Copper Fox Advances Sombrero Butte with Robust Porphyry Copper-Molybdenum Indicators and Progresses Drilling Permits

Comprehensive Sombrero Butte Exploration Model Combines Diverse Data

Copper Fox's updated exploration model for Sombrero Butte synthesizes data from the 2024 geophysical survey, recent surface mapping, high-resolution airborne magnetics, petrographic analysis, shortwave infrared (SWIR) spectroscopy, whole-rock geochemistry, trace-element analysis, fertility geochemistry, fluid-inclusion observations, and historical drilling results. These datasets collectively outline a porphyry-style footprint characterized by a significant chargeability anomaly, Laramide intrusive phases, potassic alteration overprinted by intense phyllic and spheroidal sericite alteration, hypersaline fluid inclusions, copper-mineralized breccias, and evidence of multiple high-temperature hydrothermal events.

Elmer B. Stewart, President and CEO of Copper Fox, highlighted that the convergence of key geological, geophysical, mineralogical, and alteration indicators supports the interpretation of a large porphyry system. The alignment of hypersaline fluid inclusions, spheroidal sericite, relic potassic alteration, multiple hydrothermal events, and a substantial chargeability response reinforces this conclusion.

Prime Location Amid Two Major Porphyry Copper Belts

Sombrero Butte lies at the intersection of two prolific Laramide-age porphyry copper belts in Arizona, approximately 9 kilometres east of the former San Manuel/Kalamazoo porphyry copper mine and about 3 kilometres south of the Copper Creek porphyry copper deposit. Arizona’s Laramide copper province is globally recognized for significant porphyry copper deposits, where hypogene copper mineralization typically includes chalcopyrite, bornite, and molybdenite associated with potassic and sericitic alteration assemblages.

The project's geology consists of metamorphosed Laramide-age Glory Hole Volcanics intruded by porphyritic and non-porphyritic phases of biotite and hornblende-biotite granodiorite, quartz diorite, quartz monzonite, and late-stage Copper Creek granodiorite dikes. Over 120 magmatic hydrothermal mineralized and non-mineralized breccia pipes are present within the project area, with several showing copper and molybdenum mineralization.

Geophysical Characteristics and Structural Influences

The 2024 induced polarization and resistivity survey revealed a large positive chargeability and low-resistivity anomaly measuring 3,200 metres long by 1,300 metres wide, with chargeability values exceeding 25 mrad. This anomaly displays two distinct signatures: an upper signature aligned with a shallow east-dipping layer of secondary fine-grained disseminated magnetite formed by contact metamorphism of the Glory Hole Volcanics, and a lower signature (>10 mV/V or 20 mrad) within porphyritic and non-porphyritic intrusive phases of the Copper Creek granodiorite.

Most of the Sombrero Butte porphyry target is situated between the Holy Joe and Blind Thrust fault systems, major structural features of the Copper Creek mining district. Movement on the Blind Thrust fault is interpreted to have caused vertical displacement of approximately 300–400 metres of the chargeability anomaly westward into the Copper Creek granodiorite. At surface, the Blind Thrust juxtaposes weakly sericitically altered biotite granodiorite in the hanging wall against intensely phyllic altered biotite granodiorite, quartz diorite, and quartz monzonite in the footwall.

Alteration Patterns Align with Porphyry Copper Systems

The Sombrero Butte project exhibits the three alteration patterns typical of porphyry copper systems. Early-stage potassic alteration, characterized by K-feldspar, magnetite, anhydrite, and shreddy biotite, is overprinted by intense phyllic sericite-chlorite alteration, especially spheroidal sericite, which hosts widespread quartz-magnetite veins and fracture-controlled magnetite. The Glory Hole Volcanics show widespread propylitic alteration (tremolite-actinolite, epidote, and chlorite) and vein-controlled quartz-sericite-pyrite veins now oxidized to limonite.

Spheroidal sericite commonly overprints the highest-grade porphyry mineralization and occurs within intensely altered margins surrounding mineralizing centers. This alteration style indicates retrograde reactions where cooler, acidic magmatic-hydrothermal fluids invade earlier, hotter potassium-silicate zones hosting copper sulfides such as chalcopyrite and bornite, often accompanied by pyrite.

Fluid Inclusion Data Reveal Boiling and Magmatic Processes

Petrographic and fluid-inclusion analyses of samples from the Copper Creek granodiorite, Glory Hole Volcanics, and historical drill core reveal mineralogical and alteration relationships indicative of a porphyry copper system. Findings include widespread potassic alteration, quartz-chalcopyrite-bornite veins, and hypogene enrichment demonstrated by bornite rimming chalcopyrite. Sulfide mineralization postdates quartz-magnetite veining and contact metamorphism.

A key discovery is the presence of hypersaline fluid inclusions (liquid + vapor + daughter minerals) concentrated in spheroidal sericite-altered areas over an approximately 3-kilometre by 1-kilometre zone along the footwall of the Blind Thrust fault. These inclusions indicate fluid saturation and phase separation (boiling) into vapor-rich and high-salinity brine phases. According to academic references cited by Copper Fox, hypersaline fluid inclusions in porphyry copper deposits signify epizonal intrusions, considered the most favorable sources for porphyry copper mineralization.

Historical Drilling Highlights Mineralized Breccias

Diamond drilling conducted from 2006 to 2008 targeted several mineralized breccia pipes at Sombrero Butte. Selected weighted average grades include: Sunset breccia (hole SB-05, 30-metre interval) with 3.570% copper, trace molybdenum, and 4.522 grams per tonne silver; Victors breccia (hole SB-33, 1-metre interval) with 1.562% copper, 0.004% molybdenum, and 5.509 grams per tonne silver; and Magna breccia with multiple intervals ranging from 0.663% to 1.089% copper, plus associated molybdenum, gold, and silver.

The release clarifies that intervals reported are drill core lengths and do not represent true thickness, which remains unknown. Copper-molybdenum mineralization occurs in steeply dipping, northeast-trending quartz veinlets, fractures, and limonitic, clay-altered magmatic hydrothermal breccia pipes, with lesser disseminated chalcopyrite in the Copper Creek intrusive and quartz-pyrite-chalcopyrite veins in the Glory Hole Volcanics.

Advancing Permitting for Exploration Drilling

Copper Fox has retained an Arizona-based consulting firm to prepare the necessary surveys and documentation for submitting a Geological Field Operations Plan (GFOP) to the Arizona State Land Department. This submission is required to secure approval for exploration drilling to test the porphyry target at depth. The company has not disclosed a timeline for GFOP submission or the schedule for future drilling programs.

The updated exploration model and multiple independent porphyry indicators support Copper Fox’s decision to advance toward drilling. Features such as the large geophysical anomaly, prospective intrusive phases, alteration patterns, hypersaline fluid inclusions, and widespread copper-molybdenum mineralization underpin the interpretation that upper or marginal portions of a larger porphyry copper-molybdenum system exist at depth.

Copper Fox’s Diverse Project Portfolio

Sombrero Butte is part of Copper Fox’s broader portfolio. The company holds 100% ownership of the Van Dyke in-situ copper recovery (ISCR) project, a development-stage, potential near-term, mid-size copper mine in Arizona. Copper Fox also owns a 25% stake in the Schaft Creek Joint Venture with Teck Resources Limited (75% interest and operator), hosting the Schaft Creek copper-gold-molybdenum-silver project in British Columbia’s Golden Triangle.

Additionally, Copper Fox owns 100% of the resource-stage Eaglehead polymetallic porphyry copper project in northwestern British Columbia and the Mineral Mountain advanced exploration-stage porphyry copper project in Arizona’s Laramide copper province. The company is a Canadian resource firm focused on copper development and exploration across the United States and Canada.

Quality Assurance and Qualified Person Statement

Age dating (U/Pb zircon analysis) was conducted by the Pacific Centre for Isotopic and Geochemical Research in Vancouver, British Columbia, using CA-TIMS U-Pb isotopic methods. Whole-rock and trace-element sample preparation and analyses were performed by ALS Canada Ltd in Vancouver, employing ALS codes ME-MS61L for trace elements, MS61L-REE for rare earth elements, and ME-ICP for whole-rock element analyses. Historical analytical results from 2006–2008 Bell Copper drilling were generated by Activation Laboratories using instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP) techniques.

Petrographic thin sections and cobaltinitrite staining of cut blocks were completed by Vancouver Petrographics in Langley, British Columbia. Both Bell Copper and Activation Laboratories applied various standards and blanks within their quality assurance and quality control programs. Elmer B. Stewart, MSc., P. Geol., President and CEO of Copper Fox, serves as the company’s non-independent, nominated Qualified Person under National Instrument 43-101 and has reviewed and approved the scientific and technical information disclosed.