A large coal producer with major operations in the Powder River Basin and Appalachia filed for chapter 11 bankruptcy reorganization in federal court Monday.

Blackjewell LLC said its mining operations and customer shipments are expected to continue uninterrupted during court proceedings. The company contributes to both the global steel and power generation industries, and controls more than 1.2 billion tons of high-quality metallurgical and thermal coal reserves.

In its bankruptcy petition filed Monday in U.S. Bankruptcy Court for the Southern District of West Virginia, the company estimated the value of its assets to be between $100 million and $500 million. Meanwhile, the company estimates its liabilities in the range of $500 million to $1 billion.

The company's principal assets in Wyoming are the Belle Ayr Mine, the Eagle Butte Mine and a Central Distribution Center, all based in Gillette. The remaining listed assets are in West Virginia, Kentucky and Virginia.

In its list of the 30 largest unsecured claims, Blackjewel says it owes over $60 million in royalties to the U.S. Department of the Interior.

The company also owes taxes in Wyoming: over $37 million to Campbell County and over $11.6 million to the Wyoming Department of Revenue.

Casper-based Wyoming Machinery Company is owed $5.9 million in trade, according to the filing.