Industrial actions also took place in several coal mines in Upper Silesia, where an attack against the workers occurred at Wujek Coal Mine in Katowice (see Pacification of Wujek). Altogether, after the introduction of the martial law, 50 Upper Silesian enterprises went on strike, including 25 coal mines. The Piast Coal Mine, located in the town of Bieruń, was one of them, but the very fact that the strike there lasted for so long, was a surprise. Piast was one of the newest coal mines in the region. Opened in 1976, in 1981 it employed some 7,000 people. Most of them were young, inexperienced miners, recruited from other parts of Poland. The crew was not integrated, and the miners did not identify themselves with the mine.