"I don't see a contradiction between that and having a strong climate change policy."

Each household has also been given a carbon monoxide alarm, it said.

Murray Energy is the latest to join a string of coal companies.

"we do not expect growing foreign demand for US coal to supplant weaker domestic demand or reverse the industry's decline."

In the PRB, Arch expects reduced volumes and higher unit costs in Q4.

The coal mine's annual production capacity will be 3 million tonnes.

The two projects, one located in Shanxi Province and the other in Inner Mongolia Autonomous Region.

Shanxi has been very clear its goal to lower its annual production of coal to 1 billion tons by 2020.