GILLETTE, Wyo. (AP) — At two of the world’s biggest coal mines, the finances got so bad that their owner couldn’t even get toilet paper on credit.

Warehouse technician Melissa Worden divvied up what remained of the last case, giving four rolls to each mine and two to the mine supply facility where she worked.

Days later, things got worse.

Mine owner Blackjewel LLC filed for Chapter 11 bankruptcy protection on July 1. Worden at first figured the accounts would get settled quickly and vendors of everything from copy paper to parts for house-sized dump trucks would soon be back to doing normal business with the mines.

“The consensus was: In 30 days, we’ll look back on this, and we made it through, and we’ll be up and running, and it’s a fresh start,” she said.

What happened instead has shaken the top coal-producing region in the United States like a charge of mining explosive. Blackjewel furloughed most of its Wyoming employees and shut down Eagle Butte and Belle Ayr mines, the first idled by hardship since coal mining in the Powder River Basin exploded in the 1970s.

It’s a big hit to the region straddling northeastern Wyoming and southeastern Montana, where coal has quietly supported the economies of both states for decades and fuels a shrinking number of power plants in 28 states.

Negotiations that could reopen the two Wyoming mines under new ownership — potentially previous owner Bristol, Tennessee-based Contura Energy — are stalled more than two months later. Some 600 employees remain off the job. They lost health insurance coverage in late August.

And doubts are growing about the long-term viability of the region’s coal mines — particularly Eagle Butte and Belle Ayr, the fourth- and sixth-biggest in the U.S. by production, respectively.

“I don’t think we’ll ever be that naive again,” said Worden, 44.

Blackjewel, based in Milton, West Virginia, told its Wyoming employees this week that the mines might be up and running soon and to let the company know if they wanted their jobs back.

Worden said she felt little reassurance. On a break at a part-time electrical contracting job in North Dakota, she wondered if she should accept any offer of full-time work or hold out for her old job.

She’s not the only one questioning long-held assumptions about Powder River Basin coal mines, which produce cleaner-burning coal less expensively than mines in other parts of the U.S. and weren’t widely thought of being at risk despite a push for renewable energy to combat climate change.