OF-75-04 Mineral Resources and Mining Potential in the Idaho Springs Vicinity, Clear Creek County, Colorado


Two plates depicting the mineral resources and mining potential in the Idaho Springs Vicinity, Clear Creek County. Includes descriptive text and two plates: 1) Metallic Resources and Mines and 2) Gravel Resources. 9 pages. 2 plates (1:12,000 and 1:6,000). Digital PDF download. OF-75-04D.

The purpose of this report is to identify mineral resource areas near Idaho Springs for possible designation as matters of state interest under the provisions of HB 1041. This text and maps, prepared for the City of Idaho Springs at the request of Bruce Bartlett, will describe 1) the general geology and mining history of the district, 2) character and occurrence of ore deposits (metals and nonmetals), and 3) possible hazards associate with mining. In addition, a list of published articles and reports dealing with the district’s geology, mining, and mineral resources is included.

The Idaho Springs mining district is located approximately 30 miles west of Denver in northern Clear Creek and southern Gilpin Counties. Elevations in the area range from 7,600 ft along Clear Creek to 9,935 ft on Pewabic Mountain. The district is traversed by U.S. 6 and 40 and Interstate 70 from Denver, and Colorado Routes 103 and 279. The rugged topography of the district is drained by Clear Creek, which has as its principal tributaries Chicago Creek from the southwest, Soda Creek from the south, Hukill Gulch and Virginia Gulch from the north, and Fall River and Trail Creek from the west. Other mining districts that border the Idaho Springs district include the Central City district to the north, Chicago Creek district to the southwest, and the Freeland-Lamartine and Lawson-Dumont-Fall River districts to the west.

The geology of this area was examined as early as 1873 (Stevenson, 1875), but during the late 1800’s, only brief descriptions of mineral occurrences, processing, and specific mining operations were published in various mining and engineering journals. The U.S. Geological Survey published its first formal report on the area in 1906 (Spurr and Garrey); more detailed reports appeared in 1908 and 1917. Other USGS publications dealing with the ore deposits, petrology, and structure appeared in the 1950’s and 1960’s.