mining engineering 329 history 87 ore deposits 34 uranium 25 coal 23 mineral deposits 22 crude oil 21 more ... natural gas 20 deep mining 18 silver 17 hard coal 16 brown coal 14 metallurgy 14 ores 13 deposits mining 12 mining law 11 geological survey 10 environment protection 9 caustobiolite deposits 8 metallography 8 gold 8 environment 8 safety of work 7 mines (mining) 7 mine exploitation 7 economy 7 lead 7 environmental pollution 7 mineral processing 7 business balance sheet 6 less ...