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• III IIIIIIIIIIIII III 999 P.O. Box 1887, 702 Gregg Drive, Buena Vista, CO 81211 Ph. 17191 395-3790 August 6, 2001 Colorado Division of Minerals and Geology 1313 Sherman St., Room 215 Denver, Colorado 80203 Attention: Larry Oehler Subject: Conditions for final approval Dear Mr. Oehler Fax 1719) 395-3794 FiECIE"'~"~~ Division of Minerals and Geelogf: We have reviewed the response from Michael Graber of Water Division 2 and your proposed conditions of approval and have the following to submit for final approval. We will maintain the quarry highwall as proposed by Mr. R. J. Irish's report and your Condition No. I in your letter dated August I, 2001. Cut slopes will be benched 10 fee[ wide and 20 feet high. The back wall ofeach bench will be drilled and blasted to produce a .25h:1v slope. If, due to drilling equipment that can only produce a lesser amount of depth other than 20 feet, a 10-foot bench will still be maintained, thus producing a flatter slope. We will follow the blasting recommendations as proposed by Mr. Gordon Revey in his evaluation end per yow Condition No. 2 of your letter of August 1, 2001. Maximum charge weight of 42 pounds per delay and delays of 9 milliseconds w more will be used. All blasts will be monitored by seismograph placed at the base of the dam on bedrock. Frequencies will be limited to less than 30 Flz and Peak Particle Velocities will not excced 2.0 ips. In addition, we will read the piezometers before and after each blast as well as measuring the seepage from the dam before and after. A visual inspection will also be conducted ofthe dam itself. All of this data will be recorded and kept by us for inspection by the DMG and Michael Graber of Water Division 2. Thank you for you time and assistance in this mattes. Please do not hesitate to contact us if you have any questions of comments. Project Manager RECcIVEC pUG 0 8 2001 Division of Minecals and Geolo9Y