Commercial production of natural stone is an important industry in most provinces. The value of all stone quarried in 1994 was nearly $626 million, representing a total production volume of over 109 million t. Stone is taken from a large open excavation or pit by cutting, digging or blasting, depending on the method best suited to each deposit. Quarried stone is handled with mechanical equipment appropriate to the operation, eg, draglines, loaders, conveyors, forklifts and trucks. Often quarries are owned and operated by companies associated with the CONSTRUCTION INDUSTRIES.
The principal types of stone quarried in Canada are LIMESTONE, granite, sandstone and marble. Limestone accounts for 79% of the total volume in tonnage, and 71% in value. Granite accounts for approximately 15% of the annual total tonnage, and 20% of the value. By comparison, the output of marble and sandstone is relatively small. Limestone quarries are widely distributed in Canada and economics usually dictate that sources nearest the largest markets become volume producers on the greatest scale. Ontario produces over half of Canada's annual quarry production; Québec accounts for about one-third; the balance comes mainly from British Columbia and Manitoba.
Nearly two-thirds of all the stone produced is crushed and used by the construction industries for concrete and asphalt aggregates, as a stabilizing base material in road building, for rubble and riprap used for fill and embankment reinforcement, as railway ballast, as roofing granules, and as chips for stucco and terrazzo. Other industries consume about 36% of annual quarry production. The CHEMICAL INDUSTRIES use crushed limestone in the neutralizing of acids; in the extraction of aluminum oxide from bauxite; in the manufacture of soda ash, calcium carbide, calcium nitrate and carbon dioxide; in PHARMACEUTICALS; in the manufacture of dyes, rayons, paper, sugar and GLASS; and in WATER TREATMENT.
Limestone is used in METALLURGY as a fluxing material to cleanse impurities from molten metal. Pulverized limestone is used extensively by industry as a filler and extender for CEMENT and as a whiting used in CERAMICS, PLASTICS, floor coverings, insecticides, paper, wood putty, paints and other commodities. Limestone is used in the manufacture of fertilizer and has other agricultural applications. About 3% of all stone quarried in Canada is used as dimension stone or ornamental building stone. Most prominent are the granites of Québec and the limestones of Ontario, Québec and Manitoba. Perhaps the best known of the latter is Manitoba Tyndall Stone, an attractively mottled dolomitic limestone quarried near Winnipeg.
In 1995 the value of stone exported from Canada was over $145 million. By comparison, total imports in 1995 were about $144 million. The quarrying industry is directly influenced by the construction industry: a decline in the latter causes reduced demand for building materials. In addition, stricter environmental controls could limit or even close many quarries, particularly those near larger urban centres, where dust and noise create objections and where extensive rehabilitation of spent pits may be required.