mining engineering 320 history 87 ore deposits 34 uranium 26 mineral deposits 23 crude oil 21 natural gas 20 more ... silver 19 deep mining 17 hard coal 16 brown coal 15 mining 14 metallurgy 13 ores 13 deposits mining 11 geological survey 11 mining law 10 gold 9 metallography 8 environment protection 8 environment 8 safety of work 7 lead 7 environmental pollution 7 mines (mining) 6 mine exploitation 6 metals 6 mineral raw materials 6 legal regulations 6 landscape recultivation 6 less ...