Since Brixton Metals (TSXV: BBB) started looking a year ago at the historic silver-cobalt camp near the northern Ontario town of Cobalt, the junior has picked up three past-producing underground mines that could churn out more silver someday.
Brixton announced its third acquisition — the Gowganda mine — on Dec. 19.
Gowganda, 85 km west of Cobalt, produced 40.7 million oz. silver at an average grade of 754 grams silver per tonne between 1910 and 1972.
A resource estimate in 2011 on Gowganda’s tailings showed that 2.96 million oz. silver from 1.9 million tonnes averaging 47.5 grams silver per tonne remained in the indicated category, at a cut-off grade of 10 grams silver per tonne.
Gary Thompson, Brixton’s chairman and CEO, says the once-famous silver camp offers brownfield opportunities, and his team has already grown its land position there.
In February, Brixton closed the acquisition of the Langis mine, 500 km north of Toronto. The mine produced 10.4 million oz. silver from 379,479 tonnes at an average grade of 857 grams silver per tonne between 1908 and 1989.
An aerial view of core boxes near the Simcoe No. 6 shaft at Brixton Metals’ past-producing Gowganda silver project near Cobalt in northern Ontario. Credit: Brixton Metals.
Since that acquisition, Brixton has twice added to its land holdings near the Langis mine, first in May and then again in September, bringing its total land package at Langis to 32.8 square kilometres.
Brixton also picked up the Hudson Bay silver mine in April. This mine operated from 1905 to 1943, and again in 1953, producing 6.4 million oz. silver at a grade of 4,217 grams silver per tonne. Production at Hudson Bay came from two narrow vein systems. Vein No. 1 and Vein No. 2 both had a strike length of 400 feet and extended 200 feet vertically.
Thompson says the geology is similar at all three underground mines.
“The Archean basement rocks are overlain by sediments, which have been intruded by the Nipissing diabase sill,” he says in an interview. “The silver mineralization, including native silver, is hosted within all three of the rock units in the area. The mineralized veins occur within carbonate alteration that fills fissures in moderate to steeply dipping structures, as single veins and parallel sets.”
Thompson adds that there are only a few primary silver opportunities in Canada, and says this is one of the reasons why Brixton is so attractive to its shareholders, which include Rob McEwen (9%), U.S. Global and Hecla Mining (NYSE: HL) — each holding 6% — Eric Sprott (5%), and retail (55%). Management owns 12%.
“We’re excited — it’s brownfield exploration for the most part, and you know the old saying: ‘A good place to look for a mine is near a mine,’” Thompson says. “But we’ve got work to do to get those resources defined.”
Thompson, one of the company’s cofounders, notes that the historic workings at all three mines were relatively shallow. Hudson Bay was mined down to 60 metres, Langis went down 200 metres and Gowganda reached 260 metres.
“If you’re looking at the Abitibi greenstone belt, we know that the basement rocks can have mineralization down to a significant depth, so we see an opportunity for that potential with some of the deeper structures at our projects,” he says. “We know we have large-scale regional faults, and we think the splays off those faults could be conduits for the fluid flow both at shallow levels and at depth.”
The company drilled 15 holes at Langis in mid-2016, some of which returned high grade, including 3.1 metres of 1,944.6 grams silver and 2 metres of 1,084 grams silver. One of the most intriguing holes, however, intersected 4.9 grams gold per tonne and 397 grams silver at 156 metres deep.
“We got pretty nice intercepts on our first round and we’re showing there’s gold in the system as well … as far as we could tell, there are no reported gold production numbers from this camp, and we haven’t seen any gold numbers in any of the historical drilling,” Thompson says.
Brixton’s geologists aren’t sure, however, whether previous operators assayed for gold at Langis, and if they did, whether they discounted it.
“When they drilled underground they were looking for obvious high-grade mineralization, and would sample that and toss the rest,” he says. “We took the strategy of sampling from top to bottom. If you look at the core, it’s got hematite, but it’s not obvious, high-grade mineralization, so if you were instructed to only sample the high grade. I can see why it was missed … we’re seeing gold in the system and we’re looking at the basement rocks, as well, which I don’t think was much of a focus for historic exploration.”
Thompson says Brixton will continue exploring around the old workings for extensions, but is also looking at the feeder zones at depth to build something more there.
The high-grade silver at Langis has been recovered from within all rock types and the silver-bearing veins are moderate to steeply dipping, and categorized as single vein or multiple-vein type structures. The deposit is open on strike and to depth.
Thompson says the company has been digitizing and 3-D modelling historic data. “We need to get the old paper data and get out there with the drills and start drilling,” he says. “Hopefully early in the new year we’ll do more drilling.”
Historically, the silver-cobalt camp near Temiskaming produced 500 million oz. silver, Thompson says, but when the silver price fell to US$5 per oz. in 1990, activity in the area dried up.
“When we looked at this camp we were impressed by the sheer number of mines that were in it historically,” Thompson says. “But after 1990 the camp was pretty much dead for 25 years, so we saw that as an opportunity to get established.”
Drilling next to the Langis mine intersected a new zone just before the silver price collapse, with a historic intercept of 2,115.04 grams silver over 9.4 metres and 1,262.80 grams silver over 3.9 metres.
Thompson says that the three deposits, if developed and put into production, could feed a central mill. The Hudson Bay mine property is part of the city’s limits, while Langis is just 20 km northeast of Cobalt, and Gowganda, 70 km northwest.
While Brixton focuses on precious metals, it sees cobalt production as a potential bonus. The Langis mine produced 358,000 lb. cobalt and Hudson Bay produced 185,000 lb. cobalt.
Over the last year Brixton’s shares have traded from 35¢ to $1.20 per share. At press time the junior’s shares traded at 26¢ apiece. The company has 40 million shares outstanding.
As of Sept. 30, it had $4.2 million in cash and no debt.
In addition to its Ontario properties, Brixton owns the Thorn exploration project in northwestern British Columbia.
The diabase sill is called the Nipissing diabase. Also the location is Temiskaming not Timasking.