Hillsborough Gypsum Mine

It is very, very dark inside this mine. You do not want to be without light. Bring multiple backups and extra batteries.

Bats appear to use this mine as a hibernaculum during the winter months (October to April), please refrain from entering during that time.

Depending on the angle you decide to approach from, you could encounter some caved in mineshafts that vary in depth, but are all shallow enough to climb out of. The entrance to the mine itself is located on the side of a cliff of gypsum, and there is a trail that leads right to it from the road. There is a rope to grab onto while scaling the mound of gypsum blocking a significant part of the entrance. In the mine, some parts of the floors are muddy, and others are covered with a few inches of water. There are some small trenches made by flowing water, but nothing massive. There are multiple collapsed mineshafts in the mine that once led to the surface, easily spotted by the massive mounds of dirt. In the back of the mine, there’s what is presumably a descent to the lower levels, however it is completely flooded. The water is murky, and the slope down does not appear to be gentle. Do not try to enter the water. There is a small cliff you can climb up in the deepest accessible portion of the mine, where at the top is a 15 foot sheer drop into an otherwise inaccessible part of the mine.

Mining began in the Hillsborough area around 1854, with the founding of the Albert Manufacturing Company and the construction of a plaster mill, which was the largest in Canada at the time. The gypsum in the area was considered to be some of the highest quality gypsum in the world, therefore the mill produced many types of plaster, of which gypsum was the main ingredient. This plaster would be shipped all over the world, helping to spread its reputation and encourage further exploitation of the gypsum in the area.

To produce the plaster, gypsum was first carved out of the mine walls, and loaded into carts to be hauled by horses to the main shaft of the mine, where it would then be lifted to the surface. The gypsum would also be mined in the 5 nearby quarries owned by the same company. Once the gypsum had reached the surface, it would be loaded onto the company’s private trains, which had been nicknamed “Tadd” and “Connie”. These trains would then take the gypsum to the plaster mill, where it would be ground down into powder and dried in bins over wood fired furnaces, which would burn through seven cords of wood per day, which was enough to heat a house for the entire winter.

The original plaster mill burned down in 1873, and was rebuilt, but burned down again in 1911. It was rebuilt, and continued producing plaster until 1980, when the Canadian Gypsum Company, who had bought the Albert Manufacturing Company in the same year closed the site. Nothing remains of the plaster mill today, having been demolished sometime after it closed.