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~, Introduction Blasland, Bouck & Lee, Inc. (BBL) was retained by Holcim, Inc. to provide technical support for Mine Permit Technical Revision TR-06 (TR-06) to State of Colorado Mining Permit No. M-77- 344 for the Holcim Portland plant and quarry. The Holcim Portland plant and quarry is located in Fremont County, Colorado (Figure I). The total area of the Holcim property is approximately 3,400 acres, In partial fulfillment of the Colorado Division of Minerals and Geology's requirements for TR-06, a Groundwater Monitoring Plan (GMP) was developed for the approximately 1,330 acres included within the boundaries of the mining permit (Site) (Figure 2) (BBL, 2002). The main purpose of this GMP is to meet the requirements of the Colorado Mined Land Reclamation Board's (NLRB) Construction Materials Rules and Regulations Rule 3.1.7 for the protection of existing and reasonably potential future uses of the unclassified groundwater located beneath the quarry (NLRB, 2001). These requirements have been triggered by the disposal of cement kiln dust (CKD) into previously mined sections of the Site, and the potential for leachate from CKD to adversely impact ambient groundwater quality for existing and reasonably potential future uses. In support of the GMP, two monitoring wells were installed in July 2003, and all new and existing monitoring wells were sampled in August, 2003. This document describes the procedures followed during installation of the two new wells and collection of groundwater samples, and presents the results of the groundwater analysis. The remainder of this Introduction section presents the history of the site that is relevant to groundwater quality. Section 2 describes the field activities for the installation of two new monitoring wells, measurement of groundwater levels, and sampling of new and existing monitoring wells. Section 3 presents results for the groundwater analyses and groundwater elevation measurements. Section 4 presents a description of future work. Cited references are provided in Section 5. 1.1 Site History The Portland plant, located on the southern side of the Arkansas River, until recently consisted of three (3) long, wet kilns with a combined cement production of approximately 937,000 tons per year (tpy). The Plant currently uses a single dry kiln process for production of cement with a capacity of 2,094,000 tpy. The facility utilizes afive-stage preheater/precalciner tower to prepare material for the kiln. The tower includes heat-exchanging cyclones (i.e., preheater) in which the dry feed is preheated and partially calcined by the kiln's hot exit gasses prior to entering the actual kiln. A secondary firing device (i.e., precalciner) in the lower stage of the preheater further calcinates the materials. CICD, a waste material from cement production, is dust that is generated in the cement kiln and associated equipment. Using the prior wet kiln process, approximately 100,000 tpy of cement kiln dust (CKD) was generated during the production of cement at the Portland plant (Resource Geoscience, Inc. (RGI), 1999)). The current CKD production rate ranges from 28,000 tpy to 72,000 tpy. The production of CKD strongly depends upon the chemistry of raw materials, type of process and the design of gas velocities in the kiln. Other factors such as kiln performance and dust collection systems play vital roles. To reduce dust emissions, a pug mill is used to add water to CICD prior to transporting it to the disposal area. Historically, sludge from nearby Fremont Sanitation District wastewater treatment plant had been added to the CICD disposal area as a daily cover. The sludge also served as a means of CKD dust control. With the addition of the pug mill, use of the sludge for CKD dust control was no longer required and has not been utilized since the startup of the new plant in 2001. 1:\Holcim\GW Monitoring ReportV4332186.doc l-1