mining engineering 106 history 97 mining 42 deep mining 41 landscape recultivation 28 brown coal 26 surface mining 26 more ... safety of work 25 hard coal 23 ore deposits 22 coal 21 mineral deposits 20 uranium 19 natural gas 16 geological survey 15 coal energy sources 13 mining law 13 environment protection 13 opencast quarry mining 13 mine rescue 11 caustobiolite deposits 11 undermining 11 underground structures 11 mines (mining) 10 mine exploitation 10 ores 10 deposits mining 9 workings 9 legal regulations 9 crude oil 9 less ...