A bacteria-rich process currently being used in Barberton, a town in the Mpumalanga province of South Africa, can help liberate ultra-fine gold locked in sulphide crystals. The experiment, called Biox technology, is happening in three mines owned by Pan African Resources.
Besides these three pits, there are other five gold mines around the world currently using the biological oxidation process based on dozen different types of bacteria. However, at Barberton, one strain has become dominant because of the ideal conditions, BDlive reports.
The Biox technology has proven to be an extremely clever yet simple technique to unlock gold and other metals tied up in sulphide deposits. When compared to ore treatment with cyanide, the bacterias’ recovery rate is 97 percent against only 40 percent.
The bacterial hub is kept at 42°C and fed with a bug-rich soup stuffed with air and nutrients, allowing the bacteria to expose the gold before the solution is passed into a traditional recovery process using cyanide and carbon.
This means the bacteria are able to tackle the crystals that contain the gold, making them look like Swiss cheese and allowing the cyanide to more easily reach and expose the gold.