According to Reuters, regulators had previously questioned, in light of market prices, the ability of Peabody and other miners to meet the financial criteria to self-bond. The issue has taken the spotlight more in Wyoming since Alpha Natural Resources reportedly announced in May that it no longer qualified for the WDEQ’s self-bonding program under its Land Quality Division.

The specific mines or assets were not named in the report, though Peabody’s holdings in Wyoming that are actively mining include North Antelope Rochelle, Caballo and Rawhide. North Antelope Rochelle is one of the most productive mines in the U.S.

In a recent U.S. Securities and Exchange Commission (SEC) filing, Peabody said its financial assurance for reclamation obligations as of March 31 was $2 billion and its self-bonding obligations totaled $1.38 billion. Of that, Wyoming made up $813.8 million.

Reuters also reported in June that the U.S. Office of Surface Mining Reclamation and Enforcement was also examining the program.