Gypsum is second only to coal when ranking the current importance of mineral resources to the Nova Scotia economy; and the province's gypsum mines are the largest in Canada.
A soft white rock, gypsum occurs naturally on the earth's surface, or in shallow deposits which can be readily quarried or mined. In the 18th and 19th centuries, gypsum was used mostly in fertilizer and as a paint filler; new processing techniques developed early in the 20th century made it an important ingredient in plaster, stucco and cement; it is now used primarily in producing wallboard ('gyproc') for the construction industry, and the demand is heavy.
Quarrying began in Nova Scotia in the 1770s, when farmers in Hants County first found gypsum deposits on their land and started exporting to the United States. By 1818 the industry employed over 150 men locally and 50,000 tons were being shipped annually. These early quarries were chiefly around Windsor, Falmouth and Hantsport; large deposits were subsequently opened up at Miller Creek, Wentworth and Walton.
Elsewhere on mainland Nova Scotia, development of a large deposit at East Milford, Halifax County, began in 1953; today, this huge open-pit quarry is the world's most productive. Gypsum operations are also active at McKay Settlement in Hants County, and at Brierly Brook in Antigonish County.
The existence of 'plaister' deposits on Cape Breton Island, especially along the eastern side of the Strait of Canso, was known from the earliest days of settlement. By the 1850s quarry development was underway, chiefly at River Denys in Richmond County, and at Dingwall and Cheticamp in Victoria County. Later, the Iona Gypsum Company began production at Grass Cove, Victoria County, in 1916; the mill turned out a first-class product but was one of the casualties of the Great Depression.
In 1867 gypsum was being exported from 25 different ports in Nova Scotia; today the export trade still almost entirely with the United States is concentrated in dedicated shipping facilities at Hantsport, Burnside (Bedford Basin near Dartmouth) and Point Tupper in Inverness County.
View images from Gypsum Mining in the 'Men in the Mines' Virtual Exhibit