2016-08-05_PERMIT FILE - C2010089A

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with the approved reclamation plan. Site specific conditions will determine the construction methods and equipment utilized at the time of excavation. Sediment removal and water discharges will be conducted consistent with the approved mining permit, the Water Discharge Permit, and DRMS Regulations Section 4.05.6(3)(b). All sedimentation ponds will be inspected quarterly under the supervision of a registered professional engineer and reported to the DRMS. The Water Discharge Permit is enclosed in Appendix 2.05.3(4)-3. The dewatering process will be a sporadic, operation -controlled occurrence depending on various factors which may include the location of the pit inflows, the location of standing water in the pit, or the location within the pit of the overburden and coal removal operations. When pit dewatering is required, the anticipated dewatering rate will be in the range of one to two cubic feet per second or less. Direct pit pumping into Pond NHN-001 or NI -IN -002 is planned for the mining south of Meehan Draw and into Pond NHN-003 for the mining north of Meehan Draw. Actual water flow velocity going into ponds will be controlled with adequate erosion control (i.e., rock riprap, geotextiles, synthetic liner, half -culverts, etc.) or discharged onto non -erodible bedrock material. This will minimize erosion of the pond banks. Pit dewatering will have an insignificant impact on the ponds. Pit dewatering will be sporadic versus continuous. The flow rate of one to two cubic feet per second or less compared to the designed 10 -year, 24-hour peak inflow rate the ponds were designed for is relatively insignificant. Furthermore, all discharge from the ponds will be in accordance with applicable discharge permits. Special Features Temporary Relocation for Colorado Cooperative Company (CC Co.) Second Park Lateral Ditch The CC Co. has operated an irrigation ditch known as the Second Park Lateral Ditch to irrigate lands in the area for many decades. With the mining of the Garvey property, this ditch will need to be diverted. Since the temporary diversion route involves rises and dips, a pipeline must be used. The plans enclosed in this document show the detailed design of the pipeline's temporary route and the permanent relocation. As per the successful experience at NH2 Mine, a high density polyethylene (HDPE) pipeline is the best choice for the temporary and permanent routes. Although expensive, NHN believes that this design will best suit the long term needs of the CC Co. The pipeline starts east of the east permit boundary to gain additional elevation drop as the pipeline is routed south along the county road then around the mine area to the west and then north along 2600 Road to tie into the existing ditch as it leaves the mine permit area. This additional elevation drop is desirous as it provides sufficient pressure to allow for side roll irrigation without the need for pumping. Section 2.05.3(4) Page 5 April 2016 (TR -13)