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Response to CDRMS Comments Mr. Robert Noren, P.E. <br /> Disposal of Alluvial Fill Cotter Corporation(N.S.L) <br /> _ 1.0 TEST PIT FIELD INVESTIGATION <br /> Engineering Analytics conducted a field investigation that included excavation of seven test pits <br /> at the Schwartzwalder Mine Site. The location of test pits is shown on Figure A-1. Test pit <br /> EA-TP1 was excavated in the alluvial material that will constitute the new waste rock to be <br /> placed on the existing piles. Test pits EA-TP2, EA-TP3, EA-TP5, and EA-TP6 were excavated <br /> in the existing waste rock piles. Test pit EA-TP4 was excavated in the colluvial material and EA- <br /> TP7 was excavated in the proposed topsoil material. Test pits EA-TP1 through EA-TP6 were <br /> excavated with a CAT 330C excavator operated by Kessler Reclamation personnel. Personnel <br /> from EA supervised the excavation and logged the materials encountered in the test pits. Test pit <br /> EA-TP7 was excavated with a shovel. <br /> Test pits EA-TP1 through EA-TP6 were excavated to a depth of 3 feet where a bulk bucket <br /> sample was retrieved with a shovel, by EA, from the spoils pile. The test pits were then <br /> excavated to a depth of 5 feet where another bulk bucket sample was retrieved from the spoils <br /> pile. Laboratory testing was performed on the bulk samples to measure geotechnical engineering <br /> properties of the subsurface materials. The test pit logs and photographs of the test pit <br /> excavations are included in Appendix A to this attachment. Following excavation the test pits <br /> were backfilled with the spoils. <br /> Test pit EA-TP7 was excavated in the topsoil material. This material was taken by EA, with a <br /> shovel, from ground surface in the location shown on Figure A-1. Another sample was taken by <br /> Cotter Corporation at a later date to obtain additional material for laboratory testing. The test pit <br /> log is included in Appendix A to this attachment. <br /> 2.0 LABORATORY TESTING <br /> Laboratory testing was conducted on selected samples obtained from the test pits to determine <br /> geotechnical engineering properties of the materials. Laboratory testing included measurements <br /> of in-place water content, Atterberg limits, and grain size analyses. Large scale direct shear <br /> testing was also performed. The direct shear testing was performed by Advanced Terra Testing <br /> of Lakewood, Colorado. The remainder of the laboratory testing was performed by EA's lab in <br /> Fort Collins, Colorado. The laboratory test results are included in Appendix B to this attachment <br /> and are summarized in Table A-1. <br /> Water Content: Measurements of water content were conducted on each bulk sample in <br /> accordance with ASTM test methods D2216. The values of water content ranged from 4.2 to 9.3 <br /> percent for the waste rock, alluvial, and colluvial material. The water content was 1.8 percent for <br /> the topsoil. <br /> Grain Size: The particle size distribution was determined on each bulk sample in general <br /> accordance with ASTM D4318. The particle size distribution reports are included in Appendix <br /> B. The measured value of percent.passing the #200 mesh sieve was 8.4 percent for the alluvial <br /> material, 15.2 percent for the colluvial material, ranged from 8.0 to 34.7 for the waste rock, and <br /> was 11.7 percent for the topsoil. <br /> October 26, 2016 A-I Engineering Analytics, Inc. <br />