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event is 1.8 inches and a 100-year event is 2.6 inches, a 3.6 inch event is improbable. Therefore, no <br />. emergency spillways were designed into either SS-1 or SS-2. Sedimentation and drainage control <br />utilized for the B Seam ventilation shaft facility and access is either shown on Map 151 or covered by the <br />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, the <br />mine had an option to pump this water via south submains to the process pond PP-2. This pond also <br />discharged into Scullion Gulch. In 1989, a sump dewatering hole (SDH#1) was drilled from the surface <br />to pump water from a sump that collected water from longwall workings. This water discharged into a <br />natural drainage that flowed to Red Wash. Sump dewatering hole no.2 (SDH#2) was drilled in <br />November 1990 to replace SDH#1. Sump dewatering hole (SDH#3) was drilled in 1992. The powerline <br />was extended from SDH#2 to SDH#3 during 1992 and was planned to extend to SDH#6 in 1995. See <br />Map 136. SDH#4 was permitted and drilled but later abandoned because of extensive rock partings <br />encountered within the coal seam. SDH#5 was permitted and drilled in 1993. Water from this hole was <br />directed to SDH#3 pond. Because of the abandonment of the northern working area of the D-Seam due <br />to the January 31, 1996 mine fire, SDH#6 was not drilled. Power line was not extended from SDH#5 to <br />SDH#6. Map 140 shows SDH#3 pond details including primary and secondary spillways, the "V" ditch <br />cross-sectional area and other details. Similar details and calculations related to SDH#4, associated "V" <br />ditch and culvert are found in Map 141, Map 144 and Illustration 44. <br />• The discharge water from SDH#5 was directed to a process pond at SDH#3 through an above surface <br />waterline. This line has since been dismantled. From the process pond, the water was discharged to <br />Red Wash via a natural drainage. The process pond was used to settle out total suspended solids that <br />occasionally passed through the mine sump water underground. <br />Two pipelines, one from SDH#2 to the 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 centralize <br />sampling points to a single location. Also, if needed, it would provide an additional pond for settlement <br />or treatment if water from SDH#2 were of poor quality. Pipes were laid on the ground with positive flow <br />towards the SDH#3 pond. At the road crossing, for the line coming from the SDH#2 pond, an 8" culvert <br />was installed for the 6" line to pass through. The pipe used was a 6" aluminum pipe. It carried <br />discharge from the SDH#2 dewatering hole, either directly or from the lower pond discharge pipe, to the <br />process pond located at the SDH#3 site. No water discharge through any sump dewatering hole has <br />taken place since the mine fire of January 31, 1996. <br />5DH#3 and SDH#5 pumped into the SDH#3 pond until the mine fire. The primary spillway for this pond <br />was sized to handle 307 gpm of mine discharge. See Map 140 for spillway rating. Therefore, the inflow <br />of these three sources did not exceed the 307 gpm capacity of that spillway. <br />Mine Permit Renewal #3 (Rev. 1/00) IV- 37 <br />