Phoenix-based mining corporation Freeport McMoRan has announced more layoffs to its workforce.

The company said it would eliminate 460 jobs at its Sierrita Mine in Green Valley south of Tucson. That’s in addition to the 150 reductions it made at the same mine in August.

Freeport recently announced it intends to lay off 10 percent of its mining employees and contractors and is said to be considering closing one of its five Arizona-based mines.

The company’s vice president of international affairs Melissa Sanderson said last week federal regulations have made hard times even more difficult.

“I think for any American company the preference would always be to stay at home and create new mines here and create new American jobs directly," Sanderson said. "Unfortunately, the regulatory environment in the United States is not always conducive to that.”

Freeport is one of the world’s largest copper and gold miners with 8,500 employees in Arizona alone. With commodity prices on the decline in recent months, the company is facing even more cutbacks.