The allegation was made by Sunnyside Gold Corp., which is fighting the EPA over who should pay for a potentially costly groundwater study.
The EPA is considering using robots and other sophisticated technology to help prevent mine "blowouts" or clean them up if they happen.
The UN Environment Program report tallied 40 significant mine waste accidents in the past decade. Most involved dams or other storage areas that failed.
The EPA is installing a barrier at the mine outside Silverton to prevent another spill like the one in 2015 that sent 3 million gallons of toxic water into rivers.
Utah wants cleanup compensation and unspecified damages in the 3-million-gallon Gold King Mine spill that was accidently triggered by EPA contractors.
The agency started work on safety standards after the spill and expects to soon finish them, investigators from the EPA's Office of Inspector General said.
To see the worst of the coal slump in Colorado, look no further than the state’s North Fork Valley. Since 2013, two out of three mines have closed.
Valley leaders aren’t waiting to see if promises to the coal industry are delivered. Instead, they’re seeking to build their own path.
The president's executive order instructs the Environmental Protection Agency to review the Clean Power Plan and other regulations.
The Colowyo Mine will now extract coal in territory to the north in the Collom development.