Luca Mining Corp. and EnviroGold Global Ltd. signed an memorandum of understanding during August to process the tailings at Luca’s Campo Morado mine in Mexico’s Guerrero State. The scope of the initial project is to evaluate the reprocessing of the historical Campo Morado tailings stored in the mine’s original tailings storage facility. These tailings contain approximately 3.3 million metric tons (mt) with a grade of 1.32% zinc, 0.3% copper, 0.49% lead, 1.57 g/mt of gold, and 94 g/mt of silver based on Luca’s internal company estimate from historical production records.
EnviroGold and Luca will work together to develop a definitive processing agreement that will provide a stage-gated approach to the development of the project. EnviroGold will work with Luca to complete a preliminary economic assessment (PEA).
This project follows successful pilot plant scale testwork on tailings for the Hellyer project in Australia. The historic Hellyer mine, which is also a volcanogenic massive sulphide type deposit, has very similar characteristics to Campo Morado. The 500 kg sample tested had grades of 2.59 g/mt gold, 59 g/mt silver, 0.11% copper, and 0.84% zinc. Average gold and silver recoveries achieved by EnviroGold were both more than 90%, on a cyanide leach feed using the Leachwell Accelerated cyanide leach technologies. Also, 91% of the copper and 82% of the zinc contained in the tailings reported to a pregnant leach solution, suitable for subsequent recovery and the pyrite within the sulphide minerals was broken down from 38% to less than 1%.
Initial testwork on Campo Morado tailings samples in 2021 achieved preliminary gold recoveries of approximately 60% using EnviroGold’s proprietary NVRO technology. This is similar to Hellyer’s initial testing, and EnviroGold will look to increase these recovery rates in the next stage of testing.
“We’re excited to work with EnviroGold on this project, building on the initial testwork in 2021,” said Mike Struthers, CEO, Luca Mining. “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.” Following a definitive agreement between the parties, the initial stage of the project will include further data and samples collection and testwork, followed by a PEA-level study and NI 43-101 Technical Report outlining the project concepts, costs, development timeline, etc.
A positive outcome from this initial tailings project could lead to applying the same technologies to the current plant and tailings stream at the project.
Luca Mining Corp. is a Canadian based mining company with two Mexican gold, silver, and base metal mining projects.
EnviroGold Global is a CleanTech company that uses proprietary technologies to reprocess and remediate mine waste (tailings) and recover precious, critical, and strategic metals – including gold, silver, copper, zinc and nickel.