Laserfiche WebLink
III IIIIIIIIIIIII III <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmenl of Natural Resources ~~~~~ <br />13i 3 Sherman 51., Rnom 215 <br />Denver, Color, do 80203 <br />Phone: 1303) 866 3567 <br />FA\.13031 R72-8106 <br />DfiPARTMENT OF <br />NATURAL <br />DATE: August 17, 1995 RESOURCES <br />Roy Rome <br />TO: Joe Dudash c°vern°' <br />lames 5. Lochhead <br />Enec ulive Direcwr <br />FROM: Jim Pendleton ~- Michae~B. bong <br />Division Dueclor <br />RE: Trapper M' e - C-95-017 Abatement - <br />DRAFT " o nical and Hydrogeological Study <br />of the Ashmore Reclaimed Pit Landslide" <br />(Permit No: C-81-O10) <br />I reviewed the DRAFT report of investigation delivered to my <br />attention by Hydro-Geo Consultants, Inc. yesterday. This report <br />presents the results of the remedial investigation conducted at the <br />Trapper Mine's Ashmore Pit landslide, which was the subject of NOV <br />C-95-017. The investigation appears to have been completed in <br />accordance with the work plan. Considering the weather and field <br />conditions earlier this summer, the progress of work appears <br />consistent with the magnitude of the proposed investigation. <br />The report includes a straightforward <br />results of the field investigation. <br />laboratory shear strength data for <br />analysis also includes back calculated <br />to determine the likely situations a <br />study basically concludes that the <br />abnormal precipitation which resulted <br />rendition of the conduct and <br />The study presents thorough <br />the spoil materials. The <br />stability analyses, intended <br />the time of failure. The <br />failure was the result of <br />in unusual saturation of the <br />spoil. This in turn drove pore pressure up resulting in decrease <br />in effective stress and failure of the slope. This analysis is <br />thorough and prepared in the prudent state of the art. <br />The study concludes by making three general recommendations: <br />(1) "Reduce the gradient of the steeper section of the reclaimed <br />slope, at the slope failure face, by pushing the material into <br />the failure depression. The slope in this section should <br />conform to slope in other sections;" <br />(2) "Improve the existing drainage ditches above and within the <br />landslide area. These ditches should be designed for a 10- <br />year storm event. Regular inspection and maintenance of these <br />ditches should be scheduled until the slope is stabilized;" <br />