The miner, which has assets in Pennsylvania, West Virginia and Virginia that produce both metallurgical and thermal coal, said it has issued notices to the 170 employees of Spartan Mining of the idling of the Ruby Energy, or Kielty, mine as well as the Delbarton preparation facility in Mingo County.

While it did not say if the closure was temporary or permanent, it did note that "sustained adverse market conditions…have rendered the mine uneconomic" and added that its contractors would also be furloughed.

In addition, Contura confirmed it will not proceed with the new refuse impoundment project at the Cumberland mine in Greene County as it will not be spending the US$60 million in capital needed for the work. Instead, it will "actively market" the property for sale while continuing to supply coal to its customers under amended contracts that will now expire at the end of 2022.

Contura chairman and CEO David Stetson cited the "especially adverse market conditions" as the reasion for its decisions for both mines.

"Given the current market conditions and what we expect from the near-term outlook, it is clear that these properties are not economical and will not be able to deliver the kind of value we strive for in our portfolio," he said.

"These are trying times, but we are committed to make the difficult choices necessary to maintain our long-term financial strength."