Pniówek Coal Mine
Silesia
As Pniówek Coal Mine, it operated from its opening in 1963 to 1975, when it was renamed XXX-lecia PRL Coal Mine. That super-mine was an ambitious investment – at the end of 2011, it employed 5,362 people. Although it is marked with the fourth lowest category of methane hazard, in 2022, there was a methane explosion. Eight people died, and 30 were injured in the crash.