By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Park County is in the mountainous central part of Colorado and includes a central broad basin, called South Park, rimmed on the east and north by the Front Range, on the west by the Mosquito Range, and on the south by an unnamed range of low hills. The county is drained by the South Platte River and its tributaries, most of which head in the Mosquito Range.
Gold is the principal mineral mined in the county, which ranks eighth in the State in gold production. Gold, silver, and other metals totaling $49,172,800 in gross value had been produced through 1959. Of this total about $36,725,000 (1,364,430 ounces) represents goldâ€”$27,305,000 in lode gold and $9,417,000 in placer gold. Most of the production has come from the northwest part of the county along the east slope of the Mosquito Range.
Placer gold was discovered in Park County in 1859; this was one of the earliest mineral discoveries in Colorado. Prospectors, some arriving by way of the Arkansas River and others arriving by way of the South Platte River, found gold in the streams of South Park and later rich lodes at the headwaters of the South Platte and its tributaries. Nearly all the lode gold has come from the Alma district, and the placer gold has come from the Fairplay, Tarryall, and the Alma districts.
The Alma district lies east of the Leadville district along the east slope of the Mosquito Range and includes the Mosquito-Buckskin, Montgomery, Horseshoe, and Alma placers.
The earliest discoveries in the Alma district appear to have been of lode deposits along the headwaters of Buckskin Gulch and the South Platte River (Henderson, 1926, p. 36-38). The Phillips lode in Buckskin Gulch was discovered in 1860, and other lodes were discovered in rapid succession soon after. The gold obtained from the lodes from 1860 to 1867 was worth about $710,000 (Henderson, 1926, p. 37, 196). After the easily disintegrated and oxidized ores near the surface were exhausted, the mines were closed because the sulfide ores at depth could not be successfully treated by amalgamation.
In the summer of 1871, silver ore was discovered on Mount Lincoln and Mount Bross, and mining activity in the district increased. Silver was the chief metal mined through 1885, and high silver production was maintained until 1892 when the price of silver began to drop. In later years production of silver fluctuated considerably. In 1873, outcrops of the London vein were discovered (Singewald and Butler, 1941, p. 36), but the London mine was not located and opened until 1875. It became the largest producer in the district and, though production fluctuated, it operated almost continuously until 1942.
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