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PAR - C-80-007 - 9 - March 31, 1986 1. Page one references Exhibit 1, a map showing watershed areas and associated streams reservoirs, and ditches. This map could not be located. A map should also be provided that shows the buffer zone proposed for Minnesota Creek that includes the angle of draw for subsidence. The existing 50 percent extraction "safety zone" map is unclear as to whether it includes angle of draw. 2. Page 2, Table 1. Do the drainage areas (total area in acres) begin at the mouth of the stream or at the gaging station? Do the acreage figures for area with potential to be impacted include angle of draw for subsidence? Total area for the drainage basins should begin at the mouths of the streams. The angle of draw should be included in this determination of potential area to be impacted. 3. Page 4. Has the Lower East Fork gaging station been installed? If not, when do you expect its installation will be completed? What is the percentage water contribution by basin for Minnesota Creek above the Minnesota and Turner Ditch diversions? 4, Page 4 states that springs located on the mine permit area play a minor role in maintaining low flows. Quantify, on a monthly basis for each subbasin, the contribution that springs make to maintaining low flows. also, quantify how much colluvial and bedrock discharge contributes to stream baseflow. This is necessary to make a worst case prediction of impacts. 5. Page 6 states that some surface water or groundwater may seep into the mine as a result of subsidence fracturing. Quantify the amount of mine water inflows expected. Quantify how much water the entire WECC drainage basin contributes to Minnesota Reservoir and downstream users from June to September (exclude the Deep Creek Ditch and include springs, runoff, and bedrock discharge). 6. The explanation of why springs below the F seam should not be affected by mining is not clear. Please expand this discussion so that it is clear to all parties how you arrived at this prediction, 7. Page 7. What is the percentage of capturable water for years 1981-1986? 8. Page 7 states that the Dry Fork channel will be protected by limited extraction. Quantify inflows expected from fractures that are in communication with the Creek. 9. Page 7. What are the details of WECC's mitigative plans to correct any adverse impacts on streamflow resulting from mining? How will loss of flow from Dry Fork be monitored? How will subsidence be monitored? How much subsidence can occur before mitigation action is necessary? How will the stream be reconstructed following subsidence? Will maintenance be necessary for the reconstructed stream? This information needs to be provided in conceptual form to at least enable the division to assess the feasibility of your mitigation plans.