Latitude & Longitude (WGS84):	35° 28' 43'' North , 115° 31' 56'' West
Latitude & Longitude (decimal):	35.47861,-115.53222
GeoHash:	G#: 9qmcg48jb
USGS MRDS Record:	10212814
Locality type:	Mine
Köppen climate type:	BWh : Hot deserts climate
Nearest Settlements:	Place Population Distance Sandy Valley 2,051 (2011) 38.7km Goodsprings 229 (2011) 40.3km

A baryte-Ce-REE-Au-Ag-Pb deposit/mine located in secs. 12 & 13, T16N, R13E, SBM, 1.5 km (0.9 mile) NE of Mountain Pass (town), immediately N of Interstate highway 15, and about 15 miles W of the Nevada state line, on private (patented) land. It was discovered in 1949. The property is comprised of 6 claims. First production occurred in 1951. The USGS MRDS database stated accuracy for this locality is 10 meters.

Owned & operated by the Molybdenum Corporation of America (MCA)
(100%) (1950-1974); Owned & operated by Molycorp, Inc. (100%) (same company - new name) (1974-1977); owned by the Union Oil of California
(100%) (1977); Operated by Molycorp, Inc. (100%) (1977-2005); Owned & operated by Molycorp Minerals LLC (100%), Englewood, Colorado (1983).

NOTE: The mine ceased active mining in 2002 due to environmental concerns, however the owners, Molycorp Inc., have indicated they plan to return to full production in 2011. Start-up mining activities began in August 2012. In June 2015, however, Molycorp filed for bankruptcy.

Mineral occurrence model information: Model code: 24; USGS model code 10; Deposit model name: Carbonatite. Mineralization involves vein baryte deposits with rare-earth minerals in metamorphic and igneous rocks of Precambrian age. One of the worlds largest lanthanide deposits. There are strong environmental concerns as this mine is situated next to the Mojave National Preserve.

The carbonatite complex (1.4 BP intrusion) is intruded in Precambrian biotite-garnet-sillimanite-hornblende gneisses, biotite granitic gneisses, augen granitic gneisses (Neoproterozoic gneisses) and schists. The carbonatite complex is composed of eight 100 to 2000 meter-long plugs of alkaline intrusive rocks (from shonkinites and syenites to carbonatites) and about 200 dikes of carbonatite in NW-trending rows.

The ore body strikes N10W and dips 40W at a thickness of 75 meters, a depth-to-top of 458 meters (?? - depth-to-bottom ??), a width of 1,590 meters, a length of 750 meters and an area of 1500 HA. Ore body No. 1 is tabular; No. 2 is a fissure vein and No. 3 is a shear zone. The primary mode of origin was magmatic differentiation and the secondary mode was hydrothermal activity. Primary ore control was igneous and the secondary control was fracturing. Wallrock alteration is slight (silicification and carbonitization). Alteration also includes fenitization and hematization. The vein occurs at the contact of a dike and host rock and has an aplite dike hanging wall abnd a gneiss footwall. The dikes trend N30W.

Analytical data results: An ore shoot 100 feet long and 12 to 15 feet thick was said to carry $9.00 (period values) Au per ton.

Analysis of the bastnäsite-(Ce) by Hoffman et al. (1971) have confirmed the presence of plutonium-244 isotope. However, Sakamoto (1974) has suggested, that the source of this exotic isotope may be extraterrestrial.

Workings include surface and underground openings comprised of an open pit with an area of 260 HA and an overall depth of 169.16 meters. Milling method employed was flotation. Water is obtained from wells 10 km E of the mine. Power is supplied by Southern California Edison Company. The access road is paved and labor is available at the site.

An estimated production rate in the 1980's was 1,285 metric tons/day, including 1,155 metric tons/day ore and 130 metric tons/day of dilution material. The production numbers are amount of REE's in the concentrate. This is not the same as the total recovered since there is some loss in processing the concentrate. True production is somewhat less, but loss in processing is not reported.

Reserves and resources: Type: in-situ (estimate year: 1989): Demonstrated: 28,123,000 metric tons of ore; indicated: 28,123,000 metric tons of ore. Total resources: 28,123,000 metric tons of ore. REE (Y group): 8.9 weight percent REE (1989).

Collecting is not allowed.

Regions containing this locality

North America Plate

Tectonic Plate

Regional Geology

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

Quaternary - Miocene 0 - 23.03 Ma ID: 3185380

Cenozoic sedimentary rocks Age: Cenozoic (0 - 23.03 Ma) Lithology: Sedimentary rocks Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Proterozoic 541 - 2500 Ma ID: 2943637

Precambrian rocks, undivided, unit 2 (Mojave Desert and Transverse Ranges) Age: Proterozoic (541 - 2500 Ma) Stratigraphic Name: Baldwin Gneiss; Essex Series; Fenner Gneiss; Johannesburg Gneiss; Kilbeck Gneiss; Mendenhall Gneiss; Waterman Gneiss Description: Conglomerate, shale, sandstone, limestone, dolomite, marble, gneiss, hornfels, and quartzite; may be Paleozoic in part Comments: Southern California. Primarily orthogneiss and paragneiss; includes granitoid rocks, migmatite, amphibolite, and quartzite. Includes some Mesozoic and Cenozoic rocks Original map source: Saucedo, G.J., Bedford, D.R., Raines, G.L., Miller, R.J., and Wentworth, C.M., 2000, GIS Data for the Geologic Map of California, California Department of Conservation, Division of Mines and Geology, CD-ROM 2000-07, scale 1:750,000. Lithology: Major:{orthogneiss}, Minor:{granitic}, Incidental:{amphibolite, quartzite, hornfels, marble, granofels, granite, syenite, intrusive carbonatite} 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. [133]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

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