Laserfiche WebLink
was filled with overburden material in conjunction with subsequent backfilling <br />activities. <br />All water monitoring wells currently being monitored and any others previously <br />part of the monitoring program that remain, but are not transferred to the <br />landowner as allowed by Rule 4.05.14, will be abandoned and sealed as part of <br />the final reclamation plan. <br />VI. Use of Explosives <br />EFCI conducted occasional limited underground blasting activities only during <br />active mining operations. No surface blasting was utilized at the Southfield Mine. <br />Storage and handling of explosives, and any underground blasting that occurred, <br />were conducted under the supervision of a qualified individual in compliance with <br />applicable MSHA and the Bureau of Alcohol, Tobacco and Firearms <br />requirements. No explosives will be used during the five-year permit term <br />covered by Permit Renewal No. 5. <br />VII. Coal Mine Waste Banks <br />The Division previously approved plans for use, construction and <br />maintenance of a coal mine waste disposal area. (4.10.1(1)) <br />Details on the coal mine waste bank, referred to the mine refuse area, can <br />be found in Sections 2.05.3 "Operation Plan", 2.05.4 "Reclamation Plan", <br />4.10 "Coal Processing Waste Banks", and Exhibits 15 and 18 of the <br />permit application. Maps of the refuse pile are shown on Map 18, "Mine <br />Area Surface Facilities Map" as well as the Annual Reclamation Report <br />Map for 2000. Contents of the refuse pile include sandstones, shales and <br />rock partings or inclusions that are separated from the coal in the <br />processing plant. <br />The refuse pile was initially designed for Dorchester in 1980-81 by Geo <br />Testing Laboratories, Inc. and re-evaluated by Rocky Mountain <br />Geotechnical (RMG) in 1982 to adjust for increased refuse volume. The <br />RMG report is the design basis for the ongoing refuse pile construction at <br />the Southfield Mine. In brief, the report recommended the construction of <br />a second underdrain and advocated the maximum height of the refuse <br />pile to be 75 feet, while using compaction techniques of two foot lifts to <br />provide a safety factor of 1.5. The RMG report can be found in Exhibit 18 <br />of the permit application. Technical Revision No.7, approved 3/5/90, <br />allowed for the expansion of the refuse pile. In 1992 the Division <br />expressed concerns on the stability of the pile under the practices of <br />varying fine material lifts with coarse lifts. Technical Revision No. 14, <br />approved 6/12/92, concluded that layered placement and variable coarse <br />to fine ratios would have no adverse impact on the pile's stability while <br />maintaining the 1.5 factor of safety. The Division approved two more <br />Page 29 of 36