2013-01-31_REPORT - M1973021 (2)

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in this fashion are generally small (less than approximately 11/2 foot in diameter) and collect on the benches. No major rock disturbances occurred in the North Quarry in 2012. Water continued to be stored in the North Quarry in 2012. No large scale seepage was observed above the current water level. 3.2 Central Quarry No mining occurred in the Central 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 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 indicated no visible movement or large scale erosional features. However, survey data is collected as conditions change and no survey was completed in 2012. Material stripped from areas in the South Quarry continued to be deposited in the Central Quarry. The Central Quarry is being filled southward from the north end to an elevation of approximately 6,500 feet. Minor quantities of fill were pushed over the south edge of the Central Quarry. Some minor tension cracks are visible in this area. At the time of the field investigation, the quarry was over two - thirds filled. Figures 3 and 4 are photos of the fill placed in 2012. 3.3 South Quarry Geotechnical data was collected for the areas mined in 2012. These areas include three highwall and bench combinations at elevations 7375 to 7270 (upper haul road configuration), 6700, and 6640 as approximately shown on Figure 5. Geotechnical data was not collected on bench 7450 due to access and safety concerns, and on bench 7220 due to the entirety of the highwall being covered by debris and rubble. Bench development is on -going at all of the bench elevations observed. The highwall faces are referred to by elevation for reference in this report. The benches represent a 60 -foot increase in depth of mining in the South Quarry from last year and include expanded mining areas to the south (north facing), east (west facing), and north (south facing). The type of rock encountered in the highwalls is consistent with rock types described in previous geotechnical addenda and primarily consists of fine to medium grained granitic gneiss or biotite gneiss. Occasional pegmatitic intrusions, biotite schist zones and shear zones are also present in the area. A shear zone associated with a mapped fault (Scott, 1972) was observed on the north end of bench 6700 and within bench 6640. The shear zone consists of highly weathered and altered sillimanitic gneiss. All observed highwall areas were dry at the time of the geotechnical observations. 3 Morrison Quarry Annual Report 2012 P \23514 \133- 23514- 13002\Deliverables\Dehv -01 -2012 Annual Report \Annual_Report_2012_Geotech doc January 2013