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• Land Reclamation Board for Coal Mining, for the Dorchester No.l Mine near <br />Canon City". Based upon the design and recommendations presented in this <br />report, Dorchester proceeded with siting and construction of the initial <br />stage of the permanent coal refuse stockpile. <br />The permanent refuse pile site was located on a gently sloping area <br />between the Newlin and Magpie Creek drainages, adjacent to and west of the <br />mine facilities area. This site represented the best option to insure <br />long term stability, control site drainage, prevent potential adverse <br />environmental impacts, and maintain reasonable haulage distances between <br />the coal preparation plant and refuse pile. Dorchester essentially <br />followed the construction practices presented in the initial report for <br />refuse pile construction including: <br />o Establishment of site drainage control <br />o Removal of available topsoil and vegetative materials <br />• o Establishment of rock subdrains <br />o Controlled placement and compaction of refuse materials. <br />Under this initial plan, coarse refuse materials were placed and compacted <br />in sequential horizontal lifts while fine refuse materials were placed in <br />a temporary retention pond on the stockpile surface to facilitate <br />dewatering and consolidation of the fine refuse materials. <br />As Dorchester expanded operations, coal refuse volumes increased and there <br />was a need to expand the coal refuse stockpile both horizontally and <br />vertically. In response to this need, Dorchester contracted with Rocky <br />Mountain Geotechnical (RMG), a Colorado Springs based geotechnical <br />consulting firm, to complete a revised design and stability evaluation for <br />the expanded stockpile configuration. Dorchester also began evaluating <br />alternatives to the existing fine refuse placement method. As part of the <br />stockpile extension design/evaluation work, RMG completed three (3) <br />borings; two in the existing refuse pile and one in adjacent natural <br />• grounb. Resulting stockpile and founbation material samples were testeb <br />to determine physical and mechanical characteristics. <br />2.05.3-31 <br />