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?ENEC*a Seneca Coal Company <br />July 7, 2008 <br />Mr. Dan Mathews Jet 0920 g <br />Division of Reclamation, Mining and Safety 01. , Q <br />101 South 3rd, Suite 301 rytsbnotk <br />Grand Junction, CO 81501 Il!FlmyA <br />(970) 243-1571 <br />RE: Yoast Mine Permit No. C-94-082 - <br />NOV CV-2008-001: Abatement Step 2 - Time Extension Request <br />Mr. Mathews, <br />Seneca Coal Company (SCC) is providing information regarding Abatement Step 2, as stated in the "Attachment to <br />NOV CV-2008-001, Extension of Time for Abatement", that extends the time deadline to submit a complete technical <br />revision application from June 30, 2008 until July 31, 2008. <br />Step 2. No later than ju131,. 2008 provide a complete technical revision application, which will include a slide remehation plan <br />prepared 6y a qualifiedgeoteebmeal engineer. The remedial plan will identi1 and assess the factors that contributed to the failure, will <br />include specific remedial measures to be implemented to rrpair the slide and effect compliance with the applicable requirements of Rule <br />4.14, and shall include a geotechnical stability analysis demonstrating that the remedial plan will result in a final slope that will comply <br />with Rule 4.14.2(1)(6). The application will also address both short terra and long term measures that will be taken to provide <br />adequate sediment controls in the Pond 12 watershed, consistent with long term mass stability of the failed slope. Short terra measures <br />may include cleanout of Pond 12, if the geotechnical apart demonstrates that such cleanout can be accomplished without compromising <br />slope stability. The application will include a schedule for implementation of the slide remediation plan, including the short term and <br />long term sediment control measures for the Pond 12 watershed <br />Response: The Yoast Mine is located at an approximate average elevation of 7,700 feet. At this elevation the ground <br />conditions remain wet in the drainage bottoms throughout the spring and early summer (probably into July especially <br />given the extreme snowfall experienced over the 2007-2008 winter season). Equipment, such as that needed to evaluate <br />--the root cause of the-situation, cann6t even access the area until considerable drying/dewatering has occurred. <br />SCC retained a qualified geotechnical engineering firm (NWCC) to conduct a slide evaluation and geotechnical <br />investigation of the Pond 012 area. Following is the scope of work to conduct the evaluation and investigations, <br />submitted by NWCC: <br />Sco <br />1) Advance 7 to 8 test holes across the slide area situated north/northeast of the existing Pond 12 with an all terrain drill ri g. In <br />addition, S to 6 test pits will be excavated with a trackhoe. The depth of the test holes will be determined in the field as the drilling <br />and excavations progress and as the subsoil profiles become evident. We have assumed that the test holes will be drilled to a <br />minimum depth of 20 to 40 feet and the test pits will be excavated to depths ranging from 10 to 20 feet, depending on the <br />subsurface conditions encountered The test holes and pits will be advanced to investigate the subsurface profiles, to obtain samples <br />for laboratory testing, to estimate thegroundwater level and the depth to bedrock Slotted PVC pipe will be installed in several <br />Seneca Coal Company • P.O. Box 670 a Hayden, Colorado 81639 <br />Telephone (970) 276-5219 • FAX (970) 276-5222