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Geotechnical analyses in Appendixes T and VV of Volume VI of the <br /> application show that both the Roadside and Cameo No. 1 piles are <br /> stable at a minimum safety factor of 1 .5. The Cameo No. 1 pile is to <br /> have side slopes of 2.3: 1 with a crest elevation of 5,025 feet . This <br /> configuration will result in a static safety factor of 1 .74, and a pile <br /> capacity of 2 ,240,000 cubic yards . <br /> Seepage problems on CRDA No. 1 ' s first and second benches were <br /> identified in May of 1988. Three issues were highlighted: four <br /> observed seeps that may indicate slope instability, refuse dumping <br /> practices , and inadequate drainage of the pile. The operator has taken <br /> the following steps to curtail future seepage problems. <br /> Since 1988, CRDA No. Ps three benches have been regraded to provide <br /> for better slope stability and drainage . Surface drainage has been <br /> improved by the construction of diversion ditches that allow surface <br /> runoff to exit around the pile instead of contacting the face. Coal <br /> refuse has ceased to be dumped on CRDA No. ] , pending a demonstration on <br /> future slope stability. <br /> Three piezometers were installed in CRDA No. 1 prior to December 1987 <br /> and have recorded water levels in the refuse pile for five years . A <br /> fourth piezometer was installed in May 1988 in the location of a <br /> recharging seep. Three of the four seeps observed were localized <br /> perched aquifers within the pile and have since drained to a stable <br /> water level . Only one of the four piezometers recharges seasonally and <br /> thus fluctuates in water level . CRDA No. 1 is underlain by three sets <br /> of rock underdrains . All four piezometers have been positioned in the <br /> toe of CRDA No. 1 to monitor the water levels. <br /> Cameo Refuse Areas No. 1 and 2 will be monitored throughout <br /> construction . Monitoring will include : <br /> 1 . Peizometric monitoring of the coal processing waste embankment; <br /> 2. Monitoring of side slopes to maintain a maximum slope angle of <br /> 2 .3: 1 ; <br /> 3. Monitoring compaction of constructed lifts ; and <br /> 4. Quarterly inspection for stability by a registered professional <br /> engineer. <br /> Geotechnical analyses in Appendix VV of the permit revision application <br /> show that both the Cameo Nos . 2 and 3 piles are stable at a minimum <br /> safety factor of 1 . 5. The outslopes will be constructed with 2. 5: 1 <br /> slopes between 15 feet wide horizontal benches at 30 feet vertical <br /> spacings , yielding an average slope gradient of 3: 1 . <br /> Further information on this subject can be found in Appendices VV, W14, <br /> XX, YY, ZZ and Exhibits 9B, 9C and 51-55. <br /> 1 . The disposal area will be inspected on a regular basis by a <br /> qualified professional specialist under the direction of the <br /> professional engineer, experienced in construction of similar earth <br /> and waste structures . Inspection by this person has been approved <br /> ii <br /> -32- <br />