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Profile

Rayrock is an abandoned uranium mine approximately 169 kilometres northwest of Yellowknife and 74 kilometres northwest of the town of Behchoko (Rae).  The ore body was mined between June 1957 and July 1959.  The mine and its associated mill and camp site existed in an abandoned state for over twenty years after the mine closed.  In 1987, the buildings of the mill and camp site were demolished and in 1996 remediation of the site was completed to prevent further migration of contaminants into the surrounding environment and to reduce potential health risks to people visiting the site.  The project was managed by Public Works and Government Services Canada on behalf of Indian and Northern Affairs Canada.  Currently the project is being managed by the Contaminants and Remediation Directorate of Indian and Northern Affairs Canada.

Overview

In the years following abandonment, several site assessments were undertaken to evaluate the extent of contamination and the environmental impacts.  Rehabilitation of the Rayrock mine site began in 1996.  Remediation activities included sealing mine openings, removing radioactive material from the dump, disposing of this contaminated material on the tailings, and capping the tailings piles with a layer of silty clay, followed by revegetation.  The objective of the remediation program was to contain contaminants at the site and thereby limit exposures to persons who may frequent the area.

Experience

Public Works and Government Services Canada retained Rescan in 2001 to undertake an annual post-rehabilitation monitoring program.  A comprehensive review of the long-term monitoring program was subsequently undertaken by Rescan site assessment specialists in the first quarter of 2002 to evaluate the results of the program and develop a revised long-term monitoring program manual for the site.  The revised program called for annual monitoring of gamma radiation and radon gas, surface and groundwater monitoring as well as visual inspection of the mine area, rehabilitated tailings and waste dump areas.  Annual site assessments (2002 to 2008) have been conducted by Rescan to ensure the remediation measures continue to effectively limit contaminant release into the environment.  Based on site assessments Rescan has conducted further repair to the tailings caps and expanded areas of gamma radiation surveys in response to the objectives of the Contaminants and Remediation Directorate of Indian and Northern Affairs Canada.