Home to the country’s top 10 coal producers, no federal reserves in the basin have sold since June 2012 and none are expected to sell until 2015.

Two factors have contributed to the problem. Open-pit mines in the area generally have huge reserves and therefore, immediate purchases are not required, while coal companies are reluctant to make the long-term investment to buy more.

In April, 21 environmental groups put pressure on Interior Secretary Sally Jewell to impose a moratorium on federal coal leasing in the basin.

The Interior Department has not issued a moratorium, but trends suggest a de facto scenario may have occurred.

In December, the Bureau of Land Management Wyoming office suspended plans for a March coal sale after the mining company seeking to place a bid requested the sale be postponed.

Since 2012, four companies have made similar requests, all of which have been granted by the BLM.

“The defacto moratorium is a good time for BLM to reform its leasing program”, Powder River Basin Resource Council spokesman Shannon Anderson told the Billings Gazette.

Last year, the BLM held two Wyoming coal auctions, but failed to sell any coal.