Projects

Cora - Arizona

Location

The Cora Copper Project is located 40 km southwest of Florence, Arizona and is accessible by car via Arizona State Route 87 and 20 km paved and unpaved roads. The site is serviced by the nearby communities of Eloy and Coolidge, AZ. The project is 100% owned by Aguila, secured by 46 granted BLM lode mining claims covering a total of 3.84 sq km.

The claims held by Aguila cover the flat lying pediment to the east of and adjoining the historic North Star copper mine.

Geological Setting

The Project is situated in what is known as the ‘basin and range’ physiographic province of Arizona. Porphyry deposits in this region are Late Cretaceous to Early Tertiary porphyritic to equigranular granite to diorite, emplaced during the Laramide orogeny (approximately 45Ma – 65Ma). Larger plutons are characteristically medium-grained, biotite +/- hornblende granodiorite to granite. Comparatively, smaller, shallow-level intrusions are typically porphyritic. Most of the large copper deposits in Arizona are associated with porphyritic granitic rocks.

Copper porphyry deposits of this type are common around Tucson and include the Twin Buttes, Sierrita-Esperanza, Silver Bell and Mission-Pima mines, as well as the historical Ajo mine to the west. The Ray, Miami, Pinto Valley, Morenci, Safford, Carlota, Superior and Resolution mines are examples of open-pit extraction sites for copper in east-central Arizona.

Mineralization

Arizona copper porphyry deposits are dominantly copper with subsidiary molybdenum mineralization and it is not uncommon for these deposits to have significant supergene enrichment.

Surface rock chip and historic drill chip samples from the Cora and adjacent North Star areas demonstrate chrysocolla and locally scattered blebs of chalcocite, likely representing supergene enrichment. Oxide copper minerals have also been noted in quartz-monzonite - monzonite porphyry, andesite dikes, granites, quartzite and argillaceous sediments around Cora. The volcanics at the Project area range in composition from rhyolite to felsite and are most likely of Laramide age, as they intrude the older sedimentary Paleozoic Pinal Schist found north of the Cora project site.

Porphyry copper systems within Arizona are often subjected to significant post-mineral faulting and dismembering with characteristic re-mobilization of copper fluids along post-mineral faults. In this context, the structurally controlled North Star mine adjacent to widespread copper oxide mineralization and altered intrusive rocks of the Cora project are suggestive of a shallow buried porphyry copper target.

Project History

Small scale mining at the nearby North Star Mine started in the 1949 and continued until 1970. That mining sparked exploration activity, mainly in the form of geophysics and drilling, which was carried out by Asarco, Magma Copper and Phillips Petroleum in the 1960s and 1970s. Although a large zone of disseminated copper mineralization was found in the area east of the North Star Mine, it appears that this mineralization was not further assessed and it remains a largely untested, but prospective target.

Original exploration company records held by the Geological Survey of Arizona indicate past drilling at Cora intersected oxide copper mineralization over widths in excess of 100m, beneath shallow alluvial cover, over an area of at least 1km by 1km. Intervals include:

  • DH5:   99.7m (327ft) @ 0.28% Cu, below 10.7m of alluvial cover (California Steel Co., 1950s)
  • DH4:   39.6m (130ft) @ 0.38% Cu, below 47.2m of alluvial cover (California Steel Co., 1950s)
  • DH1:   225.5m (740ft) @ 0.29% Cu, below 42.7m of alluvial cover (California Steel Co., 1950s)

Drilling results are historical in nature and have not been verified by a "qualified person" as defined by National Instrument 43-101. Drill locations are determined from maps with local grid coordinates of the day which cannot converted to modern coordinates with a high degree of accuracy. Results therefore should not be relied upon and should only be considered an indication of the mineral potential of the project.

Geological logs from holes drilled by Magma Copper Co. immediately west of Cora, indicate copper mineralization may be associated with highly altered, possible Laramide aged intrusions, consistent with a potential porphyry copper setting and analogous to many large copper deposits in Arizona.

Mapping by Magma Copper Co. identified propylitic, argillic and potassic alteration within Laramide-aged granite and monzonite intrusive rocks to the south of the North Star Mine and west of Cora, along with regular copper occurrences.

Geophysical surveys (gravity, CSAMT) were completed in the vicinity of the North Star mine by Equinox Exploration Corp in 2010 to map the thickness of cover. Based on this information, thickness of cover is expected to range between 50m and 100m at Cora.

Past exploration was predominantly focused on the fault-hosted North Star copper mine. Drilling identified a significant zone of structurally controlled copper oxide mineralization that extends below cover into the ground held by Aguila. Early explorers interpreted mineralization to be associated within detachment faults, however, a review of all available historical data by Aguila indicates a possible porphyry copper-molybdenum association.

The Aguila review noted:

  • Diamond drill logs from Magma Copper Co. describe altered intrusive rocks (monzonite, diorite, latite porphyry) throughout several drill holes, with alteration described as argillic in nature, more consistent with a porphyry copper setting;
  • The lack of reported specular hematite associated with mineralization is inconsistent with a detachment fault model as this is a very common accessory mineral in detachment fault hosted deposits in Arizona and Nevada;
  • The local presence of Laramide aged intrusions, which are associated with all major porphyry copper deposits in Arizona; and
  • The structural association with local porphyry deposits and intrusions.
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