Mercury-free gold extraction using borax for small-scale gold miners

Small-scale gold mining is the largest anthropogenic contributor of mercury pollution on planet Earth. The miners grind gold ore together with mercury in order to recover the fine gold grains. The gold amalgam is burned whereby the mercury evaporates and gold is left behind. This processing extracts only a fraction of the gold in the ore and the released mercury causes serious global health and environmental problems. However, a mercury-free method described below has proved to extract up to twice as much gold without need of investment in new processing equipment and without longer processing time. The method has successfully been tested in the Philippines, Indonesia, Tanzania, Bolivia and Zimbabwe.