Identifying Sources of Aggregates

Aggregates – sand, gravel, clay, earth and bedrock – feed our economic growth.


Without them, we couldn’t build the infrastructure we rely on, including roads, hospitals and power generating stations, as well as bridges, sewers, subways and houses.


There are no viable substitutes for aggregates, and they are non-renewable resources. That makes it important to know where high-quality aggregates are located.


Identifying Sources of Aggregates


The Aggregate Resources Inventory Program identifies and evaluates aggregate resources based on wellestablished technical and scientific principles. The information is published in reports and maps known as Aggregate Resources Inventory Papers. The program is run by the Ontario Geological Survey Branch of the Ministry of Northern Development and Mines.


The Aggregate Resources Inventory Program uses various methods to identify deposits based on the quality and quantity of the aggregate material available for extraction. These include:

  • existing geological maps and reports
  • available aggregate and other geological data
  • aerial photographs and remotely sensed images
  • physical examination of bedrock and surface material
  • existing pits and quarries
  • boreholes and test pits.

Most of southern Ontario – where most of our aggregate resources come from – has been mapped. Areas are re-mapped as new data becomes available, new specifications are developed, or new demands on resources emerge.


How Aggregate Resources Inventory Papers are Used


Aggregate Resources Inventory Papers are based on scientific research and on Ministry of Transportation and other technical specifications. They have been created to help inform land use planning decisions, and are used by:

  • municipalities, to identify and protect deposits of highquality aggregates, and to avoid building subdivisions or other developments on top of valuable aggregate resources
  • the aggregate industry, to locate resources for future development
  • provincial ministries, such as the Ministry of Transportation, to identify resources that can be used for building and maintaining highways and other critical infrastructure.