Mercury Recovery Success!

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IMG_1009When our team visited Bolivia, one of the most gratifying experiences was introducing artisanal miners to a mercury recovery system – something they had heard about but never seen before. The one pictured here looks like a crab pot and is called a retort. It reduces mercury release to the air by about 90%. The miners liked it and plan to keep using it!

In case you are new to the topic, miners use mercury to bind gold particles and separate them from surrounding dirt and sand.  The product is an amalgam of gold and mercury. Most miners then burn off the mercury with a flame, venting it into the atmosphere. Multiply this by 20,000,000 artisanal miners and you have one of the largest sources of toxic pollution on the planet.

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The retort cost $120. Mercury costs about $130 per kg. Ultimately, the mercury recovered would justify the price, so you might wonder what stands in the way of every miner adopting this practice.

A miner might make $300 per month.  The retort is almost half his monthly salary. To put this in perspective, a proportional expense for theaverage American would be about $1500. Many people would hesitate before putting that amount into a project like weatherization or keeping their car tuned, even though it might save money in the long run.

The other issue seems to be that mercury evaporating off of gold is nearly invisible and therefore appears harmless.  Long-term health effects and bioaccumulation in the food chain are not visible consequences.

The power of the retort demonstration lay in seeing the mercury appear again in silvery, liquid form ready to be re-used.  The health argument might be a stretch, but getting your mercury back seemed to make a good case.

The retort was a step in the right direction. While we’re working on installing zero-mercury technology developed by some of the best mining engineers in the world, it was exciting to see an immediate reduction with an off-the-shelf device that many mining businesses can afford.

We’re thinking that for miners who find the cost prohibitive, a program like Kiva, with its micro-loans, could help spread the cost over time. Government incentives or rebates on retorts might be another way. In the end, though, it will probably take lots of hands-on demonstrations where the proof is immediate and tangible.