2004-02-24_REVISION - M1977153 (4)

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Geotechnical Data Technical Memorandum Hazeltine -Road Runners Rest II Gravel Pit Lining Project December 2000 2.2.1 Hazeltine Pit The Hazeltine Pit mining permit (Number #M-77-153) amendment application, , submitted in August 1997, requested approval to dewater the lake, evaluate remaining quantity of mineable sand and gravel, and change the final reclaimed use of the pit to a water storage reservoir. The mining plan proposed mining , gravel from the floor of the dewatered lake down to the top of bedrock, followed by mining of sections of the pit slopes to near vertical [about O.SH (horizontal) to 1 V (vertical)]. The crest of the excavation needed to be at least 10 feet from the property line. The proposed reclamation plan for the water storage reservoir included '~ reconstructing the perimeter slopes to 3H:1 V with bedrock excavated from the floor of the lake. The bedrock fill was to be "compacted to a 95 percent ratio." ~. The crest of the reconstructed slope was to be at least 25 feet from the property line. To improve stability of the slope, a "key slot" (3-feet-deep and 11-feet- wide) would be excavated into the bedrock under the reconstructed slope, and an , 18 inch gravel blanket would be placed over the reconstructed slope to three feet , above the expected high water level. Topsoil and seed would be placed on the top of the slope. The floor of the lake would remain exposed bedrock. Reclamation would be conducted concurrently with mining operations. The small lake in the northwest corner of the Hazeltine Pit that was used as a settling pond during , mining operations would be reclaimed as wetlands. A letter from the Colorado Division of Wildlife to the DMG, dated October 1997, stated that converting the large lake into a lined water storage facility would not necessarily represent a loss of wildlife value in the area; and the Division of Wildlife had no objection to converting the small lake into a wetland bank. The , DMG approved the permit application in November 1997. 2.2.2 Road Runners Rest II Pit An application to amend the Road Runners Rest II Pit permit (Number #M-79- 195) was submitted in March 1998 to allow mining in a dry state, whereas the original permit only allowed wet mining. The application stated that dewatering would be conducted with pumps, and the dewatering operations would not affect the surrounding area. The final reclamation plans remain unchanged from the original permit. ~, LI GE[ Consultants, Inc. 2.2 oszis~g~ ~m.,e ,