Brush Creek Mine (Ante Up Mine; Lower Brush Creek Mine), Old Mountain House, Alleghany Mining District (Forest Mining District), Sierra County, California, USAi

Regional Level Types
Brush Creek Mine (Ante Up Mine; Lower Brush Creek Mine)	Mine
Old Mountain House	- not defined -
Alleghany Mining District (Forest Mining District)	Mining District
Sierra County	County
California	State
USA	Country

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A former lode Au occurrence/mine located in secs. 17, 18, 19, 20, 29 & 30, T19N, R10E, MDM, 1.4 km (0.8 mile) N of Old Mountain House (site), along Woodruff Creek, about 3¼ miles NW of Alleghany, on National Forest land. Discovered in 1849. First operated in 1868. More recently owned/operated by the Brush Creek Mining and Development Co. MRDS database stated accuracy for this location is 100 meters. The owners of this property also own 9 other Au mines in the same area. This mine was apparently idle during the periods 1875 to 1923.

Mineralization is a vein/ore shoots Au deposit (Mineral occurrence model information: Model code: 273; USGS model code: 36a; Deposit model name: Low-sulfide Au-quartz vein; Mark3 model number: 27) hosted in serpentinite, andesite, Late Permian slate and schist. The ore body is a pinch-and-swell body that strikes N and dips 53W at a thickness of 6.1 meters (20 feet). The vein is banded quartz mostly within slate and sometimes follows the serpentine contact. The serpentine is intensely altered to a carbonate-mariposite mixture, and forms the footwall in places. Post-mineralization andesite forms the hanging wall & dike, which in one place crosses the vein and intrudes the serpentine. In most places a strip of crushed slate lies between the dike and the vein. A well-marked footwall slip separates the vein quartz from the altered serpentine, near the American tunnel portal. Elsewhere the 50 foot thick altered serpentine is cut by gouge-bearing slips, against fresh serpentine which dips westward. At places quartz occurs in stringers, or banded, in altered and unaltered slate. A mile N a quartz vein strikes N20W and dips from steep to flat to W, due to surface sliding possibly, and at surface is 6 to 8 feet thick, here with as vertical dip. This vein lies between chloritic schist & serpentine to the E. 3 small bunches of high-grade ore occur. Small shoot of high-grade ore occurs where the quartz-carbonate-mariposite mix occurs. A veinlet of dense bluish quartz crossing white, coarse quartz was reported to carry much coarse Au, in the shoot on the second level. The old, lenticular quartz body was said to be extremely rich. Local rocks include ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains) and/or Tertiary pyroclastic and volcanic mudflow deposits, unit 9 (Cascade Range) and/or Paleozoic marine rocks, undivided, unit 6 (Northwestern Sierra Nevada).

Workings include surface and underground openings with an area of 42.494 HA. The original inclined shaft of 520 feet with short levels is caved. A more recent adit of 2,200 feet connects with the old shaft. These is also a 220 foot deep winze, other adits and surface workings.

Production data are found in: Averill, Charles V. (1942a).

A few thousand dollars was produced (original mine) [this seems implausible]. No other production record was found. The ore yielded $8.50 (period values) Au per ton.

More recently production had begun from the lower Brush Creek Mine site. The immediate target was approximately 9,000 tons of remnant pillars. The company had also begun a program of sampling ore blocks that are immediately accessible (21 July, 1997). The company also began a program of sampling 50,000 tons of ore blocks in the mine estimated to average 0.5 ounces per ton.

The Au in this mine has an average fineness of 811.

Mineral List

4 valid minerals.