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D. T. Mathews - 3 - January 10, 2001 <br />Pages 14-7 and 14-8 were amended to discuss the layout of the french drain <br />system. <br />4O. The purpose of the french drain system is to control seepage from the seals and <br />seepage or springs along the hillside southwest of the portal entries. The french <br />drain system was incorporated into the reclamation plan to assure this drainage <br />does not compromise the stability of the portal area backfill. There is no <br />potential for water to back up behind the seals to a depth that would cause the <br />seals to fail. Seal deterioration, if any, would occur over an extended period of <br />time which would allow the french drain system to slowly decant impounded <br />water. PCC sees no reason to install 4-inch drain pipes through the concrete <br />seals. <br />5. Issues regarding the drainage plan provided for the South Portal Facilities. <br />a) The post mine topography has been revised. The cut and fill quantities <br />were calculated using the computer program SurvCadd. The output of the <br />SurvCadd calculations are presented on Exhibit 6C. <br />b) Strategically placed sections were developed for the South Portal bench <br />highwall and other areas to show the configuration of the reclaimed area. <br />The sections are presented on Exhibits 6C and 26. <br />c) The upper diversion ditch will be re-established during the reclamation of <br />the RSRDA borrow area. Therefore, run-off from the refuse pile upper <br />diversion ditch can be directed into Pond 9 to provide sediment control for <br />the borrow area until removal of the pond is approved by the DMG. <br />Pages 14-7 and 14-8 of the reclamation narrative were revised <br />accordingly. <br />d) The SEDCAD demonstrations for ditch segments "E" "F" "G" "H" "I" and "J" <br />were revised to meet the100-year event design criteria to comply with <br />Rules 4.10.1 (1)(a) and 4.09.2(7). Enclosed are revised pages 14-6-1 and <br />14-6-17 through 14-6-18ix. Ditch sizes presented on Exhibit 26 were <br />revised accordingly. <br />e) Demolition and backfill of a portion of the conveyor tube does not mean <br />the 4-inch dewatering pipe must be rerouted. PCC will incorporate the <br />pipe in the backfill so it emerges from the ground surface west of the <br />frontage road near the river bank. A notation of this requirement was <br />incorporated in the reclamation plan on page 14-8. <br />6. Issues regarding the 3.1 acre soil borrow area to provide cover for the RSRDA. <br />a) A salvage volume estimate is presented on new Table 14-7. <br />