A subsidiary of a leading U.S. coal provider has sold the Eagle Butte and Bell Ayr mines located in Wyoming's Powder River Basin.

Tennessee-based Contura Energy, Inc. made the announcement Monday.

The two mines combined shipped 24.5 million tons of coal through the first three quarters of 2017 and gave Contura subsidiaries control of some 600 million tons of proven and probable reserves in the Powder River Basin, the company said in a statement.

The company expects to incur a book loss on the sale, which will be recorded in the fourth quarter. However, the new owner will assume all permit and reclamation obligations associated with the sale, which will eliminate $200 million in undiscounted reclamation obligations for Contura.

Contura says the sale should also generate $400 million-$450 million in income tax deductions, which would be available to offset taxable income in 2017 and future years. Contura will also receive deferred consideration of up to $50 million through various royalty payments.

"This transaction allows us to further sharpen our focus on the company's well-positioned eastern assets and a growing net sales portfolio," Contura CEO Kevin Crutchfield said. "While these PRB thermal assets will not be part of our company's operational strategy moving forward, the purchaser is acquiring two solid mines with decades of minable reserves, a top-notch, professional workforce and a great operating track record."

Blackjewel LLC is the new owner of the mines, related coal reserves, equipment and infrastructure, which it acquired for an undisclosed sum.

"I appreciate and commend the contributions that current and past employees in the PRB made toward that success, and wish them the very best in the future," Crutchfield concluded.

Following the transaction, Contura affiliates maintain control over nearly 700 million tons of proven and provable reserves in northern and central Appalachia, as well as a 65-percent ownership interest in the Dominion Terminal Associates coal export terminal in Newport News, Virginia.