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Lead-bearing ores are of widespread occurrence in the United States. Throughout the Rocky Mountains there are numerous districts in which the ore carries more or less lead in connection with gold and silver. For this reason, the lead mining industry is not commonly thought of as having such a concentrated character as copper mining and zinc mining. It is the fact, however, that upward of 70 per cent. of the lead produced in the United States is derived from five districts, and in the three leading districts from a comparatively small number of mines. The statistics of these for 1901 to 1904 are as follows:[2]

Production, Tons Per cent. District 1901 1902 1903 1904 1901 1902 1903 1904 Ref. Cœur d’Alene 68,953 74,739 89,880 98,240 24.3 26.3 32.5 32.5 a Southeast Mo. 46,657 56,550 59,660 59,104 16.4 19.9 21.2 19.6 b Leadville, Colo. 28,180 19,725 18,177 23,590 10.0 6.9 6.6 7.8 c Park City, Utah 28,310 36,300 36,534 30,192 10.0 12.8 13.2 10.0 d Joplin, Mo.-Kan. 24,500 22,130 20,000 23,600 8.6 7.8 7.2 7.8 i>e Total 196,600 209,444 224,251 234,726 69.3 73.7 81.0 77.7

a. The production in 1901 and 1902 is computed from direct returns from the mines, with an allowance of 6 per cent. for loss of lead in smelting. The production in 1903 and 1904 is estimated at 95 per cent. of the total lead product of Idaho.