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• East Cresson. The East Cresson Mine is focused at the intersection of the northeast- <br />trending Pharmacist Vein and the northwest-trending Isabella-Buena Vista vein systems, <br />in the area of the former Gold Star Mine. Diatremal breccias occur between thick <br />phonolite sills and are cut by later, north-northwest-trending phonolite and lamprophyre <br />dikes. <br />The ECOSA is located directly north of the East Cresson Mine area and it is underlain by <br />the School Section and Cameron mines. These small, historic underground mines are <br />hosted by northeast-trending structures within Tertiary phonolites and breccias. More <br />importantly, Loughlin and Koschmann (1935) described the sedimentary rocks in the <br />Cameron and School Section Mines and, in 1939, Koschmann collected samples from <br />calcareous shales/siltstones and marls (limey sediments) in the area. The extent of these <br />sediments is unknown due to the lack of drilling and detailed underground mapping, but <br />they have been intersected in drill holes that are 1,400 feet apart with thicknesses that <br />range from 5 to 25 feet thick. <br />Mineralization in the northwest portion of the district falls into the North Cresson Mine <br />area and includes Globe Hill, Ironclad, Schist Island and the SGOSA. The geology is <br />• dominated by a large, northwest-trending, elongate, Precambrian ridge of schist that is <br />surrounded by diatremal breccia. Both the schist and breccia are oxidized on the surface <br />and display moderate to strong potassic alteration and weak argillic alteration. This area <br />has been intruded by scattered and discontinuous lamprophyre and phonolitic dikes as <br />well as a small plug of porphyritic phonolite. The dominant structural trends in this area <br />display a north-northwest and northeast-trending fabric. <br />The Globe Hill-Ironclad area is underlain by breccia and phonolitic country rock that was <br />intruded by late-stage hydrothermal breccia pipes. These breccia pipes hosted most of the <br />gold mineralization in the area and are characterized by strong argillic alteration as well <br />as the presence of sulfate (gypsum and anhydrite), carbonate (calcite and rhodochrosite) <br />and quartz veining. The breccia pipe bodies are generally less than 500 feet in diameter <br />and occur at the intersection of northeast- and north-northwest-trending structural zones. <br />The Upper Cresson Mine area is located in the north central portion of the district where <br />the gold mineralization is hosted by an assemblage of shallow-dipping diatremal breccias, <br />porphyritic phonolite flows, and Precambrian granodiorite and biotite gneiss along, and <br />within, north- and northwest-trending structural zones associated with the diatreme- <br />• Precambrian contact. <br />Cripple Creek & Victor Gold Mining Company <br />Cresson Project Mine Life Extension <br />4-4