Arizona Sonoran Copper (TSX: ASCU) has nearly tripled its measured and indicated resource at the Cactus porphyry project on the site of the past-producing Sacaton mine south of Phoenix.
Cactus has 446 million measured and indicated tonnes grading 0.58% copper for 5.2 billion lb. of the metal, according to an updated resource released on Monday. That compares with 151.8 million measured and indicated tonnes at 0.53% copper in a 2021 preliminary economic assessment.
The upgrade for the combined Cactus, Stockpile and Parks/Salyer deposits is to form the basis for a pre-feasibility study now due early next year, the company said. The study had previously been slated for late this year. It may consider production of as much as 50,000 tonnes a year of copper cathode. See a 3-D Vrify map of the project.
“Our team has completed yet another key milestone in the process of reactivating the Cactus mine,” CEO and president George Ogilvie said in the release. “Driven through textbook infill drilling programs at Parks/Salyer and Cactus, our team readies an already significant copper asset in Arizona for the next step in technical reporting.”
Rio Tinto (NYSE: RIO; LSE: RIO; ASX: RIO) invested C$30.5 million for a 7.4% stake last year in the project that may use technology developed by its Nuton unit. Miners are increasingly probing historical sites to take advantage of improved recovery technology and increased metals demand even as the price of copper was $3.61 a lb. on Monday. It’s fallen below a threshold of $4 per lb. in April that most developers would like to see.
The project, ranked by S&P Global in August as one of the top 10 copper developments in the United States, aims to be a mid-tier producer with potential for a phased expansion. American Smelting and Refining (Asarco), a unit of Grupo México, operated the Sacaton mine 72 km south of Phoenix near Casa Grande from 1972 to 1984. It processed 38 million tonnes of copper ore through a flotation mill for 400 million lb. copper, 759,000 oz. silver, 27,000 oz. gold.
The site has about $30 million of infrastructure and is at an advanced permitting stage with access to water and approved water rights, Sonoran says. The project is located in an industrial park, connected to nationwide highways, railroads and state power. It envisions using a solvent extraction-electrowinning leaching process with sulphuric acid.
Inferred resources are now 233 million tonnes grading 0.47% copper for 2.2 billion lb. of the metal compared with 450 million tonnes at 0.54% copper for 4.9 billion lb. copper in a resource dated April last year.
Some parts of the project boast higher grades. The Parks/Salyer deposit contains 130 million tonnes at 1.03% total soluble copper and Cactus East holds 41.2 million tonnes at 1.06% total soluble copper within the measured and indicated resources, the company said. Drilling of 160,000 metres in 900 holes shows the deposits have consistent mineralization, it said.
New drilling will focus on the Parks/Salyer southern extensions and exposure to a 4-km trend with pockets of mineralization south of Parks/Sayler in the Gap zone and northeast of Cactus East, Sonoran said.
Arizona Sonoran shares traded at C$1.55 apiece on Monday afternoon in Toronto, valuing the company at C$168.9 million. Its shares traded in a 52-week window of C$1.49 and C$2.40.
