Chromafora thiosulphate gold leaching: design and risk notes for mine operators
Reviewed by Tom Sullivan

First reported on International Mining – News
30 Second Briefing
Chromafora’s pilot-scale thiosulphate gold leaching process in Sweden has achieved up to 92% gold recovery without cyanide, in a programme formally reported to and approved by innovation agency and co-funder Vinnova. The process uses thiosulphate lixiviant chemistry instead of sodium cyanide, targeting refractory and complex ores where conventional cyanidation underperforms. For mine operators, the results signal a potential route to maintain high recoveries while reducing cyanide handling infrastructure, permitting complexity and long-term tailings liabilities.
Technical Brief
- Reduced cyanide-specific infrastructure could simplify permitting around reagent storage, detox plants and emergency containment.
- Tailings character is expected to change materially, with implications for long-term water treatment and closure design.
- For other mining projects, thiosulphate routes may become attractive where cyanide bans or social licence constraints tighten.
Our Take
Among the 117 gold‑tagged pieces in our database, very few non‑cyanide routes report gold extraction yields above 90%, so Chromafora’s 92% figure positions this Swedish technology at the upper end of currently disclosed alternatives.
Because this work is Sweden‑based and tagged under Sustainability, it is likely to be attractive for Nordic and EU projects facing tighter cyanide permitting, where a high‑yield thiosulphate option could materially de‑risk approvals for new gold plants or plant expansions.
With no specific project named, Chromafora appears to be developing a platform product rather than a single‑site solution, which for operators means potential retrofit or modular deployment across multiple gold circuits rather than committing to a one‑mine technology roll‑out.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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