CH18 Environment – Tailings, mine dumps – Port Hope Ontario

In Port Hope, Canada, several known sites containing low-level radioactive waste from the historical refining of radium and uranium dating back to the 1930s, produced anomalies on a 1976 airborne gamma ray spectrometric survey1 flown by the Geological Survey of Canada (see figure below). The waste material contains radium226, uranium and arsenic. The airborne survey provided focus for subsequent, more detailed surveys using vehicle-borne and handheld detectors.GamX CH18 Port Hope Ontario GSC 1976 Airborne Gamma Ray Survey eU



Following some initial waste clean-up and consolidation, a second airborne gamma ray spectrometric survey2 was flown by Fugro Airborne Surveys in 2001 (Figure 2). This survey showed reduced or return-to-background surface radiation levels at some sites, and highlighted remaining areas of concern (compare the figures above and below).

GamX CH18 Port Hope Fugro 2001 Airborne Gamma Ray Survey eU


A 10-year, 1.28 billion dollar clean-up is underway3, to relocate approximately 1.2 million cubic meters of radioactive waste to an engineered above ground mound where the waste can be contained and monitored for hundreds of years.  The site will eventually be used for passive recreation such as walking trails and lookouts, with background radiation levels at surface. On completion of the project, a final airborne survey is expected to help confirm effectiveness of the clean-up.


This example illustrates the utility of the airborne surveys to identify and accurately map low-level anthropogenic radioactivity on the surface, to background radioactivity levels, thereby guiding mitigation efforts when deemed necessary.




  1. Airborne gamma ray spectrometer survey of the Port Hope Area, 1976. Geological Survey of Canada, Ottawa.
  2. Airborne survey of the Port Granby – Port Hope area, 2001. Fugro Airborne Surveys.
  3. Port Hope Area Initiative