Conventional Mining

Miners use two processes, known as conventional mining and continuous mining, to remove coal from room and pillar underground mines. Conventional coal mining replaced hand mining (mining with pick and shovel) in the 1930s. 

In conventional mining, miners use power saws to slice a deep cut 10-12 ft (3-4 m) wide, into the bottom of a coal wall. Next, holes are drilled into the coal above this cut and fill the holes with explosives. The explosions dislodge chunks of coal from the wall. Conveyors or rubber-tired electric vehicles known as shuttle cars carry the coal chunks out of the mine. 

These explosives (permissible explosives) produce an almost flame-free explosion and markedly reduce the amount of noxious fumes relative to the more conventional explosives. Other methods of breaking the coal consist of placing steel cartridges into the blast holes the cartridges are then filled with compressed air (up to 2000 psi 13.8 mp) or with liquid carbon dioxide. Release of the 

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An assessment of world potash resources (108) is shown in Table 15. Of the 67 x 10 t of total estimated reserves and resources in Canada, nearly 5 X 10 t is recoverable by conventional mining methods and the remainder by solution mining. As of 1974, Canada had about half of the known world reserves and about 90% of known world resources of potassium. 

The importance of a coal deposit depends on the amount that is economically recoverable by conventional mining techniques. The world total recoverable reserves of lignitic coals were 3.28 x 10 metric tons at the end of 1990 (3), of which ca 47% was economically recoverable as of 1994 (Table 4). These estimates of reserves change as geological survey data improve and as the resources are developed. 

Sulfur can be produced direcdy via Frasch mining or conventional mining methods, or it can be recovered as a by-product from sulfur removal and recovery processes. Production of recovered sulfur has become more significant as increasingly sour feedstocks are utilized and environmental regulations concerning emissions and waste streams have continued to tighten worldwide. Whereas recovered sulfur represented only 5% of the total sulfur production ia 1950, as of 1996 recovered sulfur represented approximately two-thirds of total sulfur production (1). Recovered sulfur could completely replace native sulfur production ia the twenty-first century (2). 

A portion of the mining in New Mexico is conducted by conventional mining methods, that is, a cycle of undercutting, drilling, and blasting with an ammonium nitrate—fuel oil mixture and loaders, use of shutde cars, and belt haulage. Such conventional methods are used, although not exclusively, in the... 

Another form of underground mining is known as conventional mining. Tliis process accounts for about 11% of deep-mined coal and consists of a series of operations that involve cutting the coalbed so that it breaks easily when blasted with explosives. The broken coal then is ready to be removed from Ihe mine. Where the geology is favorable, this is the most practical and economical underground mining method. 

By the evaporation of large inland seas or land-locked lakes of large drainage basins in geologic history, extensive subterranean deposits of sodium chloride and other salts in layers of cumulative thickness as great as 400 m have been laid down in many parts of the world. Deposits in well-consolidated strata and less than 500-600 m below the surface are usually economic to work by conventional mining techniques. In Canada, these accessible deposits amount to about 74% of the total and in the U.S.A., about 35% of the total [1, 2]. 

Potassium Chloride Recovery by Conventional Mining and Froth Flotation... 

Improved selectivity of potash recovery may be obtained by high ammonia concentrations in water, but this has not been commercially adopted. Solution mining of potash has matured from the pioneering work of Kalium Chemicals at Belle Plaine, Saskatchewan [39], to encourage adoption by at least two operations formerly based on conventional mining [40]. These operations are sited to use solar evaporation for potash recovery. One uses 162 hectares (1.62 km ) of PVC-lined evaporation ponds to produce 236,000 tonnes of potassium chloride per year [29]. Experiments with solar absorbing dyes may lead to further increases in production. 

Conventional mining is both of historical interest and is still used to produce nearly a quarter of the world s sulfur (Table 9.2). Mining brings to the surface lumps of either a volcanic or one of the many pyritic forms of sulfur. Some of the pyritic forms are pyrite (FeSi) itself, chalcocite (CuiS), and chalcopyrite (CuFeSi). The sulfur content of the raw mineral is usually 25-35%, but may run as high as 50%. To obtain the sulfur in a separated form, the original procedure was to pile the lumps of ore outside and seal these with clay or earth. Burning a part of the contained sulfur sealed into these mounds, with careful control of the air generated sufficient heat to melt any elemental sulfur present, and thermally decompose the pyrite (Eqs. 9.1-9.3) [10]. 

II. Deposits lucaled below the neutral water table but accessible by conventional mining or wellflooding techniques. 

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