The supplier of half the coal burned in Minnesota power plants, Arch Coal Inc., filed for bankruptcy protection on Monday but pledged no interruption in mining and shipments to customers like Xcel Energy and Minnesota Power.
The nation's second-largest coal producer filed for Chapter 11 reorganization and said a majority of its primary lenders had agreed to cut $4.5 billion in debt that it couldn't repay because of the depressed coal market.
It is the latest sign of distress in the U.S. coal industry, whose main customers for thermal coal are electric utilities. Three other coal companies have sought bankruptcy protection in the past year, squeezed by weak demand and low prices as utilities turn to cheaper, cleaner natural gas power generation.
Arch Coal operates two mines in the Powder River Basin in Wyoming, including the largest, which shipped 48 percent of the coal purchased by Minnesota power plants in 2014, according to the U.S. Energy Information Administration. Minnesota power plants burned coal for 38 percent of the electricity generated in the state, according to September 2015 data, the most recent available.
Minnesota Commerce Commissioner Mike Rothman, whose agency tracks state energy supplies, said through a spokesman that officials are "closely monitoring the situation," but declined to comment in detail. Xcel and Minnesota Power also said they are watching developments and don't expect problems.
Coal power plants generally store several weeks of fuel, and use multiple suppliers, although Arch is the largest in Minnesota.
"We have been well aware of the potential filing by Arch," said Amy Rutledge, spokeswoman for Duluth-based Minnesota Power, which burns Arch coal at two plants. "To help offset any potential impact, we have grown our coal inventory levels to avoid any disruption."
Arch warned investors in November that it couldn't repay its more than $5 billion in debt. The stock has been trading at under $1, and dropped another 30 percent Monday to 57 cents. If the bankruptcy plan goes through, that stock would be worth nothing, with all equity going to senior debt holders.