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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman SL, Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 832-8106 <br />Date: <br />TO: <br />FROM: <br />Septemberl5, 2003 <br />Russ Means <br />Kate Pickford <br />DIVISION O F <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />Bill Owens <br />Governor <br />Greg E. Walther <br />Executive Director <br />Ronald W. Cottony <br />Acing Division Director <br />RE: Potential for Groundwater impacts Related to the Haldorson Sand and <br />Gravel Mine, Haldorson and Sons, Inc., File No. M-2003-037 <br />The Division of Minerals and Geology (DMG) has completed a review of Adequacy Response issues, <br />dated August 28, 2003 and September 2, 2003, and the Hydrology Report, dated September 4, 2003, <br />related to the 112c permit application for the Haldorson and Sons, Inc. Haldorson Sand and Gravel Mine. <br />The DMG is concerned with potential impacts that may result from activity at the site. Therefore, the <br />DMG has the following comments regarding the items below: <br />ht the permit application, the Operator commits to confining mining activities to above the <br />groundwater surface at the site and does not intend to expose groundwater. The groundwater level in <br />the proposed mining azea is dynamic, due to irrigation in the vicinity of the site. The groundwater <br />report submitted with the application indicates that that the test holes used to identify the groundwater <br />surface were monitored during a time that irrigation water was not present. Therefore the Division <br />does not believe that the test holes, monitored as part of the groundwater study, aze indicative of the <br />groundwater surface. <br />Although the permit application specifies that groundwater will not be exposed during the mining <br />operation, the Applicant indicates that the site will be mined to a maximum depth of 40 feet, while <br />observations at the site indicate that the groundwater surface can be as shallow as 25 to 30 feet, or less. <br />It appears that the pazameters set forth in the permit application and the actual conditions at the site <br />may be in conflict with one another. Therefore the Division does not believe that the parameters <br />presented in the application will assure that the Operator will adhere to the permit limitations and not <br />expose groundwater at some point during groundwater seasonal fluctuations. <br />Therefore, since the operator is committing to mining above the groundwater level and, at this time, <br />the groundwater level has not been specifically identified; the Division believes that to permit the site, <br />the Applicant must adhere to one of the following options: <br />1. If the Operator is committed to mining without contacting groundwater, the maximum depth of <br />excavation must be reduced and monitoring of the groundwater levels must commence prior to <br />excavation and continue until a groundwater maximum can be established. Therefore, one option for <br />the Applicant is to change the maximum mining depth in the current application to 20 feet below <br />ground surface, and commit to a goundwater-monitoring plan that commences prior to mining of the <br />site, and that will monitor the groundwater surface to asswe that mining to the 20 foot depth will not <br />expose groundwater. Water level data from the monitoring wells should be submitted to the Division <br />for review. If monthly data from the wells can establish a maximum groundwater level, over the <br />course of a yeaz, which would allow for excavation to a depth deeper than 20 feet, without exposing <br />