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C. Sedimentation Ponds Seneca Coal Company will primarily use sediment ponds to prevent additional contributions of sediment to streamflow or runoff outside the permit area due to mining disturbance. Existing sediment ponds include 005, 006 and 009. Information regarding design of ponds and diversions is provided in Tab 13 of the permit application. Pond 005 was permitted as a permanent impoundment that treats runoff from 285.6 disturbed acres which drain to Dry Creek. Pond 006 was permitted as a permanent impoundment that is located in a watershed that is tributary to Hubberson Gulch. Phase I construction of the pond was completed in 1989. Phase II consisted of modifying the existing principal spillway to increase the storage capacity of the pond. Phase III included construction of a clean water diversion ditch that will divert 102.6 acres of undisturbed area into the drainage to the west. Pond 009, a temporary sediment pond, treats runoff from the smaller disturbed area which drains to Sage Creek,roughly a 439 acre watershed. Construction of the pond was completed in 1991. The watershed is approximately 73% undisturbed and 27% disturbed. The three sediment ponds described above will treat all disturbed area drainage with the exception of certain existing and proposed topsoil stockpiles depicted on Exhibits 13-2 and 13-3 and listed in Attachment 13-8. Sedimentation from these stockpile areas will be controlled by sediment traps designed to totally contain the runoff from a 10 year/24 hour storm event. The Division specifically grants exemption from the sediment pond requirement of the topsoil stockpiles listed in Attachment 13-8. The small area exemption is granted based on conformance with the requirements of Rule 4.05.2(3)(a) and (b). D. Acid-forming and Toxic-forming Spoil The applicant has submitted detailed analysis of the geochemical characteristics of the overburden and interburden found in the Seneca II-W Mine permit area. The sampled parameters were agreed upon by the Division, OSM and Seneca Coal Company during meetings held in 1980 and 1981. Parameters sampled are listed in the permit application Volume 2, Tab 6. The permit application states that these parameters were used to, "document the physical and chemical properties of the overburden and underburden, to compare these properties to ground water quality, and to determine potential reclamation success:' The data obtained from the geochemical analyses were compared to criteria derived from State and Federal agencies (USDA, BLM, Wyoming DEQ, 17