PERMFILE72271 - Laserfiche WebLink

Home Browse Search

LAFARGE 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. (Lafarge) 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 Duckworth site; permit M-2003-091, located on WCR 20'/z east of Longmont, Colorado. The program seeks to establish baseline groundwater levels in the vicinity of the site prior to the start of dewatering activities associated with the proposed mining operation. This baseline will be compared 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 any mitigation by Lafazge is necessary to offset negative impacts to neighbors due to mining activities. If mitigation is necessary Lafarge 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 Duckworth property is located in the Southeast '/< of the Northeast % of Section 16, Township 2 North, Range 68 West of the 6s' P.M. The 55.5-acre property is immediately north of WCR 20'/z ,one-quarter mile west of WCR 7. Four monitoring wells sunrounding the Duckworth 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 1 is a map showing the location of these four wells. Measurements have been taken for groundwater elevation on a quarterly basis or more frequently. Results are to be reported annually except in the case of a significant change, 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 ofmining. The second is expressed by Division regulations requiring the operator to minimize "disturbances to the prevailing hydrologic balance of the affected land and of the surrounding area and to the quality and quantity of water in surface and groundwater systems, both during and LAFARGE NORTH AMERICA INC. -Lafarge Construction Materials 1400 West 64~ Avenue, Denver, Colorado 80221 Telephone: (303) 657-0000 Facsimile: (303) 657-4037