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Eagle Mountain Mine (Eagle Mountain Iron Mine; Eagle Mountain Iron deposit; Kaiser Steel Corp.), Eagle Mountain, Eagle Mountains District (Monte Negro District), Eagle Mts, Riverside Co., California, USA

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Latitude & Longitude (WGS84): 33° 51' 52'' North , 115° 31' 13'' West
Latitude & Longitude (decimal): 33.86472,-115.52028
Köppen climate type:BWh : Hot deserts climate

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).

Mineral List

15 valid minerals.

Rock Types Recorded

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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

Cretaceous - Jurassic
66 - 201.3 Ma

ID: 2800816
Undated granitic rocks, unit 3 (Southern California)

Age: Mesozoic (66 - 201.3 Ma)

Comments: Jurassic and Cretaceous plutonic rocks in southern California.

Lithology: Major:{plutonic}

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, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Harder, Edmund Cecil (1912), Iron-ore deposits of the Eagle Mountains, California: USGS Bulletin 503: 28, 54, 63.

McMillan, W.D. and George H. Holmes, Jr. (1941 circa), Investigations of the Eagle Mountains Iron District, Riverside County, California, U.S. Bureau of Mines Preliminary Report of Investigation, 20 pp.

Hadley, Jarvis Bardwell (1942), Iron Deposits in part of the Eagle Mountains, Riverside County, California, USGS Open File Report (August), 33 pp.

U.S. Bureau of Mines (1943), Eagle Mountains Iron District, Riverside County, California, War Materials Report 97, 44 pp.

California Division of Mines (1948), Mineral Information Service: 1(8): 1-8.

Hadley, Jarvis Bardwell (1948), Iron-ore deposits in the eastern part of the Eagle Mountains, Riverside County, California, in: Iron Resources of California, California Division Mines and Geology Bulletin 129: 4.

Huseman, G.W. (1953), Kaiser Stepping up Production at Eagle Mountain Iron Mine, Engineering and Mining Journal: 154(5): 80-86.

Powell, Kenneth B. (1953), Eagle Mountain Helps Kaiser Meet Growing Western Steel Needs, A.I.M.E. Mining Engineering (May): 479-483.

Powell, Kenneth B. (1953), How Eagle Mountain helps Kaiser supply growing steel needs: Mining Engineer: 5: 481.

Trengrove, Russell R. (1956), Methods and Operations at the Kaiser Steel Corporation Eagle Mountain Iron Mine, Riverside County, California, U.S. Bureau of mines Information Circular 7735, 25 pp.

Gay, T.E. (1957) Iron industries in California. California Division Mines Bulletin 176: 247.

Canadian Mining Manual (1962), illustrated: 17, 19, 21-22.

Davis, Carl E. (1962), Electric Computation of Eagle Mountain Ore Reserves, in: Computer Short Course and Symposium on Mathematical Techniques and computer Techniques and Computer Applications in Mining and Exploration: volume 2, Tucsoin, Arizona, University of Arizona College of Mines, 1967, illustrated: E2-1-E2-13.

Carey, William W. (1963), Magnetic Properties of a Massive Magnetic Hematite Deposit, AGS, American Geophysical Union Transactions: 44(4): 862.

Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 60, 216, 247, 251, 328, 344, 387.

Ver Planck, Wm. E., Jr. (1966), Quartzite in California, California Division of Mines and Geology Bulletin 187, 58 pp.: 31, 51.

Drossel, Margaret R. (1967), Kaiser's Eagle Mountain Project - from Pot to Premium Pellet, Engineering and Mining Journal: 168(6): 101-122.

Novak, G. A. (1967), Petrography and Mineralogy of a "Rapakivi" Quartz Monzonite Pluton, Eagle Mountain Quadrangle, California, Master's Thesis, Pennsylvania State.

Dubois, R.L. and R.W. Brummett (1968) Geology of the Eagle Mountain area. In Ore Deposits of the United States, 1933-1962. The Graton-Sales volume, New York. A.I.M.E.: 1596-1606.

Minerals Processing (1968), Iron Ore Pelletizing at Eagle Mountain (February): 8-30.

USGS (1969), Geological Survey research 1969, Chapter D, includes PhD thesis of Roger Hope, geologic map, 116pp.

Skillings, David N., Jr. (1972), Kaiser Steel Corp.'s Eagle Mountain Iron Ore Mine, Skillings Mining Review (January 15): 14-19.

Allen, Clarence R. and Donald V. Helmberger (1973), Search for Temporal Changes in Seismic Velocities Using Large Exlosions in Southern California, in: Conference on Tectonic Problems of the San Andreas Fault System, Proceedings, Stanford University Publications, Geologic Science (SSGEAS): 13 (1973), Illustrated (including sketch maps: 436-445.

Pelka, Gary J. (1973), Geology of the McCoy and PAlen Mountains, Southeastern California, PhD thesis University of California at Santa Barbara.

Engineering and Mining Journal (1974), Eagle Mountain Moves 170,000 TPD (tons per day) of ore and waste: 175(11): 152-154.

Olson, Emmett K. (1974), Truck Servicing and Maintenance Program at KAiser's Eagle Mountain Mine, Mining Congress Journal: 60(3) (March): 22-26.

Wick, David E. and Edward M. Sunmoo (1974), Computer Use in Determining Ore Reserves and Stripping Ratios at Eagle Mountain, International Symposium Applied Computing Mathematics Mineral Industry Proceedings: II(12): H59-H71.

Engineering & Mining Journal (1977) International Directory of Mining and Mineral Processing Operations: 171-172.

Kaiser Industries Corporation (1977), Notice of Special Meeting of Stockholders, April 20, 1977: 41-42.

Mining Engineering (1977), Eagle Mountain Ships 100 Million Tons of Ore: 29(10) (October), 13 pp.

Skillings Mining Review (1977), Iron Ore Shipments of Companies (July): 8-9.

Engineering and Mining Journal International Directory of Mining and Mineral Processing Operations (1978), New York: McGraw Hill Mining Information Services: 168.

Engineering and Mining Journal Operating Handbook of Surface Mining, Vol. 2 (1978), New York: McGraw-Hill Inc.: 314.

Powell, R.E. and L. T. Silver (1978), Crystalline Rocks of a Portion of the Eastern Transverse Ranges, Riverside County, California, Abstracts of the Geological Society of America, Programs: 10(3): 142.

Sisselman, Robert (1978), Chiule's First Pellet Plant Incorporates Heat Recoup System and Self-Fluxing Pellets, Engineering and Mining Journal: 179(5): 90-93.

Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 72, 150, 161, 163, 367, 476.

USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10064461, 10077141 & 10189008.

U.S. Bureau of Mines Minerals Availability System/Mineral Industry Location System (MAS/MILS): file #0060650737.

Hope, Roger, Geology and Structural Setting of the Eastern Transverse Ranges, Southern California, University of California Los Angeles PhD thesis.

Straam Engineers, Inc., Capital and Operating Cost Estimating System Handbook, U.S. Bureau of mines Contract No. J0255026.

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