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Job No 360100-003-4 Client: LRM age 1 of _5 <br /> TELESTO Task Initial <br /> I ------Com acted Backfill Computed By: <br /> W. icco Date: 2/26/18 <br /> SOLUTIONS• r r F <br /> -_-Leakage Estimate <br /> . . . Checked By: E.Humphrey Date:2/27/18 <br /> Calculation Documentation <br /> Problem Statement: <br /> Loveland Read-Mix Concrete Inc. (LRM) is planning aggregate mining and concrete batch plant <br /> operations at the Knox Pit near LaPorte, Colorado. After mining, LRM will seal the pit perimeters to <br /> limit the seepage (leakage) of surrounding groundwater into the pit. LRM plans to utilize on-site, <br /> overburden materials in the construction of the perimeter seal (liner) by completing a compacted <br /> soil liner. It is unknown if overburden materials are suited for this purpose. <br /> Objectives: <br /> 1. Evaluate the potential for site overburden materials to perform as a compacted soil-liner <br /> at the Knox Pit <br /> Approach: <br /> 1. Collect overburden material samples and test their compaction and resulting <br /> permeability characterisitcs <br /> a. Compact samples to 95% of standard Proctor <br /> b. Run flexible-wall membrane permeability tests at 50 psi to ensure a factor of <br /> safety from anticipated site conditions <br /> 2. Use Darcy's Law and the results from the material tests to estimate potential <br /> performance in relation to the Colorado State Engineers Office's (SEO's) leakage criteria: <br /> ft3 ft3 <br /> Qleakage 0.03 day ft2 Lwall Davg + 0.0015 day f t2 A bottom <br /> Data and Assumptions: <br /> 1. Drilling samples and subsequent laboratory analysis from the underlying Pierre shale <br /> indicate nearly impermeable conditions- assume hydraulic conductivity is less than <br /> 1x10-7 cm/sec (0.00028 ft/day). The second term in the leakage criteria equation is <br /> thus met. Thus, the first term needs to be satisfied to meet the SEO critera <br /> 2. Backfill and groundwater geometry (definitions): <br /> Dgrc 's Law <br /> f Lsg ft <br /> Averase flow <br /> tl7lc�wens <br /> VA <br /> A„g=171=12 ft leakage = <br />