mining engineering 309 history 64 uranium 25 mineral deposits 24 coal 23 crude oil 21 natural gas 20 more ... deep mining 17 hard coal 16 brown coal 15 mining 14 metallurgy 13 deposits mining 12 mining law 11 environment protection 9 silver 9 caustobiolite deposits 8 environment 8 safety of work 7 mines (mining) 7 mine exploitation 7 ores 7 environmental pollution 7 mineral processing 7 business balance sheet 6 economy 6 coal energy sources 6 geological survey 6 metals 6 mineral raw materials 6 less ...