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To backfill the perimeter of the excavation (2950 ft) from a 1H:1V slope to a 3H:1V slope requires <br />52,700 cy, therefore, 99,300 - 52,700 = 46,600 cy is left over and must be filled in the pit. The extra <br />fill will be used to create slopes of between 3H:1V and 6H:1V, as shown in the reclamation plan. <br />The bottom of excavation is expected to be 4438' for a gravel zone of approximately 18-21 feet <br />thickness, the backfilling will raise the average level possibly 1.0 feet to 4439'. Since the ground <br />water level is expected to be 4448-4449', this would leave a lake of approximately 9.0-10.0 feet <br />depth. Once Phase 2 is mined out, the pit lake will be allowed to fill up to its natural ground water <br />level. <br />Phase 3 Minine <br />Prior to mining Phase 3, the CDPHE must issue an approval to mine in Subarea 2, which has some <br />existing petroleum contamination from the past refinery operation that must be removed. Elam will <br />provide this approval to the Division prior to entering the Phase 3 mining area, which is approxi- <br />mately 15.1 acres. As with Phase 2, the sediment pond for Phase 3 mining will be the Phase l lake. <br />The area below Trench #2 in Subarea 1 is the only portion of the property that contains salvageable <br />topsoil that is not contaminated. This area is 3.2 acres and the expected salvageable thickness is 14 <br />inches. Therefore, the volume available is 6023 cy. This material will be spread on the upper slopes <br />of the regraded Phase 1 and 2 lakes to provide a planting medium of a minimum of 6" depth over <br />approximately 7.5 acres. Since this area will not be stripped until it is mined and since no other top- <br />soil is available for reclamation, no topsoil stockpiles will be utilized for the operation. The fines <br />from gravel processing will be used as substitute topsoil material in reclaiming all other areas above <br />water level on the site. <br />The expected raw gravel obtained from the mining of Phase 3 is an average thickness of approxi- <br />mately 18' x 15.1 acres =438,500 cy. Subtracting 30% for naturals leaves 306,900 cy sand and <br />gravel to be sold. This is 460,400 tons. Using an average annual sale figure of 200,000 total tons <br />(washed gravel and asphalt), the life of the Phase 3 reserve will be approximately 2.3 years. <br />Gilsoni[e Pit 5/03 12 <br />