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Thoroughly documented subsidence case histories in the western U. S. are rare and <br />have been published only during the last twenty years; among them, the work by Dunrud <br />(1976) provides most data relevant to subsidence engineering for coal of the Mesaverde <br />Formation. Abel and Lee (1980) evaluated the influence of lithology on subsidence. <br />GeoHydro Consulting, Inc. (1983) studied the influence of outcrop barrier pillars on the <br />stability of mountain slopes containing coal outcrops; results of their study have been used <br />to deal with the potential subsidence or stability problems within the south area of the <br />property, close to the coal outcrop. <br />Brooks (1983) studied the geologic and hydrologic conditions of the proposed long- <br />term Bowie #1 Mine lease area and evaluated the subsidence potential. His work provided <br />valuable data for this study. <br />Very valuable experience has been obtained from field inspections and <br />documentation of the existing subsidence cracks above the present Bowie #1 Mine and <br />from recent landslides close to the entry of the abandoned Farmers Mine. <br />This study was formatted primarily from a report done by Bukovansky and Major <br />(1983) for the present Bowie #1 Mine which is located just west of the Bowie #2 Mine <br />property and exhibits near identical geologic and hydrologic conditions in the overburden of <br />the coal seam to be mined. Although format and references are used from the <br />Bukovansky and Major Report, it was necessary to edit the report to explain differing site <br />specific situations and experience in order to ease the limitations placed on mine plans <br />resulting from their over conservative subsidence predictions. <br />Finally, a study of several pertinent sections of mine permits from other operating <br />coal mines in the area, our general experience in subsidence engineering, and our <br />thorough knowledge of geologic and hydrologic conditions of the area obtained from our <br />work at the mines in the area during the last several years contributed to this study. <br />1.2 MINING SCHEDULE AND RATE OF SUBSIDENCE <br />Mining within the Bowie #2 Mine property will proceed for a number of years; <br />subsidence will vary at different times depending on the immediate phase of mine <br />development. It is not possible to deal completely with the subsidence as it will occur at <br />various intervals during the lifetime of the mine. <br />PR -14 - 3 - 03/14 <br />