Firm Seeks to Double Size of Borate Mining Pit

A borate mining pit in eastern Kern County, already the world’s largest, may get even bigger.

U.S. Borax Inc. wants to more than double the depth of the pit from 600 to 1,250 feet, though it has run into opposition from residents of the nearby town of Boron who said the dust raised by the open-pit drilling hurts their health and property values.

Borate is used to make fiberglass, ceramics, glass, fertilizers and wood preservatives, and is mined in open air, using blasting.

Huge piles of leftover dirt in the north and east that already cover 4,629 acres in the area would expand to cover between 6,502 and 7,141 acres respectively, residents said. They would also grow from 300 feet tall to 650 and 450 feet.

Kern County supervisors will vote on the plan during a board meeting today.