GILLETTE, Wyo. (AP) — Cleanup requirements are holding up the sale of a bankrupt coal company's mines in Wyoming and Appalachia.

West Virginia-based Blackjewel proposes to sell mines including the Eagle Butte and Belle Ayr operations in Wyoming to an affiliate of Alabama-based FM Coal with help from Tennessee-based Contura Energy.

A surety company for FM Coal announced Wednesday that Blackjewel must transfer permits and cleanup bonding for its 135 permits in Appalachia before doing so in Wyoming. The bonds would help ensure cleanup of mines that close permanently.

The Casper Star-Tribune reports the request took FM Coal by surprise.

Eagle Butte and Belle Ayr production has all but ceased and over 500 Wyoming workers are furloughed since Blackjewel filed for bankruptcy July 1.

Blackjewel attorneys say the companies will seek replacement bonds.