Clear Creek County Colorado Gold Production |
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ALICE DISTRICT
The Alice district is about 7 miles west-northwest of Central City in north-central Clear Creek County and extends into southwest Gilpin County.
Apparently the district was abandoned for many years after the oxidized ore had been removed. The increased price of gold caused a brief revival from 1935 to 1941, during which time the upper enriched part of the sulfide zone was mined (Lovering and Goddard, 1950, p. 164). The district was largely idle from 1943 through 1959. Total gold production was at least 23,000 ounces through 1959.
The country rock of the Alice district consists mainly of schist of the Idaho Springs Formation which is interfingered with granite gneiss and Boulder Creek Granite, all of Precambrian age. A stock of quartz monzonite porphyry of Tertiary age intrudes the Precambrian rocks. The Alice mine ore body is a gold-bearing pyritic stockwork in the quartz monzonite porphyry; other mines in the district are in quartz-pyrite veins in the Precambrian rocks. The deposits were oxidized near the surface and contained 1 to 2% ounces of gold per-ton. A zone of supergene sulfide enrichment, containing 0.20 ounce of gold per ton, was found beneath the oxidized zone. The primary sulfide zone, beneath the supergene zone, contains only 0.03 ounce of gold per ton and is of too low grade to mine. Quartz and pyrite, some chalcopyrite, a little arsenopyrite, and local bismuth sulfide are the constituents of the primary ore. Sooty chalcocite and bornite are locally abundant in the supergene zone (Lovering and Goddard, 1950, p. 164-165; Bastin and Hill, 1917, p. 323-330).