NVRO Metals Limited has successfully completed a 202-hour continuous production demonstration campaign of the proprietary NVRO Process using material from Hecla Mining Company’s Greens Creek operation in Alaska.

The continuous run, which followed 57.5 hours of commissioning and process stabilization, achieved approximately 97% sulfide oxidation and a 70% reduction in solids mass during leaching. Preliminary operating results indicate silver upgrading from a calculated flotation feed of 169 g/t to 1,795 g/t in the leach product, representing an overall upgrade of approximately 10.6 times. Gold upgraded from 1.51 g/t to 16.3 g/t, achieving an overall upgrade of approximately 10.8 times.

These results compare with the March 2026 bench-scale test, which reported a total gold upgrade from feed to residue of 6.6x and a total silver upgrade of 5.7x, though the companies note the campaigns were conducted on different samples. Full independent laboratory assays and complete metallurgical reconciliation remain in progress.

The campaign forms part of a collaboration between NVRO Metals and Hecla to evaluate the processing solution for Greens Creek tailings under a memorandum of understanding signed on June 23, 2026, establishing a framework for a proposed 35,000-tonne industrial-scale processing campaign at the NVRO Metals Hub. Management assesses that the successful demonstration plant run brings the technology to Technology Readiness Level 7.

“Successfully completing continuous operation over 200 hours is an exceptional milestone achievement and a demonstration of the integrated NVRO Process™ using customer feedstock. I would like to thank the entire team for their dedication to this goal.”

“The consistency of the operating performance and the preliminary metallurgical results give us confidence that the process is performing in line with our engineering expectations. We now look forward to receiving the balance of the independent laboratory results.”

— Grant Freeman, Chief Executive Officer

NVRO Metals expects to receive remaining laboratory assays, complete full metallurgical reconciliation for the Hecla Greens Creek continuous production demonstration campaign, and continue discussions with Hecla regarding the next stage of the evaluation program under the memorandum of understanding.

Read the full announcement: NVRO Metals Advances Commercial Deployment of the NVRO Process™ Through Successful Continuous Production Demonstration on Hecla Greens Creek Material