Point Edward

The Point Edward Limestone Quarry in Cape Breton was opened in 1902 by the Nova Scotia Steel & Coal Company to supply flux for its steel plant in Sydney Mines. (Flux is used in the smelting process to promote fluidity and remove impurities in the form of slag.) After the Nova Scotia Steel & Coal Company’s plant closed in 1921, the Point Edward quarry was taken over by the Dominion Steel and Coal Corporation (DOSCO), which used the limestone at its steel plant Sydney.

Stone from 4-8 inches in diameter was used by DOSCO for open-hearth flux. Material from 1.5-4 inches in diameter was used for blast-furnace flux along with limestone imported from Newfoundland.

The undersized material, less than 1.5 inches in diameter, was mostly discarded, though a small proportion of it was taken to Glace Bay and pulverized for use in dusting the coal mines. Limestone dust is often in underground coal mines to prevent, and reduce the intensity of, explosions. The limestone dust absorbs heat and helps prevent coal dust igniting and reduces the spread of flame.

Stone from the Point Edward quarry was also calcined (heated to dry it out) at the DOSCO steel plant for use in the open-hearth furnaces, the ammonium sulphate plant and in the wire mill.
From 1924-1931, the Nova Scotia Department of Agriculture operated a plant at the Point Edward quarry for the production of agricultural limestone. Limestone is a soil sweetener, meaning it increases pH. Stone for this purpose was pulverized in the plant, which had an output of 15 tons per day, so the limestone powder could be spread on farm fields.

It is not clear when the Point Edward quarry ceased operations. It is known that the quarry stopped providing flux for the DOSCO steel plant in 1939, however, production seems to have continued until at least 1943. There were significant stockpiles of crushed limestone at the site that were used for agricultural purposes for many years, perhaps decades.

The “before and after” aerial pictures below show what the quarry looked like in 1954 compared to now. The 1954 pictures shows there were both stockpiles and buildings still at the site, which suggests it was still active even if extraction was no longer taking place. The pictures also show how the site has become much greener over the years.

Flux was sourced from several Cape Breton quarries for use in Cape Breton's steel plants, including Marble Mountain and Scotch Lake.

The steel plant in Sydney Mines was the most efficient and modern steel plant in Canada in the early 1900s. It took advantage of the local supply of metallurgical coal and proximity to the iron deposits on Bell Island in Newfoundland. (Steel is mainly made of iron and carbon, and the carbon is derived from metallurgical coal.)