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provide sufficient detention time to increase sedimentation within the pond and <br />produce effluent within NPDES limitations. The orifice was reconstructed in 1987. <br />With this revised design, the pond was in compliance with the design standards of <br />Rule 4.05.6 and continues to meet NPDES permit requirements. <br />Pond 004 Pond 004, a temporary sediment pond, was constructed in 1982 when <br />mining progressed into the Fish Creek basin in the southeast part of the permit azea. <br />Pond 004 is located on Cow Camp Creek and drains an area of 393 areas. The pond <br />has a permanent pool of 10 acre-feet. <br />Pond 008 Pond 008, a temporary pond, was constructed in the Fish Creek drainage <br />basin in a tributary referred to as Bond Creek. NPDES discharge site 008 replaced <br />007, which was mined through. Pond 008 drains an azea of 247 acres of which 226 <br />acres is disturbed. The pond is designed to provide storage fora 10-yeaz, 24-hour <br />precipitation event with 2.1 acre-feet of runoff and has a capacity of 16.4 acre-feet. <br />PeCoCo Impoundment The PeCoCo impoundment was constructed in 1987 in a <br />watershed that is tributary to Little Grassy Creek. The embankment was constructed <br />to control the water level and dischazge of the impoundment. The watershed was <br />disturbed by mining activities prior to 1979. The watershed is 89.5 acres, whereas <br />11% is undisturbed and 89% is reclaimed. PeCoCo's ponding area was created as a <br />result of the last mine cut excavations of the west Lennox Pit in 1979. PeCoCo <br />contains water maintained primazily by ground water flow from upgradient <br />resaturated spoils. The pond was approved as a permanent impoundment. <br />Spill Control Pond #2 The Spill Control Pond was constructed prior to 1977 and <br />provides secondary containment for the three diesel fuel storage tanks located at the <br />Seneca II shop facilities. The impoundment does not act as a sedimentation <br />structure for any disturbed lands at the Seneca II Mine. <br />The sediment ponds described above will treat all disturbed area drainage with <br />exception to the bone yard and office azeas. The Division specifically grants <br />exemption from the sediment pond requirement listed in Attachment 7-6-7. The <br />small azea exemption is granted based on conformance with the requirements of <br />Rule 4.0~.2(3)(a) and (b). <br />D. Acid-forming and Toxic-forming Spoil <br />The applicant has submitted analysis of the geochemical chazacteristics of the <br />overburden and interburden found in the Seneca II Mine permit area. The sample <br />parameters can be found in Volume 3, Tab 6. Acid and toxic-forming materials will <br />not constitute a problem in the Wedge mining areas. The applicant submitted <br />appropriate mitigation measures that will be utilized in the Wolf Creek mining azea <br />whenever acid-forming spoil is encountered within the upper three feet of the graded <br />spoil. <br />16 <br />