ST. LOUIS (AP) — Peabody Energy, the nation’s largest coal miner, filed for bankruptcy protection Wednesday as a crosscurrent of environmental, technological and economic changes wreak havoc across the industry. The energy corporation filed for Chapter 11 bankruptcy protection in the United States Bankruptcy Court for the Eastern District of Missouri.

Mines and offices at Peabody will continue to operate as it moves through the bankruptcy process. However, the company’s planned sale of its New Mexico and Colorado assets were terminated after the buyer was unable to complete the deal.

The company’s bankruptcy filing comes less than three months after Arch Coal, the country’s second-largest miner, followed bankruptcy filings from Alpha Natural Resources, Patriot Coal and Walter Energy.

New energy technology and tightening environmental regulations have throttled the industry and led to a wave of mine closures and job cuts. Peabody makes most of its money by selling its coal to major utilities that power the nation’s electric grid.

New drilling techniques allowed U.S. energy companies to free enormous amounts of natural gas, driving prices lower. The result of those plunging prices and changing environmental regulations has pushed major utilities to choose natural gas over coal to power electric grids.

Coal demand has tumbled and the effects have been devastating in coal mining communities from West Virginia to Montana. Slowing economic growth globally has added to the pressures.

“We will seek an in-court solution to Peabody’s substantial debt burden amid a historically challenged industry backdrop,” said CEO Glenn Kellow. “This process enables us to strengthen liquidity and reduce debt, build upon the significant operational achievements we’ve made in recent years and lay the foundation for long-term stability and success in the future.”

The St. Louis miner has obtained $800 million in debtor-in-possession financing facilities. They include a $500 million term loan, a $200 million bonding accommodation facility and a cash-collateralized $100 million letter of credit facility. There were warnings last month that the coal miner had run into funding issues. It delayed interest-rate payments on a pair of loans and said it might not be able to continue operations without some intervention.

Coal companies like Peabody “are looking at the future and saying we need to be better positioned for it if we can survive it at all,” Gellert said. “So bankruptcy is not a surprise … that they would want to kind of reset the clock.”