"LWB estimates that the failure to execute the contracts with ENEA Wytwarzanie, ENEA Elektrownia Polaniec and ENEA Cieplo, in the worst-case scenario, will translate into the inability to deliver about 0.331 million tonnes of coal in 2023," Enea said.

The move comes after Bodganka lowered its full-year production target for commercial coal to about 8.3 million tonnes from a previous goal of about 9.2 million tonnes in September.

The company said then that this change was a result of sudden and unforeseen difficulties in the extraction process.

Enea said it will announce the estimated impact, including need to find alternative an source and any potential provision amount at a later date.

(Reporting by Patrycja Zaras, Editing by Louise Heavens)