The unraveling of a proposed joint venture between two coal mining giants in the Powder River Basin in the U.S. has cast further uncertainty across the beleaguered coal region.

The U.S. District Court for the Eastern District of Missouri recently upheld the Federal Trade Commission’s decision to block a Peabody Energy Corp. and Arch Resources Inc. joint venture of certain Powder River Basin and Colorado assets. The FTC said in a Sept. 29 statement that the deal would hurt competition and “likely would have raised the price of coal to the utilities, and ultimately to consumers.” The two producers accounted for 59.2% of the coal mined from the Powder River Basin in the first half of 2020, according to S&P Global Market Intelligence data.