Windsor Gypsum Company

Former mines and quarries often become parks and protected areas. The Irishman’s Road Recreation Site in Hants County is an example.

The Mosher Quarry, also later known as the Windsor Gypsum Company Quarry, was opened in 1891 in Newport Station, five miles east of Windsor. Today, the site is part of a recreation area that includes soccer fields, forest and trails.

Thomas A. Mosher ran the quarry. The Moshers were a well-known family of ship builders and Thomas ran a significant ship building operation in Newport Landing. He also had another gypsum quarry at Miller’s Creek from about 1882-94 and was on the board of the St. Croix Marine Insurance Company.

Effie Mosher (1885-1968) succeeded her father as manager of the quarry in 1923, after his death, making her one of only a small number of women to manage an operation in the historical era.

In July 1928, Clara Dennis visited Windsor and wrote an article for the Halifax Herald called, “Miss Effie Mosher: She Manages a Whole Gypsum Quarry Herself.” Dennis was a travel writer and did extraordinary work photographing Nova Scotia in her travels, including much of its industrial history. The Nova Scotia Archives has many of her photos, including many of mines and quarries.

A 1915 report described the Mosher quarry as being on a 180-acre property. A rock face of 20 feet was being worked and the quality of the gypsum was “a splendid grade.”

The gypsum was drilled by hand augers. Blasting powder and a low grade of dynamite were inserted in the drillholes and set off to free the gypsum from the rock face. The blasted rock was then loaded into horse-drawn carts and hauled two hundred yards to a railway siding that connected with the Dominion Atlantic railway, which hauled it to the company’s shipping pier in Windsor.

In 1906, almost all of the quarry’s output was taken by New York’s Higginson Manufacturing. The company was named for H. C. Higginson of Newburgh, New York, who also operated a gypsum quarry on Cape Breton’s Isle Madame in the late 1800s and early 1900s ( Gypsum is the main ingredient in Plaster of Paris, which was used for things like mouldings and medical casts, and Higginson used Nova Scotia gypsum in his plaster products.

In 1912, part of the quarry’s production was shipped to the Windsor Plaster Company’s calcining mill in Windsor, and the balance was shipped to the United States. The Windsor Plaster Company operated a number of historical quarries in Hants County and, somewhat unusually for Nova Scotia, a calcining mill. Calcining gypsum means to heat and partially dehydrate it. It's part of the process of turning gypsum into plaster so it can be used in products like wallboard, mouldings and casts. (Learn about the Windsor Plaster Company and how calcining works: For a detailed explanation of why so few Nova Scotia gypsum quarries have had calcining plants, see our post about the gypsum quarry in Iona, Cape Breton:

Effie Mosher oversaw the Mosher Quarry’s most productive years: 1924 when 27,423 tons of gypsum were produced and 1925 when 27,300 tons were produced.

An updated version of the 1915 report, which was published in 1930, said the property had grown to 225 acres and the working face on the north side of the quarry was over 350 feet in length with a height of 40 feet. The overburden, the dirt on top of the gypsum deposit, was 20 feet thick on average and was stripped off by a steam shovel and hauled to a waste dump by a Fordson tractor operating on narrow gauge tracks.

The report notes that the gypsum was being broken down to “man size.” Before mechanized loading, ships were loaded by hand. There was a standard rock size called a “one man-rock,” or “man-sized rock,” meaning a rock that an average-sized man could carry from the wagon to the ship (i.e. about the size of a basketball). The term became a unit of measurement in the industry and it’s still used in some places to describe the size of stones used in landscaping (i.e. a one-man rock, a two-man rock, etc.).

In 1930, the blasted gypsum was hauled to a loading platform and loaded into standard-gauge open rail cars on tracks laid into the quarry from Newport Station. The rail cars were hauled to Newport and from there to the company's wharf at Windsor, where the gypsum was loaded onto steamers for shipment to Newburgh, N.Y.

The quarry ceased production in 1934.

Effie Mosher was also secretary of the board of directors at the Sash and Door Factory in Windsor. The company was founded in 1852 and operated until shortly after WWII, almost a century. She also reportedly bought the wharf at the old Bennett Smith shipyard in Windsor.

She passed away in 1968.

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.

Hants County’s biggest gypsum quarry was the Wentworth Creek Quarry, which was right next to the Mosher Quarry. See its story at