Cactus Mine Project – Overview

Cactus Project Total Measured, Indicated and Inferred Mineral Resource

NOTES:
1. Total soluble copper grades (Cu TSol) are reported using sequential assaying to calculate the soluble copper grade. Tons are reported as short tons.
2. Stockpile resource estimates have an effective date of 1st March, 2022, Cactus mineral resource estimates have an effective date of 29th April, 2022, Parks/Salyer-MainSpring mineral resource estimates have an effective date of 11th July, 2024. All mineral resources use a copper price of US$3.75/lb.
3. Technical and economic parameters defining mineral resource pit shells: mining cost US$2.43/t; G&A US$0.55/t, 10% dilution, and 44°-46° pit slope angle.
4. Technical and economic parameters defining underground mineral resource: mining cost US$27.62/t, G&A US$0.55/t, and 5% dilution. Underground mineral resources are only reported for material located outside of the open pit mineral resource shells. Designation as open pit or underground mineral resources are not confirmatory of the mining method that may be employed at the mine design stage.
5. Technical and economic parameters defining processing: Oxide heap leach (HL) processing cost of US$2.24/t assuming 86.3% recoveries, enriched HL processing cost of US$2.13/t assuming 90.5% recoveries, sulphide mill processing cost of US$8.50/t assuming 92% recoveries. HL selling cost of US$0.27/lb; Mill selling cost of US$0.62/lb.
6. Royalties of 3.18% and 2.5% apply to the ASCU properties and state land respectively. No royalties apply to the MainSpring property.
7. Variable cut-off grades were reported depending on material type, potential mining method, potential processing method, and applicable royalties. For ASCU properties - Oxide open pit or underground material = 0.099% or 0.549% TSol respectively; enriched open pit or underground material = 0.092% or 0.522% TSol respectively; primary open pit or underground material = 0.226% or 0.691% CuT respectively. For state land property – Oxide open pit or underground material = 0.098 % or 0.545% TSol respectively; enriched open pit or underground material = 0.092% or 0.518% TSol respectively; primary openpit or underground material = 0.225% or 0.686% CuT respectively. For MainSpring properties – Oxide openpit or underground material = 0.096% or 0.532% TSol respectively; enriched open pit or underground material = 0.089% or 0.505% TSol respectively; primary open pit or underground material = 0.219% or 0.669% CuT respectively. Stockpile cutoff = 0.095% TSol.
8. Mineral resources, which are not mineral reserves, do not have demonstrated economic viability. The estimate of mineral resources may be materially affected by environmental, permitting, legal, title, sociopolitical, marketing, or other relevant factors.
9. The quantity and grade of reported inferred mineral resources in this estimation are uncertain in nature and there is insufficient exploration to define these inferred mineral resources as an indicated or measured mineral resource; it is uncertain if further exploration will result in upgrading them to an indicated or measured classification.
10. Totals may not add up due to rounding.

Cactus PEA Summary:

Notes: Cactus PEA dated August 7, 2024 (1) Tonnage is denoted in short tons. 

*Operating cash costs consist of mining costs, processing costs, and G&A. **Total cash coasts consist of operating cash costs plus transportation cost, royalties, treatment, and refinancing. ***AISC consist of total cash costs plus sustaining capital, closure cost, and salvage value.

The 2024 PEA supersedes the PFS titled “Cactus Mine Project NI 43-101 Technical Report and Pre-Feasibility Study, Arizona, United States of America”, dated March 28, 2024 (with an effective date of February 21, 2024) (“March 2024 PFS”) in its entirety. The PEA integrates the new Parks/Salyer additions from the MainSpring property as inferred mineral resources, re-scoped as an open pit. By applying open pit mining costs to the Parks/Salyer mineral resource estimate, it now contributes 531 M tons of feed material grading 0.530% CuT to the total 889 million tons of feed material at 0.46% CuT over the LoM. FIGURE 1 illustrates the cumulative stacked production in this PEA. Overall, the Cactus Project PEA envisages a 31-year mine life with annual average throughput of 29 million tons, for an average of 86 kstpa of copper cathodes produced annually. The result is a lower risk brownfield open pit mining operation with a long life and a streamlined permitting process on private land in Arizona with water rights and access to water from in-situ water wells. 

A total of 2,872 million tons will be mined and a total of 889 million tons processed, recovering 5.34 billion pounds of copper cathodes over the LoM or 2,669,000 tons. Copper cathodes will be produced directly onsite via heap leach and SXEW, including a four year ramp up period. Total Copper recoveries are planned at an average of 73%, extracting copper from the oxides, enriched and primary sulphides. See Exhibit 1 and 2 for mine plan, sequencing, costs and economics. Gross acid usage is calculated at 22 lbs per ton at a cost of $160 per ton.

NPV and IRR Sensitivities⁽¹⁾

Mining and Processing Operations

Mineralized material will be sourced mainly from the two open pits with an overall LoM strip ratio of 2.3:1. The Cactus West pit (1.0:1 strip ratio) and new Parks/Salyer pit (3.2:1 strip ratio) comprise 94% of the total material to the leach pads. The remaining 5% of material will be sourced from the Cactus East underground deposit utilizing sub-level cave from the 1,200 ft (366 m) level, and 1% from the Stockpile. 

Both Parks/Salyer and Cactus West will be mined using 40 ft (12.1 m) single benches, with ramps sized to allow 320-ton class haul trucks. At Parks/Salyer, all walls have been designed with 45-degree inter-ramp slopes, while geotechnical step-outs are employed to reduce the overall slope to approximately 40 degrees. At Cactus West, inter-ramp slopes range from 45–50 degrees depending on material type, with typical overall slope angles of 41-43 degrees. Gila conglomerate and alluvium constitute the large majority of the waste in the pits.

The mine schedule for open pit mining at Parks/Salyer consists of 531 million tons of feed material grading 0.530% CuT, including 453 million tons of oxide and enriched leach feed material grading 0.55% CuT and 78 million tons of primary sulphide leach feed material grading 0.41% CuT. Open pit mining will initiate in Parks/Salyer in Year -1 and operate continuously for 23 years over seven pit phases. Total waste mined in Parks/Salyer is 1,680 million tons.  

The mine schedule for open pit mining at Cactus West consists of 306 million tons of feed material grading 0.29% CuT, including 154 million tons of oxide/enriched leach feed material grading 0.26% CuT and 152 million tons of primary leach feed material grading 0.32% CuT. Open pit mining will take place at Cactus West in the years of 7-11, 15, 19, and 23-31. Phase 1 Cactus West is used to smooth stripping requirements of Parks/Salyer in the middle-years of the mine plan, while Phase 2-3 are mined in the later years and predominantly supply primary feed material. Total waste mined from Cactus West is 299 million tons.  

The Stockpile project contributes 9.8 million tons of conventional leach feed material grading 0.24% CuT which will be used for project commissioning in Year 1 of processing. 

After a comprehensive review of Cactus East¸ sub-level caving (“SLC”) was selected as the preferred underground mining method. A sublevel cave underground mine is planned for Cactus East with development beginning in Year 8 and mining completed in Year 22, peaking at 3.9 million tons per year. Total Cactus East feed material mined is projected to be 42 million tons grading 0.83% CuT. The initial Cactus East SLC level will begin at 1,325 ft (404 m) below the surface over 7 sublevels, to a final depth of 1,845 ft (562 m). Access will be via a single decline with a portal located within the existing Cactus West pit. Haulage of mineralized material to surface will be via a vertical conveyor which can be supplemented with truck haulage to surface via the open pit if necessary. 

The Cactus Project heap leaching process design includes crushing of all material types for leaching to a minus ¾” P80 size. All material types, oxides, enriched and primary are to be leached in on a single pad with an initial leaching cycle of 180 days. A maximum 3-year leaching cycle has been assumed (3 lifts) as the practical limit for effective recovery based on experience and hydrodynamic analysis of the materials by HydroGeoScience Inc. (HGS). The copper leaching metallurgical test data has been extrapolated from the testing data at one year based on the rates prevailing after one year using a logarithmic curve fit projection that considers the decaying rate of copper extraction. 

Average annual water consumption is planned at approximately 1,200 gallons per minute, the equivalent of 1,935 acre feet per year, well within ASCU’s permitted 3,600 acre feet per year industrial use allocation, using in place onsite wells.

The PEA envisages that overall tonnage will comprise approximately 25% oxide material, 50% enriched (secondary sulphides) and 25% primary sulphides within the LoM. From year 15 to 22 placed tons will consist of approximately 25% primary, whereas from year 23, will comprise 100% of the operation. Overall copper extraction is impacted by the lower rates from primary sulphides. In the PEA, ASCU includes a conservative 25% extraction rate. 

The total LoM costs, operating costs per ton ($/st) of processed material, and dollars per pound ($/lb) of cathode produced are summarized in the three tables below. Project operating costs include mine operating, process plant operating, and general and administrative costs (“G&A”). Total production costs include royalty expense. The AISC additionally includes initial Capex, sustaining Capex, reclamation & closure.  

Mining operating cost estimates, prepared by AGP Mining Consultants Inc., are based on a small owner’s team managing mining activities using an owner-operator model. Process operating cost estimates were prepared by Samuel Engineering and G&A cost estimates were prepared by M3 Engineering with input from ASCU.

The Project exists in relatively flat to slightly undulating ranching and mining locale. The Project is surrounded by other, current and past-producing, copper mines and processing facilities. The Greater Phoenix area is a major population center (approximately 4.5 million persons) with a major airport and transportation hub and well-developed infrastructure and services that support the mining industry. The cities of Casa Grande and Maricopa are nearby and, combined with Phoenix, can supply sufficient skilled labor for the Project.

Onsite infrastructure from the prior ASARCO operation includes historic data and maps, core shack, vent raise, underground development towards Cactus East deposit, production shaft to 1,800 ft (549 m) level. Additionally, ASCU benefits from open pit access to near surface remnant mineralized material, permitted water wells and a water pond, access roads, rail access to the Union Pacific Railway, power substation and administration buildings. The TruStone building, a former onsite factory, has been refurbished and is now the site of ASCU's metallurgical testing, a core storage facility and a sample preparation lab. The former core shack has been modernized with power and A/C.

Electric power is available from Arizona Public Service’s (APS) 115 kV transmission line which passes on the south side of the site and connects to an existing substation at the mine site and is owned by APS.

Ecologically, the site is within the Sonoran Desert Section of the Basin and Range Lowlands Province of Arizona in the lower Santa Cruz Basin. The area is characterized by broad, level valley plains, gently sloping pediments, and widely separated mountain ranges. Elevations at the mine vary from approximately 1,360 ft amsl to 1,460 ft amsl. Soils have very low levels of available plant nutrients and vegetation typical of the Sonoran Desert and includes bunchgrasses, yucca, mesquite, and cacti.

ASCU is dedicated to operating a responsible and carbon conscious mine site. It is the Company’s policy to ensure the community engagement and partnership outreach is developed and maintained with the support of the local communities.

As the Cactus Project is on private land, the permitting process is streamlined with no federal nexus, see below for required permits. The Company has confirmed with a Jurisdictional Delineation survey that no Federal Waters of the United States flow through the Cactus Properties. Permit approvals therefore, are limited to state and county regulatory bodies which have pre-determined approval processes and timelines. The Company aims to meet applicable requirements under the Clean Water Act (CWA), Clean Air Act (CAA) and all other applicable federal rules and regulations. 

The Company has advanced the Cactus Project to the shovel-ready stage, receiving all major permits required as per the 2021 PEA. ASCU has received both the approval to draw water from the ADWR, and the Aquifer Protection Permit related to the Cactus PEA Mine Plan, the Dust Permit and Storm Water Pollution Prevention Plan, Mined Land Reclamation Plan and its Industrial Air Permit. Based on the Prefeasibility Study, certain amendments will be required as outlined below. The Company continues to make good progress with it’s permits and is supported by regulators and the community in its development plans.

The Cactus Project will require the following major permits and certifications:
1.    Arizona Department of Water Resources (“ADWR”)’s Withdrawal of Ground Water for Mineral Extraction & Mineral Processing Permit: This permit is required for ground water withdrawal for mining operations. This permit was obtained in April 2021 and extends for 50 years, which is beyond the life of the project.
2.    The ADEQ’s Aquifer Protection Permit (“APP”): This permit is required for owners or operators of facilities that could discharge a pollutant directly to an aquifer or to a land surface or vadose zone where there is a reasonable probability that the pollutant will reach an aquifer. The permit is valid for the life of the facility. This permit was obtained by ASCU for the Stockpile Project in July 2021 and becomes effective upon demonstration of financial capability submitted along with an amendment application in respect of the full project. Following development of the PEA mine plan in 2021, an amendment for full project coverage including expanded leach facilities, waste dumps and both open pit and underground infrastructure was obtained on March 28, 2022. Upon completion of the PFS in Q1/2024, the Company will require a second amendment based on the re-scoped operations.
3.    Pinal County’s Air Quality Dust Control Permit: This permit is required for operations that have the potential to generate fugitive dust. This permit was obtained by the Company in January 2020 and is renewed yearly based on operational need.
4.    ADEQ’s Arizona Pollutant Discharge Elimination System (“AZPDES”) Permits (construction and Multi‐Sector General Permit): This permit is for stormwater discharges that enter Arizona surface waters or a Municipal Separate Storm Sewer System. This permit was obtained for both the mine facility and the nearby TruStone facility which is situated on Company property. 
5.    Pinal County’s Industrial Air Quality Control Permit: This permit is required for operations that have the potential to generate particulate matter PM10 and/or PM2.5 that can affect air quality. This permit is renewed yearly and was received in May 2023, based on the Cactus PEA mine plan. Pending the PFS mine plan, an amendment will be required. 
6.    Arizona State Mine Inspector, Mined Lands Reclamation Permit: This permit relates to all metalliferous mining units and exploration operations with surface disturbances on private lands greater than five acres and has been received by the Company. Based on the pending PFS mine plan, an amendment may be required. The Company received this permit in March 2023. 

In addition, the United State Army Corp. Of Engineers (“USACE”) Jurisdictional Determination 404 was received in February 2022. This is a determination as to whether Waters of the U.S. (“WOTUS”) are onsite or if the water on site contributes to a WOTUS waterway. ASCU received a determination that the Cactus project does not impact WOTUS, and therefore no Federal Permitting will be required.

A comprehensive metallurgical testing program for the Cactus Project leachable material (oxides and enriched) has been underway since early 2020 consisting of sequential assaying, bottle roll testing and column leach testing for the mineral resources. The two year column testing program is ongoing at the Cactus Project collecting critical leaching information for both oxidized and secondary enriched ores with different rock types, ore grades, and mineralogy from both the Cactus and Parks/Salyer deposits. Results are demonstrating typical values reported in industry.

Average copper recovery and acid consumption estimates are presented in the table below, based on the May 2023 update.

TABLE 1: Updated Metallurgical Recoveries and Net Acid Consumption

A copper heap leach column testing program to delineate the metallurgical performance characteristics of the existing stockpile and remaining unmined copper resources at the Cactus mine has been ongoing since 2020. Results have been progressively reported in PEA, commensurate with Canadian National Instrument NI 43-101 reporting requirements. Since moving the 12 column metallurgical program to the TruStone Facility onsite, the program is QP'd by Jim Sorenson and managed by ASCU Projects Director, Dan Johnson and Cheif Metallurgist, Steve Dixon. The updated PEA has an effective date of August 31, 2022 and is authored by Stantec Consulting Services (“Stantec”).

Copper recovery is estimated for acid soluble copper (“CuAS”) and cyanide soluble copper (“CuCN”) content as determined by a standard sequential copper assaying methodology developed at the Skyline Laboratory facility in Tucson, Arizona. The CuCN assay fraction is classified as enriched secondary copper sulfide mineralization (e.g. chalcocite, covellite, digenite). The combined CuAS + CuCN content of the materials represents potentially soluble copper that is recoverable using heap leaching techniques (“CuSol”). Projected copper recovery estimates previously reported have been derived based on this leachable copper content and continues to be validated in the ongoing Prefeasibility Study (“PFS”) testing program.

Primary copper in mineralization that is not readily acid or cyanide copper soluble per the assay methods (e.g. native copper, chalcopyrite, bornite) reports in the total copper assay (“CuT”). Copper assayed that does not report in the soluble copper assay methodologies is not expected to provide meaningful recoverable copper contributions with the commercial methodologies anticipated.

The Company is assessing the leachability of its primary sulphide materials with third party companies. In June 2022, an exclusivity agreement with Rio Tinto was triggered by by successfully modelling the Cactus and Parks/Salyer samples and achieving the previously contemplated preliminary indicative metallurgical recoveries of at least 72% (copper recovery to cathode), under the Investor Rights Agreement. Nuton will continue to test the application of its copper heap-leach related technology to the primary sulphide component of the Cactus Mine and Parks/Salyer Projects through column leaching and scoping out capital and operating costs and design parameters.

Ecologically the site is within the Sonoran Desert Section of the Basin and Range Lowlands Province of Arizona in the lower Santa Cruz Basin.  Major host rocks are Precambrian Oracle Granite and Laramide monzonite porphyry and quartz monzonite porphyry. The porphyries intruded the older rocks to form mixed breccias; monolithic breccias and occur as large masses, poorly defined dike-like masses; and thin well-defined but discontinuous dikes.  The deposit is structurally complex with intense fracturing, faulting, and both pre-mineral and post-mineral brecciation. It is bounded on the east and west sides by normal faults.

Chalcocite and covellite are the only supergene sulfides recognized. The chalcocite blanket in the mineralized zone is irregular in thickness, grade, and continuity. The thickness of leached capping varies from less than 100 ft (30 m) to over 650 ft (198 m), with the thicker intercepts on the north side. Substantial quantities of oxidized copper minerals are found erratically distributed through the capping. Chrysocolla, brochantite, and malachite are the most common oxidized copper minerals. In upper portions of the capping, chrysocolla predominates, while brochantite and malachite predominate in the lower portions. 

The dominant hypogene alteration assemblages in the deposit are phyllic and potassic. The major hypogene sulfide minerals in the deposit are pyrite, chalcopyrite, and molybdenite. Hypogene sulfides occur as disseminated grains, veins, and vug fillings. 

The Cactus deposit is a portion of a large porphyry copper system that has been dismembered and displaced by Tertiary extensional faulting. Porphyry copper deposits form in areas of shallow magmatism within subduction-related tectonic environments (Berger et al., 2008). Cactus has typical characteristics of a porphyry copper deposit which Berger et al. (2008) define as follows.

• One wherein copper-bearing sulfides are localized in a network of fracture-controlled stockwork veinlets and as disseminated grains in the adjacent altered rock matrix.
• Alteration and mineralization at 1 km to 4 km depth are genetically related to magma reservoirs emplaced into the shallow crust (6 km to over 8 km), predominantly intermediate to silicic in composition, in magmatic arcs above subduction zones.
• Intrusive rock complexes that are emplaced immediately before porphyry deposit formation and that host the deposits are predominantly in the form of upright-vertical cylindrical stocks and/or complexes of dikes.
• Zones of phyllic-argillic and marginal propylitic alteration overlap or surround a potassic alteration assemblage.
• Copper may also be introduced during overprinting phyllic-argillic alteration events.

The American Smelting and Refining Company (ASARCO) geologists first discovered the Sacaton mineral deposit in the early 1960’s while examining an outcrop of leached capping composed of granite cut by several thin monzonite porphyry dikes. The nature of this original find indicated the likely presence of porphyry copper-type mineralization. Following this lead, ASARCO initiated a drilling program which defined copper mineralization zones, targeting the sulfide ores, despite significant oxide zones at shallow depths. The west deposit contained an ore body which was ultimately accessed through the open pit. The deeper east deposit was the target of potential mining by underground methods, and today contributes significantly to the project economics.

ASARCO operated the mine from 1974-1984 with approximately 400 direct mine jobs created locally during the peak of operations, and numerous indirect positions also created to service the mine. During the course of operations, ASARCO processed 32 million tons of `, producing 400 million pounds of copper in addition to silver and gold from the West ore body through an onsite flotation mill. In 1982, construction began on two production shafts to 1,800 ft (549 m) depth and a headframe to the southwest of the pit to access the higher-grade East zone via underground mining methods; however, development was suspended due to market conditions and in 1984 and the mine shut down. 

Whilst operating, the Sacaton mine site included crushing facilities, coarse ore stockpiles, a flotation mill, maintenance and administration buildings, core shack, a 390-acre tailings storage facility (TSF), a return water impoundment, an approximately 80-acre Alluvium Soil Storage Area, and a 500-acre stockpile of oxides and enriched material, at the time considered waste. All concentrates were shipped via rail to ASARCO’s smelter in Texas for processing into cathodes.

It is important to understand that while 16% of the worlds copper was produced in an SXEW plant in 2019 (see figure below), in the 1970’s, the process was still being refined and tested. ASARCO therefore planned the extraction of the Sacaton sulfide ore operations with a flotation mill, leaving behind a sizeable waste rock dump consisting of oxides and low-grade enriched ore and a significant in ground ore body. Today, ASCU can benefit from the refined SXEW process and will also be exploring the potential for primary ore leaching.

Following the 2020 ASARCO-funded mine site reclamation, the core shack, rail spur, power lines, waste rock and tailings facility remain in good condition. The vent raise and shaft are still in place; however, have had minimal assessment since the initial shut down of Cactus. 

No un-remediated liabilities were transferred to ASCU during the purchase. The reclamation provided the company with a baseline environmental study approved by the Arizona Department of Environmental Quality (ADEQ).