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-56- <br />with the retaining structures left in place. Merrick and Company's <br />analyses have been found to conform with the current state-of-the-art. <br />The Division finds that the operation is in compliance with the <br />requirements of this section. <br />XVIII. Coal Processing Waste and Non-Coal Processing Waste (2.05.3 <br />WECC initially proposed the disposal of waste rock within two waste <br />piles in the original permit application. One pile, the "initial waste <br />rock pile", would contain approximately 1.25 million cubic yards and <br />would be located on the lower facilities bench. Subsequent to permit <br />approval this initial waste rock pile was deleted from their permit. <br />The second waste pile, the "upper waste pile", would be significantly <br />larger and be located on the bench above the portal area. WECC has not <br />yet commenced construction of the upper waste pile and has postponed <br />its construction indefinitely. Instead, WECC is proposing at this time <br />to construct the permanent waste pile at a location below most of the <br />surface facilities, at the west side of the mouth of Sylvester Gulch. <br />The original permit application contained limited descriptions of both <br />the initial and upper waste piles, lacked engineering detailed design <br />and plans, and proposed that the waste be considered "durable rock". <br />The Division expressed concern that the waste rock would qualify as <br />"durable rock" and, because of generation via separation through a <br />rotary breaker, may actually constitute "coal processing waste". <br />Concern was also expressed that the delineated slope stability problem <br />area 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 initial <br />and proposed waste piles and to submit appropriate detailed engineering <br />plans for review. <br />wECC subsequently revised page 3-43 of the original permit application <br />to state "for the purpose of expediting the permitting procedure the <br />waste rock shall be tentatively specified as 'coal processing waste', <br />and the initial waste pile shall be designed as though this were the <br />case". WECC also submitted a letter proposal for preliminary design of <br />the initial waste pile utilizing existing geotechnical data, and <br />redesign or revision of the design if later geotechnical data indicated <br />significant variance from preliminary material assumptions. Further, <br />WECC revised the permit application to indicate that the upper waste <br />pile design would be submitted several years in the future, following <br />delineation of the waste material classification, completion of <br />appropriate stability analyses of the slope and foundational area, and <br />the completion of the final detailed engineering design plans. <br />WECC applied for a permit revision to allow the construction of an <br />upper waste rock pile in October of 1984. The operator had noted its <br />intention to construct an upper waste pile in the original permit <br />application. The permit revision application represented the <br />submission of a detailed engineering plan for that structure, for which <br />a general plan had earlier been submitted. <br />