Montague
Gold was discovered in Montague, Halifax County, in 1862, when a boulder weighing less than 100 pounds produced $1,600 worth of gold. Other rich boulders were found and the Montague gold district was formally established in 1863.
The district was originally called the Lake Loon Gold Field but the name was changed to Montague after a retired British army major who owned land in the area.
The Montague district was worked more or less continuously until 1940 and hosted a number of mines.
The McQuarrie (aka Albion) mine opened in the early 1860s but produced only modestly until the Lawson brothers took it over in 1869 and extracted 10,000 ounces of gold in just five years through systematic work. In 1874, the Lawson brothers retired and the mine was then worked by others, but mining in the district dropped off through much of the 1870s.
Activity picked up again after George W. Stuart discovered the Rose vein on December 7, 1878, so-named because its quartz was rose-coloured. Rich boulders again played a key role, with Stuart tracing them back to the bedrock gold deposit that was their source. He did so by carefully examining the evidence of glaciation in the area because boulders that contain gold-bearing quartz are often eroded from bedrock deposits by glaciers that carry the boulders and deposit them as the glaciers melt. By figuring out what direction the glaciers had travelled, Stuart was able to find the deposit.
The property was sold to some Americans and it was a good producer. Its peak was when 80 tons of gold-bearing quartz produced 800 ounces of gold, an average of 10 ounces per ton.
However, a fault was encountered in 1880. In geology, a fault is a fracture, or zone of fractures, between two blocks of rock. Faults are caused by geological forces like tectonic plate movement and they allow the blocks of rock to move relative to each other. Faults are a challenge in mining because they can cause deposits to be split, moving part of the deposit to a different, often hard-to-find, location, which was the case with the Rose vein. The company believed it had found the extension of the vein to the east in late 1880 but mining it was not profitable and the company shut down in 1882.
The Skerry vein was found shortly after the Rose vein’s discovery and it reinvigorated activity in the district. Skerry would go on to be worked intermittently for decades.
The DeWolfe mine opened in 1872 but was worked only intermittently during the 1870s and 1880s. For example, in 1885 it hit a paystreak (rich ore) that produced 1,369 ounces of gold from just 337 tons of ore. However, the mine shut down the following year. It was reopened in 1889 by Charles Annand.
Mining in Montague continued in this fashion – up and down – for many years. In total, the Montague gold district produced 65,196 ounces of gold from 1863-1940.
Unfortunately, the historical Montague gold mines are best-known today for their environmental legacy – tailings from the mines that contain elevated levels of arsenic and mercury.
This is how early gold mining in places like Montague generally worked:
Most Nova Scotia gold is in quartz veins so miners extracted the quartz with hammers and chisels, and sometimes with explosives as they became more sophisticated.
The gold-bearing quartz and other rock (ore) was then picked over for the best material – the pieces with visible gold. The ore was sent to a stamp mill, a large machine that crushed gold-bearing rock by stamping it over and over. Each stamp weighed about 800 to 1,000 pounds and repeatedly struck the ore, crushing it down to sand-sized particles.
In the 1800s, mercury was then used to separate the gold from the sand. Gold dissolves in mercury but mercury does not absorb other impurities, so it was effective at separating the gold from the pulverized ore. The mercury/gold mixture was recollected and heated until the mercury boiled away, leaving just the gold. A simple still like those used to make alcohol would draw away the vaporized mercury and collect it. The mercury was both valuable and reusable so early miners tried to capture all of it but, unfortunately, small amounts were often lost in the process.
The gold was then refined for greater purity and formed into bricks or nuggets.
The mining and milling process created waste rock, which just means rock leftover from extraction and processing. It was sometimes left in piles (dumps) at mine sites and sometimes used in construction at mines or in community roads, buildings and railways.
The process also generated tailings, which are what remained after the ore was crushed and treated to remove the gold. The tailings were dumped into nearby lakes, streams, or other natural depressions, a practice that is obviously unacceptable today but was standard 100-150 years ago.
Historical waste rock and tailings often contain significant quantities of gold. A lot of gold-bearing rock was discarded on waste piles because it did not contain visible gold or because the miners could not profitably extract from lower-grade ore. The milling process was inefficient, and often poorly managed, so it was common for 30% or more of the gold to be lost to the tailings, just like mercury often ended up in the tailings.
Attempts were made as early as the 1880s to extract gold from tailings but they failed due to the rudimentary science of the day. Unfortunately, this led to a belief that it was not worth trying to recover gold from tailings, something that can be done successfully today both for the gold and as part of remediating historical tailings.
Historical tailings often contain elevated concentrations of mercury, the result of mercury being lost in the milling process instead of being recollected as described above.
Historical mine sites also sometimes have high levels of arsenic. All rock contains arsenic so it can leach from waste rock piles into the environment. However, it must be understood that arsenic is unstable even when it is left underground, and it often leaches naturally into groundwater. This is why so many Nova Scotia wells have high levels of arsenic. Historical miners sometimes exacerbated the problem, but the problem also exists naturally.
No industry took proper care of the environment 100-150 years ago and mining was not an exception. However, modern mining is completely different. For example, Nova Scotia gold mines have not used mercury since the early 1900s and today, waste rock is contained in engineered facilities that ensure materials like arsenic cannot impact water.
Modern tailings, usually in the form of slurry, are stored in a tailings management facility – a lined and walled area on a mine site designed to contain the tailings indefinitely. The extensive science and engineering behind tailings management protects the environment. For example, site-specific geotechnical and engineering studies are done for each tailings facility to determine the best technical option to provide containment.
Mines today can often remediate historical tailings as part of the modern mining process, often by moving them into the modern mine’s tailings facility, as is being done at the Moose River gold mine.
Also, before getting operating permits, mining companies must get government approval of reclamation plans and post reclamation bonds (money in escrow, basically) that ensure funds are available to properly take care of sites. In fact, reclamation is a key part of the mining process today and progressive reclamation - reclaiming areas where extraction is complete while continuing to mine elsewhere on-site – is standard industry practice.
