of interest, Peter Krauth, Money Morning,Nov 19- u
Post# of 8054
"Bioleaching is the use of bacterial microorganisms to extract metals from the ore where it's embedded. By feeding on the nutrients in minerals, bacteria separate the metal from its surrounding ore.
The Rio Tinto River in Spain owes its name to copper-bearing waters, thanks to microbial leaching.
Using microbes to leach metals from ore has been traced back millennia. As far back as 150 BCE, the Chinese dipped iron ore into a blue vitriol solution in order to extract copper.
But it was only in 1947 that scientists figured out that bacteria were actually responsible..
Recognizing the massive potential of having bugs do the work, the process was fast-tracked to commercialization.
Within a decade, bacterial leaching began at the Kennecott Utah Copper Company's Bingham Canyon Mine, where naturally occurring bacteria were oxidizing iron sulfides in waste piles, producing blue copper-containing solutions.
Today, some of the largest mining companies have developed bio-oxidation processes to extract metal.
Instead of using smelting or roasting processes, bioleaching is more cost-effective when metals are found in lower concentrations.
About 20% of copper today is produced through bioleaching, which emits little air and water pollution overall.
And as newer deposits are increasingly low grade, we can expect these methods to gain popularity in base metals mining.
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