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iii iiiiiiiiiiiu iii 999 RECEIVED JAN 0 9 2002 January 8, 2002 Ms. Erica Crosby Environmental Protection Specialist Division of Minerals and Geology 1313 Sherman Street, Room 215 Denver, CO 80203 Division of Minerals and Geology AGGREGATE INDUSTRIES I}~~ Re: Brighton Mine, Permit No. M-77~3'B--Technical Revision Dear Ms. Crosby: ~~ ~ r.- ~ceLil~t' L.-S~ ~~ r ~1~~ L`G This letter is submitted as a technical revision to the above-referenced permit in response to your inspection report dated November 9, 2001, and to incorporate additional reclamation detail and spillway construction proposed as a result of consultations with Urban Drainage and Flood Control District and Adams County. The corrective action for Item No. 1 of your inspection report requires a technical revision addressing the stability of the north pit slopes in relation to the South Platte River. In accordance with the recommendation of Urban Drainage, approximately four (4) feet will be cut from the top of the north pond pit slope along the riverside. The top of the slope will be built out to 100-feet or more from the river and graded in accordance with the approved mining permit to a minimum 3H:1 V slope. We would propose that these improvements be completed early in 2002, however in order to accomplish this, construction must be completed prior to seasonal increases to river flow. We would therefore request your earliest consideration and response regarding this item. We have also discussed with Urban Drainage and Adams County additional details for the reclamation of the north pit. In accordance with the amendment application approved by the Division on November 16, 2000, the north pit area, shown on the Reclamation Plan Map as the North Lake, is to be reclaimed as an unlined wildlife pond. It has been determined through consultation with Urban Drainage and Adams County that the exposed surface area of the pond will be minimized by the construction of wetlands and developed in a manner that will allow flood waters to move through the area and return to the river. This will be achieved by cutting the top of the pi[ slope along the riverside as described above and constructing a spillway as shown on the revised Reclamation Plan Map (Exhibit F), submitted herewith. The spillway length for the North Lake was found using Urban Drainage criteria. In response to comments submitted by the Adams County Floodplain Administrator and Urban Drainage during the Adams County zoning permit process for this operation, side channel spillways, located at the downsVeam 1/3 point along the riverside bank, are also proposed for the Central and South Reservoirs. Detail drawings for the proposed side channel spillways have been included on the enclosed Reclamation Plan Map. Spillway lengths on the Central and South Reservoirs are those suggested by Urban Drainage. Aggregate Industries West Central Region, Inc. 3605 South Teller Street Lakewood, CO 80235 Connie Nickle Devis, Support Services P. O. Box 337231, Greeley, CO 80633 970-336-6526 Fex: 970-378fi856 Telephone: 303-985-7070 An Equal Opportunity Employer