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*)I- INTRODUCTION <br />PECOCO has been constructed in the NW'4 NW!4 of Section 2, Township 5 North, Range 87 West <br />in a tributary to Little Grassy Creek. The embankment was constructed in 1 by Peabody <br />Coal Company to control the water level and discharge of the impoundment. PECOCO's <br />ponding area was created as a result of the last mine cut excavations of the west Lennox <br />Pit in 1979. <br />SITE DESCRIPTION <br />L and Use PECOCO is in a watershed that is tributary to Little Grassy Creek. This <br />watershed was disturbed by mining activities prior to 1979. The 89.5 acre watershed is <br />89 reclaimed and 11% undisturbed. The disturbed portion of the watershed was reclaimed <br />in 1988 according to the approved reclamation plan to ensure that the reclaimed area meets <br />or exceeds the approved postmine land use (i.e., grazing and wildlife). <br />10) <br />Embankment The embankment is a homogeneous earth fill structure. The top width of the <br />embankment is 15 feet and the upstream and downstream slopes are 4.5h:ly and 3h:ly, <br />respectively. The embankment was constructed using standard engineering practices and <br />compaction density tests were obtained during construction. The minimum test result was <br />94 percent of maximum standard proctor density. <br />CONSTRUCTION (Brief) <br />The existing principal spillway consists of a 24" diameter culvert and the existing <br />emergency spillway is a v- shaped channel. Due to the existing conditions of the <br />spillways, Peabody proposes to modify these structures. The principal spillway will <br />consist of a 24" corrugated metal pipe (CMP) with anti -seep collars and the emergency <br />spillway will consist of a trapezoidal channel (see exhibit 7 -18). These spillways will <br />be constructed according to the enclosed remedial plan. <br />Excavation (Pond Area) The incised impoundment capacity is a result o+ thr. i,ist mine cut <br />excavation of the west Lennox Pit in 1979. NOR 0 0 6 5 6 0 <br />to - The southwestern slopes of the impoundment were created os a result It l�avinq 'h.e. I;t <br />cut of the highwalI. The slopes .ire :'h :lv or flatter except for 150 foot Curti <br />steeper portion was, not further reduced because the existino dunes re , -posed <f <br />,-64-i <br />