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Geochemistry
Using wine “goggles” to find minerals
 CSIRO |
| Geochemists Ryan Noble and Cliff Stanley (not pictured) recently discovered wine and soft drinks are just as good as more conventional geochemical methods when it comes to identifying mineral deposits. |
Dentists may not see the value of sugary soft drinks or wine, but geochemists tell a different story. Researchers recently learned that soft drinks, wine and even beer can be used to detect metals in soil samples, demonstrating that these common beverages are just as good as, if not better than, the more traditional geochemical analyses used to find mineral deposits.
When mining companies search for new mineral deposits buried deep underground, they often employ geochemical techniques to identify trace minerals that have been brought to the surface by groundwater and other mechanisms. For decades, geochemists have used a variety of analyses for this purpose, and in more recent years, companies have started to market their own commercial tests. But there hasn’t been an objective way to compare the effectiveness of these various analyses, says geochemist Cliff Stanley of Acadia University in Nova Scotia. So Stanley and Ryan Noble of the Exploration and Mining division of the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Perth, Australia, developed such a test. In doing so, they also wanted to show that “with just a little bit of knowledge of the chemistry, you could really use many different things” to search for metals, Noble says.
This led the duo to examine products widely available to anyone — soft drinks, wine and beer — and compare them to a number of more conventional methods. “We’ve always known Coke could be used to take rust off a bicycle,” Stanley says, “so why not use it to dissolve elements from a soil sample?” Over the course of a few evenings, Stanley and Noble found soft drinks worked well in detecting the two metals they tested, zinc and copper, because soft drinks contain mild acids — citric and orthophosphatic acids — that solubilize the metallic elements, removing them from the rest of the soil sample.
“We were also able to address the universal question: Is Coke better than Pepsi?” Stanley says. “Pepsi is better by a small margin.” Pepsi has an additional acid — benzoic acid — that Coke lacks, he says. And Diet Coke beat out regular Coke. But even more effective than soft drinks was wine, which contains at least 15 different organic acids. Beer worked, too, but not as well as wine or soft drinks.
In June, Stanley and Noble presented their results at the International Applied Geochemistry Symposium in Oviedo, Spain, where they revealed that one of the traditional geochemical exploration methods performed best in detecting metals, followed closely by wine. The only available commercial test in the sample came in third. Noble says these results demonstrate you don’t need to spend $50 to $100 per sample on expensive commercial tests to find mineral deposits. He and Stanley spent no more than a few dollars on each of their samples using soft drinks, beer and wine, he says.
But this doesn’t mean Coke and Pepsi should run out to buy advertisements in the mining trade publications anytime soon. “I don’t foresee anyone taking this up in their exploratory program just yet,” Noble says.
