Leonardo da Vinci said, "Water is the driving force of life," and there's great truth in that simple declarative statement. More than two-thirds of our planet's surface is water, and our own bodies are mostly that compound of hydrogen and oxygen. Water sustains us; our very survival depends on the availability of water for drinking and growing food. Water is essential.
It's no surprise then that mining's impact on water resources is such an important issue and a perennial source of controversy. We need mining products for our cellphones, cars and trucks, plumbing, wiring and countless other physical components of modern civilization, but we need clean water for life itself. Minimizing the impact on rivers, streams, lakes, aquifers and oceans is, then, a crucial prerequisite for societal permission to extract minerals from the ground.
An Ontario company may have just the right technology for mining companies striving to soften environmental impact so that they can get the green light for new operations. The answer, curiously, lies in things we can't see with the naked eye: nanometer-sized organic polymers that can take out toxins and recover precious metals.
NANOSTRUCK TECHNOLOGIESHeadquartered in Mississauga, NanoStruck Technologies Inc. is a young firm with a suite of technologies that can remove molecule-sized particles from water via absorptive polymers derived from natural sources. Under the NanoPure brand, these organic polymers can be used to clean out hydrocarbons, acids, pathogens and other toxins in water. Mining companies will be particularly interested in the NanoMet processes for recovering gold, silver, palladium and other precious metal particles.
Bundeep Singh Rangar, NanoStruck's CEO and Chairman, says the removal of contaminants via "molecular sponges" is "a much cheaper and organic alternative to conventional methods that use either chemical processes or reverse osmosis processes – both of which are either environmentally not the best or capital and optics wise not the cheapest."
Reverse osmosis requires big spending on electricity to pump water at high pressure, he continues. "Our process is a lot cheaper because we don't have high-pressure systems. Ours is, I would say, more natural."
Rangar explains that the NanoStruck water-cleaning process has three basic stages. First comes a stage of removing the relatively large pieces of junk. Then there's electrolysis – "we zap the water," he says. In the third step, the polymers remove very small particles.
"That's where these molecular sponges are very active in removing the contaminants," he remarks. "What you've got at the end of that third stage is water that's very clean for environmental disposal or reuse in industrial and agricultural purposes.
"If you need to take it to a drinking-water potable situation, then you take it to a stage four, which is a bacterial purification using ozone gas or ultraviolet light or, sometimes, ultrasonic resonance.
"So, depending on the client requirements, there's two things we do: One, we take it to either stage three or stage four, depending on whether the water is intended for non-human or human consumption; and the second thing we do, which is very unique to our business model, is that we program those polymers for the specific contaminants that we found in the water.
"So when we first start with a client, we get water samples from them and we determine the contaminants via lab analysis. The chitosan copolymers are programmed for removal of the specific set of contaminants. That's the unique nature around our patent of those copolymers – the 'tuneability' of those copolymers.
"If the water sample comes from an oil refinery, for example, it will have a high degree of hydrocarbons in it. If it comes from a landfill site, it may have other pathogens like mercury or heavy metals. If it comes from a farm, it will have more bacteria and other organic waste. It really depends on what water we're treating. It is configured for the copolymers that are the most effective there.
"When we went to the mining sector to remediate their water, they said 'This is very interesting. We need to clean up our water as part of our social responsibility for our mining contract. But if you can remove metals in stage two and stage three, then you've got a whole different business model of removing precious metals from the tailings that we leave behind in our initial primary mining activities.'
"And that, as you know is a huge business. So that started developing over the course of 2012, 2013, but it really has taken form most in the last year as we've fleshed that out. We've gone from the embryonic technology two years ago to one that's now proven across different tailing samples that we've obtained from different parts of the world."
GOLD, SLIVER & PLATINUMRangar says NanoMet, the company's metals-extraction process, has physical, chemical and organic components. The physical part involves grinding mine tailings down to small particles and getting the heavier and lighter contents to separate. "You get some retrieval there," he says, "but as you can imagine there's a physical barrier as to how far down you can grind and mill down the tailings because it will eventually become too dusty."
Chemistry comes into play, he continues, when "we take the tailings and mix it with an acid solution which then effectively leaches out the precious metals into a solution. That's where we've got a remarkably high level of precious metals from tailings. We're talking 85 to 96 percent recovery of the precious metals away from those tailings into that leach solution.
"Now the question is: Once you've got it in this solution, how do you get it out? That's where the organic polymers we have play a role."
The polymers, made from crustacean shells, can be programmed to extract specific types of metal particles out of a solution, according to Rangar. He says NanoStruck's process has proven very successful in fetching silver, gold and platinum group metals from tailings. "On silver tailing samples from Mexico … we have had a 93% recovery rate, which again is incredibly high because the best anyone could do was about 20%. And we've got similarly high rates in platinum and palladium."
NanoStruck signed a letter of intent in February with Tierra Nuevo Mining to explore the potential of using the still-developing NanoMet technology to extract gold and silver from tailings at a Tierra Nuevo operation in Mexico. Rangar was quoted in a news release as saying the new arrangement "greatly accelerates the development and go-to-market strategy of our unique mine tailings processing technology."