A deposit of arsenic was discovered in Wellington, Halifax County, in 1923 but the Department of Mines considered "this deposit most hazardous as a financial venture."

That summer, Messrs. Cope and McDonald, of Enfield, found some arsenopyrite, a mineral that contains arsenic, in a quartz vein about two miles east of Wellington Station. The site was on the main line of the Canadian National Railway, a half mile south of what was then John Kelly’s farm. Today, the site is about half a kilometre due east of Leafs Lane.

The quartz vein, together with others in the vicinity, had been known previously. The Geological Survey of Canada had mapped them years earlier, but nothing had been done to develop them. However, with the discovery that the main vein contained arsenic, the Wellington Arsenic Company was organized in 1924 to explore and develop the deposit.

The main vein was 15 to 18 inches wide, and its quartz was a milky white colour. It was uncovered by trenching for 15 feet. Irregular lenses of arsenopyrite 6 to 8 inches wide occurred at intervals in the quartz, and along its contact with the slates that hosted the vein. A little pyrite was also present.

Another nine veins were uncovered in the vicinity and a shaft was sunk to a depth of about 50 feet, at which point the company asked the provincial government for financial assistance to build a concentrator to process the ore.

Arsenic is naturally-occurring in all rock and many areas of Nova Scotia have elevated arsenic levels. Arsenic-bearing minerals are often unstable and can leach naturally into groundwater, so it is important to test wells for it regularly.

Most of Nova Scotia’s arsenic deposits are associated with the province’s gold deposits because arsenopyrite often occurs with gold in nature. At different times, modest amounts of arsenic were recovered from historical Nova Scotian gold mines and exported to places like Wales, Germany and Belgium. However, various challenges, including high shipping costs, lack of markets and low gold prices, prevented the establishment of a regular arsenic industry.

There were only a couple places like Wellington where an arsenic deposit was worked specifically for arsenic – where the arsenic was not extracted as a by-product of gold mining.

A Department of Mines employee inspected the Wellington site in 1924 and a memo he subsequently wrote was harsh in its assessment: the Wellington arsenic deposit “appeared to have no commercial significance at all.”

The memo described the deposit as “rather ill-defined veins” and said, “Two of these are of some importance and on one of them a shaft has been sunk to 45 feet and about 100 tons of materials taken out.”

The shaft was filled with water at the time of his visit so he could not inspect the vein and the workings. However, he examined piles of extracted rock at surface and estimated there were only about 10 tons of good ore and 40 tons of ore that “might pay to concentrate.” The remaining 60 tons of ore “would not pay to concentrate” because they did not contain enough arsenic.

He wrote, “I trust you realize that these figures are mere personal estimates, but I mention them as I understand it is the intention of the company to ask for money to build a concentrating plant and you can see what little material they have on hand to warrant that expenditure.”

The veins “appear to be small and very discontinuous. In places the ore has shown 12 in. of solid arsenopyrite which in a few feet has almost entirely disappeared. This, I consider, condemns a deposit of a comparatively low value metals such as arsenic, especially when it contains no gold. I am of the opinion that it is the gold that makes our arsenical concentrates attractive to the smelters…

“There are two apparent reasons why this property does not appear attractive to me. First, the ore is too discontinuous. I have not seen a place where the ore has carried for ten feet. It appears to be in lenses or pockets and the material on the surface bears out the same opinion. If it were a large, well-defined deposit, it would be an entirely different matter and until such is developed the work can be considered nothing but of a prospecting nature…Secondly, the venture gives no apparent promise of becoming a financial success.”

In other words, the cost of extracting, processing and shipping ore from the site was too great for a mine to be economically viable.

The memo was blunt: “I consider this deposit most hazardous as a financial venture.”

It went on: “In conclusion, I can give no possible reason why this deposit should obtain Government aid. There are many veins in the gold districts…that contain more arsenic and a greater possibility of gold than is found at Wellington. I would also consider it unwise for reasons given to endorse this property too highly in order that this endorsement might be used for the raising of funds to build a concentrating mill which is not warranted at the present time.”

Regarding the company’s request for financial assistance, the memo said: “I do not know if the Government should give special aid to these people rather than to the hundreds of others with much more promising prospects.”

Because arsenic is often associated geologically with Nova Scotia’s gold deposits, it has left an unfortunate environmental legacy at many historical gold mines. Gold miners in the 1800s and early 1900s did not understand arsenic’s environmental impacts so waste rock and tailings that contained arsenic were often just left at mine sites, a practice that is obviously unacceptable today but was standard 100-150 years ago.

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, today, waste rock is contained in engineered facilities that ensure materials like arsenic cannot impact water.

Before getting operating permits, mining companies must now 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.