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Direct Stoping Costs for Air , Drills and Steel per Ton ( 2 000 lb ) of Ore Mined ( 41 ) Mine Cost Mine Cost Open - stope mines Cut - and - fill stopes $ 0.102 0.094 0.080 0.042 Arer of 7 lead mines in Tri - State district , 1927-1930 .
Drifts in the vein rarely require timbering , but walls in all stopes must be supported . A few narrow stopes on one vein are worked with stulls ; but usually with sets 5 ft square and 7 ft 10 in high , of 8 and 10 - in sq timber .
Dodge coal - storage system 34-29 Dome , petroliferous 44-02 rock 2-12 Domed stopes 10–204 Doming in subsidence 10-523 , 10-526 Door , ventilation 14-10 , 14-11 Doors for buildings 43-41 leakage through 14-16 at top of shaft 7-05 Dorr ...
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LibraryThing ReviewUlasan Pengguna - wackyvorlon - LibraryThing
I only have the second volume of this work, and I love it! Found at a local Value Village, it is filled with fascinating information. Details of all aspects of mine engineering, including compressed air, ventilation, and supporting structures. Baca ulasan lengkap
Conditions Methods in General
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