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4 042h/ <br />ms;?EIV%AEC <br />coal Company <br />September 22, 2009 <br />Seneca Coal Company <br />Mr. Dan Mathews <br />Division of Reclamation, Mining and Safety <br />101 South Yd, Suite 301 <br />Grand Junction, CO 81501 <br />(970) 243-1571 <br />S <br />od <br />d ?d . <br />moo. <br />d <br />RE: Yoast Mine Permit No. C-94-082 <br />Technical Revision (TR-44), Ridgeline Disturbance Area SAEs <br />Response to Adequacy Comments <br />Mr. Mathews, <br />SCC has reviewed the adequacy comments dated August 31, 2009. We have developed the following <br />responses to each remaining comment. <br />1. As noted in the cover letter to the TR 44 application, the primary purpose of the revision plan is to divert potential <br />runoff away firm the Pond 012 slide area. To provide additional assurance that this purpose would be <br />• accomplished, we request the following clarifications and/or mo&ficatrons to the proposed <br />plan. <br />a) We recommend that SAE-3 sump be located further to the east along the ridgeline, at the eastern boundary of the <br />original haul read disturbance. Drainage from the haul road disturbance is not required to be passed through a <br />sediment pond or SAE treatment structure. Thus, the sump could be located at the east edge of the haul road <br />corridor on the ridgeline, minimising the drainage area to be ditched and treated Drainage from the haul road <br />disturbance west of the relocated sump should be diverted to the north, away from the slide, using a series of small <br />berms or water bars This would eliminate the need to concentrate and collect runoff along the western end of the <br />ridge, in the vicinity of the slide. <br />b) Due to damage caused to lower sections of Ditch YPM-23 by slope movement, it is no longer ffective in conveying <br />surface flow away from the slide, and into the sediment pond If SAE-3 sump is moved further to the east and <br />water bars are installed across the haul road disturbance corridor as recommended, the upper section of YPM-23 on <br />the ridgeline should be regraded and eliminated. <br />c) Please clarify, in the amended narrative of Section 7.0 on page 14, Attachment 13-12, that the existing water bars <br />that direct runoff to the south, toward the Pond 012 slide, will be eliminated <br />Response: Per the cover letter accompanying these adequacy comments, it is understood that the SAE plan <br />is an interim drainage control plan to be utilized until a final remediation is approved and implemented. With <br />this in mind, SCC has revised the conceptual plan based on the recommendations presented in Comment 4. <br />Please see response to Comment 4. <br />• <br />Seneca Coal Company • P.O. Box 670 • Hayden, Colorado 81639 <br />Telephone (970) 276-5217 • FAX (970) 276-5222