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ii iiiiiiiiniu iu <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Deparlmeni of Nm ural Resources <br />I ]1 3 Shuman SE, Ruum 21 5 <br />Denver, Colorado HO?OZ <br />Phone 13(1 SI Hfilr 1567 <br />FA %:13(1 it H3] H7116 <br />4 April 1997 <br />Mike Altavilla <br />Seneca Coal Company <br />Post Office Drawer D <br />Hayden CO 81639 <br />SUBJECT: Yoast Mine (C-94-032) Pond O11 <br />Dear Mr Altavilla: <br />II~~~ <br />DEPARTMENT O <br />NATURAL <br />RESOURCE: <br />Roy Romer <br />Loverno~ <br />lames 5. Lochhead <br />E ~ecuovc Director <br />M¢hae B Lnng <br />U~s'~slon Dueao, <br />Referencing your letter of 3 March 1997 concerning the construction <br />of Pond Oll, I want to get this to you so you are aware of our <br />position on the dam, the site and the construction and can move <br />forward with construction this summer as planned. <br />The Division of Minerals and Geology staff has reviewed your <br />SEDCAD+ analysis and dam design and determined that the design <br />meets DMG approval with one exception - the geotechnical analysis <br />of the pond embankment. The original stipulation requested that <br />Seneca Coal Company demonstrate that the pond is as near as <br />practicable to the disturbed area and that the pond embankment has <br />a minimum static safety factor of 1.3. It is my understanding that <br />the required geotechnical analysis has not been submitted. In order <br />to comply with the stipulation and the requirement of Rule <br />4.05.6(11)(k) a suitable analysis of the pond site and proposed <br />embankment will need to be added to the Yoast permit prior to <br />construction of the pond. we appreciate your attention to that <br />detail. <br />A second issue may or may not be relevant. In the original <br />adequacy letter (question #39), the Division requested that the <br />operator add a base flow of 0.017 cfs. This was not included in <br />the SEDCAD+ model. T}3e only need to include base flow in the model <br />is if Seneca plans to pump pit water into the pond during <br />operations OR if there is a natural spring that drains into the <br />pond. The Division is not clear on whether Seneca plans to pump <br />pit water into the pond; if you do, then the Pond 011 SEDCAD+ <br />model should be revised to account for that additional flow. <br />Please feel free to call me with any questions. <br />Sincerely, <br />~, //// <br />James R. Burnell` <br />Environmental Protection Specialist <br />