2005-07-13_REVISION - M2000016 (39)

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LAFARGE NORTH AMERICA Construction Materials the immediate vicinity of well number 2216, which has been identified as low risk for impact during mining activities. Monitor wells DS03-MWOS and DS03-MWOb are also located in the immediate vicinity of well number 13697, which has been identified as high risk for impact during mining activities. Once again, because this is a long-term project, approximately 25 years, Lafarge is maintaining the position that wells located outside a current cone of depression from an existing dewatering operation should not be required to be monitored more than quarterly. In addition, Lafarge believes that the impact to the neighbors wells will be minimal, however, will accept the responsibility of conducting monthly monitoring well readings in the vicinity of the active pit azea that is conducting dewatering efforts that may impact an nearby well. Lafarge has collected over 5 years of water level data for the project and believes that one year of monthly readings across the entire site prior to the start of mining on our first 40-acre parcel will not provide benefit to the project. Lafarge believes that baseline water levels have been established utilizing our multitude of water level readings and requests consideration to the condition stated above. I8. Section 3.2 of the "Groundwater Monitoring Plan" proposes mitigation measures for alleviating offsite ground water impacts, which include delivering water to affected party(s). It appears that changes of water rights may be necessary for implementation of these mitigation measures. For water sources to be legally available when needed for mitigation, they likely need to be included in the Substitute Water Supply Plan submitted to the Office of the State Engineer. The applicant must ensure this mitigation water is approved for those zrses prior to dewatering. Given this information, the applicant must demonstrate that the proposed mitigation plans could work. The mitigation proposed in the "Groundwater Monitoring Plan" was recommended by the Division during a previous permit application and has been successfully implemented in the past. The OSE maintains jurisdiction over approved water uses and water will not be used for mitigation purposes prior to OSE approval. If mitigation is required, the method of mitigation will be agreed upon with the well owner and a temporary change of use, if necessary, will be incorporated into our Substitute Water Supply Plan. 79. The Groundwater Elevation Graphs in Appendix B of the "Groundwater Monitoring Plan"separate irrigation season and non-irrigation season groundwater elevations versus date onto separate plots. How were irrigation versus non-irrigation seasons determined? How will it be determined for future data collection? The Division would find the graphical presentation of these data more useful if the plots were overlaid as two series on one graph or integrated. The Division requests the applicant respond to these inquiries and also submit revised graphs. LAFARGE NORTH AMERICA INC. -Lafarge Aggregates, Conaete & Asphalt 10170 Church Ranch Way, Suite 200 Westminster, Colorado 80021 Televhone: 13031657-4000 Facsimile: (3031657-4037