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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 aze described below. <br />ReQtrlated 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 slung <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 erigineer 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 standazd leakage <br />criterion is attainable. With this level of assurance, contingency bonding for repair or _ <br />emen o percen o e of rneaz eet o s urry w rs accepts e. a number of <br />lineaz feet of slurry wall and the slurry wall installation costs for the site aze discussed below. A . <br />table summarizing a typical specification and quality control plan is at&ZChed. <br />Performance Bondine Option <br />In this option, the operators aze 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 <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 Fillin¢ <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 aze proposed to be reclaimed as lined storage <br />reservoirs since the passage of Senate Bill 120 in 1989. It has become cleaz 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 />