2013-01-31_REPORT - M1973021 (2)

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2.0 2012 MINING SUMMARY 2.1 North Quarry Mining in the North Quarry was completed as of December, 2007. The North Quarry is currently being used as a raw water reservoir by the Town of Morrison and Aggregate Industries. As such, there was no major rock disturbance, mining, or reclamation activity in the North Quarry in 2012. Figure 2 shows the current configuration of the North Quarry, including the reservoir, north fill slope, and north repository. 2.2 Central Quarry Mining in the Central Quarry was completed as of December, 2001. As such, no major rock disturbance or mining occurred in the Central Quarry in 2012. Backfilling with stripped material from the South Quarry continued in 2012 as shown in Figures 3 and 4. 2.3 South Quarry Mining in the South Quarry continued in 2012, with minor pit expansions occurring to the east and south. Material was mined from approximate elevations 7450 to 6640 feet. Benches mined in 2012 have temporary slope configurations consisting of 60 to 100 -foot highwalls and 30 to greater than 150 -foot benches. Three expanded highwall and two new highwall and bench areas were developed in 2012. The total highwall height increased from 800 feet in December 2011 to 860 feet in December 2012. The approximate area mined and or disturbed in the South Quarry in 2012 is shown on Figure 5. Figures 6 through 12 are photo documentaries of the highwalls surveyed for this report. In addition, the haul road within the central portion of the South Quarry was realigned. 3.0 FIELD DATA At locations exposed by mining in 2012, rock mass data including joint orientation and dip, foliation orientation and dip, rock mass rating (RMR) classification estimates, and unusual rock features such as shear zones, persistent intrusions, or weak rock zones, were documented. Orientations were collected using a Brunton compass (10 degree east magnetic declination) and recorded using the right hand rule. All orientation measurements were estimated from a safe distance back from the highwalls due to active mining activity, rockfall safety concerns, and as requested by Aggregate Industries (AI). 3.1 North Quarry No mining occurred in the North Quarry in 2012 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 2 Morrison Quarry Annual Report 2012 P \23514\ 133 - 2351 4- 13002\Deliverables\Dehv -01 -2012 Annual Report \Amnral Report 2012Geotech doc January 2013