KGHM's two most important copper mines are those in PolkowiceSieroszowice and Rudna (Fig. 15), which, with a mine capacity of 12 Mta ore each, yielded kt and kt respectively. Boliden is the No. 2 copper producer in the EU and No. 10 worldwide with a volume of Mta in 2017, after Mta in 2016.
· Bureau of Mines Bulletin 509, Injury Experience in Coal Mining, 1948; Bureau of Mines Bulletin 616, Historical Documentation of Major CoalMine Disasters in the United States Not Classified as Explosions of Gas or Dust: ; Bureau of Mines Bulletin 586; Historical Summary of CoalMine Explosions in the United States, ; Bureau of Mines .