194 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1945 



compares prices and mine production of copper, lead, and zinc during 

 the two World War periods. Despite the fact that the demand has been 

 very much larger in World War II, the output of copper and zinc has 

 been only moderately higher and that of lead substantially lower than 

 in World War I. This record can be ascribed in part to various causes 

 such as manpower and equipment shortages, the fact that the indus- 

 tries had not fully recovered from a protracted depression, and in- 

 sufficient price; but there is wide agreement that the ore-reserve 

 situation was the principal contributing cause. That depletion is well 

 advanced in these industries is an inescapable conclusion from the 

 record and the present knowledge of remaining reserves. 



Copper reserves as of 1944 have been estimated 2 at 20,000,000 short 

 tons of recoverable metal under conditions prevailing at that time. 

 Since they include some reserves available only at premium prices 

 they may be considered as a generous appraisal of commercial reserves 

 under normal conditions. Twenty-five percent of the tonnage is 

 classed as inferred. It is estimated that production could be main- 

 tained at the rate of 1,000,000 tons per year for nearly 10 years fol- 

 lowing which there would be a gradual decline to exhaustion. Sub- 

 marginal resources have been estimated at 10,000,000 tons of copper 

 contained in 1.25 billion tons of material. 



Estimated reserves of 6-cent lead 3 under prewar operating con- 

 ditions were only 5,000,000 short tons in 1944, of which only a third 

 was classed as measured and indicated. Under emergency conditions 

 the total reserve including the 6-cent lead, was estimated at only 

 6,600,000 tons. Peak war production in 1942 was 27 percent below 

 the all-time peak established in 1925. 



The quantity of zinc available at 6 cents in the reserves estimated 8 

 as of 1944 was 11,200,000 tons of recoverable metal, more than half of 

 which was in inferred ore. Under emergency prices the total reserve 

 was believed to contain nearly 17,000,000 tons. 



Production of lead and zinc may be expected to decline within a 

 few years. Zinc has been particularly affected by depletion in the 

 Tri-State district, which produced over 400,000 tons or 55 percent of 

 the total output of the country in 1926, and contributed only 200,000 

 tons or 27 percent of the total in 1943. A substantial part of the dis- 

 trict's output during the war has required premium prices, and an 

 abrupt drop is anticipated with a return to peacetime conditions after 

 the war. Without exception, all the important lead-producing dis- 

 tricts that contributed to the record output of 1925 produced con- 

 siderably less lead in 1942. 



» Cannon, Ralph S., U. S. Geological Survey, and Mosler, McHenry, U. S. Bureau of Mines. 

 * Estimates for lead and zinc by E. T. McKnight of the U. S. Geological Survey and 

 B. F. Fitzhugh, Jr., of the U. S. Bureau of Mines. 



