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1�t_] <br />Mr. Michael Boulay <br />April 8, 2014 <br />Page 3 <br />Response: The SEDCAD analysis has been revised based on a drainage area of 82.9 acres. <br />DRMS Item 11. The approved design of Pond 013 indicates a capacity of approximately 14 acre - <br />feet (at the bottom of emergency spillway). The submittal, however, indicates a capacity of 29 <br />acre-feet. Please explain this discrepancy. <br />Response: The SEDCAD analysis has been revised to reflect the as-built specifications of <br />Attachment 2.05.3(3) -18. <br />DRMS Item 12. Please include an analysis of Pond 013 capacity that includes pumpingfrom the <br />NH2 Pit. This could be done in SEDCAD, or it can be a separate analysis that includes inputs <br />from the SEDCAD model as well as information on the volume of water in the pond and estimated <br />pumping rates. <br />Response: A pit pumping value of 22.99 cfs has been determined to be the maximum allowable <br />pump rate for dewatering the remaining NH2 Pit with enough capacity in Pond 013 to hold a 10 -YR <br />event below the emergency spillway. <br />DRMS Item 13. Please explain the origin of the particle size distributions used in the SEDCAD <br />model, for both the spoil water andfor flows in and out of the pond. <br />Response: The currently approved Attachment 2.05.3(3 )-3 Typical Soil Grain Size Analysis is the <br />source of the particle size distributions. The soil type of Sandy Loam is used at New Horizon Mine. <br />If you have any questions or just require additional information, please do not hesitate to <br />contact Chris Gilbreath at (303) 254 -3291 or cgilbreath r tristategt.org. <br />�incerely, <br />Chris Gilbreath <br />Manager <br />Water, Waste, and Mining Compliance <br />CSG:JS:pvt <br />Enclosure <br />cc: DRMS, Grand Junction Field Office <br />Rob Zuber, DRMS (via email) <br />Jason Storey (via email) <br />AN EQUAL OPPORTUNITY / AFFIRMATIVE ACTION EMPLOYER <br />A Touchstone Energy'C.vperative <br />