EnviroMetal Technologies aims to be the future of sustainable, efficient, and low-cost precious metal recovery. The company develops and commercializes solutions and technologies for recovering precious metals in an environmentally friendly and sustainable way. EnviroMetal Technologies’ most recent finding displays groundbreaking potential for the gold industry.
The company created a proprietary non-cyanide, neutral pH, water-based, treatment process for gold recovery to increase yields while reducing risks. After comprehensive testing, EnviroMetal Technologies has now released results of the process’ effectiveness.
To test the process, the company compared calculated gold grades from non-cyanide extracted samples with industry standard gold grades purchased from a North American-based miner.
The test yielded notable results. The extracted gold contained 58 grams more than the purchased sample of 1,671 kilograms. The final calculated grade for the non-cyanide extracted gold was 485 grams per ton, while the industry standard sample came out to 450 grams per ton.
Between the two samples, the non-cyanide extracted gold provided 35 more grams per ton, equating to approximately $2,100.
EnviroMetal Technologies also conducted the same test on a smaller sample size of 620 kilograms. The non-cyanide extracted gold yielded 480 grams per ton, while the assayed grade provided 437 grams per ton. This sub-sample showed a 43 gram-per-ton difference, equating to $2,550.
The comparison testing displays a negative bias regarding grade estimation practices required for concentration value calculations. Given the data, the company believes concentrate producers and miners should reduce or eliminate their reliance on smelters like cyanide. The EnviroMetal Technologies process for on-site gold extraction can provide higher yields with improved safety and sustainability.
“Our findings highlight the risk miners face when relying on assays to determine the amount of gold in concentrates sold to smelters particularly when the concentrates are high grade or contain large gold particles or ‘nuggets,’” Wayne Moorhouse, the company’s CEO explains.
“Our data confirms the suspicions of concentrate producers and we are proud to offer a solution that helps miners maximize value. The EnviroMetal process can be incorporated in new or existing processing plants allowing miners to reduce assay risk and get paid for more gold,”
Comparison testing specifications:
EnviroMetal Technologies received the 1,671 kilograms of gold concentrate from a North American-based miner following typical commercial smelter terms. The two companies determined the trade’s price based on the product’s weight, sampling, preparation, and moisture content, according to International Standards Organization (ISO) Standards.
Both the seller and EnviroMetal Technologies received concentrate samples to assay the grams-per-ton for compared and averaged results. Using an accredited, third-party assayer, both results returned within 11 grams per ton, averaging at 450 grams per ton, the figure used in the data discussed above.
The company processed the 630-kilogram sub-sample in six batches, with each leached for 24 hours, regardless of yield. The calculated yields were measured based on the assay confirmed by electrowinning and refining. The processing of the entire 1,671 kilogram sample occurred prior to the 630 kilogram sub-sample calculations.
Prior to EnviroMetal Technologies’ onsite testing, additional researchers studied the concept of chlorine-based extraction processes for reduced toxicity and improved gold yields. In 2021, a research team from Finland’s Aalto University was the first to successfully replace cyanide in the gold extraction process in a larger lab setting.
“With our process, the amount of gold we’ve been able to recover using chloride is as high as 84%. In comparison, using the standard cyanide process with the same ore yielded only 64% in our control experiment,” Ivan Korolev, one of the project’s researchers and a doctoral candidate explained.
The research team worked under a broader sustainability project on campus collaborating with a Finnish mining tech company, Metso Outotec. “With EDRR, we apply short pulses of electricity to create thin layers of metal—in our case copper—on the electrode and cause a reaction that encourages gold to replace the copper layer by layer,” Korolev explained. “The method has low energy consumption and doesn’t require the addition of any other elements.”
In 2021, these developments were groundbreaking. “It’s one thing to do an experiment like this on a small scale, but nobody had ever done it at the scale that we have done,” Korolev noted. “The extraction methods of the past have always left some valuable metals behind. Now, as demand for metals grows all the time, even these small amounts are important.”
“It would be great to see a mining company interested in this technology and willing to test with their ore on site.” Fast forward to 2023, and EnviroMetal Technologies has achieved this larger-scale testing goal.