- 行业: Mining
- Number of terms: 33118
- Number of blossaries: 0
- Company Profile:
The U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.
Founded on May 16, 1910, through the Organic Act (Public Law 179), USBM's missions ...
A method of mining in which tunnels or drifts are extended at regular intervals from the floor of the pit into the orebody. The extension of the drift beyond the working face is made great enough to facilitate the handling of several cars at a time. The ore is mined above the drift level, and the cars are loaded by lifting short boards that span an opening, through the lagging on and above the centerline of the drift. The method avoids the construction of raises and chutes and facilitates the filling of the cars.
Industry:Mining
A method of mining pillars in which a narrow pillar of coal, called the stump, is left along the goaf (worked-out space) to support the roof while driving the pocket. This coal acts as a protection for the miners. When the pocket has been completed, the stump is worked back, then another pocket is driven, and so on.
Industry:Mining
A method of mining pillars in which no stump is left; the pockets driven are open on the goaf side and the roof is supported on timbers.
Industry:Mining
A method of mining pillars in which successive slabs are cut from one side or rib of a pillar after a room is finished, until as much of the pillar is removed as can safely be recovered. This system has the disadvantage that the open area is always increasing and the loaders are working away from the solid pillars toward the goaf.
Industry:Mining
A method of mining pillars seldom followed. A room is first driven through the pillars, splitting them into smaller blocks. The pockets are turned at right angles and are driven into the blocks. This method is really gouging the pillars and is wasteful.
Industry:Mining
A method of mining using a system of haulageways beneath the block of ore, which has had its top surface exposed by the removal of the overburden. Over the haulageways are 1372 chutes that extend up to the surface, and are spaced at intervals of 50 ft (15.2 m) or at any other convenient distance. The excavation of the ore begins at the top of the chute, and broken ore is removed by loading it out from the chutes into cars on the haulage level. The ore block is worked from the top down. The method is similar in principle to underhand stoping.
Industry:Mining
A method of mining using a system of haulageways beneath the block of ore, which has had its top surface exposed by the removal of the overburden. Over the haulageways are 1372 chutes that extend up to the surface, and are spaced at intervals of 50 ft (15.2 m) or at any other convenient distance. The excavation of the ore begins at the top of the chute, and broken ore is removed by loading it out from the chutes into cars on the haulage level. The ore block is worked from the top down. The method is similar in principle to underhand stoping.
Industry:Mining
A method of moving large quantities of material with a bulldozer. Each trip is made in the same path; thus the spillage from the sides of the blade builds up along each side. All material pushed into the slot is retained in front of the blade; bigger loads are handled.
Industry:Mining
A method of narrow heading ventilation in coal mines by means of a brattice partition. The air is led to the face along the wide section of the heading and the contaminated air returns from the face along the narrow section. In this way, workers in the heading are placed in relatively clean air.
Industry:Mining
A method of obtaining pig iron, consisting of charging a retort with a mixture of iron ore, coal, and enough water to form a paste; and injecting compressed air at 2 to 4.2 kg/cm<sub>2</sub>pressure and at 815 to 930 degrees C to burn the coal. In a few minutes the entire mineral charge is heated to 980 to 1,095 degrees C, which is the optimum range for hydrogen reduction; then hydrogen is injected at a temperature of 815 to 923 degrees C at 2 to 8 kg/cm<sub>2</sub>pressure so that it penetrates the entire mass and reacts with the iron oxide to produce steam and metallic iron. About 50% of the injected hydrogen reacts with the ore to produce sponge iron. Sulfur is oxidized by the hot air and is eliminated by the hydrogen.
Industry:Mining
