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-51- <br />the surface facilities with the retaining structures ]eft in <br />place. Merrick and Company's analyses have been found to conform <br />with the current state-of-the-art. The Division finds that the <br />operation is in compliance with the requirements of this section. <br />XVIII. Coal Processing Waste and Non-Coal Processing Waste <br />WECC initially proposed the disposal of waste rock within two waste <br />piles. One pile, the "initial waste rock pile", will contain <br />approximately 1.25 million cubic yards and will be located on the <br />lower facilities bench. The second waste pile, the "upper waste <br />pile", will be significantly larger and be located on the bench <br />above the portal area. <br />The original permit application contained limited descriptions of <br />both waste piles, lacked engineering detailed design and plans, and <br />proposed that the waste be considered "durable rock". The Division <br />expressed concern that the waste rock would qualify as "durable <br />rock" and, because of generation via separation through a rotary <br />breaker, may actually constitute "coal processing waste". Concern <br />was also expressed that the delineated slope stability problem area <br />within the surface facility complex might compromise the upper <br />waste pile's structural integrity. The applicant was directed to <br />analyze the slope and foundational stability of the proposed waste <br />piles and to submit appropriate detailed engineering plans for <br />review. <br />WECC subsequently revised page 3-43 of the original permit <br />application to state "for the purpose of expediting the permitting <br />procedure the waste rock shall be tentatively specified as 'coal <br />processing waste', and the initial waste pile shall be designed as <br />though this were the case". WECC also submitted a letter proposal <br />for preliminary design of the waste pile utilizing existing <br />geotechnical data, and redesign or revision of the design if later <br />geotechnical data indicated significant variance from preliminary <br />material assumptions. Further, WECC revised the permit application <br />to indicate that the upper waste pile design would be submitted <br />several years in the future, following delineation of the waste <br />material classification, completion of appropriate stability <br />analyses of the slope and foundational area, and the completion of <br />the final detailed engineering design plans. <br />WECC has subsequently submitted a report entitled "Report, <br />Preliminary Design Recommendations, Initial Waste Rock Pile, Mt. <br />Gunnison Coal Mine, Somerset, Colorado, for ARCO (WECC) Coal <br />Company", prepared by Geo-Hydro Consultants, Inc. This report, <br />which constitutes Phase I of the studies proposed on page 3.43c of <br />Exhibit letter 3.2.8.A of the revised permit application, is <br />prepared in conformance with the current state-of-the-art of <br />geotechnical science. The report does propose one variance from <br />normal waste pile practice. The variance requested within the <br />