Molycorp, the U.S.’s only miner and processor of rare earths, said it would transition the facility to a “care and maintenance” mode, adding it plans to continue serving its rare earth customers via its production facilities in Estonia and China.

Molycorp Inc., the only U.S. producer of rare earths, on Wednesday said it would mothball its mine in California, laying off nearly 500 workers and suspending the country’s sole source of the 15 elements used in magnets, batteries and other high-tech products.

The facility, machinery and equipment will be maintained for safety purposes as well as to meet regulatory needs, officials said.

In July, when Molycorp progressed via the chapter course of, firm officers, which produces lighter uncommon earth minerals utilized in units resembling telephones and catalytic converters.

In a statement, Molycorp based its decision on declining rare earth pricing, which has fallen dramatically over the past four years. Some of the company’s R&D efforts have been geared toward setting up a recycling system to harvest and recycle rare earth metals from discarded electronics and fluorescent light bulbs. The court eventually allowed Molycorp to move forward with $130 million in interim financing provided by Oaktree to support going operations.