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• IV.J.2 Installation Diversion ditches and dikes which intercept runoff from undisturbed areas and <br />direct it away from disturbed areas and into the natural drainage system were installed prior to <br />grading activities in an area. Ditches within disturbed areas were constructed during grading <br />activities in an area. Sediment ponds in the Refuse Disposal area were installed prior to grading <br />activities. <br />The sediment pond for the D Portal Area could not be constructed prior to grading activities since it <br />was located on top of the Scullion Gulch stream diversion pipe and it could not collect runoff from all <br />of the "D" Portal Area until most of the 2,750-foot-long diversion pipe was in place. Construction of <br />the Scullion Gulch diversion had to be completed concurrently with the "D" Portal Area grading since <br />it was covered with fill material cut from the bench areas above the bottom of the Gulch. <br />Construction of the Scullion Gulch diversion pipe started at the lower end of the "D" Portal Area. <br />Construction of the Portal Area sediment pond began immediately after the Scullion Gulch diversion <br />pipe installation was completed above the pond location. The installation of the diversion and <br />sediment pond was completed within 6 months after construction work began. <br />When construction began, it was determined that suitable clay materials for construction of the <br />Portal Area sediment pond could not be found in the Portal Area, suitable clay material was <br />imported from areas to be disturbed in the Refuse Disposal Area. All material borrowed from the <br />• Refuse Area was replaced with material from the "D" Portal Area that is suitable for use as nontoxic <br />fill material. <br />To control sediment from the disturbed "D" Portal Area which might have been carried down <br />Scullion Gulch during the first summer of construction, a series of three loose rock check dams were <br />constructed in the Scullion Gulch stream bed below the sediment pond location. The dams are <br />approximately 100 feet apart and the spillway bottoms are approximately two feet high above the <br />streambed. These rock check dams are shown on Map 32. <br />The layout of the ponds andlor ditches are presented on Maps 24, 25, 26 and 27, ("D" Portal), Maps <br />103a and 114 (LOadout Area), Map 89 (East Portal), Map 77 and Map 77A (Refuse Disposal Area). <br />Pond details are presented on Maps 34, 35, 78, 79, 80 and 80A. <br />IV.J.3 Operation and Maintenance During the mine life, all sedimentation and drainage facilities <br />will be inspected regularly, cleaned and maintained as required. The ponds will be cleaned and the <br />sediment disposed of in the Refuse Area along with coal processing waste. The sediment level will <br />be checked quarterly during normal inspections. <br />An NPDES discharge permit was obtained for each of the sedimentation ponds, with monitoring of <br />the pond discharge proceeding in accordance with the appropriate permit. Copies of the NPDES <br />• Fc'rrrritRet~.4(f1i20J2j t2/-4G <br />