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VII . Coal Mine Waste Banks <br /> 1 . The Division has approved plans for use, construction and <br /> maintenance of a coal mine waste disposal area. <br /> (4 . 10 . 1 (1) ) <br /> Details on the coal mine waste bank, referred to the mine <br /> refuse area, can be found in Sections 2 . 05 . 3 "Operation <br /> Plan" , 2 . 05 . 4 "Reclamation Plan" , 4 . 10 "Coal Processing <br /> Waste Banks" , and Exhibits 15 and 18 of the permit <br /> application. Maps of the refuse pile are shown on Map <br /> 18, "Mine Area Surface Facilities Map" as well as the <br /> Annual Reclamation Report Map for 2000 . Contents of the <br /> refuse pile include sandstones, shales and rock partings <br /> or inclusions that are separated from the coal in the <br /> processing plant . <br /> The refuse pile was initially designed for Dorchester in <br /> 1980-81 by Geo Testing Laboratories, Inc . and re- <br /> evaluated by Rocky Mountain Geotechnical (RMG) in 1982 to <br /> adjust for increased refuse volume . The RMG report is <br /> the design basis for the ongoing refuse pile construction <br /> at the Southfield Mine. In brief, the report recommended <br /> the construction of a second underdrain and advocated the <br /> maximum height of the refuse pile to be 75 feet, while <br /> using compaction techniques of two foot lifts to provide <br /> a safety factor of 1 . 5 . The RMG report can be found in <br /> Exhibit 18 of the permit application. Technical Revision <br /> No. 7, approved 3/5/90, allowed for the expansion of the <br /> refuse pile. In 1992 the Division expressed concerns on <br /> the stability of the pile under the practices of varying <br /> fine material lifts with coarse lifts . Technical <br /> Revision No. 14, approved 6/12/92 , concluded that layered <br /> placement and variable coarse to fine ratios would have <br /> no adverse impact on the pile ' s stability while <br /> maintaining the 1 . 5 factor of safety. The Division <br /> approved two more expansions to the refuse pile with <br /> Technical Revisions 30 and 31 (approved on 19 June 1998 <br /> and 21 August 2000 , respectively) . The final, approved <br /> refuse pile encompasses 37 . 9 acres . <br /> 2 . With the construction of the two underdrains, an <br /> alternative subdrainage system for the coal mine waste <br /> area has been approved. The Division finds that such an <br /> Southfield Mine Permit Renewal 03 <br /> 48 <br />