Sidewinder Mine, Sidewinder Mountain, Rodman Mts, Belleville District, San Bernardino Co., California, USA
|Latitude & Longitude (WGS84):||34° 38' 3'' North , 117° 6' 6'' West|
|Latitude & Longitude (decimal):||34.63417,-117.10167|
A former Au-Ag-Cu-Mn occurrence/mine located in the SW¼ sec. 4, and the SE¼ sec. 5, T6N, R2W, SBM, 6.2 km (3.8 miles) WNW of Sidewinder Mountain summit (coordinates of record) (0.7 mile E of Black Mountain summit), on private land. The property is comprised of 3 patented claims. MRDS database stated accuracy for this location is 10 meters. Opened in the 1880's and worked intermittently until 1942. This was the largest gold operation in the Barstow-Victorville area.
Mineralization is a vein deposit hosted in rocks of the Galice Formation (rhyolite of the Sidewinder volcanic series, dacite and Late Jurassic quartz monzonite). The ore body is irregular in form, strikes NW and dips 35 to 45. A fault separates rhyolite and dacite on the SW from quartz monzonite porphyry on the NE. The former are part of the Sidewinder volcanic series of probable Jurassic or Triassic age. The quartz monzonite is believed to be of Late Jurassic age. A siliceous vein lies in the fault and is exposed laterally for 3,000 feet. The strike of the veins are variable according to Bowen, from N80E at surface to N80W. The veins appear to be discontinuous. In the vicinity of the Doherty shaft, the hanging wall rocks are meta-dacites and meta-felsites of the Sidewinder volcanic series, and the footwall is quartz monzonite. Both walls in the most eastern workings are hydrothermally altered felsite. Both walls are quartz monzonite in the most easterly of 3 west shafts. Local rocks include Mesozoic volcanic rocks, unit 3 (Mojave Desert, Death Valley area, and Eastern Sierra Nevada).
Local structures include a shear zone striking N80E, and dipping 64-80S, 200 feet SE of the main adit vein in quartz monzonite. It is paralleled by a normal fault which crosses the open cut N of the main adit portal.
Workings include underground openings with a length of 914.4 meters and an overall depth of 243.84 meters and comprised of 2 inclines, the Doherty and Armstrong shafts. The Doherty is 600 feet deep with 4 levels spaced at 100 foot intervals and with drifts totaling 1,000 feet, 1,300 feet, 400 feet and 300 feet, respectively. There is a SW-trending adit on the 200 foot level. The Armstrong shaft is about 800 feet deep. There are also several shallower shafts on the property. The combined length of workings totals approximately 3,000 feet. Detailed descriptions of workings can be found in Bowen (1954).
Production data are found in: Bowen (1954), and Tucker & Sampson (1931).
The ore produced in 1887 had an estimated yield of $30 (period values) Au/ton (free-milling). Cumulative production from estimates by the U.S. Bureau of Mines.
1 valid mineral.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Cretaceous - Triassic|
66 - 252.17 Ma
|Mesozoic volcanic rocks, unit 3 (Mojave Desert, Death Valley area, and Eastern Sierra Nevada)|
Age: Mesozoic (66 - 252.17 Ma)
Description: Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks.
Comments: Southeastern California and eastern Sierra Nevada. Mostly rhyolitic to dacitic ignimbrites and tuffs. Includes andesite, basalt, pyroclastic rocks, and sedimentary rocks. In part strongly metamorphosed. Continental and marine
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
Wright, L.A., et al (1953), Mines and mineral resources of San Bernardino County, California: California Journal of Mines and Geology, California Division of Mines (Report 49): 49(1-2): tabulated list No. 181, p. 57; 81.
Bowen, O.E., Jr. (1954), Geology and mineral deposits of Barstow quadrangle, San Bernardino County, California: California Division Mines Bulletin 165: 123, 131-134.
Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 114.
Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 298.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10086498 & 10140901.
U.S. Bureau of Mines, Minerals Availability System (MAS) file #0060710181.