Laserfiche WebLink
1111111111111111111 <br /> 999 <br /> STATE OF COLORADO <br /> DIVISION OF MINERALS AND GEOLOGY <br /> Department of Natural Resources ov.00 <br /> 1313 Sherman St.,Room 215 * i <br /> Denver,CO 80203 * 1876 <br /> e j <br /> Phone:(303)866-3567 <br /> FAX:(303)832-8106 <br /> Roy Romer <br /> Governor <br /> I.,,/April 26, 1993 Michael B.Long <br /> Division Director <br /> Larry Perino <br /> Sunnyside Gold Cor oration <br /> P.O. Box 177 <br /> Silverton, CO 81433 <br /> RE: Lake Emma Groundwater Interce lion and Diversion Proposal, <br /> Technical Revision TR-15, Sunnyside Mine, File No. M-77-378 <br /> Dear Mr. Perino: <br /> The following is a list of concerns regarding the proposal to <br /> divert groundwater around the Lake Emma hole as detailed in your <br /> technical revision submittal received by the Division of Minerals <br /> and Geology (Division) on April 5, 1993 . Please respond to each <br /> item prior to the May 5, 1993 decision due date set for technical <br /> revision TR-15. <br /> 1. Any topsoil, or other material encountered that could serve as <br /> a plant growth medium, that is excavated during the course of this <br /> project, should be segregated from other excavated materials and <br /> stockpiled for use in reclamation. <br /> 2 . Under this proposal, the final configuration of the groundwater <br /> interception structures proposed will depend on feasibilities <br /> determined during the course of construction. For this reason, the <br /> Division will require that as built details be submitted once <br /> construction is complete. Any ditches left as permanent features <br /> must be capable of passing intercepted surface flows resulting from <br /> the probable maximum precipitation event, plus the flow of <br /> intercepted groundwater. The ditch sizing and hydrological <br /> analysis can be provided with the as-builts. <br /> 3. In addition to the filter cloth proposed to wrap the clean <br /> aggregate in locations where pipe drains may be employed, filter <br /> compatibility between the aggregate and the back-fill should also <br /> be assured. Representative sieve analysis of the aggregate and the <br /> backfill must be provided with the as-builts, showing that the <br /> following criterion has been met: <br /> D15 of filter <br /> --------------------- < 5 <br /> D85 of protected soil <br />