Piast Coal Mine
Silesia
On December 14, 1981, in response to the imposition of martial law, the longest post-war underground strike took place in the coal mine built in Bieruń in 1972–1975. It was organized at a depth of 650 m and lasted 14 days. The mine operated from 1972 to 2016, and currently, it belongs to the Piast-Ziemowit Coal Mine.
