Heap Leaching Applications

Replacing Cyanide in Heap and Vat Leaching

Heap and vat leaching remain the dominant processes for gold recovery worldwide, representing nearly half of all global production. For decades, sodium cyanide has been the standard lixiviant due to its ability to form stable gold complexes under alkaline conditions. However, cyanide’s extreme toxicity, strict handling protocols, and mounting regulatory restrictions have created both operational challenges and social opposition, particularly in environmentally sensitive jurisdictions. These factors are driving the industry’s urgent search for safer, more sustainable alternatives.

RZOLV™ as a Drop-In Alternative

RZOLV™, Innovation Mining’s proprietary water-based non-cyanide reagent, is specifically engineered to perform in heap and vat leach environments. Operating at mildly acidic pH and moderate oxidation-reduction potentials, RZOLV™ dissolves gold into stable solution complexes without producing hydrogen cyanide gas or other hazardous by-products. This allows operators to utilize existing leach pads, ponds, and vat infrastructure with only minor adjustments to solution management. Early bulk-scale tests have shown that RZOLV™ can deliver comparable or superior recoveries to cyanide across a wide range of ore types—including oxide, sulfide, and complex ores—while maintaining stable chemistry under open-air conditions.

Technical and Economic Advantages

In heap leaching, RZOLV™’s stability at ambient temperature and its compatibility with irrigation and percolation systems enable continuous gold recovery under conditions nearly identical to cyanide operations. In vat leaching, where ores are agitated and residence times are shorter, RZOLV™’s fast kinetics and strong gold complexation provide high extraction rates within practical processing windows. Additionally, the reagent is designed for closed-loop regeneration using electrochemical oxidation, which significantly reduces operating costs and reagent consumption compared to cyanide make-up.

ESG and Social License Benefits

Perhaps most importantly, RZOLV™ eliminates the health, safety, and environmental risks associated with cyanide. With no risk of HCN (Hydrogen Cyanide) off-gassing and substantially lower aquatic toxicity, RZOLV™ enables mining projects to advance in jurisdictions where cyanide use is restricted or outright banned. This strengthens operators’ ability to secure permits, reduce community opposition, and align with increasingly stringent ESG expectations. By replacing cyanide in heap and vat leaching applications, RZOLV™ delivers not only technical performance but also a sustainable pathway to responsible gold production.