2016-10-20_REVISION - C1981018 (4)

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SDH -4 was permitted and drilled in 1993 but abandoned because of extensive rock partings encountered within the coal seam. The ponds permitted for SDH -4 were not constructed. This hole was plugged, and the site and road reclaimed. SDH -5 was permitted and drilled in 1993. Discharge water from SDH -5 was pumped to a treatment pond at SDH -3 through an above surface waterline. SDH -5 has since been plugged, the waterline dismantled and removed, and the pad and road reclaimed. SDH -6 was drilled but not intersected by the mine workings because of the abandonment of the northern working area of the D -Seam due to the January 31, 1996 mine fire. Power lines were not extended to SDH -6. SDH -6 has been plugged and the site and road reclaimed. Service Holes SH -3 and SH -4 provide means to pump excess mine water from the B -seam to the surface for treatment and discharge. Two sets of treatment ponds at the surface provide for adequate settling and storage of suspended solids. Within the pond system at SH -3 discharge enters artificial wetlands to allow polishing if needed. At the base of both pond areas a final `Last Chance' pond provides a final opportunity for water treatment prior to discharge through flumes at the Outfalls. The layout of these facilities are shown on Map 157 and Map 160. Construction of the light use road to access B -Seam ventilation shaft facilities required installing culverts at three places along the access route. Two locations each have a 72 -inch culvert; the third location has a 30 -inch culvert. Map 151 shows the locations and dimensions of the culverts installed. The 25 -year 24-hour runoff from the watershed above the proposed 30 -inch culvert was modeled using SEDCAD. These runoff volumes as well as the culvert sizing calculations for the 30 - inch culvert are included in Illustration 44. From Illustration 10, the 25 -year 24-hour peak runoff for the SGW-1 watershed, shown on Map 23, is 235 CFM. Using 235 CFM, the culvert sizing utility in SEDCAD was used to size the two culverts where the access road crosses Scullion Gulch. These calculations demonstrate that a 72 -inch culvert is adequate to pass this flow. These calculations are also included in Illustration 44. IV.J.1 Control Systems Control systems consists of the following: a. Diversion dikes and ditches which reroute runoff from undisturbed areas around disturbed areas into natural drainage systems. b. Diversion ditches that collect runoff from disturbed areas and direct it into sedimentation ponds. Technical Revision TR -70 (10/2016) IV -3 8