Reduce cyanide in gold and silver mining through integrated on-site gas generation
Gold and silver mines still rely on cyanide leaching to extract metal from low-grade and increasingly complex ores. At the same time, sites face stronger environmental expectations, higher reagent costs, and more frequent audits. This puts pressure on teams to reduce cyanide use while maintaining stable recovery.
Many operations are now finding that one of the most effective ways to reduce cyanide is not a new chemical or a major process change. It is simply maintaining steady, high-purity oxygen in the leach tanks.
Atlas Copco's onsite gas generation supports process reliability by stabilizing key parameters like dissolved oxygen, helping teams achieve consistent yields with lower cyanide consumption in gold and silver circuits.
Before exploring how these systems work, it is helpful to understand why cyanide optimization is receiving more attention across the precious metals sector.
Cyanide in modern gold and silver operations
Why cyanide is used in mining
Cyanide remains widely used because it is highly selective for gold and silver, enabling efficient recovery. It is also cost‑effective, allowing profitable processing of low‑grade ores that would otherwise be uneconomic.
However, without adequate dissolved oxygen, cyanide cannot perform optimally. Increasing cyanide concentrations alone may raise costs without improving recovery.
Typical applications:
- Heap leaching (low-grade ores): Cyanide slowly dissolves gold or silver, achieving 60–80% recovery over weeks.
- Agitation leaching (high-grade ores): Milled ores are treated in tanks with cyanide and mixing, reaching up to 95% recovery in days.
Maintaining sufficient dissolved oxygen is critical in both applications.
Adequate oxygen:
- Increases reaction rates
- Stabilizes silver–cyanide complexes
- Reduces unnecessary cyanide consumption
Operational challenges and compliance
Environmental risks from cyanide spills and contaminated tailings disrupt production, while refractory ores limit recovery efficiency and inflate operational expenses in gold and silver operations. Stringent standards, such as the ICMI Code, require verifiable reductions in usage and effective detoxification. These pressures highlight the need for controls that minimize consumption, reduce handling risks, and maintain stability across polymetallic circuits.
Most operators know this challenge well: keep the leach kinetics efficient, stay compliant, and control the detox load in the tailings.
| Challenge | Operational impact |
| Reagent overuse | Higher costs and increased detox demand |
| Oxygen variability | Yield inconsistency across ore types |
| Regulatory audits | Downtime risks and ICMI scrutiny |
Operational and ESG advantages
Reducing cyanide use in gold and silver mining aligns with economic and environmental goals. Lower reagent volumes cut procurement, transport risks, and waste in tailings, especially for silver's higher-volume processing needs.
Optimized management enhances ESG profiles by minimizing toxicity liabilities, supporting social licenses, and enabling cost savings through efficient recovery, a vital step to take in sustainability-driven operations.
Gas generation for process optimization
Cyanidation process
The cyanidation process treats gold and silver ores with cyanide solution in the presence of oxygen, forming soluble complexes for recovery. Maintaining dissolved oxygen levels between 5-10 mg/L improves leaching kinetics, enabling reduced cyanide use without yield loss in both metals.
Atlas Copco’s oxygen generators provide continuous, high-purity, oil-free oxygen supply that integrates into leaching circuits, ensuring reliability in extreme conditions like winter cold snaps, where downtime dropped significantly.
With over 140 years as a leader in mining equipment, Atlas Copco delivers patented oil-free compression for pure oxygen and nitrogen. Proven even in harsh winters, these systems benefit from global service networks for installation, training, and repairs.
Implementation best practices
- Integrate gas generation early in gold and silver process upgrades, matching flows to ore types and circuit demands.
- Monitor dissolved oxygen and cyanide levels for real-time dosing adjustments, cutting overuse.
- Prioritize preventive maintenance and staff training on integration to sustain uptime and adapt to polymetallic feeds.
Insights for reliability-focused operations
If your priority is uptime, on-site gas generation brings a welcome level of predictability. Fewer deliveries mean fewer potential interruptions. Fewer moving parts than cryogenic systems mean fewer mechanical failures. A constant gas supply means operators spend less time chasing dissolved oxygen swings and more time optimizing recovery.
Mines that adopt oxygen and nitrogen generation as part of their cyanidation strategy frequently report the same pattern: more stable yields, lower cyanide use, improved ESG scores, and fewer surprises.
Are you looking to quantify how much cyanide you can save, or how much uptime your current oxygen supply is costing you? Our specialists are ready to help.
Frequently asked questions
Is cyanide use in gold mining here to stay?
Yes, but smarter integration ensures compliance and efficiency. Cyanide isn’t disappearing from gold and silver mining, but the way it’s managed is absolutely changing.
Steady, high-purity oxygen and safe, consistent nitrogen supply allow operations to reduce reagent use, cut detox burdens, strengthen ESG performance, and gain real control over their process.
Is oxygen really that important in gold and silver cyanidation?
Absolutely. Oxygen is what allows cyanide to dissolve metals efficiently. When dissolved oxygen falls, recovery slows and cyanide use climbs.
How much cyanide can a mine typically save?
Every site is different, but operations that stabilize dissolved oxygen usually see reductions in the 10–20% range and sometimes more when combined with advanced control systems.
Is there a good payback when adding a onsite oxygen generator to improve the Cyanidation process?
Yes, absolutely. Due to the reduction of cyanide use and the environmental benefits linked to this the payback is always short
Do I need high purity oxygen for the cyanidation process?
Onsite oxygen generators can deliver 90-95% oxygen purity and that is sufficient for the cyanidation process.
Download
- Mining application booklet 2025 31.7 MB, PDF
- OGV+ VSA Oxygen generator brochure 5.1 MB, PDF