Japan tests in Chile bacteria-based method to revive depleted copper mines

A Japanese government-backed firm has begun testing a new technology to extract copper by using sulphuric acid mixed with multiple species of bacteria at a mine in Northern Chile.

Japan Oil, Gas and Metals National Corp., known as JOGMEC, will conduct a two-year large-scale experiment to examine whether the red metal can be extracted on a commercial scale from ores that have very low copper content, news agency EFE reports (in Spanish).

According to Taro Kamiya, chief researcher at JOGMEC, the bacteria used in the method 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 was quoted as saying.

If successful, the revolutionary process would make possible to resume mining operations in most abandoned copper mines, the company said.

“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,” Kamiya added.

According to data from Chile’s Ministry of Mining, Japan is the third largest investor in Chile’s mining sector, representing a 9.8% of the almost $112 billion in expected for the industry between 2013 and 2021.

In the last two to three years, biomining techniques have gain a "mining of the future” reputation, as they are much cheaper and greener than traditional methods, they generate less CO2 emissions, and carbon and water footprints are lower than when using conventional technology.

Forms of biomining, such as bioleaching, are already in use in several countries, including South Africa, Brazil and Australia.

Overall, about 20% of the world's copper production comes from bioleaching.

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