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West of the Globe Hill-Ironclad area and north-northwest of the Main Cresson <br />• Mine deposit is an azea designated as "North Cresson." The North Cresson Mine area is <br />hosted in part by an assemblage ofshallow-dipping diatremal breccias and porphyritic <br />phonoli[e flows. North Cresson Mine area mineralization occurs in two distinctive types: <br />l) As volcanic-hosted mineralization controlled by a complex stratigraphy, low- <br />and high-angle structures, and cross-cutting dikes; and <br />2) As granodiorite/biotite gneiss-hosted mineralization along and within <br />structural zones and along the diatreme-Precambrian contact. Mineralization <br />generally is accompanied by K-feldspar-pyrite alteration and quartz micro-veining <br />locally associated with iron oxides. <br />Based on the field mapping conducted during construction of the existing VLF, <br />three rock types compose the bedrock geology of the existing VLF and the proposed <br />• Phase N VLF extension (see Asch, Glenn and Tim Hams, 1994, Geologic Report <br />Cresson Leach Pad Foundation in Golder Associates, 1994, Final Report Cresson <br />Project Quality Assurance Monitoring and Test Results Heap Leach Pad 1994 <br />Construction Seasoat, Teller County, Colorado Amendment No. 6, Volume N, <br />Appendix S.) The diatreme/granodiorite contact occurs beneath the existing and active <br />AGOSA and, with the exception of the El Paso valley area (Coal Creek), is <br />approximately traced by existing State Highway 67, which, in tum, generally traced the <br />Midland Terminal Railroad route between Cripple Creek and Victor. The diatreme in the <br />Arequa Gulch area was defined by the presence of Cripple Creek lapilli tuff and breccia. <br />The predominant unit in the footprint of the existing and Phase N VLF area is <br />undifferentiated Precambrian (Proterozoic) granodiorite. This unit is primarily a pinkish <br />gray, medium to coarse grained biotite-rich granodiorite. Locally, this basement rock is a <br />biotite schist, or augen gneiss. The granodiorite is often cut by feldspar pegmatite or <br />aplite dike. In the southern part of the existing VLF, several Precambrian diabase dikes <br />• and sills were exposed. <br />18 <br />