Environmental Innovators Create Virtuous Circles By Correspondents *
The Villachica family extracting gold without mercury. Credit:Milagros Salazar/IPS Buy this picture
MONTEVIDEO, Sep 14, 2011 (Tierramérica) - A method to revolutionise gold mining; biofuel from used cooking oil; a container where garbage and wastewater go in and four useful products and zero waste come out: Latin American science applied to the environment.
Clean gold is possible
Peruvian metallurgical engineer Carlos Villachica has devoted his life to seeking a balance between his country’s two greatest riches: the mineral deposits concentrated in the Andes mountains and Amazon basin, and its huge wealth of flora and fauna.
Villachica has invested 42 of his 62 years in research. His latest innovation is the "ecological gold" method for small mining, which makes it possible to extract fine gold without a drop of toxic mercury.
More than 250,000 families earn their livelihoods from small-scale gold mining in Peru, and most of them use mercury to recover gold from black sand, a mix of gravel, rock, sand and various minerals found in numerous Amazon basin rivers, such as those in the environmentally degraded region of Madre de Dios in southeastern Peru.
Villachica’s method separates fine gold from the other minerals by spinning the black sand in a device similar to a blender with water, a few drops of alcohol and phosphate.
Inside the "blender" – a mechanical adaptor used in mining, specially fitted out for the project – the alcohol and air create small bubbles to which the fine gold flakes adhere because of the presence of phosphate.
As a result, the gold floats to the surface of the mixture and is ready to be smelted.
This makes it possible to extract the gold without the mercury normally used by small-scale miners for this purpose. As well as preventing the river and soil contamination and health risks associated with the use of mercury, this innovative method is faster and recovers more gold than the traditional method.
Extracting 40 grams of gold can take two and a half hours using mercury, which makes it possible to recover 80 percent of the gold in black sand. With the "ecological gold" technique, 95 percent of the gold is extracted in just half an hour.
"We have mega biodiversity that needs to be protected and is more important than the minerals we have. And that is why more innovative technology must be created," Villachica told Tierramérica.
Since a mere six milligrams of alcohol and phosphate are used per liter of water, these substances do not pose a threat to the environment. The toxic dosage of this mixture for trout fry, for example, is 1,200 milligrams per liter of water.
The method, presented with an award in June by the governmental Science and Technology Programme, does not depend solely on Villachica. His three daughters have taken the baton and are now working alongside their father to carry the project forward: Joyce, a chemical engineer, Leslye, a metallurgical engineer, and Eileen, an environmental engineer.
"The challenge lies in defending the ideas and demonstrating that they can be put into practice," Leslye Villachica, 31, told Tierramérica.
Four small-scale miners are already using the Villachica family’s invention in Madre de Dios. The next step planned by the Villachicas is a project they will undertake in partnership with indigenous Amazon communities.
Tests have been conducted and contacts have been made with buyers in France and Switzerland who are willing to pay 15 percent over the market price for every ounce of gold recovered through this method.
According to Villachica, the technology could also be applied on a wide scale if the government agreed to promote it. By 2016, the amount of mercury used by small-scale miners could be reduced by as much as 80 percent, he estimates.
The method is also much more profitable in the medium and long term. A small-scale miner spends between 200 and 300 dollars a month on mercury to obtain two to three kilograms of gold. Villachica’s machine for this volume of production might cost 4,000 dollars, which means the investment would be recouped in around 10 months.
Moreover, several miners could share the device, as will soon be done by an Amazon rainforest community.
In the meantime, for a medium-sized mining operation that spends 600 dollars a month on mercury, the machine would cost 12,000 dollars, and would therefore pay for itself in savings on mercury alone in less than two years. --Jamie Kneen, Communications & Outreach Coordinator, MiningWatch Canada http://www.miningwatch.ca/
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