In San Juan Cien, high in the mountains, Bret and Jack found miners doing something wonderful - processing ore with very little use of toxic mercury. It was a technique developed by Peruvian engineers, and adopted by the villagers.

The ore is fed through a pipe into the top of this contraption (see the first photo below) - a combination shaking table and sluice that sits on springs powered by a battery.

As the ore washes down the various tiers, heavier sediment is caught in the ridged carpet lining each sluice box, and filtered out. What is left then goes into a centrifuge machine (the green drum) that spins and separates out the lighter mixture (containing small bits of gold). The miners are unable to work with this fine mixture so they sell it to a larger operation that uses cyanide to remove the gold.

The heavier mixture is flushed out of the pipe into the area below the centrifuge, where there is a boulder. This is where the miners use mercury. A man stands on boulder, rocking back and forth. This force creates an amalgam of the mercury and gold. The miners use a retort to burn the amalgam to release the mercury and extract the gold. The retort feeds into a bowl of water to form a make-shift water box condenser. This recaptures most of the mercury, preventing the toxin from being released into the environment. The mercury is then reused.

This is a great intermediate step towards a totally mercury-free method of gold mining. While it is not perfect, in Peru, this is a model small-scale mine.