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The Division would propose two permitting options suitable for assuring that the post mining <br /> land use of developed water resources will be established at the site through the installation of <br /> slurry walls. These options are described below. <br /> Regulated Construction Option <br /> The applicant may provide design drawings and specifications for the installation of the slurry <br /> wall along with a quality assurance/quality control plan. These documents would be binding <br /> under the terms of the permit, and the Division would require a statement that the plans and <br /> specifications, once approved, could not be altered without consent by the Division. The <br /> operator would be required to advise the Division of the schedule for construction of the slurry <br /> wall so that inspections could be scheduled at appropriate times during installation. The operator <br /> would be further required to provide a construction report detailing the installation of the slurry <br /> wall, describing any problems that occurred, and listing the results of testing that was conducted <br /> under the approved quality assurance/quality control plan. A certification would be required to <br /> accompany the construction report with a statement from the quality assurance engineer that the <br /> slurry wall was constructed in accordance with the approved plans and specifications. <br /> With the level of regulatory control over the installation of the slurry wall described above, the <br /> State would gain a high degree of assurance that the SEO required design standard leakage <br /> criterion is attainable. With this level of assurance,contingency bonding for repair or <br /> replacement of 20 percent of the total linear feet of slurry wall is acceptable. The number of <br /> linear feet of slurry wall and the slurry wall installation costs for the site are discussed below. A <br /> table summarizing a typical specification and quality control plan is attached. <br /> Performance Bonding Option <br /> In this option,the operators are left to their own devices in the design, installation, and testing of <br /> the slurry wall,but would be required to demonstrate that.the slurry wall limits leakage into the <br /> pit in accordance with the State Engineer's criteria. In this case, the Division would not have <br /> regulatory control over construction of the slurry wall, and would bond for the cost to install a <br /> complete replacement slurry wall. The performance bonding option considers the worst case <br /> scenario where the slurry wall has been installed and the pit has been mined out, but it is <br /> determined that the slurry wall leaks in excess of SEO requirement. Another consideration that <br /> enters into bonding for this worst case scenario is the potential for leakage into the pit.through�=ti <br /> the bedrock pit floor. Unless the applicant can provide a geological evaluation of the proposed <br /> pit floor bedrock that demonstrates that leakage will not occur, the Division should bond for <br /> sealing fractured or sandy bedrock that may be uncovered during mining and that may leak in <br /> excess of SEO established criteria at this time. <br /> Reservoir Filling <br /> Past practices by the Division in permitting lined reservoirs included a requirement to provide <br /> bond sufficient to purchase enough water from a reliable source to fill the reservoir one time. <br /> Numerous gravel pits have been reclaimed or are proposed to be reclaimed as lined storage <br /> reservoirs since the passage of Senate Bill 120 in 1989. It has become clear that there is a great <br /> demand for lined storage in over appropriated basins. It is no longer a substantial concern to the <br /> Division that lined reservoirs will not be filled and put to their intended beneficial use along the <br /> Front Range. In the worst case, virtually any reservoir along the Front Range could be filled <br />