2008-04-15_REVISION - M1980244 (309)

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• District and ongoing activities require that the operator submit and receive approval for a Mining Development Plan through Teller County. Appropriate documentation will be submitted to Teller County by CC&V to obtain County approval for all of the activities proposed pursuant to this MLE. 4.4 Geology The Cripple Creek Mining District lies near the southern end of the Colorado Front Range and is located on the southwestern flank of the Pikes Peak uplift. The country rocks surrounding the district are dominantly Precambrian in age and include gneisses, schists, quartz monzonite, augen gneiss/granodiorite and granite. Approximately 32 million years ago, in the Tertiary period, volcanic activity took place in with the emplacement of an alkaline diatreme-intrusive complex which included plugs, flow domes, small stocks, and late-stage diatremal pipes and dikes. The volcanic rocks occupy a diatreme, which has the general aspect of a steep-walled crater with a crudely elliptical outline at the surface. More recently, Jensen (2003) used the following lithologic designations for the alkaline rocks of the district: volcanic breccias, phonolites, tephriphonolites, phonotephrites, tephrites, nepheline syenites, • nepheline monzosyenites, nepheline monzodiorites and, in the last intrusive event, lamprophyres. Following the emplacement of the lamprophyres, large volumes of rock were subjected to intense potassium metasomatism, hydrothermal brecciation, and gold mineralization. Carbonate-rich styles of alteration post date the precious metal mineralization event. The carbonate alteration plays a major role in the ground water chemistry of the area, as evidenced by the alkaline nature of regional ground water draining from the Carlton Tunnel. The mineralogy of the main Cresson Mine area is quite diverse. Intrusive and breccia lithologies spanning the entire alkaline suite from leucocratic phonolites through ultramafic lamprophyres occur in the Cresson Mine area. Volumetrically, the main lithologies are volcanic diatremal breccia, phonolitic breccia, and phonolite. Alteration in the mineralized area is variable. Irregularly oxidized assemblages of K-feldspar f pyrite and sericite-clay ± pyrite are most common within the ore body. Accessory carbonate, while believed to be partially leached from the oxidized areas in the Cresson Mine area near the surface, was widely noted in the district by Lindgren & Ransome (1906). The geology of the East Cresson Mine is similar to that of the main Cresson Mine with the exception that there are volumetrically more phonolites than diatremal breccias in • Cripple Creek & Victor Gold Mining Company Cresson Project Mine Life Extension 4-3