mining engineering 329 history 89 ore deposits 33 uranium 26 mineral deposits 24 coal 22 crude oil 21 more ... natural gas 20 silver 19 deep mining 18 hard coal 16 brown coal 15 mining 14 ores 13 deposits mining 12 geological survey 11 mining law 11 gold 9 caustobiolite deposits 8 environment 8 safety of work 7 mines (mining) 7 mine exploitation 7 economy 7 metallography 7 environment protection 7 lead 7 environmental pollution 7 mineral processing 7 business balance sheet 6 less ...