Cheyenne, Wyo. • The U.S. government has approved the expansion of a Wyoming uranium mine and is reviewing plans for a new mine not far away.

Both projects involve the use of wells rather than pits or shafts to extract uranium in a process called in-situ mining. Wyoming produces more uranium than any other state and all of it comes from in-situ mines.

The U.S. Bureau of Land Management announced Tuesday it has approved an expansion to double the surface area of Littleton, Colorado-based Ur-Energy's Lost Creek Mine.

The BLM is meanwhile reviewing the company’s plans for an in-situ mine located at a former conventional uranium-mining site about 50 miles away.

Water pumped from in-situ mines is processed into a uranium concentrate. The concentrate is then processed into nuclear fuel.