Gypsum Overview
Nova Scotia has historically been one of the world’s largest suppliers of gypsum. Gypsum’s main use is as an ingredient in wallboard and most walls in Nova Scotia contain gypsum quarried in the province.
327-342 million years ago, global sea levels rose and fell many times. This repeatedly flooded Nova Scotia with what we call the Windsor Sea. Nova Scotia was near the equator at that time so the sea also evaporated repeatedly in the tropical sun.
This process gave us huge gypsum deposits because gypsum forms when water high in calcium and sulfate evaporates, leaving the calcium and sulfate behind as sediment. The sediment builds up and is eventually turned into gypsum rock by heat and pressure.
When gypsum mining started in Nova Scotia in the late 1700s, it was done by farmers who extracted blocks of it from their farms, hauled it by horse and cart to shipping points near Windsor and sold it to local traders. The gypsum was then exported to the east coast of the United States for use as fertilizer.
US inventor Ben Franklin learned of gypsum’s benefits as a fertilizer from the French and brought the idea to the United States.
Wallboard (aka drywall) was invented in the United States in 1918. Plaster made from gypsum was sandwiched between two sheets of paper and within ten years, large scale production was revolutionizing the construction industry. This changed the gypsum industry in Nova Scotia as vertically-integrated, international companies brought economies of scale and more advanced equipment to the province.
Since then, most of Nova Scotia's gypsum production has gone into wallboard. An average home has about seven tons of gypsum in its walls.
Below is a reclaimed area at the largest surface gypsum quarry in the world in Milford, Hants County. It is an example of "progressive reclamation" - reclaiming areas where extraction is complete while continuing to mine elsewhere on the same site. This minimizes the overall footprint of an ongoing operation and is an example of how mining companies are always working to take care of the environment.
The upside-down tree shown below gives raptors (eagles, hawks, ospreys) a place to nest and the island gives various birds protection from coyotes and foxes.
Before getting operating permits, mining companies must get government approval of reclamation plans and post reclamation bonds (money in escrow, basically) that ensure funds are available to properly take care of sites. In fact, reclamation is a key part of the mining process today and progressive reclamation is standard industry practice.
Reclaimed area of the Milford mine.
An upside-down tree in a reclaimed area of the quarry offers a nest to raptors.
