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Independent Environmental Monitoring Program: Dyno, Bicroft, and Madawaska Mines

In 2019, Canadian Nuclear Safety Commission (CNSC) staff completed the Independent Environmental Monitoring Program (IEMP) in the Bancroft area, Ontario, which consists of the Dyno, Madawaska, and Bicroft decommissioned mine sites. The uranium tailings managed at these sites resulted from processing low-grade uranium ore at the associated mines.

Dyno decommissioned mine site

EWL Management Ltd. is licenced by the CNSC to manage the historic Dyno decommissioned mine site, located at Farrel Lake, about 30 kilometers southwest of Bancroft, Ontario. The mill at Dyno operated between 1958 and 1960. The site has been decommissioned and consists of capped mine openings, mine tailings and a containment dam. The Dyno decommissioned mine site is under long-term monitoring and maintenance.

Madawaska decommissioned mine site

EWL Management Ltd. is licenced by the CNSC to manage the historic decommissioned Madawaska mine site located near Bancroft, Ontario. Madawaska, operated between 1957 and 1982, and decommissioned in the 1980s. In 2015 EWL began rehabilitation and maintenance work on the two tailings management areas (TMA) and some of the underground workings. The Madawaska decommissioned mine site is under long-term monitoring and maintenance.

Bicroft decommissioned mine site

Barrick Gold Corporation is licenced by the CNSC to manage the decommissioned Bicroft tailings storage site, located in Cardiff, Ontario. The Bicroft site was constructed to contain tailings from mining operations that were carried out at the nearby Bicroft mine, which operated from 1956 to 1962. As part of the decommissioning, remediation work included vegetation of tailings in 1980 and upgrading of dams in 1990s.

EWL Management Ltd. and Barrick Gold Corporation implement an environmental monitoring program for the Dyno, Madawaska and Bicroft decommissioned sites respectively, to ensure that their safety systems are operating as planned and to demonstrate that they are meeting their human and environmental safety requirements as required by the NSCA and their licences.

Independent Environmental Monitoring Program (IEMP) results from 2019, along with conclusions of available health studies for uranium processing facilities, confirm that the public and the environment in publically accessible locations in the vicinity of the Bancroft mines are protected and that there are no expected health impacts.  


Dyno, Bicroft, and Madawaska Mines


Results Table

1 The < symbol indicates that a result is below the provided laboratory analytical detection limit.

2 N/A – not available

CNSC staff  collecting sediment sample near Bancroft mine sites in 2019.

CNSC staff collecting sediment sample near Bancroft mine sites in 2019.


Under the Nuclear Safety and Control Act (NSCA), licensees of nuclear facilities are required to implement environmental monitoring programs to demonstrate that the public and the environment are protected from emissions related to the facilities’ activities. The results of these monitoring programs are submitted to the CNSC to ensure compliance within applicable guidelines and limits, as set out in regulations that oversee Canada’s nuclear industry.

The CNSC has implemented its IEMP to verify that the public and the environment around licensed nuclear facilities are protected. It is separate from, but complimentary to the CNSC’s ongoing compliance verification programs. The IEMP involves taking samples from public areas around the facilities, and measuring and analyzing the amount of radioactive and hazardous substances in those samples. CNSC staff collect the samples and send them to the CNSC’s independent laboratory for testing and analysis. The area around the Bancroft mines was sampled in 2019.

2019 results

IEMP sampling at Bancroft mines for 2019 focused on radioactive and hazardous contaminants. A site-specific sampling plan was developed based on the licensees’ environmental monitoring programs, and the CNSC’s regulatory experience with the areas around the sites. In August 2019, samples were collected in locations around the Bancroft mines and included samples of sediment and water. The concentrations of radioactive and hazardous contaminants in water samples were below screening levels and federal and provincial guidelines with the exception of two water samples.

While uranium concentrations at two water sampling locations exceeded the guideline for the protection of aquatic life (15 µg/L) issued by the Canadian Environmental Quality Guidelines (CCME), they have significantly decreased since decommissioning of Madawaska with improvement over the last two decades. These results are also slightly above the Ontario provincial drinking water standard (20 µg/L) but are well within the range of safety margins incorporated into the development of this standard (i.e., 100 fold safety factor incorporated). It should also be noted that none of the samples taken were from locations that should be used as untreated drinking water sources.

The sediment results indicate little to no environmental impact as they are either similar to those measured at the reference stations, below the screening guidelines, or marginally above the lower bounding guideline value. As this sampling campaign was completed in watersheds supporting mining, slightly elevated concentrations are to be expected as demonstrated by the number of reference stations exceeding the lower bounding values.

Furthermore, multiple environmental and human health assessments have been completed by the licensee and/or federal-provincial authorities over the last two decades and demonstrate no unreasonable risk.

Focus on health

The CNSC also conducts studies and reviews third-party research to assess the health of the public near nuclear facilities. For example, the CNSC funded a study conducted by Cancer Care Ontario to examine the risk of lung cancer mortality among miners who worked at the Bancroft, Elliot Lake, and Agnew historical mine sites from 1954 to 1996. The study concluded that in general, for all causes of death, male mine workers were healthier than the general male population, and their health was similar to that of the general male population, considering all causes of cancer death. However, uranium miners did have higher lung cancer mortality than the general male population, due to working in conditions prior to radon protection measures. As radon exposure increases, the likelihood of developing lung cancer increases. Ontario miners also had higher rates of silicosis, from exposure to ore with high silica content.

Find out more about the health of past miners, including those from Elliot Lake mines, in Ontario Uranium Miners Cohort Study Report.

CNSC staff have also reviewed the Hastings Prince Edward Public Health Unit’s Population Health Assessment, which includes Bancroft and found that cancer rates were comparable to those in other similar regions where there are no nuclear facilities.

For more general health information and data for your community, visit the following websites:


IEMP results from 2019 indicate that the public and the environment around the Bancroft mine sites are protected and there are no expected health impacts. These results are consistent with the results submitted by the EWL Management Ltd. and Barrick Gold Corporation demonstrating that the licensees’ environmental protection program protects the health and safety of people and the environment.

The CNSC is transitioning to an online reporting format for the IEMP. All IEMP information will be available on the online dashboard once this upgrade is complete. The CNSC recommends referencing online material for the most up to date and accurate data.

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