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vvrVC <br />Wright Water Engineers, Inc. <br />2490 Wes[ 26th Ave., Suite I OOA <br />Denver, Colorado 8021 I <br />~303~ 480-1700 TEL <br />J303J 480-1020 FAX <br />November 29, 2005 <br />vvv/w.wrightwatec com <br />e-mail:wwe®wrightwarec com <br />Via First Class Mail and Fax 303/832-8106 <br />Mr. Thomas A. Schreiner <br />Environmental Protection Specialist <br />Colorado Division of Minerals and Geology <br />1313 Sherman Street, Ste. 215 <br />Denver, CO 80203 <br />RECEIVEQ <br />NOV 3 0 2005 <br /> <br />Re: Response to Questions Raised in Adequacy Review of <br />Heit Sand and Gravel Mine, Technical Revision No. 2 (DMG Permit No. M-2003-016) <br />Dear Mr. Schreiner: <br />This letter responds to the questions in your November 3, 2005 letter regarding Technical Revision <br />No. 2 for the Heit Sand and Gravel Mine. This letter is being submitted on behalf of the owner SW <br />Chambers, LLC. The following responds to the questions in the order that you raised them. <br />"Post mining" groundwater data means data collected following completion of installation <br />of the slurry wall at the operation. Post mining data refers to "mining or operational phase" <br />data, as described in your letter. <br />2. Figure 3 of the report entitled Groundwater Evaluation for Proposed Heit Aggregate <br />Operation, Weld County, Colorado (March 2003) shows the extent of the mounding and <br />shadowing effects predicted. As this figure shows, mounding of 2 feet is predicted to extend <br />approximately 350 feet to the southwest of the pit; a shadow effect (drawdown) of 2 feet is <br />predicted to extend approximately 100 feet to the north. <br />There are no known structures, including basements, septic tanks, and wells, within the <br />predicted area of mounding. Most of the area where mounding will occur is wetland, which <br />would not be negatively impacted. <br />The only structure known to exist within the predicted area of the shadow is an irrigation <br />well owned by Aquatic and Wetland Nursery, Inc. This well has Permit No. 50354-F, and a <br />reported depth of 26 feet. A shadow effect (i.e., drawdown) of 2 feet is predicted at this <br />well. This represents less than 10 percent of the estimated saturated thickness. This amount <br />of shadow effect is within the natural range of expected groundwater fluctuation, and should <br />not have a significant impact on the well. <br />3. A final report listing the findings of the investigation can be submitted to the DMG in the <br />form of a technical revision, if required. This can be done within thirty days of the trigger <br />being leached. <br />GLENWOOD SPRINGS DURANGO <br />~970J 945-7755 TEL ~970~ 945-9210 FAX ~970~ 259-741 I TEL ~970~ 259-8758 FAX <br />