Stirling Mine

In the mining industry, we say new mines are often found next to old mines because historical sites worked with basic tools and little science can now be mined profitably and environmentally-responsibly with modern science and engineering. The Stirling Mine is an example.

It is also an example of Nova Scotia’s potential to produce the critical minerals used in green technologies like electric vehicles, wind turbines and solar panels.

Copper and lead-zinc mineralization were reportedly discovered in Stirling, Richmond County, in 1885 in Copper Creek (believed to now be called Strachans Brook, which is in the Stirling mine site). Initial mining efforts focussed on extracting the copper. However, that era’s unsophisticated metallurgy (the science of separating metals from their ores, or host rock) made the mine unprofitable, at least partly because of the complexity caused by the lead-zinc mineralization.

By 1915, advancements in metallurgy made recovering zinc and lead from the ore more feasible, and interest in the area picked up again. The Sterling Mining and Smelting Company, founded by Neil R. McArthur, James Nolan and John Madore, acquired the property, which was on the farm of John McLeod. (“Stirling” is sometimes spelled “Sterling” in historical records so we use both spellings to be true to the source material.)

The company did prospecting in 1917-18 and found that “the ore bodies were quite extensive,” according to the Department of Mines annual report for that year. “In one trench, a width of 66 feet of ore material was exposed and was traced in the general direction of the strike for over 300 feet. Assays [tests] of the ore made at the laboratory of the Mines Branch, Ottawa, show that the ore varies from 4% to 30% zinc, with as high as 7.5% lead and 3.5% copper, with small amounts of gold and silver.”

Sterling Zinc Ltd., a subsidiary of the American Cynamid Company of New York, took the property over in 1925. The company sank a shaft to a depth of 120 feet by October that year. In 1926, the shaft reached 400 feet and horizontal tunnelling was done to access the ore.

In 1927, the British Metals Corporation, operating as Stirling Mines Ltd., opened the Stirling Mine by pumping out the shaft to the 200 feet level and doing additional tunnelling. The company later dewatered the rest of the shaft and deepened it. It also built a mill with a capacity to process 250 tons of ore per day. It installed other new equipment and built various buildings, including a shaft house, hoist room, boiler house, garage, storehouses, water tank and tower, and a boarding camp for 20 men.

Mining continued until 1931 but then ceased due to low metal prices.

The mine was operated again by Stirling Mines Ltd. from 1935-38 but then shut down due to low zinc prices.

The property remained dormant until 1949 when Mindamar Metals Corporation did some exploration and optioned the project to Dome Explorations Ltd. in 1951. Dome built a larger mill and sank a second shaft over 1000 feet. It mined the deposit until 1956 when low base metal prices forced it to shut down.

In total, the Stirling deposit has produced 1.2 million tons of ore that contained 6.4% zinc, 1.5% lead, 0.74% copper, 2.2 ounces of silver per ton and 0.03 ounces of gold per ton.

The area has been an exploration target ever since the mine closed because of its interesting geology and potential to return to production. The mine’s historical tailings also contain significant quantities of metals that could potentially be extracted.

Minerals like zinc and copper are essential in green technologies. For example, zinc’s main use is in alloys to galvanize (protect) steel. Zinc oxidizes/rusts more quickly than the metal it is protecting, and the underlying metal will not corrode until all the zinc has been sacrificed. This extends the life of a wide range of products and infrastructure and makes galvanized steel one of the strongest construction materials. About 60% of global zinc supply is used for galvanizing.

Wind turbines require about six tons of zinc per megawatt of capacity because they are mostly made of steel that needs to withstand the elements. Galvanized steel is also used in electric vehicle bodies and in various parts of EVs and solar panels.

The deposit also contains magnesite, which is a critical mineral today, used as an alloy with aluminum to make it stronger and more corrosion-resistant. Magnesite had no economic value when the Stirling Mine operated, so past exploration did not determine how much of it is at Stirling.

Stirling’s mixture of metals represents an exciting opportunity now but it was a significant metallurgical challenge for past operations and was repeatedly a factor in them shutting down. Metals are usually hosted in rock from which they need to be separated in the milling process. Also, metals deposits almost always have multiple metals in them because of how they form, so the metals also need to be separated from each other, not just from the host rock.

Historically, the science behind milling ore was rudimentary compared to how sophisticated it is today. As a result, historical metals mines were often unable to capture the full economic value of a deposit, losing significant quantities of minerals to tailings. They also often caused environmental damage. (Learn more about historical tailings at

The modern mining industry is completely different. It is a sophisticated, science-based business that takes excellent care of the environment. Today, the Stirling deposit has the potential today to provide multiple important metals., which provided the photos below, is an excellent source of additional information about the Stirling Mine.

See the story of the Galena Mine in Cheticamp, another site whose complex geology created metallurgical challenges for early miners: