2016-01-27_REVISION - M1979059 - Laserfiche WebLink

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January 20, 2016 W S I Weiland, Inc. Environmental & Engineering AN 272016 DIVISION Or RECLAMATION MINING AND SAFETY Michael Cunningham Environmental protection Specialist Colorado Division of Mining Reclamation & Safety 1313 Sherman St., Room 215 Denver, Colorado 80202 Environmental Support for; • Transportation • Land Development • Mining • Industry Re: M-1979-059; Response to Preliminary Adequacy Review letter dated October 7, 2015 Michael, The following numbered responses correspond to your numbered comments in the 2nd Adequacy Review Letter dated October 7, 2015. Additional supporting documents have been attached. 1. The Amendment to include the additional affected land on the Pfeiff property was filed November 30, 2015. The Amendment application also included revisions to the specific Exhibits in response to adequacy comments as described below. 2. A backfilling specification and affidavit of clean fill is given as Attachment 6.4.5-A in the amended application. 3. Groundwater modeling was conducted for the pumping operations at the Flying W Pit (M-2005-004) which is downstream of the Brownwood site south of the Big Thompson River adjacent to 1-25. Based on a pump rate of 1,040 GPM, the model predicted the cone of depression extended to no more that approximately 1,200 ft. The report text and pertinent drawing (Sheet 5) have been attached for reference. In the unlikely event that the applicant does adversely affect the ability of surrounding wells to pump their full supply of water in accordance with their permitted uses, the applicant agrees to mitigate the water supply per items a) through d) as indicated in the revised Exhibit G. A figure has also been added to Exhibit G (Figure 1) to show the proximity of permitted groundwater wells south of the Big Thompson River to the Brownwood Site. PO Box 18087. BOULDER. CO 80308 ph 303-443-8521