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EN EC <br />? <br />coal company <br />July 29, 2008 <br />Mr. Daniel Mathews <br />Division of Reclamation, Mining and Safety <br />101 South 3rd, Suite 301 <br />Grand Junction, CO 81501 <br />(970) 242-5025 <br />RE: Seneca II-W Mine (Permit C-1982-057) <br />Addendum to 2008 Rill & Gully_Survey_ <br />Mr. Mathews, <br />Seneca Coal Company <br />RECEIVED <br />JUL 31,2008 <br />Mining and Safety <br />Seneca Coal Company (SCC) is submitting this package in response to items requested in your II-W Mine Inspection <br />Report, dated 6/18/08. <br />SCC retained a qualified geotechnical engineering firm (NWCC) to conduct a slide evaluation and geotechnical <br />investigation of the Pond 016 slide area and the shrub plot slide. Following is the scope of work to conduct the <br />evaluation and investigations, submitted by NWCC: <br />Scope. <br />Shrub Plot Slide <br />1) Advance S to 6 test pits across the slide with a trackhoe provided by the client. The depth of the test pits will be determined in the <br />field as the excavations progress and as the subsoil profiles become evident. We have assumed that the test pits will be excavated to <br />depths ranging from 10 to 20 feet, depending on subsurface conditions encountered <br />Pond 016 Slide <br />1) Advance S to 6 test holes across the slide area situated north of the existing Pond 16 with an all terrain drill rig. In addition, S to <br />6 test pits will be excavated with a trackhoe provided by the client. The depth of the test holes and testppits will be determined in <br />the field us the drilling and excavation progrr s and as subsoil profiles become evident. We have assumed that the test holes will be <br />drilled to a minimum depth of 30 to 40 feet and the test pits will be excavated to depths ranging from 10 to 20J eet, depending on <br />the subsurface conditions encountered The test holes and pits will be advanced to investigate the subsurface profiles, to obtain <br />samples for laboratory testing, to estimate the groundwater level and the depth to bedrock. Slotted PVC pipe will be installed in <br />several of the test holes so that the groundwater levels and soil movement can be monitored <br />2) Conduct a laboratory-testing program to determine the strength, compressibility or swell characteristics, classification and <br />permeability of the soil and bedrock materials obtained from the site. <br />3) Analyze the results of the field and laboratory investigations so that we can provide alternatives for repairing and/ or stabilizing the <br />existing slope failure. <br />Seneca Coal Company a P.O. Box 670 • Hayden, Colorado 81639 <br />Telephone (970) 276-5219 • FAX (970) 276-5222