582 



UNITED STATES MINERAL RESOURCES 



of mining copper, lead, zinc, and gold deposits, and its pro- 

 duction is thus largely dependent on the production of these 

 metals. For this reason, the imbalance between domestic 

 production and consumption of silver is markedly increased 

 by the permanent closure of one-third of our domestic lead 

 and zinc smelters. 



Silver production could be increased by the discovery and 

 development of new silver resources. Among the better pos- 

 sibilities are several kinds of copper-silver deposits such as 

 the northern Idaho-Montana disseminated copper deposits, 

 new porphyry copper deposits, and massive copper-zinc sul- 

 fides. Increased prices would encourage development of po- 

 tential resources in low-grade disseminated silver and copper- 

 silver sandstone deposits and in copper shales, would en- 

 courage the reopening of silver-bearing native copper de- 

 posits in Michigan, and would encourage the search for man- 

 ganese-silver and other epithermal silver deposits which 

 could help fill the short-term gap. New environmentally 

 clean smelters and wet recovery methods are needed and 

 must be developed and built as quickly as possible. 



INTRODUCTION 



Silver is a critical element in our national economy, 

 and one in which our nation and the free world are 

 confronted with a long-range problem of serious 

 imbalance between consumption and new production. 

 Silver is comparatively rare in the earth's crust, 

 being the 67th element in order of natural abun- 

 dance, but minerals containing it occur in small 

 quantities widely distributed throughout the world 

 in many different types of deposits. The physical 

 properties of silver make it desirable for a wide 

 range of uses for which adequate low-cost substi- 

 tutes are very difficult to find. It is exceptionally 

 ductile and malleable, it has the highest electrical 

 and thermal conductivity of all metals, its com- 

 pounds are extremely photosensitive, and it is stable 

 in air and water except for tarnishing readily when 

 exposed to sulfur compounds. 



Silver was one of the first metals known to man, 

 and was used for ornaments and utensils made from 

 native silver as early as 3000-2500 B.C. (Ageton, 

 1970, p. 723) . It has been used as a precious metal 

 and as a monetary medium and basis of wealth for 

 more than 2,000 years. It was used extensively for 

 coinage until the late 1960's when such use was dis- 

 continued by the United States and most other 

 countries, except for commemorative coins, because 

 of the serious imbalance between consumption and 

 new production. The principal uses of silver are 

 listed in table 120. 



Annual mine production of silver in the United 

 States in recent years has been a fairly stable 32-43 

 million troy ounces of recoverable silver (Hoyt, 1971, 

 p. 1006). In 1969 almost 42 million ounces was pro- 

 duced, which was valued at more than $75 million, 

 an average price of $1.79 per troy ounce (Hoyt, 



Table 120. — Principal uses of silver 



[Data from U.S. Bur. Mines (1970, p. 1007)] 



Percentage 



Photographic materials 29 



Electrical and electronic products 22 



Sterling ware 20 



Electroplated ware 10 



Brazing wares 10 



Other, including dental and medical products, 



catalysts, bearings, and jewelry 9 



1971, p. 997). Since then the price had decreased 

 markedly, but by October 1972 had risen to $1.80 

 per troy ounce. Table 121 gives the mine production 



Table 121. — Mine production, in troy ounces, of recoverable 

 silver, 1965 and 1969, in the United States, by States 



(From U.S. Bur. Mines (1970. v, I-II, p. 1006)] 

 State 196B 1969 



Alaska 7,673 2,030 



Arizona 6,095,285 6,141,022 



California 196,787 491,927 



Colorado 2,051,105 2,598,563 



Idaho 18,456,809 18,929,697 



Kentucky 1,931 



Maine '319,718 



Michigan 457,851 1,009,022 



Missouri 299,522 1,442,090 



Montana 5,207,031 3,429,314 



Nevada 507,113 884,155 



New Mexico 287,472 465,591 



New York 11,441 31,755 



Oklahoma '358,477 C) 



Oregon 8,801 4,749 



Pennsylvania (') (') 



South Dakota 128,971 124,497 



Tennessee 94,142 78,614 



Utah 5,635,570 5,953,567 



Washington O C) 



Wyoming 52 (') 



Total 39,806,033 41,906,311 



1 Production of Maine, Oklahoma, Pennsylvania, Washington, and 

 Wyoming combined to avoid disclosing individual company-confidential 

 data. 



- Production of Oklahoma, Pennsylvania, and Washington combined to 

 avoid disclosing individual company-confidential data. 



of recoverable silver for 1969 in the United States. 

 By far the most important silver-producing State is 

 Idaho — mostly from the Coeur d'Alene district — 

 followed by Arizona, Utah, Montana, Colorado, then 

 by the two midwestem States of Missouri and Michi- 

 gan which have markedly increased their production. 

 Michigan and Missouri now produce more silver per 

 year than several western "silver" States such as 

 Nevada, New Mexico, South Dakota, and California. 

 Idaho production for 1972 was seriously reduced as 

 a result of the May 1972 fire in the Sunshine mine. 



The world production of silver in 1969 is given in 

 table 122. The largest producers of silver were 

 Mexico, mostly from epithennal veins and replace- 

 ment deposits, and Canada, where the probable larg- 

 est single source of silver is the Kidd Creek massive 

 sulfide zinc-copper-silver mine at Timmins, Ontario, 

 which has produced between 12 and 14 million troy 

 ounces per year since 1968. 



