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h. All principal spillways will have 2 seep collars installed within the dam which will be <br />at least 2x the pipe diameter. All dam fill will be compacted around the seep collars <br />and principal spillway pipe to 90% of the maximum dry density of the fill material. <br />i. The emergency spillways will be a rip-rap lined trapezoidal channel of 10 feet <br />bottom width and 2:1 sideslopes. <br />The sediment storage capacity of the sedimentation ponds will be monitored and modified as <br />described in section 2.05(3)-3. The excavated material handling and inspections is also described <br />in section 2.05(3)-3. <br />Pit dewatering will be primarily a seasonal occurrence. The dewatering process will be a sporadic <br />operation-controlled, occurrence depending on various factors which may include the location of <br />the pit inflows, the location of standing water in the pit, or the location within the pit of the <br />overburden and coal removal operations. When pit dewatering is required, the anticipated <br />dewatering rate will be in the range of one to two cubic feet per second or less. Most dewatering <br />discharges will be directed to Pond 010, which is the main pond for the amendment area. <br />However, direct pit pumping into Pond 010 may occur if conditions warrant. These procedures will <br />be applied for in W FC's NPDES Permit, which will be similar to Permit CO-0000213 for Pond 007. <br />Actual water flow velocity going into Pond 010 will be controlled with adequate energy dissipators <br />(i.e., rock riprap, geotextiles, metal or concrete energy dissipator boxes, etc.) or discharged onto <br />non-erodible bedrock material. This will minimize erosion of the pond banks. <br />Pit dewatering will have an insignificant impact on Pond 010. Pit dewatering will be sporadic <br />versus continuous. The flow rate of one to two cubic feet per second or less compared to the <br />designed 25-year, 24-hour peak inflow rate of 136.5 cubic feet per second is insignificant. In <br />addition, pit water high in suspended solids will be allowed to set for a period of time so the solids <br />are allowed to settle out of the water and will remain in the active pit area. Furthermore, all <br />discharge from Pond 010 will be in accordance with applicable discharge permits. <br />All ponds will be maintained until the disturbed areas are reclaimed and the vegetation success <br />requirements of Section 2.05.4(2)(e), Revegetation, are met, the untreated drainage from the <br />disturbed area ceases to contribute additional suspended solids above natural conditions, and the <br />drainage leaving the pond meets applicable State and Federal water quality requirements, if any, <br />for the receiving streams. The ponds will be removed when the appropriate sections of the <br />regulations are satisfied. <br />f~J <br />(Revised 12/01) Attachment 2.05.3(3) -10-4 <br />