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<br />May 31, 1994 <br />-2- <br /> <br />943-2720.010 <br />Generally the tails are classified as low to non-plastic sand with silt. They are classified as <br />SM under the Unified Soil Classification System (ITSCS). The tails are generally loose to <br />medium dense and dry to moist down to the water table. The depth to the water table varies <br />with the valley bottom shape and the relative position to the pool location for each <br />impoundment. Direct shear and CIU triaxial testing performed by Woodward-Clyde (1990) <br />measured internal friction angles of approximately 38° for the tailing material. In-situ dry <br />densities ranging from 69.3 to 99.0 pcf were also measured. <br />2.3.3.2 Carlton Mill Tailings Impoundments 1. 2. and 3 <br />Analytical Procedures <br />ANALYTICAL PROCEDURES <br />CARLTON MILL TAILINGS <br /> Geochemical Testing Procedure and Number of Samples Tested <br /> <br />Component EPA Method <br />1312 Acid-Base <br />Accounting <br />TCLP <br />Cyanide <br />MWMP' <br />Nl Tailings Pond -surface 3 solids <br />~3 Tailings Pond -surface 1 solids <br />1f 1 Tailings Pond -subsurface L solids 1 solids 1 solids 1 solids <br />lY1 Tailings Pond -subsurface 2 solids 2 solids 2 solids 2 solids <br />Meteoric Water Mobility Procedure <br />Geochemical Analytical Results <br />Comparison of TCLP and 1312 results of analyses <br />Tables 6 and 7, present a comparison of the TCLP and 1312 analytical results. Aside from <br />the differences in detection limits for the two protocols, the results aze essentially the same. <br />The numeric values for cadmium, chromium, lead, selenium and silver are the same, given <br />the variation in detection limits and, do not exceed the TCLP "Concentration for Toxicity". <br />Arsenic is slightly different but in all cases does not exceed the TCLP "Concentration for <br />Toxicity". Barium is mazginally different but in ail cases does not exceed the TCLP <br />"Concentration for Toxicity". The Barium values in all TCLP and 1312 analyses are close <br />to the limit of detection and may be below the practical quantitation limit of the analytical <br />protocol used. <br />