Cloud Peak Energy

Negotiations between NTEC and Montana continue.

Two former Blackjewel mines, Eagle Butte and Belle Ayr, returned to production in the fourth quarter after their purchase by another company.

A spokesman for the Navajo Transitional Energy Company says he can't comment because the bond negotiations are active.

Cloud Peak filed for Chapter 11 bankruptcy May 10.

The auction, originally scheduled for Thursday, will take place 11 a.m. EDT Aug. 15 in New York.

Nearly 600 people worked at the vast, open-pit mines, which were among the most productive in the U.S.