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│_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. _b._ This figure includes only the output of the mines at Bonne Terre, Flat River, Doe Run, Mine la Motte and Fredericktown. It is computed from the report of the State Lead and Zinc Mine Inspector as to ore produced, the ore (concentrates) of the mines at Bonne Terre, Flat River and Doe Run being reckoned as yielding 60 per cent. lead. _c._ Report of State Commissioner of Mines. _d._ Report of Director of the Mint on “Production of Gold and Silver in the United States,” with allowance of 6 per cent. for loss of lead in smelting. _e._ From statistics reported by “The Mineral Industry,” reckoning the ore (concentrates) as yielding 70 per cent. lead.