Mining in California

The state’s mineral industry is growing, with the extraction of gold and construction sand and gravel leading the way. A strong recovery by California’s construction industry has pushed up sand and gravel production by 67.2% since the recession year of 1982 to an estimated 135.7 million short tons worth $536.8 million, according to the U.S. Bureau of Mines.

The growth in gold mining has been even more spectacular. In 1980, just 4,078 ounces were produced. But the introduction of huge, open pit mines with machinery to quickly process thousands of tons of low-grade ore has sent production zooming to an estimated 602,071 ounces last year, worth more than $267 million, according to the U.S. Bureau of Mines.

At least 10 major gold mines are operating in Imperial, San Bernardino and Kern Counties, according to one recent survey. Most of the mines are near the Colorado River, where gold is thought to have been extracted by the Spanish as early as 1775.

More than just gold and gravel is mined in Southern California. Molycorp Inc., a subsidiary of Los Angeles-based Unocal, owns a rare earths mine in Mountain Pass that accounts for about 97% of the nation’s production. Various rare earths are used to improve the yield of gasoline in refining heavy crude oils, to reduce the energy consumption of fluorescent light bulbs and to make powerful magnets and better ceramic capacitors for electrical power generation.

Tungsten, borax and even gem stones are also produced in the region. The nation’s only tungsten mine produces about 840,000 pounds a year from the slopes of Mount Baldy north of Ontario, said Ronald L. Curtis, chief executive of Tungsten Inc. The mineral sells for about $3 a pound and is used to make photographic film, light bulbs and special tool steels.

Fiberglass, soap, fertilizers, porcelain enamels and scores of other products are made from borax, which is mined outside the town of Boron in Kern County. And for more than a century, the hills between Mesa Grande and Pala in northern San Diego County have yielded rare, green tourmaline gems.