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INTRODUCTION <br /> As the national energy base shifts from oil to coal and oil shale, vast <br /> areas of the United States will be subjected to greater underground mining <br /> activity. Increased interest has therefore been generated in the extraction <br /> of thick and steeply dipping coal seams located mostTy .in rugged and remote <br /> areas of the West. <br /> Recent environmental legislation by both the Federal and state govern- <br /> ments has placed severe restrictions on mining impacts to the surface <br /> environment. One major constraint on the extraction of thick and steeply <br /> dipping seams by longwall techniques has therefore been a fear of the con- <br /> sequences of the associated surface subsidence. <br /> At the present time, adequate methods for predicting the characteristics <br /> of subsidence and the impact of subsidence on the surface environment are not <br /> well developed for mining environments in the United States . In .,any Eurepean <br /> countries , notably the United Kingdom, the area of subsidence prediction has <br /> been developed on an empirical basis using extensive subsidence data bases <br /> collected over a long period of time. These empirical capabilities are rou- <br /> tinely utilized by mine planners to minimize the surface impacts of under- <br /> ground mining. <br /> Under the Nation's energy program, studies of mining conditions and <br /> associated subsidence characteristics in the U.S. coal fields are being ini- <br /> In continuing this effOt De' rt:;� , t 0 pray has issue : <br /> tiate, g <br /> • Request 'for Proposal (RFP) No. DE-RP22-80PC30118, "Characterization 3f Subsi- <br /> dence Over t�lul ti pl e Lift Longwal 1 Panels" . <br />