15 November 2023

Soil microbe analysis can replace drilling in the mining sector


A Canadian study shows how microbes can be reliable indicators of the presence of diamonds underground. Analyzing their DNA can prevent high-impact exploration

by Matteo Cavallito


Analysis of the soil and its microbes could allow potential diamond deposits and other resources to be explored without resorting to a high-impact operation such as drilling. This is suggested by research from the University of British Columbia in Vancouver, Canada. By analyzing the DNA of microbial communities on the surface, in particular, researchers identified the presence of kimberlite.

These rocks are known not only as potential diamond deposits, but also for their ability to capture and store atmospheric carbon.

Microbes as indicators

The research, the results of which were published in the journal Nature Communications Earth and Environment, starts with an assumption: by interacting with the soil, a mineral at the same time ends up changing the communities of microbes present. Scientists thus conducted an experiment in the laboratory by inserting kimberlite and analyzing the changes at the microbial level.

“We took those changed communities of microbes as indicators for the presence of ore materials, or biological fingerprints in the soil of buried mineral deposits,” explained Bianca Iulianella Phillips, Ph.D. candidate in the Department of Earth, Ocean and Atmospheric Sciences (EOAS) at the University of British Columbia, quoted in a press release from the Vancouver university.

The field study

Using these “indicator” microbes and their DNA sequences, the researchers analyzed surface soil from an exploration site in the Canadian Northwest Territories in which the presence of kimberlite had previously been confirmed through classic drilling. In doing so, “they found 59 of the 65 indicators were present in the soil.” Morevover, 19 of them were present “in high numbers directly above the buried ore.”

After identifying new indicator microbes to add to their series, the scientists tested the system at a second site where the presence of kimberlite had been hypothesized but not yet confirmed. The result was satisfactory. Indeed, the researchers “precisely located the topological outline and location of kimberlite buried tens of metres beneath the earth’s surface.”

New applications

The study once again highlights the importance of microbial analysis for studying soil dynamics and characteristics. Microbial community analysis, they point out, also proved to be a particularly effective assessment tool. Proving, in particular, to be more accurate when compared with the technique of geochemical analysis. The implications of the study, moreover, are not limited to the search for diamonds.

“DNA sequencing of soil microbial communities also has potential application across a broad array of metallic deposits, like porphyry-type copper deposits, for which the greatest mineral potential exists in terrains with thick cover such as northern Chile and British Columbia, Canada,” the research states.

Moreover, “Use of DNA sequences from microbial communities as vectors towards buried ore mineralization represents a powerful example of how such microbial information may become essential for meeting future human resource needs.” Including those elements deemed crucial to the ecological transition. “You could use this technique to find minerals to fuel a green economy,” said senior author Dr. Sean Crowe, EOAS and M&I professor and Canada Research Chair in Geomicrobiology. “Copper is the most important critical element that we’ll need more of going forward.”