Mabou Harbour Mouth

Gypsum was quarried intermittently in Mabou Harbour Mouth, Inverness County, from 1877-1940.

The first record of production in the Mabou area was in 1877 when 200 tons of gypsum were extracted. The Department of Mines annual report for the year does not provide any details such as who did the quarrying and what was done with the gypsum.

The Mabou Gypsum Company opened a quarry in 1891 on the north side of Mabou harbour, along the left-hand side of the aerial picture below. The company was also operating the nearby Mabou coal mine. The Mabou Gypsum Company built a wharf that both operations could use for shipping.

Only 298 tons of gypsum were produced as the operation ramped up in 1891 but specimens from the quarry were displayed at the 1891 Jamaica International Exhibition. By 1893 production had grown to 11,700 tons.

It is not known whether the Mabou Gypsum Company was still operating in 1894 because records indicate that the coal mine was only worked for 22 days and it recorded no gypsum production. There was also no production recorded by the company in 1895. It was around this time that a company called the Mabou Coal and Gypsum Company was liquidated, presumably the same firm, perhaps pushed into bankruptcy by an 1893 rock fall in the Mabou coal mine that forced the company to abandon the workings and drive a new tunnel.

There is no recorded production from the gypsum quarry between 1894 and 1925.

In 1926, the Nova Scotia Coal and Gypsum Company, a subsidiary of Gypsum, Lime and Alabastine Canada Ltd. (GLA), restarted operations at the quarry.

According to a 1929 report, the Nova Scotia Coal and Gypsum Company produced over 35,000 tons of gypsum in 1927-28.

The quarry face was over 50 feet in height at that time. Overburden, the dirt on top of the gypsum deposit, was removed by horse and cart. The extracted rock was hauled in small cars on tram tracks to the crusher at the storage shed 200 yards away.

There was, according to the report, ample room to extend the quarry. It suggested that a short tunnel would provide access to another large area of gypsum to the east of the existing operation.

The rock from the quarry was hauled up an incline and dumped into a hopper from which it was fed into a jaw crusher set to crush the gypsum down to pieces about three inches long. From the crusher the gypsum was elevated to a conveyor belt that deposited it in a storage shed that had a capacity of 10,000 tons. A 24-inch conveyer belt, running in a tunnel underneath the storage shed, allowed the rock to be loaded directly into vessels.

The mouth of the harbour was dredged to make it deep enough for 4,000-ton boats.

The Nova Scotia Coal and Gypsum Company shipped to GLA’s mill in Montreal from the wharf pictured below, which was built in 1926 by the lighthouse in Mabou Harbour Mouth.

GLA, incorporated in 1927, was the largest manufacturer of gypsum products in Canada. The company was a combination of the Canada Gypsum & Alabastine Company, the Ontario Gypsum Company, the Nova Scotia Coal and Gypsum Company and the Toronto Builders' Supplies Ltd.

Domtar Gypsum bought GLA in 1959 and did some exploration work in Mabou Harbour Mouth in 1960. Domtar drilled 17 holes and estimated that 1.86 million tons of gypsum is still in the area. Gypsum reserves below sea level were not calculated because the amount of gypsum available would not warrant the extra cost of pumping out the water that would enter the mine at that depth.

While 1.86 million tons of gypsum is a significant amount, it was not enough to interest Domtar in reopening the quarry and the area has not been mined since.

Before wallboard/drywall became the most common way to finish walls, walls were usually made of laths (thin, flat strips of wood) with plaster spread over them. Ground gypsum was, and still is, a key ingredient in plaster. This method of making walls died out after wallboard was invented in the United States in 1918 by sandwiching plaster between two sheets of paper.

Today, wallboard is used in most buildings. An average home has about seven tons of gypsum in its walls. Most walls in Nova Scotia contain gypsum quarried in the province.

Safety is the main reason gypsum is in wallboard. Gypsum is 21% water at the molecular level so it slows the spread of fire and helps save lives.