Could there be gold in the mountains in the Cobequid Highlands?
Geologists with the Department of Natural Resources are enthused by what they’ve found over the past few months, and are optimistic for the future.
“Mining is a bit of luck sometimes, and with very small odds,” said Garth DeMont, community liaison geologist with the department. “All we need is the discovery of one significant gold vein and the Cobequids will light up.”
It was back in 2011 the department chose the Cobequid Highlands area to re-map, and federal funding saw them initially doing some geoscience. Geologist Trevor MacHattie was conducting geoscience research to map and age date the various rock types found in the area, which provides foundation knowledge used to identify mineral deposits and environmental geohazards.
That’s when he recognized volcanic rocks in the area, which commonly hold epithermal gold deposits. When mineral deposits are formed, the deposit host rocks, in this case the volcanic rocks, are physically and chemically altered in the mineralized areas. This alteration is the clue geologists look for when exploring for mineral deposits.
The federal government had also provided funding for a LIDAR (Light Detection and Ranging) survey – measuring topographic and vegetation elevations through laser pulses shot from an aircraft.
At the time, some local prospectors had staked a claim on the land, however those claims were dropped mid-2015. That’s when the department began focusing on gold deposits thanks to the information they had collected, and information on mineral occurrences from other prospectors available in the Mineral Occurrences Database. Because of the collective information, the department put a closure on more than 30,000 hectares of land, which still remains today.
“Nobody else can stake claims on that land until we release the closure,” said DeMont.
Throughout the summer, MacHattie and two others – economic geologist Geoff Baldwin and surficial geologist Denise Brushett – collected samples in the highlands just outside Wentworth.
“Fifteen to 20 per cent is outcrop at most, or bedrock exposed,” explained Baldwin.
Baldwin collected about 780 stream sediment samples during the summer months, up until about mid-October, and Brushett another 200 samples. Some samples have been sent off to the lab for analysis, while the geologists were able to use a portable analysis unit on the rest, giving them almost instantaneous results.
“We’ve seen some interesting anomalies,” said Brushett.
“We have a nice area of focus now,” Baldwin added, noting a downside to the portable analyzing unit is it doesn’t detect gold. “It’s remarkable we found anything in the outcrop – the deposits are small, but it’s quite exciting.”
Thanks to the work that’s been done over the last couple of months between the three geologists and three assistants, DeMont said they are almost to the first stage of an exploratory program.
Throughout the work they’ve been doing, DeMont and the other geologists say they’ve been keeping residents informed, as well as the municipality. They’ve also been working with the Tatamagouche Water Supply.
“We’ve started discussing what we’re finding and where we go from here,” he said. “We want to create a code of best practice so that any drilling done will maintain the integrity of the water supply. One of the most sensitive areas you can work in is in someone’s water supply.”
The gold deposits and volcanic rock the geologists have found in the highlands are similar to what has been found in the south, so MacHattie and Baldwin travelled to Nevada, visiting mining operations there.
“They’re looking at the same types of deposits, but they’re hard to find they’re so small,” said DeMont. “These ones are tipped over. With the volume of rock here, they’re more massive.”
In Nevada, the gold deposits are found in a sequence of volcanic flows roughly 150 to 200 metres thick. Locally, there are multiple volcanic flow sequences totaling more than five kilometres in thickness.
“If we play the odds, given the differences in overall volumes of the volcanic rocks in the Cobequids versus the Nevada deposits, there should be greater chances of finding a gold deposit in the Cobequids than the Nevada area,” said DeMont.
DeMont said the deposits are some of the richest found in the world, and Baldwin said the gold is one of the highest grades found.
Baldwin said one of the risks, however, is mine drainage.
“The concern is having mining in the water supply,” added DeMont. “But there’s an opportunity to have a milling component outside, in a different water draining water shed.”
Volcanic rock, he said, is like hot springs and high in mercury. When mineralized fluids that form epithermal gold deposits reach the surface of the earth, they form hots springs and geysers. Most of the metals (arsenic, gold, antimony, etc.) are deposited in the rocks before the fluids reach the ground surface. One of the elements that is generally retained in the mineralized fluid and gets deposited at the surface in deposits formed by the hot springs or geysers is mercury.
“That’s what we’re using as a tracer element. Then there’s gold below that,” he said.
Through their samples and analysis, Baldwin said they think they’ve found three different horizons, with DeMont calling them gold ‘districts.’
“There could be several mines operating,” DeMont said. “There could be several different deposits if they’re individual systems.”
If it does come to a point where a company or companies are mining for gold, it could mean 200 to 300 jobs, if the company builds a mill as well.
“That’s the absolute best case scenario. But we’re optimistic and enthusiastic about what we’re seeing,” said DeMont.
He said the next step will be to host an open house for the community, to bring them up to speed on their progress. Then, it could be a Request for Proposals (RFP) to see if there’s interest from mining companies, an RFP containing concerned identified during meetings with the municipality and Tatamagouche Water Supply committee, as well as the upcoming open house. The exploration opportunity would be promoted during a Prospectors and Developers Conference next year.
DeMont, however, said it will probably take another decade of exploration before any mining is done, and if it comes to mining, the drill rig would be about the size of a cube van. An underground mine operation would have a footprint of around five to 10 acres, with a mill site slightly larger, requiring construction of a tailings pond and a mill.
“We’re trying to attract deep enough pockets for a proper exploration program,” DeMont said, adding deep pockets will be needed to sustain this type of project. There are many times when companies begin exploration, however pull out of the area after running out of money.
“We’re hoping to attract a bigger company. They’ll understand the scope of this.”
He said any type of exploration will include community engagement plans, as well as include those with the Tatamagouche Water Supply.
“We need to create some best practices for them to follow, with good community benefits,” he said.
In the meantime, MacHattie will continue to map the rest of the Cobequid Highlands, and the geologists will continue to try and identify other areas of potential throughout the province.
“We’d seen the epithermal model in the past, but people didn’t understand the geology. It’s a guide of where to explore. It’s going to attract the attention,” said DeMont.
With the geologists having completed their sample collecting, DeMont said they aren’t too concerned about people coming into the area because of the land closure.
“We may get people panning,” he said. “But the land is pretty secure.”
“With the traditional panning method, it may or may not work,” Baldwin noted. “The gold we found is just so fine.”
DeMont and the geologists will be hosting a DNR Cobequid Projects Open House on Nov. 25, 11 a.m. to 3 p.m., at the Warwick Mountain Recreation Club. Anyone interested in learning more about the project and what’s next are welcome to attend.