdenum. 
 Production was sporadic until Climax Molybdenum Co. ac- 
 quired the property in 1963 (26). 
 
 The Henderson ore body was discovered from an ex- 
 ploratory program trying to find extensions of the Urad ore 
 body. This led to the discovery of the Henderson ore body 
 on the other side of Red Mountain, but considerably deeper 
 than the Urad ore body (27). 
 
 The mine employs the panel-caving system, with a capaci- 
 ty of 27,210 mt/d Mo ore. The mining system makes full use 
 of raise boring machines, LHD'S and rubber-tired drill jum- 
 bos. Henderson ore reserves have been increasing since 
 discovery. The recoverable reserves as of January 1983 are 
 223 mt ore at an average grade of 0.251 pet Mo. Based on 
 these reserves, the mine will have a life of at least 31 yr (25). 
 
 Mount Emmons 
 
 The Mount Emmons deposit is in the Elk Mountain min- 
 ing district, Gunnison County, with coordinates of N38° 
 52'08" latitude and W107° 02'19" longitude. The mineralized 
 area lies just inside the western edge of the Colorado mineral 
 belt, at the juncture of the northwestern border of the belt 
 and the estern edge of the Elk Mountains. Molybdenum 
 mineralization also occurs in a breccia complex that outcrops 
 in the Redwell Basin glacial cirque. Within the basin, pro- 
 truding outcrops of a mineralized breccia pipe stand about 
 33 m above the basin floor. 
 
 Three major zones of mineralized rock were identified 
 within the Redwell Basin complex: one zone containing the 
 base metals lead, zinc, and copper, and two lower zones 
 related to the rhyolite and granite porphyry stockworks (28). 
 The major minerals in the stockworks are molybdenite and 
 cassiterite. Molybdenite occurrences vary from composite 
 veinlets of quartz-molybdenite-pyrite to quartz-molybdenite, 
 to monomineralic molybdenite veinlets as well as 
 disseminated rosettes. Huebnerite generally occurs in veinlets 
 with pyrite and in some places with quartz. Where pyrite- 
 huebnerite veinlets occur with molybdenite-bearing veinlets, 
 the former always cut the latter. 
 
 The Mount Emmons molybdenum deposit is about 366 
 m below the surface in the south slope of Mount Emmons. 
 The ore body forms a series of inverted cuplike shells posi- 
 tioned above the intrusive body. The mineralized shells form 
 concentric patterns with a diameter of about 702 m and an 
 average thickness of about 91 m. 
 
 Early mining in the area was for lead-silver-copper ores. 
 The Keystone Mine produced these metals for many years 
 until it was shut down in 1959. The Climax Molybdenum Co. 
 began exploring the area for molybdenum in 1974, and a drill- 
 ing program was started in 1975. 
 
 The size of the ore body was first published in 1977 at 
 81.7 million mt ore. The current recoverable resource is now 
 
 estimated at 132.4 million mt with an average grade of 0.258 
 pet Mo (25) at a cutoff grade of 0.12 pet Mo. 
 
 Mount Emmons is a well-explored deposit, but develop- 
 ment seems still very remote. Aside from the substantial 
 capital investment requirements, environmental problems 
 facing the project present a major obstacle. The major areas 
 of concern are land disturbance (subsidence), flora and fauna 
 disturbance, air and water quality, esthetic qualities, and 
 sound pollution. In addition, the residents of nearby Crested 
 Butte firercely oppose the development. On February 4, 1984, 
 Amax Inc. announced an indefinite delay of the project (29). 
 
 New Mexico 
 
 Questa 
 
 The Questa Mine is situated in the Red River mining 
 district of New Mexico, with a latitude of N36°41'50" and a 
 longitude of W105°29'31". 
 
 The Questa deposit lies on the west side of the Taos 
 Range, a part of the Sangre de Cristo Mountains. The range 
 is underlain by Precambrian rocks and a Tertiary complex 
 (Miocene) of volcanics and intrusives. The granites were the 
 first instrusions into the Precambrian rocks and were fol- 
 lowed by an andesite flow overlying the granite. The 
 andesites are capped by a sequence of rhyolite prophyries, 
 tuff, and tuff breccias. Quartz porphyry plugs, consisting of 
 quartz monzonites and granites, intruded the Precambrian 
 rocks. The Tertiary intrusives and volcanics are considered 
 to be the sources of mineralization that occurs principally 
 along the flat-lying contact between the andesite and granite 
 and extends both above and below these contacts. The 
 mineralization is characterized by fracture filling ranging in 
 size from hairline cracks to fissures 0.6 m wide and contain- 
 ing mostly quartz, pyrite, and molybdenite, with conspicuous 
 amounts of fluorite, biotite, and calcite. 
 
 The property was first located in 1916. In 1920 
 Molybdenum Corporation of America (Molycorp) acquired the 
 property and started production. The mine shut down in 1921 
 owing to weak molybdenum demand. Mining resumed in 1923 
 at a rate of 45 mt/d from an underground operation and con- 
 tinued until 1956. All production was from high-grade fissure 
 veins. The deposit, selectively mined, provided an average 
 mill feed of about 2.4 pet Mo (30). 
 
 Under contract with the Defense Mineral Exploration 
 Association, exploration work was undertaken from 1957 to 
 1960 to determine the feasibility of establishing low-grade 
 surface mining. After the contract expired, Molycorp con- 
 tinued the exploration work. In 1964, sufficient reserves had 
 been blocked out to justify a 9,070 mt/d operation. A high 
 stripping ratio forced the decision to phase out surface min- 
 ing operations in 1985, the same year that the newly 
 discovered ore body (Goat Hill) is planned to be fully opera- 
 tional. The Goat Hill ore body is to be mined by an 
 underground block-caving method. At the present in situ 
 reserve of 1 13 million mt, the mines have a life of 20 yr, at 
 an annual capacity of 6 million mt ore (30)). 
 
 Idaho 
 
 Thompson Creek 
 
 The Thompson Creek Mine is in a metasomatized quartz 
 monzonite core of the Thompson Creek granodiorite stock. 
 It is located in the Bay Horse mining district of central Idaho 
 (Custer County) between Thompson and Bruno Creeks at an 
 
25 
 
 elevation of 1.890 to 2,680 m. In the mineralized zone are 
 a large number of coarse-grained, quartz biotite, feldspar- 
 muscovite veins and veinlets containing the majority of the 
 molybdenum mineralization. Molybdenite is the sole ore 
 mineral with a gangue of quartz, biotite. muscovite, or- 
 thoclase. microcline. sericite. and pyrite. The molybdenite is 
 found as veinlets. stringers, and disseminations in the altered 
 zone. Most of the ore mineralization occurs in quartz-rich 
 veins. Some tungsten is present, but there are no plans for 
 its recovery (SI). 
 
 The deposit was discovered in 1967 by Cyprus Explora- 
 tion Co. An open pit mine. Thompson Creek began produc- 
 tion in 1983. At full capacity, the mine will have an annual 
 production of about 8.051.400 mt ore, containing about 18 
 million lb Mo (recoverable). At this capacity, the 175.1 million 
 mt ore will last for about 22 yr (38). 
 
 White Cloud (Boulder Creek) 
 
 The property is in the Little Boulder Creek mining 
 district of central Idaho (Custer County). The deposit is within 
 the Sawtooth National Recreation Area in the headwaters 
 of Little Boulder Creek. The elevation of the deposit ranges 
 from 2,600 m to 2.850 m along the southeastern margin of 
 White Cloud Peak. 
 
 The White Cloud deposit is a molybdenum stockwork con- 
 taining molybdenum-rich quartz veinlets in a more intense- 
 ly fractured zone where mineralization is confined. Minor 
 amounts of mineralization are disseminated throughout the 
 remainder of the rocks (33). 
 
 The grade of mineralization is relatively uniform on the 
 surface and at depth. The grade decreases away from the 
 intrusive. Molybdenite is the sole ore mineral, with quartz, 
 feldspar, diopside. calcite, hornblende, garnet, epidote, 
 chlorite, biotite, pyrite, and arsenopyrite as gangue minerals. 
 Scheelite is found throughout the deposit, but in amounts too 
 small to consider economically recoverable (33). 
 
 White Cloud Peak is an area of great scenic beauty, so 
 that any mining-related activity met strong public opposition. 
 This public opposition led to the creation of the Sawtooth Na- 
 tional Recreation Area, which imposes severe restrictions on 
 mining activities. Mine development of this property seems 
 a very remote possibility. 
 
 Available resource data on the deposit are limited and 
 conflicting. Tonnage estimates range from 90 million to 229 
 million mt. 
 
 Montana 
 
 Big Ben 
 
 The Big Ben deposit lies in the Little Belt Mountains on the 
 north slope of Poverty Ridge in Cascade County. The deposit 
 is covered mostly by unpatented claims in the Lewis and 
 Clark National Forest. The explored deposit is located at 
 N46°5751" latitude and W110°42'43" longitude. 
 
 The Big Ben deposit is a stockwork molybdenum deposit 
 emplaced near the contact of an Eocene hypabyssal alkali 
 granite stock within a Precambrian basement of gneiss and 
 schist (3U). The stock is composed of four crudely zoned 
 phases, which formed the cupola of an early Tertiary 
 batholith. Emplacement of the batholith as laccolithic intru- 
 sions has uplifted the Little Belt Mountains to form a broad 
 east-west anticlinal arch (55). It is localized along a 130- to 
 170-m-wide. east-northeast trending shear near the southern 
 contact of granite porphyry. The shear dips about 50° south 
 
 and defines a segment of a major fault. Higher grade por- 
 tions of the deposit appear to result from overlapping of 
 several mineralizing phases (Si). 
 
 Molybdenum mineralization occurs as molybdenite in and 
 along the walls of numerous intersecting quartz veinlets. The 
 most prominent quartz-filled fractures trend north 20° to 80° 
 east and dip steeply north and south. Higher grade 
 mineralization is associated with stronger silicification. Minor 
 chalcopyrite, galena, sphalerite, and fluorite are found in open 
 crystal cavities. Principal gangue minerals are finely 
 disseminated pyrite and quartz (36). 
 
 The deposit was staked between 1922 and 1940 and ex- 
 plored by two adits (37). In 1942, the Bureau of Mines and 
 the U.S. Geological Survey made preliminary examinations 
 of the property as part of the governments strategic minerals 
 investigation program, to locate emergency sources of open- 
 pit molybdenum. The following year, the Bureau completed 
 four diamond drill holes totaling 422 m in depth. In addition, 
 the Bureau channel-sampled the underground workings and 
 performed metallurgical testing of the samples. 
 
 The resource used in this availability study for the pro- 
 posed mine was 107 million mt. The deposit would be mined 
 by open-pit methods at a rate of 15,286 mt/d ore and 41,272 
 mt/d waste for a life of 20 yr. 
 
 Nevada 
 
 Tonopah (Hall) 
 
 The Tonopah molybdenum mine is located in the San An- 
 tone mining district (Nye County) on lands administered by 
 the Bureau of Land Management. The deposit is situated at 
 approximately N38°19'23" latitude and W117°17'31" 
 longitude. 
 
 The locus of mineralization of the Tonopah deposit is the 
 contact area between the intrusive quartz monzonite stock 
 and the intruded rocks consisting of sericitic quartzite, quartz 
 mica schist, limestone, and tuffaceous limestone. Many nar- 
 row veins characterize the contact zone, which constitutes 
 about 30 pet of the rock volume. Sulfides associated with vein- 
 ing are concentrically zoned. Molybdenite mineralization is 
 found in relative abundance, in a ring-shaped band of 
 chalcopyrite farther from the stock; sphalerite and minor 
 galena occur at the fringes of the sulfide depositions (38). 
 
 In plan view, the ore body is ring shaped with a radius 
 of 635 m from the center of the stock to the center of the 
 molybdenum zone. It has an approximate thickness of 103 
 m. Sulfide mineralization diminishes outward from the zone 
 for a distance of 660 m or 1,295 m from the center of the 
 stock (38). 
 
 The pipelike stock is separated vertically into three zones. 
 The upper and the middle zones are exposed in the west and 
 central portion but are covered in the east by a series of 
 volcanic rocks. The upper zone ranges in depth from m on 
 the west to 240 m on the east. One oxidized zone, made up 
 of copper minerals in quartz monzonite, constitutes the cop- 
 per ore body. The upper zone must be stripped before the 
 molybdenum ore body can be mined. The middle zone, lying 
 immediately below the upper zone, is unoxidized and com- 
 posed of chalcocite and molybdenite in quartz monzonite; it 
 constitutes the main molybdenum ore body. The lower zone 
 
 unrated from the middle zone by 120 m of barren rock. 
 Approximately 90 m thick, the lower zone contains 
 molybdenite in quartz monzonite. 
 
 The San Antone district was discovered in 1 Xfi.'i, and 
 there had been intermittent production of silver, lead, and 
 
26 
 
 gold until 1920 (39) when mining ceased. Since then, several 
 companies prospected, explored, and sampled the area, in- 
 cluding the Bureau of Mines. Anaconda, which has been ex- 
 ploring the area intermittently for 25 yr, acquired the pro- 
 perty in 1955 (40)). Serious exploration began in 1975 when 
 three drilling rigs completed 91,440 m of core from approx- 
 imately 300 holes. Current resources stand at 150 million mt 
 with an average grade of 0.096 pet Mo. At full mining capaci- 
 ty of 7 million mt/yr, the deposit will have a productive life 
 of about 22 yr (41). 
 
 Buckingham 
 
 The Buckingham molybdenum deposit lies in the copper 
 basin area in the northeastern part of the Battle Mountain 
 mining district, Lander County, at an average elevation of 
 1,770 m. The deposit is located in an area of mixed private 
 and Bureau of Land Management (BLM) administered lands, 
 at an approximate latitude of N40°36'56" and longitude of 
 W117°03'42". 
 
 The Buckingham deposit is a calc-alkaline, molybdenum 
 stockwork porphyry system with potential credits in silver, 
 gold, tungsten, and copper. Molybdenite was deposited in 
 quartz veins and as fracture coatings. Copper and tungsten 
 appear to form a halo near the outer 0.05 pet MoS 2 and 0.10 
 pet MoS 2 rock boundaries, respectively. Chalcopyrite occurs 
 in quartz and quartz-molybdenite veins, while the tungsten 
 occurs predominantly in pyrite veins and as fractures which 
 cut molybdenite mineralization. 
 
 No reserve-resource data have been published on the 
 Buckingham deposits. Using available data and economic 
 criteria, a resource tonnage of 217 million mt was calculated 
 as a part of this availability evaluation. At a mining capacity 
 of 20,000 mt/d ore, the mine would have a life of about 31 yr. 
 
 B&C Springs 
 
 The B&C Springs deposit is in the Paradise Peak min- 
 ing district, Nye County. It is situated on lands administered 
 by both the BLM and the U.S. Forest Service. The deposit 
 has a latitude of N38°46'50" and longitude of W117°48'06". 
 
 The deposit was first detected by an airborne 
 magnetometer and induced polarization surveys, flow in 1968. 
 A diamond drilling program in the area was initiated in 1969, 
 when a nearly horizontal ore zone containing 0.030 to 0.075 
 pet Mo was confirmed. 
 
 The irregular ore bodies are interlayered and interbedded 
 and appear concentrated within fractured carbonates. 
 Molybdenite and chalcopyrite are the major ore minerals. The 
 accessory sulfide minerals are pyrite, tetrahedrite, sphalerite, 
 and covellite. The gangue minerals are predominantly calcite, 
 dolomite, quartz and some magnetite. 
 
 Proposed mining and beneficiation proposals are based 
 on 33,641,000 mt of demonstrated resources. At the proposed 
 production rate of 6,282 mt/d, which include 943 mt of dilu- 
 tion, the deposit will have a mine life of about 18 yr. 
 
 Mount Hope 
 
 The Mount Hope molybdenum deposit is located on the 
 southeast side of Mount Hope in Eureka County, in T22N, 
 R21 and 52E. The deposit lies between the southern ends 
 of the Roberts Mountains and the Sulphur Spring Range. 
 
 Except for a few patented claims in the central part of 
 the deposit, both surface and mineral rights of the property 
 are managed by the Bureau of Land Management. Exxon 
 
 Mineral Co., which has a lease-option on the patented claims, 
 applied to purchase about 10,000 acres of Federal land in the 
 general area to construct and operate the mine and process- 
 ing plants. 
 
 The Mount Hope area was discovered in 1870 and opened 
 in 1886 for lead and zinc. Other compaines worked the area 
 including Universal Exploration Co., which operated the mine 
 for lead, cadmium, and silver from 1943 to 1947. Exxon began 
 exploring the area for copper in 1978; however, in 1981, Ex- 
 xon declared the area had potential for molybdenum instead 
 of copper. 
 
 Initial results of exploration indicated an inferred reserve 
 of 408.2 million mt with a grade of 0.078 to 0.192 pet Mo (42). 
 
 If the inferred resource is brought to the demonstrated 
 level in the future, Exxon proposes to mine the deposit by 
 open-pit method at a daily capacity of 27,210 mt ore and about 
 68,000 mt waste. Based on this capacity, the deposit is 
 estimated to have a minimum productive life of 41 yr. The 
 capital investment to develop the deposit was estimated in 
 1983 at $600 million (43). 
 
 Washington 
 
 Mount Tolman 
 
 The Mount Tolman deposit lies on the Colville Indian 
 Reservation, Ferry County. This explored deposit is located 
 at N48°03'20" latitude and W118°43'35" longtitude in north- 
 central Washington. The topography is mountainous with 
 moderate to steep slopes, with elevation rising from 390 m 
 at the San Poil arm of Lake Roosevelt to 1,080 m at Mount 
 Tolman, 2 km to the west. 
 
 Mount Tolman is a hydrothermal quartz stockwork 
 copper-molybdenum deposit. Ore occurs mostly within a 
 610-m-thick, intense quartz stockwork zone in the Mount 
 Tolman granodiorite phase of the pluton. Post-ore dikes form 
 an interval of waste and increase in density to the east, even- 
 tually eliminating ore (4-4). 
 
 The mineralized zone is steep-faulted down to the east 
 and north by a series of northeast-and northwest-trending 
 normal fault systems. Primary ore minerals are molybdenite 
 and chalcopyrite. Molybdenite occurs in quartz fracture fill- 
 ings and less commonly in replacement veins of quartz sericite 
 and pyrite. Chalcopyrite and some galena and sphalerite oc- 
 cur as discrete grains scattered irregularly within the replace- 
 ment veins of quartz sericite and pyrite. Associated magnetite 
 is also present (.4.4). 
 
 The deposit is approximately 1.6 km wide, 3.2 km long, 
 and 370 m thick, with a central zone containing greater than 
 0.12 pet MoS 2 (U). 
 
 No production has been recorded from the numerous 
 small prospects located near Mount Tolman. In 1953, Bear 
 Creek Mining Co., an exploration subsidiary of Kennecott 
 Copper Co., began examining the area in detail. In 1964, a 
 permit from Colville Tribes was acquired to explore and 
 evaluate approximately 20,000 acres. Upon expiration of the 
 exploration permit, no new lease was signed. In the spring 
 of 1978, the Tribal Business Council solicited competitive bids 
 from interested mining companies. Amax Inc. was selected 
 and a 3-yr exploration agreement was signed on August 8, 
 1978. 
 
 Based on the 91,140 m of diamond drilling, the prospect 
 has an estimated resource of 900 million mt ore, with a grade 
 of 0.09 pet Cu and 0.06 pet Mo using a cutoff grade of 0.05 
 pet Mo (45). In 1982, Amax Inc. abandoned the property (46). 
 
27 
 
 CANADA 
 British Columbia 
 
 Endako 
 
 The Endako Mine, the largest primary molybdenum pro- 
 ducer in Canada, is located in central British Columbia at a 
 latitude of N54°02'00" and a longitude of W125°07'00". The 
 crest of the open-pit mine has an elevation of 1,070 m. 
 
 The Endako deposit is within the interior system of the 
 Canadian Cordillera in the Nechako Plateau (47). The deposit 
 occurs in the Endako Quartz Monzonite, which is one of the 
 rock types of the Composite Topley Intrusion that are in- 
 truded into late Paleozoic and early Mesozoic sedimentary 
 and volcanic rocks. 
 
 The ore body is an elongated elliptical stockwork measur- 
 ing 3,360 m long and 370 m wide. The east half of the ore 
 body, where the open pit has been developed, has a depth 
 of 3*70 m over a length of 1,830 m. The west half of the ore 
 body attains a maximum depth of 150 m, adjacent to the West 
 Basalt Fault. It is characterized by intense fracturing and 
 veining. 
 
 The most abundant primary minerals are molybdenite, 
 pyrite, and magnetite with minor amounts of chalcopyrite 
 and traces of bornite, bismuthinite, scheelite, and specularite. 
 Ore minerals occur in two types of veins: in large quartz- 
 molybdenite veins and in fine fracture fillings and veinlets 
 in the form of a stockwork. 
 
 The molybdenite deposit was discovered and staked in 
 1927, but exploration w r ork was sporadic until 1962 when a 
 diamond drilling program was initiated by R and P Metals 
 Corp. Ltd. Endako Mines was incorporated in October 1962, 
 at the same time when Canadian Exploration Ltd. (a sub- 
 sidiary of Placer Development Ltd.) entered into an explora- 
 tion agreement. Following a positive evaluation, as a result 
 of the diamond drilling program and underground sampling, 
 a decision to develop the property was announced in March 
 1964 (47). The present demonstrated resources are estimated 
 at 195 million mt ore. 
 
 The open pit operation has an annual production of about 
 10,320,000 mt ore. The ore is processed in a standard crush- 
 grind-float concentrator. The final concentrate is transfer- 
 red to the roasting facility located adjacent to the mill for 
 conversion to Mo0 3 . 
 
 Boss Mountain 
 
 The molybdenum deposit is near the headwaters of 
 Molybdenum Creek on the northeast slope of Takomkane 
 Mountain. The deposit is north-northeast of Vancouver, BC, 
 with location coordinates of X52°06'00" latitude and 
 \V120'56'00' longitude (: t H). 
 
 The Boss Mountain deposit is part of the Quesnel Trough 
 containing breccia pipe bodies about 335 m in depth, 60 to 
 120 m in length, and 9 to 30 m in width. Molybdenite-rich 
 quartz veins surround the upper breccias. 
 
 Molybdenite mineralization occurs in three different 
 forms: U) as disseminated fine grain mineralization within 
 the quartz matrix of the breccia pipes, (2) as coarse-or fine- 
 grained layers in quartz stringers, and (3) as a fine-grained 
 film or paint along fractures, joints, and shear planes. 
 
 Molybdenite was first discovered on Takomkane Moun- 
 tain in 1917. and in the fall of that year several hundred 
 kilograms of molybdenite ore were shipped to Ottawa. In 
 1930, several hand trenches were excavated on one of the 
 
 larger quartz-molybdenite veins and on a molybdenite-bearing 
 breccia. Sporadic exploration work was done in the area un- 
 til 1955 when the claims were acquired by H.H. Heustis. In 
 1956, Climax Molybdenum Co. Ltd. optioned the claims and 
 completed over 1,000 m of diamond drilling before ter- 
 minating the option in 1960. 
 
 Noranda optioned the property in 1961. After 4 yr of ex- 
 ploration and development work, production was started in 
 1965 at a mill rate of 900 mt/d. Production continued until 
 1972, when the mine was closed because of the depressed 
 molybdenum market. The mine was reopened in early 1974. 
 
 The ore deposit has been mined by both underground 
 open stope and open-pit operations. The current remaining 
 demonstrated reserve is calculated at 4.9 million mt ore. With 
 a production rate of 1,832 mt/d from underground and 1,466 
 mt/d from open-pit operations, the current reserve will main- 
 tain a productive life of about 6 yr (4.9). 
 
 Ores from the mine are treated in a single-product flota- 
 tion concentrator. Molybdenite concentrate is the final 
 marketable product. The concentrate is packaged and 
 transported to Vancouver. 
 
 Kitsault 
 
 The Kitsault molybdenum deposit is located in northern 
 British Columbia, near the Alaskan border. The mine is 
 located 7 km southeast of the town of Kitsault with location 
 coordinates of N55°25'00" latitude and W129°25'00" 
 longitude. The deposit lies within the rugged mountain cost 
 ranges, with an elevation of about 610 m. 
 
 The Kitsault deposit is an intrusive complex composed 
 of at least five separate stocks and related dikes. The first 
 three intrusives were essentially barren of sulfide mineraliza- 
 tion. The last two intrusives were composed of more differen- 
 tiated magmas and supplied the source for molybdenite and 
 other sulfides (50). 
 
 The Kitsault property was first placed into production 
 by British Columbia Molybdenum Ltd. a subsidiary of Ken- 
 necott Copper Corp., in the late 1967. The open pit and mill 
 were designed to operate at a rate of 5, 440 mt/d. The opera- 
 tion was shut down in mid-1972 because of a depressed 
 market. 
 
 AMAX Inc. purchased the Kitsault property from Ken- 
 necott in late 1972 and reopened the mine at an expanded 
 capacity. Reconstruction started in May 1979 and produc- 
 tion in January 1982. Due to market conditions, the mine 
 again was closed in October 1982 and remains closed 
 indefinitely. 
 
 The Kitsault deposit was mined by an open pit operation 
 with a design capacity of 10,886 mt/d ore. The overall strip- 
 ping ratio is 1.86 to 1.00. The current demonstrated resource 
 is estimated at 104.3 million mt (25). 
 
 Ore from the mine was processed in the Kitsault concen- 
 trator by crushing, grinding, and single-product flotation. 
 Molybdenite concentrate was packaged and transported to 
 Vancouver, BC. 
 
 Glacier Gulch 
 
 The Glacier Gulch molybdenum deposit is located on the 
 east flank of Hudson Bay Mountain, a glaciated pile of 
 Mesozoic rocks near Smithers, BC. The deposit coordinates 
 are N54°49'00" latitude and W127°18'00" longitude, with an 
 exploration adit driven at an elevation of about 1,066 m. 
 
 The oldest and most widespread lithologic unit exposed 
 on the Hudson Bay Mountain is the Hazelton Group, 
 
28 
 
 characterized by a thick sequence of poorly layered volcanic 
 and sedimentary rock of Jurassic age. In the mineralized area, 
 only volcanic members of the Hazelton Group are present (51). 
 
 The occurrence of numerous small concentric mineral 
 zones is the main geologic feature of Hudson Bay Mountain. 
 The Central zone is defined by the Glacier Gulch Mo-W-Cu 
 mineralization. Molybdenite mineralization is confined in frac- 
 ture veins and veinlets, except for minor disseminated oc- 
 currences in the quartz-monzonite stock immediately beneath 
 a rhyolite plug (51). 
 
 William Yorke-Hardy and Associates first staked several 
 claims over some of the molybdenite-bearing veins in Glacier 
 Gulch in 1956. Later the claims were optioned and explored 
 by various groups within AMAX Inc. In 1971, Climax 
 Molybdenum Corp. Ltd. (an AMAX Inc. subsidiary) pur- 
 chased the property. An exploration program consisting of 
 3,000 m drifting and 53,900 m of core drilling has defined 
 a deposit that could become an economic source of 
 molybdenum in the future. The delineated resource is 
 estimated at 18 million mt grading 0.21 pet Mo. 
 
 Ajax 
 
 The Ajax deposit is located in the Skeena mining district 
 in British Columbia. The claims lie approximately 13 km 
 northeast of Alice Arm with location coordinates of 
 N55°35'00" and W129°24'00". 
 
 The eastern flank of an anticlined structure is the locus 
 of a belt of small intrusive bodies of Tertiary age, which are 
 composed of quartz monzonite porphyry, quartz-diorite por- 
 phyry, granodiorite, and associated intrusive rock types with 
 which molybdenite is associated (51). The surface exposures 
 of these intrusives show an elliptical shape measuring approx- 
 imately 915 by 762 m, with the long axis oriented to the 
 northwest. 
 
 Molybdenite mineralization is associated with secondary 
 quartz and occurs in quartz veinlets in hair line fractures, 
 as stringy lenses with pyrrhotite, or as coatings along frac- 
 ture surfaces. Minor amounts of molybdenite are also found 
 in disseminated form associated with interlocking quartz and 
 pyrorhtite within the highly siliceous and sericitized section 
 of the porphyry. The majority of the molybdenite is found 
 within the fine quartz veins with molybdenite concentrated 
 along contact boundaries of the veinlets (52). 
 
 Properties peripheral to the molybdenite zone were first 
 prospected for lead-zinc-silver in the early part of the cen- 
 tury. The presence of molybdenite mineralization reported 
 in the 1927 Minister of Mines' Annual Report, prompted S.J. 
 Barclay in 1965 to locate property for Newmont Mines Ltd. 
 Drilling and underground exploration work done between 
 1965 and 1967 indicated that the molybdenum mineraliza- 
 tion zones are lens-like in form and extremely erratic in lateral 
 and vertical extent. This prospect has a resource estimate 
 of 418.4 million mt using 0.036 pet Mo as a cutoff grade. 
 
 Adanac 
 
 The Adanac deposit is located within the Atlin mining 
 district in the extreme northeast portion of British Colum- 
 bia, near the head of Ruby Creek Valley. The location coor- 
 dinates are N59°42'30" and W133°24'00". The deposit lies at 
 an elevation of 1,463 m in an open alpine valley. 
 
 The deposit is situated within the northern edge of Mount 
 Leonard Boss, and is divided by the Adera Fault into a nor- 
 thern area (53). Six major and several minor rock units were 
 identified in the vicinity of the deposit. 
 
 Veins occur in all major rock types, but are most com- 
 mon in the coarse granite, crowded porphyry, and porphyritic 
 granite. The Adanac deposit is approximately 1,036 m long 
 and 550 m thick. Molybdenite mineralization extends beyound 
 these dimensions but in small amounts (54). 
 
 The discovery claims on the Adanac deposit were staked 
 by Adanac Mining and Exploration Ltd. in 1967. During 1968, 
 Adanac Mining commenced an exploration program that in- 
 cluded a geochemical survey and diamond drilling totaling 
 1,502 m from 12 holes. In 1969, a total of 11,273 m of dia- 
 mond drilling was completed from 68 holes. Kerr Addison 
 Mines Ltd. optioned the property in 1970 and carried out an 
 extensive exploration program. At the end of 1971, the ex- 
 ploration program accomplished 19,812 m of diamond drill- 
 ing, 1,219 m of rotary drilling, and 823 m of underground 
 development including bulk sampling, pilot mill tests, and a 
 full-scale feasibility study of the property. 
 
 From 1972 to 1978, exploration was again conducted on 
 the property by Adanac Mining, Noranda Mines Ltd., and 
 Climax Molybdenum Corp. (BC) Ltd. In December 1978, 
 Placer Development Ltd. and Adanac Mining and Explora- 
 tion Ltd. reached an agreement to develop the deposit. In 
 1979, Placer conducted additional exploration work. Placer 
 terminated the option agreement in January 1983, because 
 of the depressed market. 
 
 The current minable ore reserve is estimated at 201 
 million mt at an average grade of 0.059 pet Mo. The ore will 
 be mined by conventional open-pit method, with an overall 
 stripping ratio of 1.56 to 1.00 (54). 
 
 Red Bird 
 
 The Red Bird property consists of 239 claims in west- 
 central British Columbia about 160 km south of Smithers. 
 The deposit is situated on the eastern edge of the rugged 
 Coast Range Mountain, immediately outside the west boun- 
 dary of Tweede Mine Park and the Eutsuk Nature Conser- 
 vancy. The location coordinates are N53°18'00" and 
 W127°0r00". 
 
 The deposit consists of three zones which are located 
 within a peripheral ring around the main mass of a quartz 
 monzonite porphyry pluton. This pluton is roughly elliptical 
 in shape, measuring about 1,200 m north-south and 800 m 
 east-west. 
 
 The mineralized zones occur at or near the volcanic por- 
 phyry contact and peripheral to the contact. Mineralization 
 is restricted to the quartz monzonite porphyry. However, ex- 
 ceptions do occur, especially in the southwest zone, where 
 molybdenite values in excess of 0.12 pet Mo are present in 
 volcanic rocks. Quartz veining, with which the molybdenite 
 mineralization is associated, is most abundant within about 
 45 m of the volcanic-porphyry contact. The intensity of vein- 
 ing tends to decrease rapidly away from the pluton. 
 
 The claim on the property was first staked in 1959 by 
 Phelps Dodge Corp. personnel. The claim group was enlarg- 
 ed in the following years. Major exploration work on the pro- 
 perty, which included mapping, trenching, geophysical 
 surveys, and diamond drilling, was conducted from 1963 to 
 1967. During that time, 17,350 m were drilled from 70 holes. 
 
 In 1979, Craigmont Mines Ltd. optioned the property, 
 and additional exploration work was done on the deposit (56). 
 From 1979 to 1980, Craigmont completed approximately 
 14,000 m of diamond drilling from 53 holes. Craigmont drop- 
 ped the option agreement in 1981 due to the declining 
 molybdenum market. 
 
29 
 
 Although mineable resources are currently not yet fully 
 established, they are estimated at approximately 100 million 
 mt ore. This prospect would be mined using a conventional 
 open-pit method. 
 
 Mount Thomlinson 
 
 The Mount Thomlinson deposit is located 38 km northeast 
 of Hazelton. BC. with location coordinates of N55°35'00" and 
 W127°29'00'. 
 
 Molybdenum mineralization occurs along the north- 
 western contact of stock cutting argillites of the Bowser Lake 
 Group. The concentration of molybdenite and chalcopyrite 
 are found in a quartz vein system along the northwestern 
 border of the stock. 
 
 Molybdenite, pyrite. and a lesser amount of chalcopyrite 
 occur in altered, sheared, and fractured biotite granite and 
 in a tabular stockwork zone up to 100 m wide along the north- 
 west contact of the stock. The mineralized zone is characteriz- 
 ed by abundant leucogranite and felsite dikes that are 
 crosscut by the stockwork. The richest molybdenite 
 mineralization is most intimately associated with intense 
 argillitic alteration. Pyrite content commonly reaches 2 to 
 3 pet in the mineralized intervals. It is generally associated 
 with molybdenite or chalcopyrite. 
 
 Molybdenum showings in the area were originally stak- 
 ed in 1962. and in 1963 the property was optioned, mapped, 
 trenched, and sampled by Butte Lake Mining Co. Ltd. In 
 1963, the property was examined and later optioned by 
 Southwest Potash Corp., a subsidiary of AMAX Inc. The 
 following year. Southwest Potash Corp. conducted explora- 
 tion work including mapping, surveying, and drilling of 1,377 
 m from five holes. A resource of 1.8 million mt ore grading 
 0.108 pet Mo, centered in the southern end of the mineraliz- 
 ed zone, was determined. In 1965, exploration was directed 
 toward the evaluation of the northern part of the mineraliz- 
 ed zone. The option was terminated in 1965, because the 
 grade was considered too low. 
 
 The published ore resource figure for the Mount Thomlin- 
 son deposit is 40.8 million mt grading 0.07 pet Mo (57). 
 
 Trout Lake 
 
 The Trout Lake molybdenum deposit is in southeastern 
 British Columbia, about 3 km from Trout Lake Village. The 
 location coordinates for the Trout Lake deposit are 
 N50°38W and \V117°36W. The Selkirk Mountains, where 
 the deposit is located, have an elevation ranging from 700 
 to 2,700 m. 
 
 The molybdenum deposit is situated at the north end of 
 the Kootenay Arc. which is a bow-shaped formation 
 characterized by a belt of highly deformed, heterogeneous 
 sedimentary rocks. 
 
 The Trout Lake molybdenite stockwork deposit is one 
 of a series of calc-alkaline stocks located in the Kootenay- 
 Upper Arrow Lake area. Molybdenum mineralization is 
 associated with several of these calc-alkaline stocks. 
 
 Molybdenite mineralization occurs over a vertical range 
 of more than 1 .000 m in two zones: the upper, smaller "A" 
 zone, which outcrops; and the larger, irregular, vertically at- 
 tenuated "B" zone, which is up to 300 by 200 m wide as defin- 
 ed by the 0.060 pet Mo contour. Molybdenite, as fine to 
 medium flakes and rosettes accompanied by pyrite and pyr- 
 rhotite, is mainly present along the margins of veins in a 
 quartz stockwork. Occasionally, in higher grade zones (in ex- 
 cess of 0.06 pet Mo), the molybdenite is strongly disseminated 
 in microfractured intrusive bodies up to 20 m wide by 200 
 
 m long, accompanied by large veins and intense quartz 
 flooding. The major control of molybdenum grades is the loca- 
 tion of the schist intrusive contact; a lesser control is exerted 
 by premineral faults (58). 
 
 Geologic ore resources, as indicated by drilling, are cur- 
 rently estimated at 48.7 million mt grading 0.115 pet Mo, 
 within which there are several zones of higher grade material. 
 Although the ore body is open at depth, no drilling has been 
 done at the lower levels of the deposit. 
 
 The proposed mining method for the Trout Lake deposit 
 is underground blasthole open stoping with delayed cemented 
 backfill. At present, the ore body is accessed by an adit ex- 
 tending 1,372 m through waste rock and 610 m across the 
 ore body at its approximate midpoint. 
 
 MEXICO 
 Sonora 
 Cumobabi 
 
 The Cumobabi ore deposits (San Judas, Transvaal, 
 Transvaal West, and Molibdeno) lie on the southern end of 
 the great southwest U.S. Copper-Molybdenum Province in 
 La Verde mining district in the State of Sonora. The approx- 
 imate coordinates are N29°50'00" and W109°58'00". The mine 
 is situated in a rugged terrain with peaks rising 1,700 m above 
 sealevel. 
 
 About 60 pet of the Cumobabi area is covered by volcanic 
 rock. The volcanic sequence has been intruded by a body of 
 predominantly acidic nature and is sometimes covered by 
 rhyolite outflows (59). Strong tectonic activity took place 
 following the intrusion which formed the breccia ore bodies 
 (San Judas, Transvaal Breccia, Transvaal West, and 
 Molibdeno). 
 
 The San Judas ore body is 70 m wide, 300 m deep, and 
 300 m along strike. Mineralization is found in the upper level 
 of the ore body which is dome-shaped and has clearly defin- 
 ed the lower limit. 
 
 The Transvaal Breccia ore body contains high copper 
 values and some silver. This intensely fractured ore body is 
 somewhat smaller than the San Judas, measuring 200 m in 
 length, 50 m in width, and 450 m in known depth. 
 
 The Transvaal West is a contact breccia consisting of a 
 silicified, intensely fractured zone. Molybdenite mineraliza- 
 tion is essentially associated with quartz and orthoclase. 
 
 The Molibdeno Breccia resembles the Transvaal in that 
 it contains high copper values in the upper layer. The cen- 
 tral portion contains the highest molybdenum values. The 
 mineralized body has the form of an inverted cone, with the 
 base measuring 170 m by 120 m and the apex at a depth of 
 300 m. 
 
 Small-scale mining has been recorded in the Cumobabi 
 area since the late 1800's. In 1966, Minera Hermosillo S.A. 
 acquired several claims in the area and conducted diamond 
 drilling and underground exploration which continued 
 through 1970. In 1978, Minera Cumobabi S. A. de C.V. ac- 
 quired the claims including the San Judas breccia, which was 
 developed and mined (5.9). 
 
 The present composite proven ore reserves, which in- 
 cludes the extension of San Judas-Transvaal porphyry arid 
 the two Transvaal breccias, are estimated at 17.15 million 
 mt. A large inferred resource is believed to be present, but 
 sufficient drilling has not yet been conducted to accurately 
 
 hlish the total resources. 
 
 Thf- first ore body mined was the San Judas, by conven- 
 
30 
 
 tional open-pit method. The pit was designed to handle a 
 capacity of 4,300 mt of ore and waste. 
 
 Opodepe 
 
 The Opodepe deposit is about 70 km northeast of Her- 
 mosillo, the capital city of the State of Sonora. The location 
 coordinates for the deposit are N29°29'00" and W110°39'00" 
 at an elevation of approximately 1,000 m above sea level. 
 
 Mineralization of economic interest at Opodepe consists 
 mainly of molydbenite and secondary copper mineralization 
 located on the southern flanks of Creston Hill. Accessory 
 metallic minerals such as galena, sphalerite, and chalcopyrite 
 were observed, but these minor occurrences are of no 
 economic importance. Most of the molybdenum mineraliza- 
 tion occurs as fine-to coarse-grained (0.1-to 3.0-mm) crystals. 
 The main host rock is the Creston Granite, which makes up 
 the bulk ( + 70 pet) of the Creston stockwork molybdenum 
 deposit as presently known. 
 
 Over 20 pet of the mineralization is in the quartz matrix. 
 Here the molybdenite occurs in fine-grained flakes (0.05 to 
 
 1 mm), at the very contact of the quartz matrix with the brec- 
 cia fragment. The remaining molybdenite occurs as coarse- 
 ly disseminated rosettes in short zones of massive coarse- 
 grained sericite. This type of molybdenite occurrence is com- 
 monly found in Creston Granite (60). 
 
 Exploration work in the area was carried on intermit- 
 tently from the 1920's until 1959, when Cia Minera Penoles 
 blanketed the area with mining claims. Several other com- 
 panies conducted exploration work in same area, but later 
 withdrew. In 1974, AMAX Inc. decided to negotiate an ex- 
 ploration contract and initiated an exploration program which 
 included geological mapping and geochemistry, followed by 
 diamond drilling. A total of 40 holes were drilled between 
 1974 and 1979. Cia Minera Fresnillo S.A. de C.V. assumed 
 management of the property in 1981. 
 
 An indicated geologic resource was estimated at 180 
 million mt grading 0.09 pet Mo. Owing to limited explora- 
 tion work, the full potential of the deposit is not yet deter- 
 mined. The property can probably be mined as a conventional 
 open-pit operation. 
 
 

 
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