- Industry: 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 that makes use of an airstream at a pressure of 4 atmospheres for atomizing molten pig iron into minute particles. The molten metal falling into an air stream formed by an annular slit in a steel cyclone is atomized, the particles falling into a water bath and subsequently dried.
Industry:Mining
A method used by companies for checking the amount of refuse in coal. The refuse is picked daily from a few cars of run-of-mine coal, and when the amount of refuse is considered unreasonable, it is shown to the miner and the laborers. They may be suspended from work if the amount and size of refuse is too high.
Industry:Mining
A method used in large deposits with a very strong roof. In this method, a deposit is divided by levels and on every level chutes are raised to the next one. Mining starts from the mouth of the chutes in such a way as to develop a funnel-shaped excavation (mill, glory) with slopes so steep that the broken ore falls into the chutes and thus to the cars on the lower level. A sufficiently strong pillar is left for protection at the higher level.
Industry:Mining
A method used in large deposits with a very strong roof. In this method, a deposit is divided by levels and on every level chutes are raised to the next one. Mining starts from the mouth of the chutes in such a way as to develop a funnel-shaped excavation (mill, glory) with slopes so steep that the broken ore falls into the chutes and thus to the cars on the lower level. A sufficiently strong pillar is left for protection at the higher level.
Industry:Mining
A method used in quarrying to reduce large masses of stone to smaller size. By using a hammer drill, a row of shallow holes is made along the line where a break is desired. The feathers consist of two iron strips flat on one side for contact with the wedge, and curved on the other to fit the wall of the drill hole. They are placed in the hole and the plug (a steel wedge) is placed between them. They are sledged lightly in succession until a fracture appears. Wherever possible, such fractures are made parallel with the rift of the stone.
Industry:Mining
A method used in quarrying to reduce large masses of stone to smaller size. By using a hammer drill, a row of shallow holes is made along the line where a break is desired. The feathers consist of two iron strips flat on one side for contact with the wedge, and curved on the other to fit the wall of the drill hole. They are placed in the hole and the plug (a steel wedge) is placed between them. They are sledged lightly in succession until a fracture appears. Wherever possible, such fractures are made parallel with the rift of the stone.
Industry:Mining
A method used in room-and-pillar mining where the lease requires at least 80% of recovery. Basically it consists of turning the rooms on 70-ft (21.3-m) centers then working the room up 30 ft (9.1 m) wide and butting it off at its completion, then withdrawing the remaining 40 ft (12.2 m) of pillar immediately.
Industry:Mining
A method used in the braking of alternating-current winders. This method absorbs power equal to the energy destroyed and dissipates it in the liquid controller as heat. Two phases of the stator supply are interchanged by bringing back the driver's lever to the off position and then to that for the opposite direction of drum rotation. The amount of braking depends upon the position of the lever, since the lower the resistance in the controller, and therefore in the rotor circuit, the greater the rotor current and the braking torque produced. When the direction of rotation of the stator magnetic field is reversed, the voltage between the stator and the rotor is doubled and the insulation of both must be adequate to prevent breakdown.
Industry:Mining
A method used to consolidate floor dust in mine roadways in which calcium chloride is applied with a wetting agent.
Industry:Mining
