Rio Tinto Borax open pit, Rio Tinto Borax Mine, Kramer Borate deposit, Boron, Kern County, California, USAi

Regional Level Types
Rio Tinto Borax open pit	Pit
Rio Tinto Borax Mine	Mine
Kramer Borate deposit	Deposit
Boron	Town
Kern County	County
California	State
USA	Country

The primary mineralization is borax, precipitated in a permanent shallow lake, fed from thermal (volcanic) springs rich in sodium & boron. Kernite was formed later upon deep (+1500 ft (ca. 457 m)) burial and temperatures above 53 °C (Christ and Garrels, 1959). The sodium borates together with claystone are hosted as a core facies within the Middle Miocene (16 mybp) Kramer beds (Barnard & Kistler, 1967) and are completely enveloped by ulexite-bearing shales (Gale, 1946). Stratigraphic and structural studies indicate the Kramer borates were deposited in a small structural, non-marine basin, elongated in an east-west direction and limited on the south by the Western Borax fault
(Joe Siefke 2010).

The open pit mine of the U.S. Borax Mine, located in secs. 14 & 23, T11N, R8W, SBM, N of the town of Boron. A borate mine removing 10,000 tons/day during 1984. Owned by U.S. Borax & Chemical Corp.

In 1913 a borate mining claim was registered by O. Suckow, following identification of colemanite nodules during well drilling in the Kramer area of Kern Co. California.

This discovery claim was later bought out by the Pacific Coast Borax Company, whose subsequent exploration drilling in the district discovered the Na-borate deposit in 1925.

Their first exploitation was underground, via the shaft known as the Baker mine, which lies near the eastern end of the Na-borate orebody. During 1926 & 1927, two other companies, Suckow Borax Mines and the Western Borax Co., began working further west in the deposit. Both of these operations were taken over within the next few years by Pacific Coast Borax [Western Borax in 1933].

In the late 1940s, the former Western Borax property was bought by the California Borate Co. which since seems to have faded from the scene, although I can find no reference to its demise. In 1956 Pacific Coast Borax merged with United States Potash Corporation, to become US Borax, and in 1957 changed from underground to opencast working.

The Jenifer Mine was a shaft located about halfway between the Western Borax and Suckow Borax mines, and is now included within the US Borax property. In 1968 US Borax became part of the Rio Tinto Group.

Zeolites occur in basalt underlying the borate deposit.

Other Regions, Features and Areas containing this locality

References