Design of a Monitoring Plan for a Former Uranium Mine Using Uncertainty and Feasibility Analyses. R. C. Lee, R. Robinson, M. Kennedy, and S. Swanson, Golder Associates Ltd., 940 6th Ave. SW, Calgary, Alberta, Canada; and M. Nahir, Public Works and Government Services Canada, Edmonton, Alberta, Canada
The former Rayrock uranium mine in the Northwest Territories (Canada) was remediated in 1996. Remediation involved capping of tailings piles as well as sealing of shafts and adits. Monitoring plans for the site were designed to satisfy regulatory requirements and to ensure that potential human health risks from ionizing radiation remain minimal. A high-level uncertainty analysis was conducted in conjunction with dose estimations to determine sensitivity of risks to uncertainties associated with radionuclide concentrations or radiation levels in exposure media including gamma radiation, radon, soil, water, and consumption of wild game and fish. Incremental doses associated with site-related concentrations/levels were evaluated by subtracting background (non-site related) concentrations/levels. The site is located in a remote area; therefore many forms of data collection are expensive and difficult. Feasibility of further data collection in different media was evaluated by consultations with experts using criteria such as cost, transport and equipment considerations, time of year, etc. Human health risks under current conditions at this site are minimal under any conceivable exposure scenario. Gamma radiation is the greatest source of incremental residual risk, and off-site exposures contribute little to residual risk. Recommendations for long-term monitoring focus on the exposure pathways of greatest concern, combined with the feasibility of further data collection. Changes to the plan are recommended if statistically significant upward trends in media concentrations/levels are seen over time. In general, maintenance of tailings caps and adit/shaft seals should ensure that residual risks remain minimal at this site.
Acknowledgments: E. Hornby and S. Mitchell of DIAND, B. McCallum and C. Clement of LLWRMO.
Go to . . .
1999 SRA Table of Contents
1999 SRA Author Index
Main Abstracts Menu Page
RiskWorld Home Page