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But 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 ...
If light - colored rock dust is used , the color as darkened by coal dust is an important indication . ANAL YSIS OF SAMPLES need be made only for moisture and ash , except in case of limestone or other dust giving off CO2 .
To cause shock - bumps , besides conditions named above , there must be : ( a ) strong , rigid rocks above the ... ( 6 ) subsidence of some kind under these rigid rocks ; ( c ) excessive roof span , so that overlying rock breaks and ...
Apa yang dikatakan orang - Tulis resensi
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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