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~~ <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman 6t., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 832-8106 <br />November 19, 2002 <br />Mr. Ken Rollin, P.E. <br />Rollin Consulting <br />840 Eagle Drive <br />Eaton, CO 80615 <br />RE :NCCI Pit #1, Technical Revision No. <br />Class: Revision, Type-Seq.: TR-1 <br />File No. M-2001-107 <br />Dear Mr. Rollin: <br />DIVISION O F <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />Bill Owens <br />Governor <br />Greg E. Walther <br />Executive Director <br />Ronald W. Cottony <br />Acting Division Director <br />The Division has reviewed your request for a technical revision to the file for NCCI #1 Pit to reduce the <br />bonding requirement for liner installation from 100% to 20%. Listed below aze adequacy review concerns <br />that will need [o be resolved prior to December 6, 2002. Please respond on or before December 6, 2002. <br />1. The NCCI #1 typical clay liner x-sectional diagram shows a reservoir side slope of 2.5 /1. Please note <br />that the side slope configuration will need to be at least 3:1 or greater per Rule 3.1.5(7). Please <br />address. <br />2. Please provide the following information: Submittals - Provide a basic earthwork operations plan and <br />schedule for the installation of the soil liner and the soil liner cover fill. Inclade a description of the <br />equipment and quality control procedures [o be used, including lift thickness control, composite <br />material preparation, and methods for moisture conditioning. <br />3. Construction Quality Assurance Plan -The applicant specifies the CQA monitor will be responsible <br />for prepazing a construction certification report. Please commit to submittal of such certification report <br />to the Division within 30 days of completion of the liner, or within 30 days of completion of each <br />section of liner if [he liner will be installed in sections. A certification will be required to accompany <br />[he construction report with a statement from the quality assurance engineer that the slurry wall was <br />constructed in accordance with the approved plans and specifications. The construction report will <br />need [o include a discussion of the installation of the slurry wall, a description of any problems that <br />occurred, and a listing of [he results of testing that was conducted under the approved quality <br />assurance/quality control plan. <br />4. In order to qualify for the 20% bonding option for liner installation, the applicant will need to 1) <br />provide a statement that the plans and specifications, once approved, can not be altered without <br />consent by the Division, and 2) advise the Division of the schedule for construction of the liner so that <br />field inspections can be scheduled at appropriate times during liner installation. <br />Once again, [he Division will look forward to your response on or before December 6, 2002. Please call <br />me at (303) 866-3567 if you have questions. <br />Sincerely, <br />omas A. Schreiner ~~~~%~V <br />Environmental Protection Specialist <br />