2010-02-02_REPORT - M1973021 (2)

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3.1 North Ouarry No mining occurred in the North Quarry in 2009 and thus no new orientation data related to mining activity was collected. Observations of the existing highwalls and benches were conducted and compared with previous observations. Localized instabilities were observed and local raveling of the rock faces has occurred. This raveling is likely due to adverse jointing, rock weakened by alteration, and/or weathering actions such as freeze thaw cycles. Blocks loosened in this fashion are generally small (less than approximately 1 1/2 feet in diameter) and collect on the benches. No major rock disturbances occurred in the North Quarry in 2009. Removal of unstable fill material from benches 2, 3, 4, and 5 on the western side of the North Quarry (North Fill Slope) was conducted in 2009. Approximately 74,000 cubic yards of North Fill Slope material was removed. This material was removed and the slopes were stabilized above elevation 6600 feet. The material removed was placed to an elevation of approximately 6,730 feet in the North Repository Area of the quarry. The North Fill Slope and the North Repository Area are shown and as-constructed footprints are provided in Figure 10. Upon completion of the excavation process, the lower bench of the North Fill Slope was graded into the slope and to the south to facilitate site drainage. The current design allows for the bench to drain down the existing access road. Water stored in the Central Quarry was pumped into the North Quarry in 2009. Prior to the transfer of water from the Central Quarry to the North Quarry, minor seepage was observed near the bottom elevation of the North Quarry. Pumping of seepage water was discontinued in December 2008. 3.2 Central Ouarry No mining occurred in the Central Quarry in 2009 and thus no new orientation data related to mining activity was collected. Observations of the existing highwalls and benches were conducted and compared with previous observations. Localized instabilities were observed and local raveling of the rock faces has occurred. This raveling is likely due to adverse jointing, rock weakened by alteration, and/or weathering actions such as freeze thaw cycles. Blocks loosened in this fashion are generally small (less than approximately 1 1/2 feet in diameter) and collect on the benches. Observations of the stabilized slope area indicate no visible movement or large erosional features. Aggregate Industries provides survey support to monitor movement of this slope as well. However, survey data is collected as conditions change and no survey was completed in 2009. After transferring the water stored in the Central Quarry to the North Quarry, material stripped from areas in the South Quarry was deposited in the north end of the Central Quarry. The Central Quarry is being filled to an elevation of 6,500 feet and at the time of -3- Morrison Quarry Annual Report 2009 February 2010 P:\23514\133-23514-10003\Deliverables\Deliv-0l-Annual Report\Annual_Report_2009_Geotech, 1-25-10.doc