2011-09-09_APPLICATION CORRESPONDENCE - C2010089 (2)

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C- 2010 -089 PAR No. 2 New Horizon North Mine 9- Sep -2011 Page 7 of 25 7. WFC has done a good job with their initial baseline data collection efforts for ground water information with regard to monitoring well depths and locations. These are consistent with the discussions held with WFC regarding groundwater monitoring sites during the planning phases of this project. However, additional down gradient monitoring and a point of compliance well(s) may be required. The Division agrees with WFC's assessment that there are no current users for the relatively small amount of groundwater that is currently moving through the shallow bedrock zones, overburden and coal toward the crop line to the southwest. Because this groundwater is potentially usable it must be monitored and the extent and magnitude of any mining impacts must be determined. Given the information we now have as provided on geologic cross - sections, piezometric level maps, and the disturbance boundary as shown in the application the Division believes that one additional group of nested wells may be warranted. The reason for this is that the full extent of the disturbed area is not being monitored in the downgradient direction (i.e., the southwest end of the southernmost mineable block). WFC has other existing monitoring wells in this general vicinity that may be suitable and could potentially be included in the monitoring plan for this purpose. Additionally, there is no discussion of groundwater points of compliance for the proposed project. Please review your ground water monitoring program specific to establishing a groundwater point (or points) of compliance at the New Horizon North Mine, and specify which well or wells will be available as point of compliance well(s). The PAP should address the need for points of compliance and be updated accordingly. The Division believes that a meeting would be beneficial to clarify and discuss our questions regarding the need for additional downgradient monitoring and point(s) of compliance. DRMS: The Division identified the need for additional downgradient groundwater monitoring and the potential need for a point of compliance well. WFC responded by stating they will consult with CDRMS on location of additional nest site and point of compliance site and that the new sites would be constructed following permit approval and prior to new disturbance. Please provide a plan for an additional group of nested wells at a downgradient location as requested. The Division will require an approved plan and design for the additional nested well site prior to permit approval. The wells shall be drilled and installed prior to disturbance. The need for points of compliance can be determined at a later date following permit approval. 8. Response accepted. 9. Response accepted. 10. Response accepted. 11. On page 11 Springs and Seeps are described. There are three identified spoil springs at the New Horizon 1 Mine as described but it is unclear what their current status is. This should be added to the discussion. Please describe in detail the existing spoil springs at the New Horizon Mine #1 include a discussion of whether or not they are still discharging and whether or no they are being monitored. If applicable, add to the discussion the approximate time that monitoring ceased for all spoil spring locations. DRMS: Response accepted. However, there are typos at the top of page 13 of the revised text. Please remove the underlining from the first paragraph of page 13; the last sentence of the same paragraph is fragmented and needs to be revised. 12. Response accepted.