Mining Engineers' Handbook, Volume 1Robert Peele, John Adams Church J. Wiley & sons, Incorporated, 1941 |
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Halaman 5-2
... rock . Costs vary Character and formation of rock affect drilling speed , amount of explosive , size into which the rock breaks , mode of breaking , and tonnage handled . DRILLING SPEED . In hard , tough rocks this is generally much ...
... rock . Costs vary Character and formation of rock affect drilling speed , amount of explosive , size into which the rock breaks , mode of breaking , and tonnage handled . DRILLING SPEED . In hard , tough rocks this is generally much ...
Halaman 10-498
... rock to Holmes seam . The rock - hole is partitioned to make a manway and a coal chute . On entering Holmes seam , a battery breast is driven 24 ft wide up the pitch . For ventilation , 2 or more rock - holes , breasts and headings must ...
... rock to Holmes seam . The rock - hole is partitioned to make a manway and a coal chute . On entering Holmes seam , a battery breast is driven 24 ft wide up the pitch . For ventilation , 2 or more rock - holes , breasts and headings must ...
Halaman 13-3
... rock cover , and to keep workings far enough below buried outcrops to avoid danger . Preliminary exploration of rock surface should be done by borings suf- ficiently close together for making a fairly reliable contour map of the buried rock ...
... rock cover , and to keep workings far enough below buried outcrops to avoid danger . Preliminary exploration of rock surface should be done by borings suf- ficiently close together for making a fairly reliable contour map of the buried rock ...
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angle Ariz aver bench black powder blasting block bottom broken caps cars caving chalcocite chalcopyrite churn drills chutes coal copper core cost per ft cribbed cross-sec crosscuts crystals Data deposits depth diam driven dynamite excavation explosives face filled stopes floor footwall ft deep ft high ft long ft wide fuse gelatin grizzly ground hammer drills hanging wall haulage level hematite hoisting holes horiz igneous rocks inclined intervals iron jackhammers labor lagging limestone loading magnetite manway Mesabi Range method minerals mining mucking orebody pillars pipe porphyry posts powder pump pyrite pyrrhotite quartz quartzite raises rock rods samples sand schist scraper sets shift shovel shrinkage stopes side sill sinking slice sludge soft sphalerite square-set steel stope stulls sub-level sulphide surface Table thick timber tons top-slicing Total tunnel usually veins ventilation waste width