NVRO Metals Makes Progress in Tailings Processing in Alaska
NVRO Metals Ltd. has successfully completed 202 hours of continuous processing of tailings from the Greens Creek mine, owned by Hecla Mining Company, located in Alaska. This achievement moves the company closer to implementing its unique metals recovery technology on an industrial scale.
Grant Freeman, CEO of NVRO, described this milestone as “an exceptional achievement” that showcases the effectiveness of NVRO’s integrated processing method using materials provided by Hecla.
During the processing campaign, NVRO’s technology managed to oxidize around 97% of the sulfide materials found in the Greens Creek tailings, while also decreasing the solid mass by approximately 70% during the leaching process. This transformation resulted in a metal-rich concentrate, known as leach residue, which contained impressive amounts of silver (1,795 grams per metric ton) and gold (16.3 grams per metric ton). These figures mark significant upgrades compared to the original feed grades of 169 grams of silver and 1.51 grams of gold, achieving a 10.6-fold increase for silver and a 10.8-fold increase for gold.
Following the initial 57.5 hours of commissioning and stability checks, NVRO now possesses over 250 hours of operational data from its demonstration plant. Freeman expressed optimism about the results, stating, “The consistent performance and initial metallurgical findings reinforce our confidence that the process aligns with our engineering expectations.” The preliminary findings were based on analyses conducted by the Western Australian firm Nagrom on a subset of samples.
To finalize their results, NVRO plans to conduct a comprehensive metallurgical reconciliation with additional samples currently being analyzed by independent laboratories.
Advancing Towards Technology Readiness
This recent campaign not only highlights NVRO’s technological advancement but also represents a significant step in the commercial application of their proprietary process, which aims to recover precious and critical metals from mine tailings and waste rock. Hecla has joined forces with NVRO to facilitate the readiness of this technology and assess its potential for reprocessing tailings from the Greens Creek silver mine.
Hecla has noted that over the 36 years of mining at Greens Creek, more than 10 million tons of tailings have accumulated, with an estimated value of over $6 billion in metals—including approximately 50 million ounces of silver and 600,000 ounces of gold, along with zinc, lead, copper, and nickel. Additional materials found in the tailings also have significance for U.S. supply chains.
In earlier phases of testing, NVRO demonstrated the ability to recover an impressive 98.1% of silver and 99.5% of gold from the Greens Creek samples, while also efficiently oxidizing the sulfide minerals, which is crucial for minimizing environmental risks associated with tailings storage.
Following these encouraging results, Hecla sent a 20-metric-ton sample of tailings to NVRO’s demonstration facility in Western Australia, where it underwent continuous processing for 202 hours.
With the continuous campaign achieving over 97% sulfide oxidation and consistent performance, NVRO’s leadership believes they have reached Technology Readiness Level 7 (TRL 7), indicating that the technology has been effectively demonstrated in a real-world setting. The next steps involve further advancing the metals recovery technology toward TRL 9, which signifies proven commercial viability.
Looking Ahead: The NVRO Metals Hub
The next phase for NVRO focuses on establishing the NVRO Metals Hub in Australia’s Northern Territory. The company aims to acquire Northern Territories Resources Pty Ltd., which owns a project related to multiple metals, including copper and zinc, located south of Darwin. This acquisition would enable NVRO to leverage an existing hydrometallurgical processing facility to process both its resources and those from third parties.
Expected to finalize the acquisition by the third quarter of 2026, NVRO is set to combine its technology with industrial-scale processing capabilities. Executive Chairman David Cam expressed excitement about this development, emphasizing the integration of proprietary technology and production capacity into a single framework.
A recent memorandum of understanding outlines plans for a larger trial involving approximately 35,000 metric tons of Greens Creek tailings, dependent on the success of current demonstrations and acquisition processes. This move presents a chance for NVRO to test its technology on a much larger scale.
Overall, this partnership with Hecla not only stands to add value to the Greens Creek mine but also aims to address environmental concerns associated with past mining activities. “If we can successfully reprocess our tailings offsite, it could greatly benefit both metal production and decrease our environmental obligations,” remarked Mike Satre, Hecla’s director of government affairs.
