2012-02-28_PERMIT FILE - C2009087A (4)

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RULE 2 - PERMITS within the PSCM disturbance area; however, runoff to PECOCO Pond is from the former Seneca II Mine areas that have been successfully reclaimed and revegetated — most of the drainage area has been approved for Phase I and Phase II Bond Release. The watershed for Pond 004 will not be disturbed by any PSCM surface operations during the 5 -year permit term. Pond 002 will treat runoff from a portion of the reclaimed and revegetated Seneca II Mine, as well as the South Surface Facilities and Portal Area. Pond 003 will treat runoff from the North Facilities Area. Runoff from the reclaimed and well established revegetated Seneca II Mine areas in the Pond 002 watershed is intercepted by a series of approved postmining channel networks. The PM -4 /PM- 6/PM-9 channel system collects runoff from approximately 900 acres; the runoff is routed to PECOCO Pond. Channel PM- 2/PM -23 collect runoff from a 150 acre watershed and convey the runoff to PECOCO. Discharge from PECOCO Pond flows through Channel SCM -2 to the Upper Sump and then through the drainage network to the Lower Sump and ultimately Pond 002. The PM- 3 /PM -5 channel system collects runoff from a 540 acre watershed; the runoff is routed through channels SCM -3 and SCM -4 to Pond 002. A series of new collection ditches will intercept disturbed area runoff from the South Facilities Area and route it through sumps located north of PECOCO pond and at the north end of portal/coal handling facility. Discharge from the Lower Sump will flow to channel PM -1 and then into Pond 002. There are a series of existing diversion ditches constructed as part of the former Seneca II Mine operations in the North Facilities Area. These ditches are included in the drainage and surface water control plan for PSCM. The Shop Diversion Ditch collects runoff from the Shop /Bathhouse area and conveys the runoff to Pond 003. The Old Boneyard Diversion Ditch, the Northwest Diversion Ditch and the Office Diversion Ditch collect runoff from an existing 5.4 acre small area exemption. All diversion and collection ditches and postmine channels are designed to safely pass the peak runoff from the 10 -year, 24 -hour event, or if the drainage basin is greater than 640 acres, the 100 - year, 24 -hour design storm. SCCC also has designed and sized culverts to convey runoff flows under or through active mine disturbance areas, including roads. Design information for ditches and culverts is provided in Exhibit 2.05.3 -E2, Drainage and Sediment Control Plan. The operational ditch profiles are shown on Map 2.05.3 -M5, Operational Channel Profiles. The upper sump will have a runoff storage capacity of 3.7 ac -ft. The lower sump will have a runoff storage capacity of 6.4 ac -ft. Both sumps are designed with both principal and emergency spillway structures. Cleanout of sediment from the sumps will be conducted on an as needed basis; the required runoff water storage capacity will be maintained. The principal spillways are designed for the 10 -year, 24 -hour storm event; the emergency spillways are designed to pass the peak flows from the 25 -year, 24 -hour storm event with a minimum of one -foot of freeboard. Design information for the sumps, as well as, Ponds 002, 003, 004 and PECOCO Pond is present in Exhibit 2- 05.3 -E2, Drainage and Sediment Control Plan. Runoff and Stormwater Control and Discharge — SCCC has initiated the process of securing a Colorado Discharge Permit System (CDPS) permit for the PSCM Permit that will include a stormwater management component. SCCC will insert a copy of the CDPS permit for the PSCM operations as Exhibit 2.05.3 -E3, CDPS Permit, upon receipt. Pond 002 is the primary stormwater retention structure for the proposed south facilities area, as well as, existing Seneca 11 Mine areas, TR- 01 -10. 2.05 -23 Revision 02/11