Company officials confirmed that the deal between IUOE Local 400 and the surface mining complex in Colstrip, operated by subsidiary Western Energy, would extend through February 28, 2019.

The two were also able to come to terms before the expiration of its prior agreement.

“This new agreement provides us certainty to continue to serve the needs of our customers,” chief operating officer and president Robert King said.

IUOE Local 400 business manager Chuck Cashell said the contract was a direct result of the union and company working together to “look towards the future with some degree of certainty and stability that will benefit everyone”

“After very contentious negotiations and a strike in 2009, the company and the union came together and, with the assistance of the federal mediation and conciliation service, used interest-based bargaining as a framework to do things differently this time around,” he said.

“We feel that this process has worked well and has been successful in addressing the needs of both parties.”

The news comes as Westmoreland settles into its significantly larger footprint at the complex.

In July, officials confirmed it had signed a lease deal with an unnamed party for 56.4 million tons on 2557.4 acres neighboring the Rosebud operation.

Portfolio-wide, Westmoreland holds an estimated 486Mt of proven and probable reserves.

The Rosebud operation produces about 12Mt of coal per annum.

Westmoreland Coal is the nation’s oldest independent coal company.

It has operations in the Powder River Basin of Montana, sub-bituminous mining interests in Wyoming and lignite mining operations in Montana, North Dakota and Texas.

The IUOE currently has about 400,000 members in 123 local unions throughout the US and Canada.