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1 <br />1 ARCADIS <br />1 <br />I In 2001, the wet kilns were replaced by a single dry kiln with a clinker capacity of <br />1,873,898 tpy. The dry kiln allows all of the CKD generated to be recycled within the <br />I process. However, during the production of low- alkali clinker, calcium chloride is added <br />to the process to assist the removal of alkalis from the raw material. Some of the alkalis <br />are removed by taking a portion of the raw material out of the process via the alkali <br />I bypass system. The "alkali bypass dust" removed from the process is similar in <br />chemistry to the prior CKD and is transported to the CKD disposal area in the quarry. <br />Where possible, bypass dust is sold to customers to eliminate the need for disposal on <br />1 site. Outside uses for the bypass dust must be approved by Holcim. Bypass dust is <br />produced now at a much lower rate than CKD when the wet kiln system was in <br />operation. From 2005 to 2010, bypass dust production averaged 10,229 tpy. <br />I In 2001, with the construction of the new kiln, a pug mill was installed to add water to <br />the bypass dust prior to transporting the bypass dust to the disposal area in the quarry. <br />1 The purpose of adding water is to reduce dust emissions. With the addition of the pug <br />mill, use of sludge from the Fremont Sanitation District wastewater treatment plant for <br />CKD emissions control was discontinued. <br />' The uarr is located on the northern side of the Arkansas River across from the plant. <br />q Y p <br />I The bypass dust is currently being disposed of in a previously mined section (cut) of <br />the limestone quarry to the south of former monitoring well MW -10. The locations of <br />cuts previously used for CKD disposal are indicated on Figure 2. The bottoms of these <br />I cuts coincide with the top of the underlying CodeII sandstone, which is the primary <br />water- bearing unit in the quarry area. To prevent contact of CKD /bypass dust with <br />regional groundwater, approximately 10 feet of shale was backfilled and compacted in <br />I the bottom of these cuts prior to placement of bypass dust/CKD. Descriptions of the <br />site geology and hydrogeology are provided in the Groundwater Monitoring Plan <br />(GMP; Blasland, Bouck & Lee, Inc. [BBL] 2002). <br />1 1.3 Site Regulatory History <br />I In Colorado, the regulatory responsibility for CKD disposal requirements is delegated to <br />the DRMS. Therefore, the requirements for CKD management are incorporated into <br />each facility's Mined Land Reclamation Permit. Specific requirements for protection of <br />I groundwater are described in Rule 3.1.7(7)(i) through (viii) of the "Construction Material <br />Rules and Regulations" (Mined Land Reclamation Board [MLRB] 2001) and the <br />Colorado Department of Public Health and Environment (CDPHE), Water Quality <br />1 Control Commission (WQCC) Regulation No. 41 "Basic Standards for Ground Water" <br />(CDPHE 2008). <br />1 <br />1 <br />2011 Groundwater <br />Monitoring Report <br />Florence, Colorado <br />2 <br />