Aggregate is a construction product made from sand and gravel or by crushing bedrock. It is fundamentally important to modern society as it is used to construct:

  • Roads and highways
  • Buildings ranging from homes to hospitals
  • Infrastructure that protects and serves the public, such as dams and airports

Ontario Geological Survey

The role of the Ontario Geological Survey is to identify areas of potential sources of aggregate in the province by:

  • Outlining areas of sand and gravel, and bedrock at or near the surface of the Earth.
  • Assessing the potential quality and quantity of the aggregate sources.
  • Producing maps and reports containing this information; these are referred to as Aggregate Resource Inventory Papers.
  • Recommending areas with high aggregate potential for protection in municipal land-use plans.


Aggregate, whether it is produced from surficial materials (sand and gravel) or bedrock, is a fixed-location, relatively low-value, bulk construction material that generally is used close to where it is produced. Land containing aggregate, particularly around cities, is often under pressure to be used for a variety of competing uses. If not protected for future resource development, the province’s supply of aggregate will dwindle.

By identifying aggregate resources that can be protected and used before the land is built upon, the Ontario Geological Survey helps ensure a continued supply of close-to-market building materials. This in turn lowers the cost of aggregate; an important consideration as 60% of the aggregate produced is used in public infrastructure projects and paid for with taxpayer dollars.