Sombrero Butte is a Laramide age, exploration stage, porphyry copper project located in the Bunker Hill Mining District, 44 miles northeast of Tucson, Arizona. Historical copper production is reported to have occurred between 1903 and 1920 from breccia pipes on the Audacious claim at the north end of the property with reports of ‘low-grade ore assaying 3-5% copper and higher-grade ore from along open cuts and tunnels assaying 20-33% copper.’ Arizona is a favorable mining jurisdiction with respect to taxation, regulation, infrastructure and labour.
In 2012 Copper Fox purchased a 100% working interest in the Sombrero Butte project. The project consists of three Arizona Mineral Exploration Permits, 77 BLM mining claims and two patented mining claims covering approximately 1,389 ha. In October 2021 Copper Fox made their final option payment to own a 100% interest in certain unpatented and patented mining claims.
Systematic exploration completed between 2015 and 2019 consisting of mapping, geophysical surveys and alteration studies has outlined two large porphyry copper targets.
Copper Fox completed a high sensitivity, combined airborne magnetic and radiometric survey in the spring of 2022. These surveys are expected to better define the location and depth of late stage intrusives related to a buried porphyry system prior to commencing drill testing of identified targets.
Target #1 is located at the north end of the property measuring approximately 2,000m by 1,200m and is underlain by the Copper Creek Granodiorite. Within this target a 600m by 600m area hosts 28 mineralized breccia pipes, the focus of the historical mining activities (i.e., Magma Chief Mine). A chargeability/resistivity body (500m long by 500m deep) occurs at a depth of approximately 400m below the mineralized breccia pipes exposed on surface.
Target #2 is in the center of the property approximately 2,800m long by a minimum of 400m wide (open to the east) hosted in the Copper Creek Granodiorite and Glory Hole Volcanics. The western portion of the chargeability body appears to have been dismembered by a NS trending range fault related to the period of crustal extension approximately 20Maago. Sixty leached, intensely altered mineralized and non-mineralized breccia pipes have been located within this target. This target consists of copper-molybdenum mineralization in outcrop and a positive chargeability/resistivity signature that extends from surface to a depth of greater than 800m. The surface mapping, alteration geochemistry and mineralization support the geophysical interpretation.
The Sombrero Butte project is in the Laramide age porphyry copper metallogenic province of the southwestern United States at the intersection of ENE and NNW trending belts of copper porphyry deposits. The project is underlain by the Laramide age Copper Creek stock and is located 2 miles south of the Copper Creek porphyry copper deposit. Two areas within the Copper Creek stock exhibit mineralized breccia pipe swarms, large chargeability/resistivity signatures and the mineralization and alteration consistent with the Laramide age mineralizing event.
Historical diamond drilling (2006-2008) of mineralized breccia pipes in Target #1 intersected masses, clots and sheeted veins of chalcopyrite, bornite and pyrite. In outcrop several styles of breccia pipes have been located. These pipes are leached and characterized by secondary copper minerals (malachite, chrysocolla, azurite) and abundant limonitic, geothite, jarosite veins (after pyrite). Mineralized veins/fractures outside the breccia pipes occurs along N50-85E and N-S to N25W trends consistent with other Laramide copper porphyries in Arizona.
2019 Exploration Program
The 2019 rock characterization program better constrained the geology, alteration and mineralization in Target #2. The mapping located a significant number of mineralized NNW and ENE trending steep and shallow dipping veins and veinlets hosted in potassic and phyllic altered Copper Creek Granodiorite and Glory Hole Volcanics. The higher copper-molybdenum concentrations occur in grey porphyry dikes. A comparison of the trace element geochemical data from Target #2 with “pathfinder” elemental (Mo, W. Se, Te, As and Sb) ranges for porphyry copper systems suggests the current topographic surface in Target #2 is either at or near the transition from the deep sericite (phyllic) zone (above the copper shell) to the potassic zone. Approximately 60 leached and intensely altered mineralized and non-mineralized breccia pipes have been located within Target #2. Twelve breccia pipes contain the clay mineral dickite, a hydrothermal alteration mineral (high temperature-acidic conditions) that occurs in multiple porphyry copper deposits throughout Arizona including the San Manuel-Kalamazoo deposit located 5 miles west of the property.
Historical Drilling Results
Between 2006 and 2008, Bell Copper drilled 34 diamond drill holes into seven breccia pipes in the vicinity of the former Magma Chief Mine in the north end of the property. Selected mineralized intervals from the Bell Copper drilling program are listed below.
|Pipe||DDH||From (m)||To (m)||Int. (m)||Cu (%)||Mo (%)||Au (ppm)||Ag (ppm)|
The mineralized intervals listed in the above table do not represent true widths.