Shares of Core Natural Resources Inc. (CNR) plummeted 5.31% in pre-market trading on Thursday following the release of disappointing first-quarter results. The company reported a net loss of $1.38 per diluted share for Q1 2025, a significant downturn from earnings of $3.39 per share in the same period last year, and worse than the $1.28 loss per share expected by analysts.

The coal mining company's financial performance was heavily impacted by merger-related expenses of $49.2 million and a loss of $11.7 million associated with debt extinguishment. Despite reporting revenues of $1.02 billion, up from $546.7 million a year earlier and slightly above analyst expectations, the bottom-line results clearly spooked investors.

Adding to the company's woes, Core Natural Resources faced operational challenges at its Leer South mine. The longwall production at Leer South was idle during the entire first quarter due to a previously announced combustion-related event. However, the company stated that it expects to resume longwall operations at the mine by mid-year, which could potentially improve performance in the second half of 2025. Despite these setbacks, Core Natural Resources increased its merger synergies target by 10% to a range of $125-$150 million, signaling some optimism for future cost savings and operational efficiencies.