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techniques and sealant were used for all five portal seals. Once the seals were in place, the entry <br />between the seal and opening was filled with overburden material in conjunction with <br />subsequent backfilling activities. <br />Drill holes from 1987 and 1988 exploration projects within the permit area have been filled and <br />sealed, as described in the "Proposed Decision, Phase I Bond Release" document dated <br />September 15, 1990. <br />EFCI has made concerted effort in recent months to seal additional bore holes and to update the <br />characterization of these holes in the PAP. This has entailed research of old documents related <br />to the bore holes and a field survey to check locations of the holes (as shown on Map 12 of the <br />PAP) and to document the status of the reclamation of the holes. A final report by EFCI is <br />pending at the time of the writing of these findings. <br />VL Use of Explosives <br />EFCI conducted occasional limited underground blasting activities only during active mining <br />operations. No surface blasting was utilized at the Southfield Mine. Storage and handling of <br />explosives and any underground blasting that occurred were conducted under the supervision of <br />a qualified individual in compliance with applicable MSHA and the Bureau of Alcohol, <br />Tobacco, and Firearms requirements. No explosives will be used during the five -year permit <br />term covered by Permit Renewal No 6. <br />VII. Disposal of Excess Spoil <br />Because Southfield Mine was an underground operation, this section is not applicable. <br />VIII. Coal Mine Waste Banks <br />The Division previously approved plans for use, construction, and maintenance of a coal mine <br />waste disposal area (Rule 4.10.1(1)). <br />Details on the coal mine waste bank (also known as the RDA) can be found in Sections 2.05.3, <br />2.05.4, and 4.10 of the PAP as well as Exhibits 15 and 18. The location of the refuse pile is <br />shown on Map 18. Contents of the refuse pile include sandstones, shales, and rock partings or <br />inclusions that are separated from the coal in the processing plant. <br />The refuse pile was initially designed for Dorchester in 1980 -1981 by Geo Testing Laboratories, <br />Inc. and reevaluated by RMG in 1982 to adjust for increased refuse volume. The RMG report is <br />the design basis for the ongoing refuse pile construction at the Southfield Mine. The report <br />recommended the construction of a second underdrain and advocated the maximum height of the <br />refuse pile to be 75 feet, while using compaction techniques of two -foot lifts to provide a safety <br />factor of 1.5. The RMG report can be found in Exhibit 18 of the PAP. Technical Revision No. 7 <br />(approved March 1990) 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 varying fine material lifts <br />with coarse lifts. Technical Revision No. 14 (approved June 1992) concluded that layered <br />placement and variable coarse to fine ratios would have no adverse impact on the pile's stability <br />while maintaining the 1.5 factor of safety. <br />24 <br />