Rzolv recovers 67.51% gold at Arizona mine

Executive Summary

• Rzolv Technologies successfully completed a bulk-scale vat leach metallurgical test at an operating gold mine in Arizona, marking a significant milestone in the commercial validation of its proprietary non-cyanide gold extraction technology.
• The test processed 73.5 tonnes of low-grade oxidized gold mineralization, achieving an overall gold recovery of 67.51% over 40 days, with performance comparable to laboratory-scale reference tests using sodium cyanide.
• The program confirmed stable solution chemistry, predictable scale-up behavior, and compatibility with conventional carbon adsorption and electrowinning circuits, generating design-ready data for future commercial deployment.

Key Details

• Test Scope: Processed 73.5 tonnes (specifically 73.55 tonnes) of low-grade oxidized gold mineralization hosted in gneissic and granitic lithologies.
• Recovery Metrics: Achieved an overall calculated gold recovery of 67.51% over a 40-day period.
• Process Conditions: Run-of-mine material was crushed and screened to minus one-half inch (12.5 mm) plus 18 mesh (1 mm) and treated in a lined vat leach configuration.
• Solution Stability: Solution chemistry remained stable throughout the test, maintaining targeted pH and oxidation-reduction potential (ORP) ranges with no evidence of instability, precipitation, compaction, or channeling.
• Operational Compatibility: Effective gold adsorption onto carbon was achieved, confirming compatibility with conventional carbon adsorption and electrowinning circuits. Dore production and final weight were consistent with calculated carbon loadings.
• Laboratory Comparison: Parallel bottle-roll testing showed Rzolv achieved dissolved gold concentrations of 1.48 to 1.55 grams per tonne Au (gpt) over 48 hours, compared to 0.98 to 1.02 gpt for a reference solution containing 1,000 ppm sodium cyanide.
• Kinetics: Early-time leach kinetics for Rzolv were observed to be equal to or faster than cyanide, with materially higher dissolved gold tenors achieved within the first five hours.
• Design Data Generated: The program produced design-ready data including solution flow rates, residence-time distribution, reagent management, carbon loading/stripping behavior, equipment sizing envelopes, and preliminary operating cost inputs.
• Environmental Controls: The test was conducted within a fully contained, closed-loop process circuit with no discharge to surface water or groundwater systems.

Notable Quotes

• "This bulk-scale vat leach test represents an important inflection point for Rzolv. Processing more than 73 tonnes of ore at an operating mine allowed us to validate not only metallurgical recovery, but solution stability, hydrodynamics, reagent behaviour and carbon performance under real-world conditions." — Duane Nelson, President and CEO