Borate Mining in Death Valley, California: 1960's to 2005

My first job out of college was in Death Valley.  I graduated from San Diego State University in August 1974 with a Bachelor of Science degree in geology.  My other job offer was for mud logging on the North Slope of Alaska.  The position in Death Valley was with Tenneco Mining Company, a subsidiary of Tenneco Oil, a subsidiary of Tenneco Inc.  Tenneco had acquired the borate project via the acquisition of Kern County Land Company in 1967.  The acquisition was made mainly for the fee land holdings in Kern County, California for their oil and gas holdings.

In 1960, Kern County Land purchased the claims from the Pacific Coast Borax with the famed 20 mule team wagons.  They paid $200,000 for the claims that contained the Boraxo, Billie and Sigma borate deposits.

Tenneco's foray into borate mining lasted until 1976 when it sold its borate properties to Owens Corning vis the subsidiary of American Borate Company (ABC).  Owens Corning was the largest customer to the borate products.  In 1990, Owens Corning spun-off/sold ABC.  ABC intermittently produced borates from the Billie mine from 1990 until 2005.




Borate deposits of Death Valley and the Armargosa area (Source:  Barker and Barker, 1985).

The famous 20 Mule Train hauling borates.

 

The Boraxo and Sigma pits were mined by Tenneco in the 1970's.  The borates were trucked the mill in Nevada north of  Death Valley Junction.  Exploration and development drilling conducted within the monument.  The Billie deposit was drilled out on a 100-foot rectangular grid.  Conventional rotary drilling was done until borates were encountered and then the deposit was core drilled.  Tenneco was not allowed to build drill roads, so the drill and 4WD vehicles were driven cross country over the boulder-strewn wash.

The borate deposits of Death Valley are in the Pliocene Furnace Creek Formation.  They are stratiform deposits that form in a lacustrine environment.  The "ore" is composed of colemanite, probertite and ulexite.  Typical grade is approximately 22% boron.  The Boraxo and Billie mines yielded beautiful colemanite crystals some of which are honey colored.

Three colemanite specimens and one probertite (lower left); collected from the Boraxo pit in 1974.

The Billie deposit ranges from 200 to 1,350 feet below the surface.  It was 3,700 feet in length, 900 feet in width and up to 250 feet in thickness. 


Satellite image of a portion of Furnace Creek showing the Boraxo and Sigma open pit borate mines and the surface projection (approximate) of the Billie borate deposit that was mined underground by American Borate Company.  The north-south road that leads to the shaft is immediately east of the National Monument boundary.

 

                                          

                                              Ken's Blog with Photos of Death Valley

 

Screen shot of YouTube video of a flyover of the Billie mine (click on link below).

Billie mine drone flyover by Mathew Priest

Cross section of the Boraxo deposit.  The deposit was mined from an open pit by Tenneco Mining and then the portion that extends down-dip from the pit was mined underground with a continuous miner.  (Source:  Wilson, 1976).

 

 

 

Underground mine development for the Billie mine, Agapito is tasked with closure of the mine for  American Borate Company (Source:  Agapito Associates, Inc. website).

A front-page article in the Los Angeles Times on September 17, 1975 by Robert A. Jones warning the Tenneco Mining may someday have an open pit strip mine in the view of the Zabriskie Point scenic turnout.  The news item was the result of claim staking by Tenneco in the vicinity of scenic area.  The monument's superintendent James B. Thompson was quoted saying "We'll be able to stand right here and watch trucks haul away part of the view.  And if the legal situation doesn't change, we'll be helpless to stop it."

 

 Death Valley Nation Monument was an exception in that mining was allowed because of existing talc and borate mines at the time that it was designated as a monument by President Herbert Hoover in 1933.  In 1994, Death Valley National Park was created.

 

Front-page photo from the LA Times on September 15, 1975.

 Additional articles in the Times in 1975 and 1976 resulted in the banning of mining in Death Valley and eventually its status was changed to a National Park.  However, American Borate Company was eventually allowed to mine the Billie borate deposit since it was an  underground mine.  The shaft and head frame were just east of the monument and the only surface structure for the mine in the monument was the secondary escape way.

 

 

Zabriskie Point Death Valley has not be trucked away as predicted by the LA Times (Photo 2007).

The geologists that worked for Tenneco Mining were a great group of new geo's, mostly fresh out of college.  They had brand new geology degrees from southern California schools.  Many went on to have careers in mining, exploration, New Mexico Tech and the USGS.

 

Suggested Reading:

 

 

Barker, C. E., and Barker, J. M., 1985, A re-evaluation of the origin and diagenesis of  borate deposits, Death Valley region, California; in J. M. Barker and S. J. Lefond, eds., Borates-Economic Geology and Production: Symposium Proceedings, SME-AIME, New York, p. 101-35.

 

Barker, J. M., and Wilson, J. L., 1976, Borate deposits in the Death Valley region: Nevada Bureau of Mines and Geology, Special Report 26, p. 22-32.

 

McAllister, J.F, 1970, Geology of the Furnace Creek borate area, Death Valley, Inyo County, California:  California Division of Mines and Geology Map Sheet 14, 9 p.  1:24,000.

 

Wilson, J.L., 1976, Geology and engineering aspects of Boraxo pit, Death Valley, California:  unpublished M.S. thesis, University of Southern California, 95 p.