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-52- Water from the underground workings will be collected and pumped to a sump near the portals. Water in this sump will then be pumped to a collection ditch which routes the flow into Pond D for settling. Disturbed area drainage from adjacent surface areas not controlled by the Area Z pit or Pond D are routed to other existing sedimentation ponds. All disturbed area drainage required to be treated will be passed through a pond or detention pit prior to discharging. Na exemptions to this requirement have been requested. As a result of surface and underground disturbance at the Foidel Creek t4ine, water discharged from the mine would be high in total suspended solids. To mitigate this condition, the operator has designed the sediment control system to remove suspended solids prior to the water being discharged to Foidel Creek. The final water discharged must the discharge requirements of their NPDES permits. Surface water runoff volumes and rates were calculated using the Soil Conservation Service model - SCS Technical Release No. 55, Peak Flows in Colorado, 1977. Rainfall data was obtained from NOAA Atlas 2, Volume III far Colorado. Most of the initial calculations were submitted and approved in Section 780.11 of Permit No. 79-171. Additional calculations were provided to show that the proposed modifications are in compliance with the design and performance standards of the regulations. Pond storage volumes and appurtenant designs are in compliance even with the additional water anticipated to be pumped from the underground mine. The operator will inspect the pond and report findings quarterly. A variance was requested from Rule 4.05.18 which pertains to stream buffer zones. This rule prohibits surface or underground disturbance within 100 feet of a stream unless specifically approved by the Division. The applicant does not plan any new surface disturbance within the established 100 foot buffer zone on Foidel Creek. They do however, plan to develop underground mine entries below the creek. The exemption covers an area north of the portal area under Foidel Creek ranging from 1,200 feet wide on the north side to 550 feet wide on the south side of the stream. The boundaries are clearly identified on Map No. 10 -Water Control Plan. (See Section XX of this document for a discussion of subsidence beneath Foidel Creek.) The Division hereby approves of the variance based on the following findings required by Rule 4.05.18(1): a. The original stream channel will not be disturbed such that restoration is required;