Red Top Copper Project

Superior (Pioneer) Mining District, Pinal County, Arizona

HIGHLIGHTS

• Porphyry copper exploration project 8 km north of Rio Tino – BHP’s Resolution Deposit
• 5,165 meters of drilling by Zacapa in 2021-22 discovered a granite porphyry intrusion with vein-controlled copper mineralization beneath the strongly altered outcrop at Red Top Hill
• Land position expanded to 431 unpatented mining claims (8,387 acres) with local copper occurrences associated with historic workings
• Airborne magnetotellurics geophysical survey identified strongly conductive zone southeast of previous drilling

Location

The Red Top project is located in southwestern Arizona north of the town of Superior, approximately 25 miles east of the Phoenix metropolitan area. Access is via US Highway 60 and the Happy Camp Canyon road on U.S. Forest Service land. Elevations range from 3000 to 5000 feet. 

HISTORY

Zacapa acquired 100% of the Red Top project through the exercise of an option agreement with EMX Royalty Corp in January 2022. The option was fully executed in January, 2022. The Red Top project is part of the Superior (Pioneer) mining district which includes the historic Magma mine and Rio Tinto-BHP’s Resolution mine development project (1.8 Gt @ 1.5% Cu). This district is immediately west of the Globe-Miami district, which includes many other porphyry copper deposits such as Superior East, Pinto Valley, and Miami-Inspiration. Most historic production at Superior came from the Magma vein approximately 4 miles south of Red Top Hill. Originally termed the Silver Queen, the Magma Mine was located in the late 1870’s and by the time it closed in 1996 had nine shafts down to nearly 5,000 feet. Over the life of the Magma Mine it produced more than 27.6 million tons of ore averaging approximately 4.9% copper. In total, approximately 2.6 Blbs of copper, 73 Mlbs of zinc, 34.3 Moz of silver and 686 koz of gold were recovered from the Magma vein and manto deposits.

Alteration at Red Top hill has generated interest from explorers for some time. Historic exploration in and around the Red Top area probably started in the early 1900’s and there are numerous adits and pits, as well as a historic miners cabin in the area. Prior to Zacapa’s exploration at Red Top, modern exploration included several geophysical surveys and at least five drill holes. No information is publicly available about the prior drilling results.

Geology

Regional Geology

The Red Top project occurs in the Basin and Range province of central Arizona where Tertiary extension has resulted in complex faulting and tilting of pre-existing geology. Precambrian basement rocks consist of Pinal Schist and granitic plutons (Ruin Granite) overlain by Proterozoic sedimentary rocks all of which are intruded by diabase sills. These older units are unconformably overlain by Paleozoic carbonate and clastic units and Mesozoic volcaniclastic and clastic successions. Late Cretaceous to early Paleogene compression associated with the Laramide Orogeny produced folds and thrusts and introduced metaluminous plutons and dikes (e.g. quartz monzonite to granodiorite porphyry) and andesitic to rhyolitic volcanic rocks, and associated porphyry copper mineralization. Erosion stripped much of the Laramide volcanic cover and later arc magmatism introduced Oligocene felsic plutons and volcanic rocks that are locally associated with polymetallic vein deposits. In the Miocene, regional extension resulted in faulting that locally dismembered and rotated earlier porphyry copper deposits and was associated with the deposition of extensive coarse-grained sedimentary rocks and mafic to intermediate volcanism. 

Local Geology

The Red Top project area is dominated by a porphyryitic granitic intrusion into Precambrian Pinal Schist. The granitic intrusion outcrops west of Red Top hill. At Red Top hill the Pinal Schist is strongly altered with a large zone of illite-sericite-pyrite alteration and a higher temperature core containing pyrophyllite. Erosional deposits surrounding Red Top hill contain 1-2 meter thick layers of ferricrete and manganocrete, indicating strongly acidic conditions during weathering and erosion of sulfide minerals. To the east of the project area a quartz monzonite porphyry intrudes the Pinal Schist. To the north of the project area weakly metamorphosed clastic, carbonate, and volcanic strata of the Proterozoic age Apache Group are exposed, resting unconformably overtop of the Pinal schist. The Pinal Schist and Apache Group are cut by 1.1 Ga diabase dikes and sills. Regional extension resulted in tilting of from 10 to more than 40 degrees to the east.

Mineralization

In drill holes the quartz-eye biotite granite porphyry intersected below the outcropping Pinal Schist contains sheeted veins, consisting principally of green to white sericitic alteration (muscovite-illite-smectite±chlorite), with lesser quartz-sericite-pyrite and chlorite alteration. Alteration occurs in vein selvages and as rims on mafic phenocrysts. Quartz-sulfide (pyrite, chalcopyrite, sphalerite, galena, bornite, molybdenite) -sericite veining and local associated hydrothermal breccias occur throughout most drill holes, with average volumes of about 1-2%. Locally intense veining and quartz-sericite-pyrite alteration is associated with pyrite contents of up to 10%. The observed alteration and mineralization is interpreted as a copper enriched peripheral zone to a porphyry copper system.

Geologic Model

Exploration is targeting copper bearing porphyry intrusions interpreted to be the cause of shallow high-level illite-sericite and pyrophyllite alteration at Red Top Hill. The porphyry alteration patterns in the area are interpreted to have been tilted approximately 25 degrees to the east by complex extensional faulting.  

References

Briggs, D.F., 2015, Superior, Arizona – An Old Mining Camp with Many Lives: Arizona Geological Survey Contributed Report, CR-15-D, 13 p.

Leveille, R.A. and Stegen, R.J., 2012, The Southwestern North America Porphyry Copper Province, in Hedenquist, J.W., Harris, M., and Camus, F., eds., Geology and Genesis of Major Copper Deposits and Districts of the World: A Tribute to Richard H. Sillitoe: Society of Economic Geologists Special Publication 16.

Ransome, F.L., 1914, Copper Deposits near Superior, Arizona: U.S. Geological Survey Bulletin 540-D: p. 139-158.