2004-11-09_REVISION - M2000016 (6)

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~LAFARG E NORTH AMERICA Construction Materials INTRODUCTION 1.1 Scope and Purpose This report presents a proposed well monitoring program to be conducted by Lafarge West, Inc. (Lafazge) at the request of Colorado Division of Minerals and Geology (the Division). The monitoring program has been developed in response to concerns about groundwater levels relative to a proposed gravel mining operation at the Riverbend site; permit M-2000-016, located west of Highway 85, just south of Ft. Lupton, Colorado. The program seeks to establish baseline groundwater levels in the vicinity of the site prior to the stazt of dewatering activities associated with the proposed mining operation. This baseline will be compazed to data collected during the life of the operation to determine if any significant changes to groundwater levels have occurred. The result of this analysis is compared to qualitative information goals to establish whether mitigation by Lafarge is necessary to offset negative impacts to neighbors due to mining activities. If mitigation is necessary Lafazge will use, at the direction of the Division, the most appropriate mitigation method or combination of methods to remedy the situation. 1.2 Project Location and Description The Riverbend site is a series of Lafazge-controlled properties located in portions of Sections 7, 18, and 19 of Range 66 West and Sections 12, 13, and 24 of Range 67 West of the 6`h P.M., Weld County, Colorado. The 1,368-acre site is between WCR 6 and Highway 52, one-quarter mile west of Highway 85. Thirty (30) monitoring wells surrounding the Riverbend site at varying distances have been established for taking measurements associated with the monitoring program. These wells have either been modified for this use or driven specifically for this purpose, generally consisting of 2"PVC tube with a perforated end piece. Figure 2 is a map showing the location of these 30 wells. Measurements have been taken for groundwater elevation on a quarterly basis or more frequently. Baseline conditions are included in this report; future measurements will be reported to the Division in each annual report. Special reporting will occur in the event of a significant change, specifications regarding a significant change and resulting actions are detailed in Section 3. 1.3 Information Goals The primary goal of the monitoring program is to determine within a certain confidence level what the groundwater condition was before mining begins and what it is like after mining has commenced, and whether the difference is significant. This has two ramifications. The first is the ability of neighbors to legally use groundwater at the same rate as they had prior to the start LAFARGE NORTH AMERICA INC. 'Lafarge Construction Materials 10170 Church Ranch Way, Suite 200, Westminster Colorado 80221 Telephone: (303) 657-0ODO Facsimile: (303) 657-0037