- 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 ...
CH<sub>4</sub>; carbureted hydrogen or marsh gas or combustible gases; formed by the decomposition of organic matter. The most common gas found in coal mines. It is a tasteless, colorless, nonpoisonous, and odorless gas; in mines the presence of impurities may give it a peculiar smell. It weighs less than air and may therefore form layers along the roof and occupy roof cavities. Methane will not support life or combustion; with air, however, it forms an explosive mixture, CH<sub>4</sub>+2O<sub>2</sub>-->CO<sub>2</sub>.2H<sub>2</sub>O. The gases resulting from a methane explosion are irrespirable. Methane is often referred to as combustible gases because it is the principal gas composing a mixture that, when combined with proper proportions of air, will explode when ignited. Breathing methane causes ill effects only where the air is so heavily laden with it that oxygen is supplanted.
Industry:Mining
In a fissure that has been filled by successive deposits of minerals on the walls, the place where two sets of layers thus deposited approach most nearly or meet, closing the fissure and exhibiting either a drusy central cavity or an interlocking of crystals.
Industry:Mining
In relatively unventilated cavities in coal mines, such as wastes, it is frequently found that the methane percentage or concentration is higher at roof level, lower at midheight, and least at floor level. This is termed stratification of methane.
Industry:Mining
Compaction of soil in layers generally not greater than 6 in (15 cm) deep, by various methods, including the use of the frog rammer, vibration, sheepsfoot roller, pneumatic tired rollers, or similar machines.
Industry:Mining
Pneumoconiosis of the lungs that can be related to the amount (and possibly the nature) of the dust breathed by miners over the years.
Industry:Mining
Mine workings are usually subdivided to form a number of separate ventilating districts. Each district is given a specified supply of fresh air and is free from contamination by the air of other districts. Accordingly, the main intake air is split into the different districts of the mine. Later, the return air from the districts reunite to restore the single main return air current at or near the upcast shaft.
Industry:Mining
Consists of a 60 degrees cone with a short cylindrical top section. It is provided with a stirring shaft, located in its vertical axis, carrying several sets of horizontal arms with rings of nozzles projecting through the sides of the cone for the admission, at several horizons, of the required water currents. At the base of the cone, a classifier column several feet long is fitted, through which refuse discharges continuously to an inclined refuse conveyor. Water is supplied by a centrifugal pump.
Industry:Mining
In a sediment, the water-content boundaries between the semiliquid and plastic states (known as the liquid limit) and between the plastic and semisolid states (known as the plastic limit).
Industry:Mining
On a longwall face, the term implies the use of some type of cutter loader with perhaps self-advancing ports, giving a quicker turnover and higher productivity. In the case of a 1144 rock drivage the term would mean the regular use of a shovel loader.
Industry:Mining
Mining in which the continuous mining machine cuts or rips coal from the face and loads it onto conveyors or into shuttle cars in a continuous operation. Thus, the drilling and shooting operations are eliminated, along with the necessity for working several headings in order to have available a heading in which loading can be in progress at all times.
Industry:Mining
