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.'tr Ch <br />Y <br />Kp <br />_ £s \ Is <br />.40\,, <br />092 <br />Y?up 75?y'- et <br />4s QCs <br />of <br />?? ? I b f ! 092 C <br />4s Kip <br />Pitt <br />k5 Oac <br />Figure 2. Geologic map of the mine and the immediate vicinity form Morgan and others (2003). Map <br />scale is 1:24.000 (1 inch = 2,000 ft.). <br />Brittle deformation features are abundant within the Precambrian granite, sandstone, <br />and limestone outcrops in the vicinity of the fault zone (e.g., slickensides. altered zones, <br />fractures, and fault gouge), which indicate additional numerous, small, unmapped fault and <br />shear zones within the mine area. <br />History of rock failures at the mine <br />The Pike View quarry has had a history of failures and significant rockslides. Morgan <br />and other's (2003) cited that, "Numerous landslides have occurred in the Pikeview Quarry as a <br />result of mining operations exposing dipping carbonate layers of the Manitou Limestone. " The <br />1994 mine permit also mentioned that three major slippages have occurred. Two happened in <br />the mid 1970's, where rock slabs 20-30 feet thick and hundreds of thousands of tons in size <br />slipped. After those events MSHA wrote a prescient memo dated September 17, 1986 that <br />specifically warned about the type of massive rockslide that occurred in December 2008. The <br />1994 permit also mentioned a large event occurring in 1993 below Peak 3 (near the same area