Excelsior Mining has announced that Nuton, a venture by Rio Tinto, has elected to proceed to Stage 2 of their existing Option Agreement. This agreement focuses on evaluating Nuton’s copper heap leaching technologies at Excelsior’s Johnson Camp mine in Cochise County, Arizona. Excelsior will remain the operator while Nuton funds the two-stage work program.
With the decision to move to Stage 2, Nuton will make a US$5 million payment to Excelsior for using the existing infrastructure at Johnson Camp. Nuton will also cover all costs associated with Stage 2, which is expected to take up to five years. The program aims to demonstrate the Nuton technologies at an industrial scale, with milestones covering engineering, mobilization, infrastructure, construction, mining, leaching, copper production, and post-leach rinsing. Mining is set to begin in the first year, with the first production of Nuton copper anticipated in 2025.
Upon completing all milestones, full-scale commercial production of Nuton copper will commence at Johnson Camp. Revenue from operations will first repay Stage 2 costs to Nuton, after which profits will be credited to Excelsior’s account, accounting for any applicable royalty and stream obligations.
Fred DuVal, Chairman of Excelsior, highlighted the significance of Nuton’s technologies in maximizing copper recoveries and expressed optimism about the positive impact of these clean copper technologies on the development of the Johnson Camp mine.
Nuton’s advanced copper heap leaching technologies target primary sulfide minerals, including lower-grade deposits, which are not economically viable with traditional methods. These technologies offer cost-effective copper production with significant environmental benefits compared to conventional sulfide processing.
After Stage 2, Nuton will have the option to form a joint venture with Excelsior for the continued development of Johnson Camp, with Nuton holding a 49% interest and Excelsior a 51% interest. If Nuton chooses not to exercise this option, the companies will negotiate Excelsior’s continued use of Nuton technologies under certain licensing terms. The infrastructure arrangement at Johnson Camp is non-exclusive, allowing Excelsior to use the facilities for processing Gunnison solutions and other copper sources, provided the capacity requirements for the Stage 2 work program are met. 
