The mining industry largely concerns itself with the inanimate resources of nature: rocks, metals and chemicals. However, there is an increasing interest in how living organisms – small, singlecelled microbes – can breathe life into the mining cycle and limit its environmental impacts.
Monique Haakensen sees a lot of microbes in her role as president and principal scientist at Contango Strategies. Using DNA-sequencing technology, the company provides a microbial community profiling service which identifies the microbiological population at mining projects and provides lab results, guidance on remediation strategies or even suggestions on which living plants will add to an ecosystem to help microbes thrive. And according to Haakensen, microbes are finally getting the respect they deserve for their role in remediation.
“Until this type of technology came about, it was a guesstimate, and because of that there have historically been a lot of failures in passive water treatment because they were not based on informed decisions,” said Haakensen.
By using tools now available, Haakensen said she can understand how the environmental system at a project works, what is influencing the system and develop a more robust remediation project.
Remediation is just one of several applications of biotechnology, which rely on microbiology and microbes found in the environment to help extract metal from ore bodies or neutralize contaminants from waste material. Microbes can also be deployed in hydrometallurgical applications to aid in the leaching process.
In recent years, the potential environmental and financial benefits of biotechnology and the increasing precision with which it can be applied have made it attractive to mining companies looking for new approaches to engineering problems. The field is set up to grow, with new efforts to understand which microbes can be the most effective partners for a specific mining operation at their basic, genetic level.
Bioleaching and biooxidation are two common biohydrometallurgy techniques, explained Corale Brierley, consultant and vice-president of the U.S.-based National Academy of Engineering. Both are microbe-based metal production processes that use a water-based solution.
By adding specific microbes to a traditional heap leaching system, bioleaching can extract base metals like copper, nickel and zinc. Biooxidation is a similar process, typically applied to refractory gold ore prior to cyanide leaching. The main difference is that in bioleaching, the targeted metals are brought into solution whereas in biooxidation they remain in a solid state.
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