2017-06-27_REPORT - M1973021 - Laserfiche WebLink

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Aggregate Industries Morrison Quarry GEI Consultants, Inc. Geotechnical Addendum, 2016 Annual Report 3 January 2017 2. 2016 Mining Summary 2.1 North Quarry Mining in the North Quarry was completed in 2007 therefore no mining activity occurred in the North Quarry in 2016. The North Quarry is currently being used as a raw water storage reservoir for the Town of Morrison and production water storage for AI. The pond has a water elevation of approximately 6396 feet above MSL. Fig. 2 shows the current configuration of the North Quarry, including the reservoir and the North Repository. 2.2 Central Quarry Mining activity was completed in the Central Quarry in 2001. No mining activity occurred in 2015 and the Central Quarry experienced no major rock disturbances. Reclamation is now complete to El. 6500 in the Central Quarry and the south side of the quarry (Fig. 3) is now being used to temporarily stockpile stripped materials including overburden, sillimanitic gneiss, and other undesirable material from the South Quarry as future reclamation backfill material. AI does not anticipate increasing the reclamation elevation. In addition, jade air fines slurry was placed in the Central Quarry, filling the remaining area to be reclaimed. Fig. 3 shows the configuration of the Central Quarry. 2.3 South Quarry Mining operations continued in the South Quarry in 2016. The 2016 mining operations did not result in an expansion of the South Quarry 2015 mining footprint. Mining occurred primarily on the west (east facing) and south (north facing) portions of the South Quarry. A new lower bench, Bench 6600, was established in 2016. The general configuration of the South Quarry is shown in Fig. 4. Mining in the South Quarry occurred between approximate elevation 6600 and 7360 above MSL. The mining resulted in several temporary mine highwall configurations of approximately 15 to 75 feet high with benches of 20 to greater than 50 feet wide. Mining in 2016 resulted in existing highwall expansion and highwall development, including the establishment of a new, lower bench, Bench 6600. Upper sections of former haul roads were developed into highwall benches and reclaimed benches. Total highwall height increased to a total of 40 feet resulting from the new Bench 6600. In addition, mine haul roads were modified to accommodate the revised highwall configuration, resulting in new or modified haul road highwalls. The approximate areas mined or disturbed in the South Quarry are shown in Fig. 4, 27, and 28. Fig. 5 through 23 show the highwalls included in the scanline surveys conducted for the 2016 Geotechnical Addendum.