FLAGSTAFF, Ariz. (AP) — The Navajo Nation will not financially back bonds a tribal energy company needs for a trio of newly acquired coal mines off the reservation, the tribal president said Tuesday, explaining that it’s too risky and his administration wants the company to move away from coal.

The Navajo Transitional Energy Co. recently bought Montana’s largest coal mine and two mines in Wyoming at auction after Cloud Peak Energy declared bankruptcy.

The mines can keep operating for now because more than $370 million in reclamation bonds posted by Cloud Peak remain in place, state officials said.

Tribal President Jonathan Nez said he canceled agreements the energy company might have relied on to seek the Navajo Nation’s financial backing for the bonds. He said the company wasn’t forthcoming about information related to acquiring and operating the mines, and he wants to protect the tribe’s finances as revenues decline from the loss of a coal plant and mine on the reservation. Tribal lawmakers had been considering legislation to do the same thing.

“The Navajo Nation’s financial portfolio as well as our resources would be placed in a state of uncertainty if we allowed NTEC to proceed with finalizing the bonds needed to operate these three mines using the (Navajo) Nation’s consent ...” Nez wrote in a statement.

The development marks the latest turmoil to hit the Powder River Basin of Montana and Wyoming, the nation’s largest coal-producing region, where bankruptcies and declining demand have put a pall over a once-vibrant industry. Hundreds of people in the region were put out of work for months after another bankrupt company, Blackjewel, drastically scaled back operations at two of the biggest coal mines in the U.S.