Bruce A. Cosgrove, BSc MSc Independent researcher in botanical chemistry and plant-derived chemical systems based in Burnaby, British Columbia, Canada.
Technical Papers - Botanical Chemistry
Botanical Alternatives: Toward Safer, Evidence-Based Gold Recovery
Cosgrove, B.A. (2026). Botanical Alternatives: Toward Safer, Evidence-Based Gold Recovery. Research preprint. View publication (DOI): https://doi.org/10.13140/RG.2.2.19442.77769
Among the emerging approaches, botanical and plant-derived systems have attracted increasing attention as potential tools for mercury-free gold recovery. Research demonstrates that plant-based lixiviants can replace mercury & synthetic cyanide salts in gold extraction, achieving effective recovery while reducing environmental & health risks—advancing safer, evidence-based solutions for sustainable gold mining.
Ecuador Four-Stage Action Plan for Botanical Lixiviant Systems
Cosgrove, B.A. (2026). Ecuador Four-Stage Action Plan for Botanical Lixiviant Systems. Technical presentation. View Publication (DOI)
A four-stage ESG aligned transformational strategy Action Plan designed to provide a plant-based alternative to mercury and synthetic cyanide salts in artisanal small-scale gold mining (ASGM) in the Portovelo-Zaruma Mining District Ecuador with Manipueira.
"Dear Bruce, Many thanks for sharing this transformative strategy Action Plan. This will surely be a gamechanger in Artisanal and small-scale gold mining. A webinar on this to share more on the study findings and experiences on this approach will be invaluable."
Regards
PROF. D. MOYO FRCP; FFOM; MFOM; MOHS; MAppMgnt
SPECIALIST OCCUPATIONAL PHYSICIAN
Associate Professor: National University of Science and Technology, Zimbabwe. Visiting Associate Professor: University of the Witwatersrand, South Africa
A Review and Sustainable Alternative to Sodium-Based and Cyanide-Containing Gold Leaching Agents - Glycine–Thiosulfate Hybrid System (Sustainable Technology eJournal - Research Paper - November 2025). DOI:https://dx.doi.org/10.2139/ssrn.5801183
This research advances sustainable hydrometallurgy by developing and validating a glycine–thiosulfate hybrid leaching system as a non-toxic, cyanide- and mercury-free alternative for gold extraction. The study demonstrates that this hybrid system achieves high gold recovery efficiency under mild pH and temperature conditions while minimizing reagent consumption and environmental impact.
Through detailed solution chemistry analysis, the work clarifies the stable coordination behavior of gold complexes in mixed amino-thiosulfate media, supporting its adaptability to existing processing circuits such as Merrill-Crowe or carbon adsorption.
This innovation directly supports the global phase-out of mercury and cyanide under the Minamata Convention and planetGOLD initiatives, providing an economically viable and scalable pathway for artisanal, small-scale, and industrial mining sectors. By eliminating highly toxic reagents, the glycine–thiosulfate hybrid system promotes responsible gold production, environmental stewardship, and human health protection, advancing key UN Sustainable Development Goals.
"Dear Dr. Bruce,
Congratulations on the publication of your article on alternatives to gold leaching.
In Brazil we have suffered major problems with the use of mercury in artisanal, especially in the Amazon region.Thank you for sharing the article.
Best regards, from Brazil
Mário Parreiras de Faria, Labor Inspector - Occupational Physician and Master in Public Health."
An Examination, Solution, and Transformative Strategy to Replace Mercury and Cyanide Salts in Artisanal Small-Scale Mining (ASM): Southern Ecuador.(Environmental Chemistry eJournal - Research Paper - January 2025). DOI: https://dx.doi.org/10.2139/ssrn.5049829
This research presents a 4-stage ESG-aligned transformative strategy designed to replace mercury- a potent neurotoxin and synthetic cyanide salts used by artisanal and small-scale gold (ASG) miners to recover gold from ore and toxic tailings with Manipueira in Ecuador's Portovelo-Zaruma mining district.
Manipueira, an extract solution from the cyanogenic bitter cassava plant when used as a lixiviant (leaching agent), is scientifically documented to sustainably recover greater than 99.3% of gold from ore concentrates and 99.6% from mercury-contaminated tailings in just two hours (Marcello M. Veiga & Pariya Torkaman, 2021). Manipueira advances safe, sustainable gold recovery, reduces neurotoxic exposure, and promotes circular-economy practices.