Eagle Mountain Mine (Eagle Mountain Iron Mine; Eagle Mountain Iron deposit; Kaiser Steel Corp.), Eagle Mountain, Eagle Mountains Mining District (Monte Negro Mining District), Eagle Mountains, Riverside County, California, USAi

Regional Level Types
Eagle Mountain Mine (Eagle Mountain Iron Mine; Eagle Mountain Iron deposit; Kaiser Steel Corp.)	Mine
Eagle Mountain	Mountain
Eagle Mountains Mining District (Monte Negro Mining District)	Mining District
Eagle Mountains	Mountain Range
Riverside County	County
California	State
USA	Country

A former open pit Fe-Al-Ca-magnesite-P(phosphates)-silica-S occurrence/mine located in secs. 23, 24 & 25, T3S, R13E and in secs. 27, 28, 29, 30, 34, 35 & 36, T3S, R14E, SBM, at Eagle Mountain (town) and W across the Eagle Mountains. MRDS database stated accuracy for this location is 10 meters.

This very large open pit mine complex used to provide iron ore to Kaiser Steel Corporation's smelter in Fontana, California. The pit is currently (2009) owned by Kaiser Ventures, of Ontario, California, who had wanted to use it as a trash dump which had been planned to receive 20,000 tons per day of Los Angeles City garbage for the next 117 years. Because of numerous objections from environmentalists, who feared the site's impact on neighboring Joshua Tree National Park, which surrounds the pit on three sides at a distance of 2.5 km, and also objections from neighboring jojoba farmers, the trash disposal plans have been held up in court for years. On November 12th, 2009, the ban on the trash disposal plan was upheld by the Ninth U.S. Circuit Court of Appeals.

Mineralization is a replacement deposit hosted in limestone, dolomite and quartzite. The ore bodies form bands and lenses. The ore bodies strike N70W and dip 45N at a thickness of 40 meters, depth-to-top of 76 meters, width of 343 meters and a length of 4,120 meters. Ore body No. 1 is a tabular replacement body. The primary mode of origin was metamorphism. The secondary mode was contact metasomatism. Primary ore control was lithology and the secondary control was fracturing. Wallrock alteration is moderate (sericitic; carbonate silicification). The ore replaced beds of dolomite. Local alteration includes oxidation and hydrothermal alteration. The metasediments are probably Paleozoic, and possibly Precambrian. The ore minerals are probably Cretaceous and certainly Mesozoic. Associated rocks include quartz monzonite. Local rocks include pre-Cenozoic metasedimentary and metavolcanic rocks undivided and/or Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges).

Local structures include an East-West-trending anticline, and NW-striking faults.

Workings include 3 very large open cast mine pits in an E-W direction across the Eagle Mountains. The pits, from E to W, are the East pit, Central deposit pit and Black Eagle area pit. There are numerous tunnels 75 to 200 feet long, open cuts up to 100 feet long and 40 feet deep plus extensive trenching. A road was constructed 19 km from Interstate highway 10 for mine development. Water was obtained from wells. The first well drilled was 14 km NE of the mine at Pinto Wells. Electrical power was brought in from the S, a distance of 8 km from the Metropolitan Water District Eagle Mountain pumping plant. An 84 km, standard gauge railroad line was built during the period of 1947-1948 between the mine and Ferrum, California, a station on the Southern Pacific railroad, 5 km SE of the Salton Sea station.

Production data are found in: Dubois and Brummett (1968): 1596. (1-4) World Mining Developments 1979-1980: 417.

Produced 21,600,000 tons of ore from 3 deposits. The ore is 35 to 50% Fe. The average ore grade was estimated at 33.4% Fe, 19% silica, 8% magnesia (MgO), 4% lime (CaO), 4% alumina (Al203), 0.07% P and 0.7% S.

Reserves and resources: Type: In-situ (estimated year - 1978): Demonstrated 345,000,000 metric tons ore; indicated: 100,000,000 metric tons ore; measured: 245,000,000 metric tons ore; Total resources: 345,000,000 metric tons ore. Commodity: Fe: 35 weight percent (1978).

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References