2018-03-08_PERMIT FILE - C1981035A (5)

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SEDIMENT POND One sediment pond is utilized for the King II Mine. The sediment pond is located at the southeast corner of the mine bench and sized to contain the precipitation events as required by regulation. Surface runoff reaches the sediment pond through a combination of sheet flow, berms, culverts and "V" ditches. Detailed plans, certifications and maps can be found in Appendix 11 and Maps King II -007, King II -007 A -D 8s King II - 007F -G. The pond contains a primary spillway at elevation 7233' and an emergency spillway at elevation 7234'. The spillways are both vertical 24" CMP risers with oil skimmers constructed as shown on Map King 11- 007F, Detail 1. The spillways are always open. The minimum magnitudes of storm events that will cause the spillways to discharge, subtracting a 60% sediment clean-out level of 1.5 acre feet, are as follows: Primary Spillway: 4.36 acre feet - 1.5 acre feet = 2.86 acre feet Emergency Spillway: 5.22 acre feet - 1.5 acre feet = 3.72 acre feet Faces of pond embankments are stabilized with vegetation. Due to evaporation and infiltration, water is not normally impounded except immediately following storm events or snowmelt. While there is no mechanism in place to suddenly draw down the water level, standing water can be pumped as necessary to the native channel at the south end of the site. Prior to water being pumped from the pond to the native channel, the water will be sampled, and it will not be discharged to the native channel unless it meets effluent limitations. TOPSOIL Sufficient suitable topsoil resources exist in the Umbarg soil map unit to provide topsoil replacement depths of six inches. This replacement depth will require stockpiling and ultimate replacement of 20,570 cubic yards of topsoil from the A and B horizons of the Umbarg series. Topsoil was salvaged and stockpiled using truck/ shovel or scraper methods. Topsoil was salvaged and stockpiled during construction in piles constructed adjacent to the sediment pond and north of Coal Stack Tube #2. The topsoil pile is stabilized using the seed mix proposed for final reclamation. To further minimize the potential for accidental contamination, a berm was constructed around the perimeter of the toe of the topsoil piles. The berms are of sufficient size (18" to 24" high, 4' to 6' wide) to prevent machinery from intruding on the topsoil stockpile. GCC Energy, LLC King II Mine Section 2.05.3 Page 6 August 14, 2017 (RN -07 AR#2)