Copper from old mines and low-grade deposits
New technology to extract of copper using sulphuric acid mixed with multiple species of bacteria has been initiated at a mine in northern Chile. Japan Oil, Gas and Metals National Corp (JOGMEC) will conduct a two-year experiment to understand whether copper can be extracted on a commercial scale from low-grade ores. According to Chief Researcher at JOGMEC, Taro Kamiya, the bacteria used in this new method of extraction, is naturally found on copper ores. “As copper ores from [the testing area} provide high iron content rates, the bacteria can be easily activated,” he is reported as saying.
The company believe that if this new method proves to be a success, most abandoned copper mines could be revived, adds Kamiya “This technology makes it possible to extract copper at more than double the speed that can be achieved if humans extract copper with sulphuric acid alone.”
JOBMEC reports that “Japanese companies have been studying mine development using hydrometallurgical technology in the following three cases:
- Recovering copper from low-grade sulphide minerals, which lowers the marginal level of ore grade for exploitation and increases minable ore reserves
- Looking for economic efficiencies in developing small and medium-sized mines with a small initial cost and a short development period
- Producing copper concentrate with a large proportion of impurities such as arsenic, antimony, and bismuth at sites in the vicinity of SX-EW plants.”