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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman 51., Room 215 <br />Oenver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 832.8706 <br />Date: July 5, 2006 <br />To: Deb Gonima, Carl Mount <br />From: Tom Schreiner ~s~(~~ <br />RE: " 2nd Adequacy Review Comments", Siegrist Pits/Del Camino Properties <br />Permit No. M-1982-015, Class: Revision Type-Seq.: AM-1 <br />COLORADO <br />D I Y I S! O N O F <br />MIN SRALS <br />GEOLOGY <br />0.EC LAMATION•MINING <br />SAFETY•SCIfNOE <br />Bil(Owens <br />Governor <br />Russell George <br />Executive Director <br />Ronald W. Cattany <br />Division Director <br />Natural Rewurce Trustee <br />Listed below are Z"d adequacy review comments on the above amendment application, based <br />upon the Division's review of documents received on June 13, 2006 and June 28, 2006. Please <br />note that the applicant has resolved Items 2, 3, 4, 7, 8, 9, 1Q, 12, 13, 14, 15, 16, 17, 18, 19, 21, & <br />22 from Tom Schreiner's May 22, 2006 adequacy review memo to Deb Gonima, Carl Mount. <br />Items 1, 5, 6, 11, & 20 from the May 22, 2006 memo require either clarification or additional <br />information. <br />6.4.3 EXHIBIT C -Pre-Mining and Minint Plan Map(s) of Affected Lands <br />1. The Applicant states that they have submitted a revised copy of the Stonnwater Management <br />Plan, however the copy submitted appears to be the same version that was sent with the original <br />application. Did the Applicant intend to send a revised stormwater management plan? Please <br />clarify. Also, In the adequacy comments the Division refers to Stormwater Management Plan <br />mans not the Stormwater Management Plan itself. Where new maps submitted, and if so which <br />maps should the Division refer to. If not, the Applicant will need to submit the maps requested. <br />Please clarify. <br />6.4.5 EXHIBIT E -Reclamation Plan <br />2. The "Supplemental Geotechnical Engineering Report" prepared by Terracon in Amendment <br />Application submittal indicates that the slurry cut-off walls should be "keyed" or "socketed" into <br />the relatively impermeable competent/intact claystone or sandstone bedrock to reduce <br />groundwater seepage. The report further states that supplemental coring and packer permeability <br />testing in the area of Boring Numbers 45, 47, & 48 indicated that the upper 5 to 10 feet of the <br />sandstone layer was moderately to severely fractured and that "keying" or "rocketing" into this <br />type of sandstone bedrock could result in excessive seepage losses, and that deeper keyways for <br />the slurry cut-off walls wi111ikely be required in this area. <br />Office of Office of Colorado <br />Mined Land Reclamation Active and Inactive Mines Geological Survey <br />