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2.2 North Ouarry <br />Mining in the North Quarry continued in 2006 and primarily expanded the existing pit to the south <br />and east. Material was mined to elevations ranging from 6366 to 6406 feet above MSL utilizing <br />the default slope configuration of 1: I (H: V) and consisted of 40 to 50 foot highwalls and 40 to 50 <br />foot benches. The elevations material was mined to in 2006 corresponds to Bench A and Bench B <br />elevations noted in previous geotechnical addenda. The azea mined in 2006 is shown on Figure 2. <br />3.0 FIELD DATA <br />At areas exposed by mining in 2006, rock mass data including joint orientation and dip, foliation <br />orientation and dip, rock mass rating (RMR) classification, estimates and unusual rock features <br />such as shear zones, persistent intrusions, or weak rock zones, were documented. Orientations <br />were collected using a Brunton compass (10 degree east magnetic declinations) and recorded using <br />the right hand rule. All orientation measurements were estimated from a safe distance back from <br />the highwalls due to active mining activity and as requested by AI. <br />3.1 CentralOuarrv <br />No mining occttrred in the Central Quarry in 2006 and thus no orientation data related to mining <br />activity was collected. Observations of the existing highwalls and benches were conducted and <br />compared with previous observations. Localized instabilities were observed and local raveling of <br />the rock faces has continued. This raveling is likely due to adverse jointing and/or weathering <br />actions such as freeze thaw cycles. Blocks loosened in this fashion are generally small (less than <br />approximately 1 '/z feet in diameter) and collect on the benches. <br />Observations of the stabilized slope area indicate no visible movement or large erosional features. <br />Aggregate Industries provides survey support to monitor movement of this slope as well. <br />However, survey data is collected every three years or as conditions change and the next survey is <br />expected to be completed in 2007. <br />3.2 North Ouarrv <br />Geotechnical data was collected for the areas mined in 2006. These areas include two highwall <br />faces mined to base elevations of 6366 to 6395 feet above MSL as shown on Figure 2. The two <br />highwall faces are referred to as the lower and upper highwalls respectively for reference in this <br />report. These areas represent expanded mining areas to the south (north facing) and east (west <br />facing). The depth of the quarry did not change in 20062. <br />The type of rock encountered in the highwalls is consistent with rock types described in previous <br />geotechnical addenda and primarily consists of fine to meditun grained granitic gneiss slightly <br />interfoliated with biotite gneiss/biotite schist. Occasional pegmatitic intrusions are also present in <br />the area. The gneiss observed in this area is slightly to highly weathered and generally displays <br />two prominent joint sets and a foliation surface. Joint spacing ranges from approximately 4 inches <br />up to 7 feet. Joint surfaces generally are slightly smooth to rough and are usually closed. When <br />joint surfaces are open or exposed, the joint faces are typically slightly weathered with iron <br />staining. The joints generally do not contain any in611 material. Foliation spacing ranges from less <br />1 Topozone, 2007, "Topographic Map of Morrison Quadrangle, Morrison, Colorado", <br />http://www.topozone.com/map.asp?sat=39.65361 &lon=-105.19056 <br />'- Per conversations with the current Aggregate Industries Morrison Quarry Plant Manager. <br />F:V919_038~Annual_Report_2006Wnnual_Report 2006.doc - 2 - Apn12007 <br />