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headgate and discharges it into a stage loader. The stage loader <br /> feeds the coal onto a conveyor belt to be carried out of the mine <br /> to the surface coal handling facilities. The roof along the face <br /> of the longwall is supported by chocks or shields which are <br /> advanced as the face advances . The roof caves immediately behind <br /> the chocks or shields . <br /> Longwall mining is projected as a partic- <br /> ularly effective method for mining thick coal when a multi-lift <br /> mining technique is used . A thick coal bed can be mined in <br /> layers, or slices, by this method . Mid-Continent is currently <br /> performing an experimental test in the Dutch Creek (#l) mine to <br /> mine the top lift as well as the lower panels by the retreating <br /> method . The top face will be extracted first and, after the <br /> caved area in the mined out- panel has reconsolidated, two dual <br /> entry developments will be driven in the relaxed zone under the <br /> gob just inside the top lift panel to provide access for the <br /> lower retreating panel . The bottom slice will then be removed . <br /> A coal and/or rock band is left between the upper and lower <br /> panels which serves as the roof of the lower panel . <br /> Refinements in longwall mining techniques <br /> applicable to Coal Basin should result from the ten year demon- <br /> stration/research program undertaken between Mid-Continent and <br /> the Department of Energy as outlined in II. A. 2 . e. <br /> (4) Mining support activities <br /> (a) Ventilation <br /> A sophisticated ventilation system is <br /> required in the Coal Basin mines because of the high liberation <br /> 17 <br />