Ministry of Mines
Home » Search GeologyOntario » Ontario Assessment File Database description
We are committed to providing accessible customer service. If you need accessible formats or communications supports, please contact us.
The Ontario Assessment File Database (OAFD) comprises geotechnical reports and maps from over 70 years of geological exploration, by mining companies and prospectors, on Crown Land in the Province of Ontario. Since the 1940s, the Government of Ontario has required individuals who perform exploration on claims staked over Crown Land to submit the details of that work, including reports, maps and results, in exchange for the right to retain the claim. Reports contain geoscience data such as airborne geophysics, ground geophysics, geology, geochemistry, diamond drilling and many other geotechnical work types. The OAFD description is useful to exploration companies and individual prospectors in their efforts to locate new deposits within the province of Ontario by allowing effective access to past exploration activity reports.
The GeologyOntario application provides access to the OAFD through a quick and effective search engine. Searches can be done by using simple keywords or by using focused searches using Boolean operators. Keywords can include the OAFD file number, 2-dot number (2.#####), geographic area (NTS, township), claim holder, performed for, and author. An overview and description of the search types including Boolean can be found on the Help page.
The OAFD description can be downloaded from the GeologyOntario application. It is available as a packaged product provided in 2 formats: 1) a relational database and 2) a geospatial GIS (ESRI® shapefile) format. The OAFD captures details on location, property ownership, type of work done and commodities sought for each Assessment File. Spatial data is collected for each file in the form of polygons indicating property outlines that are digitized and displayed on a provincial base map.
The Assessment Work data found on our OGSEarth page can also be viewed in Keyhole Markup Language (KML) format using Google Earth Opens in a new windos or other applications compatible with KML.
Further database information and metadata are found within the download package.