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Stormwater plana¢ement Plan 01/04/98 <br />• reclaimed quarry areas. Due to the improved status of the land from the granite quarry <br />floor, the road from the quarry to the southeast part of the permit area, parallel to the <br />berm, will remain for the long term likely use by the ranch. <br />HighwallsBenches <br />The quarry benches will involve 15 to 22 acres. Several points along each highwall will be <br />blasted to create "talus slopes" impeding access to the benches, controlling key erosional <br />areas along and from the benches and blocking access to and along the benches. The <br />highest benches will have a bench 25 - 37.5' wide and will not be vegetated due to access <br />and limited bench width. The lower benches will vary in width from 25' to 50'. Areas <br />along the lower benches will be reclaimed and seeded, left barren or have an artificial talus <br />slope generated from blasting. The benches will have a 1-2% grade down from the crest <br />to the highwall toe to drain storm water runoff back into each bench and along the bench <br />drainage into intermittent talus slopes. The remaining final highwalls are expected to be <br />50' high with a 0.25:1 slope. <br />The reclaimed benches will have 12" of topsoil and/or topsoil admixture placed on them. <br />The extent of topsoil placeritent will depend upon the available topsoil. Any admixture <br />will be tested first to ensure suitability as a plant growth medium. Test plots will be <br />developed in the granite areas as soon as quarry development has progressed to a point <br />where permanent test plots can be located. Test results from such a test program will be <br />provided to the Department of Fish and Wildlife for review and recommendations. If <br />• suitable, such mixtures will be developed for use in the quarry area. <br />The proposed post-mining bench plan includes several alternatives to create wildlife <br />habitat and improve the "straight-line" bench characteristic of open pit mining. <br />1) About 10% of the final highwalls along all benches, high and low, will have 45 <br />degree "talus slopes". <br />2) About 33% of the highwalls aze at higher elevations in the northeast corner of the <br />mining property. These highwalls aze expected to have reduced bench widths and <br />0.25:1 sloped highwalls to blend into the adjacent non-mined land steeper <br />topography. <br />3) About 25% of the remaining highwalUbench areas will be reclamed with topsoil <br />and/or mixture and reseeded. <br />4) The remaining 22% of the highwal]/bench areas will not be reclaimed. <br />The post-mining highwall slope stability of the highwall features is within reasonable and <br />conservative engineering limits for long term safety. Several rock samples were tested in <br />confined and unconfined tests at the Colorado School of Mines and evaluated by Azurite, <br />Inc. for stability. (See the Geotechnical Stability Analysis for supporting test results and <br />documentation of the highwall bench proposal.) <br />Floors <br />• The remaining 43-50 acres of the granite quarry and 2 acres of the sandstone quarry will <br />be bottom cut floor. Current vegetation exists over about 25 - 33% of the pre-mined <br />Page 21 <br />