Parks/Salyer Drilling Has Shown Better Than Expected Thicknesses

CASA GRANDE, AZ - Arizona Sonoran Copper Company Inc. reported on 6 infill holes from the Parks/Salyer Pre-Feasibility Study (PFS) level drilling program. The infill to Indicated drilling program was completed on time and within the budget, with the remaining assays from 10 drill holes expected by the middle of May. This program will be used to generate an updated resource model and mine plan to support the declaration of first reserves in the pending PFS by Q1 2024. As announced March 6, 2023, the PFS is exploring an integrated operation for Parks/Salyer and Cactus targeting 50 ktpa production.

PFS-level drilling at Parks/Salyer included geotechnical (HQ), hydrological (HQ) and metallurgical (PQ) holes, in addition to the infill drilling (HQ). Having completed the programs, the three drill rigs are now focused on: 1) Feasibility Study to include Measured-level infill drilling; Additional geotechnical, metallurgical and hydrological holes at Cactus East and Cactus West; Exploration drilling to begin after completion of the Cactus West geotechnical drilling.

Doug Bowden, Arizona Sonoran VP Exploration commented, “As we complete drill programs to finalize an indicated resource estimate (PFS), support engineering and mine planning, we note the drilling is performing as planned, and in instances, with better than expected grade thicknesses. Parks/Salyer intercepts indicate a continuous deposit with typically 100-300 meter enrichment thicknesses that could potentially support a bulk mining scenario. Infill drilling has continued to expand the high-grade core at Parks/Salyer within the inferred resource area defined by the original 500 ft (152 m) drill pattern.”

A total of three metallurgical holes (PQ – 3.345 inch diameter) were completed to provide material for the column leach testing taking place onsite at the TruStone Facility. The columns are now 90 and 120 days complete, and preliminary results are expected shortly. Two metallurgical holes, along with one HQ (2.5 inch diameter) drill hole, were converted to hydrology monitoring holes. A total of five oriented core and geotechnical holes are being surveyed for fracture and directional analysis ahead of mine planning; via Acoustic Tele-viewer survey.

The infill to indicated drilling program was planned to infill to 250 ft (76 m) drill centers, extending through the leachable oxides and enriched mineralization, or secondary sulfides, for inclusion as our base case mine plan. To ensure a complete view of the deposit, for ASCU records and as it relates to the Nuton sulphide leaching technologies, ASCU also drilled through the primary sulfides to the basement fault at Parks/Salyer defining a deposit that extends 2,900 ft (884 m) by 2,200 ft (670 m), at the south-western end of the 4 km mine trend.

Infill drilling on the west side of the Parks/Salyer deposit continues to define the westward continuation of thick, higher-grade, enriched and primary mineralization (ECP-126 and ECP-131). Drill holes ECP-134, ECP-133 and ECP-127 demonstrate continuation of the enrichment blanket to the west, albeit with thinner, stacked layers of copper mineralization that have suffered leaching near the faults that define the edge of the orebody. Drill holes ECP-127, ECP-130 and ECP-133 show a similar definition of the enrichment blanket. A NS cross section through the area demonstrates the continuity of the enrichment zone on the western edge of Parks/Salyer and the effect of late oxidation on the enrichment blanket in the area of ECP-130.

The dacite dyke shown in the cross section is similar in width and continuity to dacite dykes seen in Cactus West on the southern edge of that orebody. These dykes are very late stage relative to the mineralizing event and acted as dams to the enrichment process, with very good enrichment and oxide grades ponding above them, as shown in ECP-131.

There are many occurrences of native copper around the deposit. While native copper does not represent a significant contribution to the oxide resource, it does indicate directional flow of the secondary copper fluids, sometimes pointing toward ponded enrichment areas as shown in ECP-131. The team is currently mapping instances of both native copper and cuprite as they typically exist within close proximity of each other.

ASCU drilling has defined the edge of a potassic zone associated with lower grades in the primary mineralization in the northwest quadrant of the orebody. Higher primary grades are commonly associated with zones of phyllic alteration (commonly as an overprint), which at Parks/Salyer follows the general mine trend NE orientation. This phyllic zone represents the larger area of thicker, higher grades.