Introduction
The Sombrero Butte Project is a 100% owned, early-stage porphyry copper exploration target located in the Bunker Hill Mining District, Pinal County, Arizona, approximately 3km south of Faraday Copper’s Copper Creek porphyry copper project, a develpment-stage asset that underscores Sombrero Butte’s potential to host a large porphyry copper deposit. Arizona is a Tier 1 mining friendly, politically secure jurisdiction with excellent and readily accessible infrastruture.
Sombrero Butte shares a nearly identical geological setting to the Copper Creek porphyry deposit, including the Laramide age Copper Creek intrusive, widespread mineralized magmatic-hydrothermal breccia pipes (over 120 pipes mapped) and similar structural controls. Historical mining of these high-grade breccia pipes, widespread alteration and copper-molybdenum mineralization combined with the strong underlying chargeability anomaly suggests potential for a blind porphyry system, makes Sombrero Butte a highly prospective exploration asset in a Tier 1 mining jurisdiction.
Historical mining at the Magma Chief mine exploited high grade copper mineralization from magmatic-hydrothermal breccia pipes located in the northern end of the property. Historical drilling (2006-2008) of the breccia pipes intersected multiple intervals of high grade mineralization such as DDH SB-07-23 intersected a 60m core interval averaging 1.01% copper, 0.022% molybdenum, 0.067g/t gold and 3.01g/t silver from 446m to 506m and DDH SB-07-14 returned 1.16% copper over an 86m core interval from surface.
Property Description
Copper Fox through its subsidiary Desert Fox Sombrero Butte Co., owns 100% working interest in the Sombrero Butte project consisting of three Arizona Mineral Exploration Permits, 77 BLM mining claims and two patented mining claims covering approximately 1,389 ha.
Porphyry Footprint
Exploration has defined a porphyry footprint indicitive of a large, highly evolved, porphyry copper target with indications of hypogene enrichment and superimposed hydrothermal events that exhibits a strong spatial correlation to a large near surface underlying chargeability/resistivity anomaly (>12mv/v/25mrad). The geology of the porphyry footprint consists of Laramide age Glory Hole volcanics and underlying Copper Creek granodiorite, a composite, Laramide age weakly Peraluminous to Mealuminous calc-alkaline intrusive occupying the same regional structural setting as the Copper Creek porphyry copper deposit.
Copper-molybdenum mineralization is hosted in steeply dipping, northeast trending quartz veinlets, fractures, and in breccia pipes with lesser amounts of disseminated chalcopyrite in the Copper Creek intrusive. The Glory Hole volcanics is characterized by large zones of moderate to intense bleaching and clay contained in a significantlly larger zone of moderate to intense limonite staining due to weathering/oxidization of quartz-pyrite-sericite veinlets typically observed in the phyllic alteration zone. Mineralized, limonite stained leached, intensley clay altered breccia pipes and non-mineralized breccia pipes of magmatic hydrothermal origin are concentrated in the central portion of the porphyry footprint.
The criteria supporting the prescence of a buried porphyry copper system are:
- Laramide age Glory Hole volcanics and porphyritic and non-porphyritic phases of the Copper Creek granodiorite and occuping the same structural setting as the Copper Creek porphyry copper deposit.
- A chargeability anomaly (>12mv/v/25mrad) measures approximately 3,200m long by 1,300m wide and interpreted to extend to depths of more than 1,200m below surface.
- A typical porpyry alteration pattern; a potassic altered core surrounded by widespread phyllic (quartz-pyrite (limonite)-sericite) and distal advanced argillic, prophylitic and tourmaline alteration.
- Multiple episodes of mineralization; ‘hypogene enrichment’ (i.e. bornite rimming chalcopyrite), superimposed high temperature hypothermal events and the presence of hypersaline fluid inclusions with liquid + vapor + solid phases of halite, hematite, chalcopyrite and anhydrite typically observed in porphyry copper deposits.
- Mineralized and non-mineralized, leach, intensely clay altered magmatic hydrothermal breccia pipes contained within a large zone of limonite staining due to weathering of quartz-pyrite-sericite veins, typically observed in the phyllic alteration zone of porphyry copper systems.
- Thermal metamorphism of the Glory Hole volcanics suggesting a relatively thin cover of Glory Hole volcanics overlying the Copper Creek granodiorite intrusive.