Publication information

Geological Survey of Canada
Open File 7992

Groundwater chemistry of uranium-thorium-rare earth element deposits, Bancroft Area, Ontario 

Desbarats, A.J. and Percival, J.B.

© Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources, 2016

doi:10.4095/297779

Publications in this series have not been edited; they are released as submitted by the author.

View the licence agreement at http://data.gc.ca/eng/open-government-licence-canada

Recommended citation

Desbarats, A.J. and Percival, J.B., 2016. Groundwater chemistry of uranium-thorium-rare earth element deposits, Bancroft Area, Ontario; Geological Survey of Canada, Open File 7992, 1 .zip file. doi:10.4095/297779  

Contents

Small, low-grade, granite-hosted Uranium-Thorium-Rare Earth Element (REE) deposits are found throughout the Grenville geological province in Ontario, Québec and Labrador. Renewed exploration for this class of deposit has raised concerns about potential impacts to groundwater quality from mining activities. In order to inform public debate, government policy, and regulatory decision making, NRCan scientists conducted a retrospective investigation of groundwater quality at historical mining sites in the Bancroft area of Ontario, focusing on metals and radionuclides that may exceed Health Canada regulatory limits for drinking water. Groundwater samples were obtained from flooded mine shafts, flowing adits, and diamond drill holes. Results of this study show that uranium is highly mobile in shallow groundwater systems and may be present at high concentrations in mine drainage. The Health Canada (2014) Maximum Acceptable Concentration (MAC) was exceeded in approximately 70% of samples. In groundwater from similar but unmineralized bedrock, the MAC for uranium was exceeded in only 5% of cases. Natural attenuation processes are not always effective in reducing uranium loading in discharge to downstream surface waters. Mine waters exhibiting uranium concentrations less than the MAC are unlikely to exhibit radium-226 and lead-210 radionuclide activities in excess of their respective regulatory limits. Thorium and REE are not very mobile in the mine water environment and occur at concentrations within the range of natural background values.

Directory structure

Readme.rtf

of_7992.pdf

of_7992_Bancroft-all.xlsx
This Microsoft Excel® file contains the collated data set including spatial coordinates of sample locations, field parameters and groundwater geochemical data. 

of_7992_Bancroft-2011.xlsx
This Microsoft Excel® file contains the geochemical analyses and laboratory QA/QC results for groundwater samples collected in 2011.

of_7992_Bancroft-2012.xlsx
This Microsoft Excel® file contains the geochemical analyses and laboratory QA/QC results for groundwater samples collected in 2012.
of_7992_Bancroft-2013.xlsx
This Microsoft Excel® file contains the geochemical analyses and laboratory QA/QC results for groundwater samples collected in 2013.

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Author contact information

Alexandre.Desbarats@canada.ca
Alexandre Desbarats
Geological Survey of Canada
601 Booth Street
Ottawa, Ontario
Canada
K1A 0E8

Availability information

This publication is available for free download through GEOSCAN (http://geoscan.nrcan.gc.ca/).