mining engineering 330 history 80 ore deposits 28 uranium 25 mineral deposits 24 coal 23 crude oil 21 more ... natural gas 20 deep mining 18 silver 17 hard coal 16 brown coal 15 metallurgy 14 mining 14 deposits mining 12 mining law 11 geological survey 10 environment protection 9 gold 9 caustobiolite deposits 8 environment 8 safety of work 7 mines (mining) 7 mine exploitation 7 economy 7 metallography 7 environmental pollution 7 mineral processing 7 business balance sheet 6 coal energy sources 6 less ...