Mining sector eyes treetop needles, bark for help with hitting pay dirt

VANCOUVER – British Columbia’s trees could hold the key to unearthing the whereabouts of promising new mineral deposits hidden in remote and inaccessible regions of the province.

A provincial science group has released the results of an innovative pilot project that collects and studies samples from the tops of spruce trees for trace amounts of precious minerals in order to help mining companies hit pay dirt.

“It’s a bit of a holy grail,” said Bruce Madu, vice-president for minerals and mining with Geoscience BC, an independent public agency.

“Imagine if you can only sample the vegetation to learn about what’s in the soil, as opposed to actually having to dig holes.”

Conifers have long been known to absorb metals and other elements from the surrounding soil and concentrate them in their twigs, bark and needles.

Analyzing the tree elements over a large region and mapping them out could offer a glimpse into the types and abundance of commercially valuable materials deep beneath their roots, Madu said.

“We know that mineral deposits are getting harder to find. They’re lower grade and they’re more deeply buried,” Madu said.

“So we’re forced to try to find new techniques to see them, to discover them.”

Over six days last June, workers travelled by helicopter and collected samples from near the tops of 421 trees located about 1.5 kilometres apart and scattered across a 1,000-square-kilometre plateau region in central B.C.

The samples were analyzed over several months to reveal trace concentrations of 52 elements, from gold and silver to thallium and molybdenum.

“This is a raw-data release, so the final judgment of the success of the program will be by the resource sector,” Madu said.

“We hope that this is actually another useful tool to help explorers find those more deeply hidden and maybe even lower-grade deposits that are currently a real challenge to discover.”

The new sampling method offers another way for mineral-exploration companies to quickly study regions that are otherwise difficult to access and is intended to supplement other techniques.

Traditional methods of prospecting include flyovers to detect aberrations in the magnetic field beneath the earth, or chemical analysis, which includes studying surrounding rocks, soil and streams.

The treetop method isn’t cheap because of helicopter costs, but its benefits include speed and relative ease.

The initiative is part of a $4-million Geoscience BC project designed to investigate the geology and mineral potential of a 24,000-square-kilometre area in the province’s Interior.

The agency aims to attract investment to the province and to inform resource decisions.

— Follow @gwomand on Twitter