mining engineering 334 history 88 ore deposits 34 uranium 25 mineral deposits 24 coal 22 crude oil 21 more ... silver 19 natural gas 19 deep mining 17 hard coal 16 mining 14 brown coal 13 ores 13 metallurgy 12 deposits mining 11 geological survey 11 mining law 10 gold 9 caustobiolite deposits 8 metallography 8 environment 8 safety of work 7 mines (mining) 7 mine exploitation 7 economy 7 lead 7 mineral processing 7 business balance sheet 6 coal energy sources 6 less ...