EnviroMetal recovers gold from mine dust
Widens the potential of non-cyanide gold dissolving formula Metal Tech News – February 9, 2022
Last updated 2/15/2022 at 3:04pm
Broadening the potential applications of its environmentally sustainable metal leaching formula, EnviroMetal Technologies Inc. reports that it has successfully extracted 221 ounces of gold from roughly 150 kilograms (330 pounds) of dust collected in baghouse filters from a Canadian gold producer.
The company says this milestone demonstrates the effectiveness of its proprietary non-cyanide formula in recovering exceptionally high-grade gold from otherwise difficult to process mine-related materials.
"The successful performance of our chemistry technology to recover gold from this unique material once again demonstrates its broad applicability and high efficiency," said EnviroMetal Technologies President and CEO Duane Nelson. "I expect this will open additional opportunities within the gold mining industry."
EnviroMetal's water-based formula is a blend of five ingredients that are FDA approved for human consumption that can dissolve gold contained in ores, concentrates, recycled electronics, and now dust trapped in complex filter material. The aurum is then recovered with a diamond-based electrochemical process developed by the British Columbia-based metals recovery company.
While the environmental, social, and governance advantages of replacing cyanide with a benign water-based solution are enormous, recent studies show that these ESG advantages do not come as a sacrifice to performance.
According to tests carried out by the global analytical firm SGS, the EnviroMetal formula outperformed cyanide on high-grade ore samples from a Canadian mine.
A one-gram-per-liter concentration of the EnviroMetal formula recovered 99.6% of the gold from a 675-grams-per-metric-ton gold sample in just six hours, compared to a 93.9% recovery in 24 hours with the same concentration of cyanide.
As part of the analysis, SGS carried out a series of ten locked cycle tests to evaluate the reusability of the EnviroMetal formula. While there was variance with each sample, there was no evident trend of reduced recoveries, and the formula was still recovering 96% of the gold by the tenth round.
Nelson said the water-based solution used to recover the high-grade gold from the filter material was recycled and reused.
"This integral element of our process underscores the sustainability of our solution and the benefits we offer beyond strictly financial," he said.
On the financial front, EnviroMetal received a $397,859 (C$496,687) payment from the gold recovered and poured from the filter material.
The company is currently processing additional high-grade gold materials and will report on the recovery when processing is complete.
In addition to recovering gold from mining concentrates and other byproducts, the EnviroMetal formula is being tested as an alternative to cyanide for heap leaching, a method of gold recovery that involves stacking ore in a lined facility and using a formula to dissolve the gold.
Group 11 Technologies Inc., a company partially owned by EnviroMetal, is working toward testing the EnviroMetal formula for in-situ gold mining, a non-invasive method that involves circulating fluids underground that dissolve the sought metals and then pumping the fluids back to the surface to extract the metals.
Group 11 Technologies President Janet Lee-Sheriff says the "recyclability of the environmentally friendly chemistry" of the EnviroMetal formula makes it an attractive option for in-situ gold recovery.
The company has optioned a property in Wyoming, a state familiar with in-situ mining of uranium, to advance in-situ gold recovery using the EnviroMetal formula.
Further details on Group 11 and the use of EnviroMetal's (formerly EnviroLeach Technologies) formula for in-situ gold recovery can be read at Wyoming is ideal for in situ gold mining in the April 21, 2021 edition of Metal Tech News.