The short answer is that aggregate is stone, sand and gravel. But that’s just scratching the surface.

Aggregate is in the buildings we live and work in. It’s the roads and sidewalks we drive and walk on. It plays a vital role in the water purification process and can even be found as filler in paper and some pharmaceuticals.

When you think about it, aggregate is quite literally the foundation of our economy and society – which is a very impressive accomplishment for something as small as a grain of sand.


Aggregate is surface-mined in pits and quarries across Ontario.

Quarries are large, naturally occurring deposits of rock – like granite, limestone and sandstone – used in building materials. While the term “mining” is used to describe the process of rock extraction and generally conjures up images of tunnels stretching deep into the earth, quarries are actually located at the surface. In fact, they rarely reach a depth greater than 100 feet.

Pits are located in areas where glaciers left behind clean deposits of sand and stone. Sometimes the gravel is deeper than the groundwater table and the gravel is extracted leaving behind clean ponds and lakes.

Like petroleum deposits and other types of minerals, aggregates are only found in places where nature put them. Planning around aggregates is a challenge as operations have to be located where the resource is (unlike other types of land uses such as industrial and residential areas, which have much more flexibility).