2011-10-24_PERMIT FILE - C1983059

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.•.-.-.,....~„ ~r.PAiC'1 hll:nl ut It L.'. 1-.11, Water .~~i.. L~~~ uontruL uiv LS ion Rationale - Page 2. PERMIT NUMBER: COG•850000 INDUSTRY LESCRIPTION: • Coal is mined in the state using both surface mining and underground mining methods. In surface mining the coal is located relatively clo;:e to the surface. 7'he overburden and topsoil are removed using equipment such as truck-mounted shovels, bulldozers, and wheeled tractor scrapers and later replaced c~r reclaimed. Surface mining is typically accomplished using a dragline. Underground mining methods are used for coals locat~ad farther under the surface where the removal of the overburden is not economic=ally feasible. Underground mining involves blasting down to the coal, drilling and cutting Co extract ttie coal, and removing coal using equipment such as conveyors or shuttle c:~rs. The raw cnal or "run-of-mine" coal may require processing prior co use, This processing; is referred to as coal preparation. Coal preparation is the process o:: upgrading raw coal by physical means and includes crushing, sizing, cleaning, and refuse disposal operations. The initial step in the coal preparati~~n process often involves crushing of the coal with crushers or pulverize::s to remove large rock fractions and to free impurities such as clay, rock, and pyrite Erom the coal. The coal is then sized using equipment such as s~~reens, cyclones, and separators. Different crushing and :sizing technique; are used for Fine coal and coarse coal processing. Coal cleaning is a preparation process performed to improve product standardization, to increase the heating value of the coal, and to reduce the ash and sulfur content of the coal. Coal cleaning processes include both wet and liry cleaning nethods. However, many coal preparation plants use water in the . separation process. The mining of coal does not involve the use of water other than small amounts for dust control and equipment cooling. The major sources of water entering the mine area are precipitation, groundwater infiltration, and surface runoff. Water is considered to be a hinderari~.• to mining activities and the removal of water from the active inane area is generally required to ensure the efficiency and safety of the mining operation. !or underground mines removal involves pumping the water out of the inane area. The majority of the coal preparation processes use water. The amount of water used at coal preparation facilities varies widely depending on the degree of cleaning, the equipment or processes used, and the characteristics of the raw coal. Er.amples of unit operation requiring water include wet screening, tables, jigs, cyclones, gravity and heavy media separation. Additionally, water is used fog; equipment cooling, dust control, and as a transport medium for the c•.oal between process units. The major: types o£ wastew~`er in the coal mining industry are: 1, inn Drainage - Any drainage and any water pumped or siphoned from an act:-ve mining area or postmining area.