Laserfiche WebLink
. '1a III IIIIIIII I <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmenl of Natural Resources <br />1313 Sherman 51., Room 215 <br />Denver, Colorado 80203 <br />Phone: (3031 BbG-3567 <br />FA%: 13071 832 8106 <br />STATE OF COLORADO <br />MEMO TO FILE <br />File No.: C-94-082 - Yoast Mine <br />Operator: Seneca Coal Company (SCC) <br />Date: August 9, 1996 <br />Specialist: Susan Burgmaier <br />Subject: Pond 10 Construction <br />Type of Interaction (Meeting, Phone, OtflerJ: Phone <br />Person(s) Contacted and Affiliation: Michael Altavilla, Seneca Coal Company <br />(970) 256-3707 <br />Brian Len, Northwest Colorado Consultants <br />(970) 879-7888 <br />SUMMARY AND RESOLUTION OF INTERACTION: <br />I~~~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />Roy Romer <br />Gorernor <br />lames 5. Lochhead <br />Executive Dneaur <br />M¢hael B Long <br />Division Director <br />Michael Altavilla telephoned in response to my correspondence yesterday regarding Pond 10 <br />at the Yoast Mine. He and Brian Len were on a speaker phone. Their responses, in the <br />order followed in my letter, were: <br />l.a. The material used in the embankment was excess material generated at the road cut <br />between stations 13+00 and 15+00. Drainage control was present on the road <br />construction project. <br />l.b. Preliminary investigation of the foundation material and other conditions resulted in a <br />predicted slope stability of 1.2. The analysis indicated the failure would be through the <br />bearing surface. Northwest Colorado Consultants (NWCC) subsequently reviewed <br />their assumptions of field conditions, and believe the slope stability in the as built will <br />be 1.3 or greater. This is because the initial stability analysis was based on an <br />embankment with a 125' bottom width, at a 3:1 slope. The constructed embankment is <br />wider at the base, and is a 4:1 slope. A drill rig will be on site Monday to core the <br />embankment to obtain information on the foundation material. Once this information <br />has been obtained, a new slope stability analysis will be completed, based on actual <br />