Mining Engineers' Handbook, Volume 2Robert Peele, John Adams Church J. Wiley & sons, Incorporated, 1941 |
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Halaman 23-47
... rock - dusting , now approved in all countries , where efficiently done , has not yet failed . Rock - dusting method ( 66 , 67 ) is to spread 3 parts shale or preferably limestone dust for each 1 part of coal dust , as checked by ...
... rock - dusting , now approved in all countries , where efficiently done , has not yet failed . Rock - dusting method ( 66 , 67 ) is to spread 3 parts shale or preferably limestone dust for each 1 part of coal dust , as checked by ...
Halaman 23-48
... rock dust required . For first dusting after cleaning an aver entry , use 2-4 lb of dust ; for a room , 4 lb or over . Subsequent amounts depend upon rapidity of deposition of coal dust . In some mines 0.5 ton rock dust to 1 000 ton ...
... rock dust required . For first dusting after cleaning an aver entry , use 2-4 lb of dust ; for a room , 4 lb or over . Subsequent amounts depend upon rapidity of deposition of coal dust . In some mines 0.5 ton rock dust to 1 000 ton ...
Halaman 23-54
... rocks above the coal seam and immediate roof ; ( b ) subsidence of some kind under these rigid rocks ; ( c ) excessive roof span , so that overlying rock breaks and falls , striking on the immediate roof and causing a shock - wave ...
... rocks above the coal seam and immediate roof ; ( b ) subsidence of some kind under these rigid rocks ; ( c ) excessive roof span , so that overlying rock breaks and falls , striking on the immediate roof and causing a shock - wave ...
Isi
COMPRESSED | 15 |
Applications Definitions Data | 15-44 |
Accident Compensation Pensions | 16-1 |
Hak Cipta | |
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adjustment Aerial Tramway anthracite approx assay aver borax buckets Bur Mines capac carriers cars charge chute claim coal mines compressor concentrate conveyer copper cost crusher crushing cu ft cupel cyanide deflection diam discharge distance drill dust elev engineer explosions feed filter fire firedamp gold hoisting horiz intercooler labor lamp less litharge loaders loading lode long ton machine material mechanical metal method mill mineral motor operation pipe plant plate plumb-bob pump pyrite rock safety lamps sample screen shaft sheave short ton side silver sizes Sodium carbonate solution speed station steel stopes surface survey Table tape telescope temp tension tests timber tion tons Total towers track cable traction rope tramway Trans transit traverse underground usually vein vertical wire zinc