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IV.J Sedimentation and Drainage Control <br />Sedimentation and drainage control systems utilized in the "D" Portal Area are shown on Maps 24, <br />25, 26, 27 and 34, in Loadout Area are shown on Map 103a, in the Refuse Disposal Area are shown <br />on Maps 77, 77a, 78, 79 and 80, along the Conveyor and Slot Storage area on Maps 106-113, in <br />the East Portal Area are shown on Map 89. These measures were in addition to the use of mining <br />and reclamation procedures intendled to protect the quality and quantity of the existing surface and <br />groundwater. Emergency spillways on afl ponds have been designed to safely pass the peak flow <br />from a 25-year, 24-hour storm event. Illustration 40 shows that the spillway design for Pond RR-1 <br />can pass 14.39 cfs when only 11.5 cfs is the maximum flow of runoff. Illustration 39 shows that the <br />ponds at the slot storage area (S~S-1 and SS-2) have double the capacity of a 10-year, 24-hour <br />storm event. Since a 10-year, 24-hour event is 1.8 inches and a 100-year event is 2.6 inches, a 3.6 <br />inch event is improbable. Therefore, no emergency spillways were designed into either SS-1 or <br />SS-2. Sedimentation and drainage control utilized for the B Seam ventilation shaft facility and <br />access is either shown on Map 151 or covered by the Small Area Exemptions in Illustration 44. <br />Early in the mine's history, the underground mine water was primarily being discharged via the East <br />Portal into the Scullion Gulch. This; water was pumped from a main sump in the mine. If required, <br />the mine had an option to pump this, water via south submains to the process pond PP-2. This pond <br />also discharged into Scullion Gulch. In 1989, a sump dewatering hole (SDH#1) was drilled from the <br />• surface to pump water from a sump that collected water from longwall workings. This water <br />discharged into a natural drainage i:hat flowed to Red Wash. Sump dewatering hole no.2 (SDH#2) <br />was drilled ~n I'Vovember 1990 to replace SDH#1. Sump dewatering hole (SDH#31 was drilled in <br />1992. The powerline was extended from SDH#2 to SDH#3 during 1992 and was planned to extend <br />to SDH#6 in 1995. See Map 147. SDH#4 was permitted and drilled but later abandoned because <br />of extensive rock partings encountered within the coal seam. SDH#5 was per~~itted anc :±rilled in <br />1993. Water from this h^le was directed to SDH#3 pond. Because of the abandonment of the <br />northern working area or'the D-Seam due to the January 31, 1996 mine fire, SDH#6 was got urii~;;d. <br />Power line was not extended from SDH#5 to SDH#6. Map 140 shows SDH#3 punt uatail.. <br />includin,; primary and secondary spillways, the "V' ditch cross-sectional area -nd one. details. <br />Similar details and calculations related to SDH#4, associated "V" ditch and culvf:;~i are found in l~:ap <br />141, Map 144 and Illustration 44. <br />The discharge water from SDH#5 vvas directed to a process pond at SDH#3 through an above <br />surface waterline. This line has since been dismantled. From the process pond, the water was <br />discharged to Red Wash via a natural drainage. The process pond was used to settle out total <br />suspended solids that occasionally passed through the mine sump water underground. <br />Two pipelines, one from SDH#2 to ttie pond at SDH#3 and the other from the discharge pipe on the <br />lower pond near SDH#2 to where it tied into the proposed line to SDH#3 pond was installed to <br />Permit Rev. 4 (11/2002) IV-37 <br />