EnviroGold Global Limited (EnviroGold Global), a clean technology company accelerating the world’s transition to a circular-resource economy, and Luca Mining Corp. (Luca) announced the signing of a memorandum of understanding on August 1st, 2023, to process tailings at Luca’s 100% owned Campo Morado Mine in Guerrero State, Mexico (the Project).
Image Credit: Oleksii Holikov/Shutterstock.com
The scope of the initial project is to assess the reprocessing of historical Campo Morado (Campo) tailings currently stored in Campo’s original tailings storage facility. Luca’s internal estimate from historical production records shows that these tailings consist of approximately 3,290,622 tons at 1.32% Zn, 0.3% Cu, 0.49% Pb, 1.57g/t Au, and 94 g/t Ag.
To provide a stage-gated strategy for the Project’s development, EnviroGold and Luca will collaborate to create a definitive processing agreement. EnviroGold and Luca will collaborate on the Project’s preliminary economic assessment (PEA) as per standard procedure.
This initiative comes on the heels of a successful pilot plant-scale test conducted on tailings for the Hellyer Project in Australia (refer to EnviroGold's press release dated June 29, 2023). The historical Hellyer Mine shares characteristics akin to the Campo Morado deposit, both being volcanogenic massive sulphide-type formations.
Notably, the 500 kg sample subjected to testing exhibited grades of 2.59 g/t Au, 59 g/t Ag, 0.11% Cu, and 0.84% Zn.
EnviroGold demonstrated impressive gold and silver recovery rates surpassing 90%, utilizing the Leachwell TM Accelerated cyanide leach technologies for cyanide leach feed.
Furthermore, the process facilitated the extraction of 91% copper and 82% zinc from the tailings, channeling them into a pregnant leach solution suitable for subsequent recovery. Additionally, EnviroGold's efforts reduced pyrite content within the sulfide minerals from 38% to less than 1%.
Using EnviroGold’s proprietary NVRO technology, initial gold recoveries of approximately 60% were achieved on Campo tailings samples in 2021. This is comparable to Hellyer's initial testing, and EnviroGold will aim to improve these recovery rates in the next testing stage.
Following the parties’ definitive agreement, the project’s initial phase will involve additional data and sample collection, testing, and a PEA-level study and NI 43-101 Technical Report detailing the project’s concepts, costs, timeline for development, etc.
If this initial tailing project succeeds, the Project may decide to use the same technologies on its current plant and tailings stream.
We are looking forward to working with the Luca team. Having recently completed our pilot plant testing on the Hellyer Project, we are confident that the NVRO process can be adjusted to work on the Campo tailings. Furthermore, it will be a pleasure to be back working in Mexico again.
Dr Mark Thorpe, CEO, EnviroGold Global Limited
Mr. Mike Struthers (CEO of Luca) adds, “We’re excited to work with EnviroGold on this project, building on the initial test work in 2021. The encouraging results from those initial tests, plus the very real potential to also recover base metals from the tailings, could generate significant value from this old tailings facility. More importantly, if the initial project is successful, the potential to add this metals recovery stream to the existing plant could add considerable future value to Campo Morado.”