Panel Report

12.1 The Midwest Site

The decommissioning and reclamation of uranium mines and their associated tailings facilities is intended to return areas disturbed by mine development to their natural state, or as close to it as possible. For the Midwest project, decommissioning proposed in the EIS includes dismantling surface buildings and their associated infrastructure; sealing shafts and underground raises; cleaning up waste; salvaging and decontaminating usable material; disposing of non-salvageable material underground; eliminating or contouring waste rock piles; installing a cover over the JEB tailings management facility; pumping at the pit site until consolidation levels are acceptable; revegetating all sites disturbed by the project, including the JEB tailings management facility; and monitoring of environmental impacts for at least five years after mining ceases.

The mining regulations administered by both the federal and provincial governments require that a site-specific conceptual decommissioning plan, which includes proposed reclamation activities, be submitted and approved before operating licences can be issued. Mining companies are encouraged to conduct decommissioning and reclamation activities as soon as possible and the conceptual plans are reviewed regularly to keep them current. When the time arrives for a mining operation to cease, government approval of a final decommissioning plan, based on existing mine conditions and the best available knowledge at that time, is required. After decommissioning has been completed, the mining company is required to monitor the site for a number of years. Only after it has been proven that decommissioning has been successful is a release granted from further requirements.

The physical condition of the Midwest mine and JEB tailings management facility after the departure of the mining company is a primary concern of the public. Many residents of northern Saskatchewan spoke about the need for local communities to be consulted on conceptual and final decommissioning plans, including periodic reviews of these plans. Local residents should also be involved in reclamation and monitoring activities. The panel considers that the Environmental Quality Committees, now established in northern Saskatchewan, provide an ideal vehicle through which to consult northern communities on decommissioning issues.

The decommission that's going to be done, is it the people, the local people that ... will be involved in the whole decommission?

E. Benoanie, Transcript of Midwest Public Hearings, Wollaston Lake, Saskatchewan, June 8, 1996, p. 9.

Other concerns expressed during the hearings include the need for decommissioning plans to address the potential rehabilitation of Mink Arm, the possible elimination of waste rock piles at the mine site, the need to treat contaminated water and the safe disposal of resultant sludge from the water treatment plant. Regarding waste rock piles, it was suggested thatmaximum use be made of disposal areas underground and at mined-out pits on the McClean Lake site.

The fate of the existing abandoned uranium mine and tailings areas situated in northern Saskatchewan was also raised as an issue by the public. It was suggested that resources be identified to clean up these sites.

12.2 The JEB Tailings Management Facility

If the JEB TMF is approved for disposal of mill tailings, the proponents propose to decommission it by covering the tailings with a cap consisting of about 20 m of sand, waste rock and till. [The Midwest Project Environmental Impact Statement, Tailings Management - Additional Information, Cogema Resources Inc., April, 1997, pp. 13-1 to 13-6.] The purposes of the cap would be to prevent plants, animals, birds and people from accidentally coming in direct contact with tailings, and to drain surfacewater away from the pit.

Once the tailings reach a predetermined level, they would be covered by two meters of sand. The water cover would then be reduced to about 1 m and, during the following winter, 2 m of clean waste rock would be placed on the ice. When the ice melts during the subsequent summer, a leachate collection system would be installed to dewater the sand layer.

Temperature and pressure transducers would be installed in the tailings and, when instrumentation has indicated that all of the ice has melted, the remainder of the pit would be filled with sufficient waste rock to create a mound over the site. It is anticipated that the weight of this mound would cause approximately 14 m of settling due to consolidation of the tailings. This consolidation process would expel porewater into the sand layer where it would be recovered by the leachate collection system and sent to the water treatment plant.

During the consolidation stage, occasional recontouring of the mound would be necessary to maintain a well-drained surface. When consolidation is complete, a final cover of till would be placed to bring the top of the mound above the artesian water level in that area. The mound would then be graded and revegetated.

Do you have some examples of other mine sites that have used the solid cap and was it effective?

G. Ross, Mayor of Pinehouse, Transcript of Supplementary Public Hearings for Midwest and Cigar Lake, La Ronge, Saskatchewan, August 26, 1997, p. 153.

At the hearings, members of the public questioned the ability of Cogema to place waste rock on top of a pit filled with semi-solid tailings. In particular, it was suggested that, over time, the rock cover might sink into the pit and the tailings, instead of consolidating, might ooze up over the edges of the pit. When asked directly for examples of other places where this approach had been successfully applied, the company's reply was evasive.

In our opinion, the method proposed for decommissioning the JEB TMF is conceptually acceptable. Theoretical indications are that capping of the pit in the manner proposed would provide for the greatest environmental security in the long term. However, experimental verification of the effectiveness of the proposed approach should be sought before deposition begins. Experiments designed to test the response of aged paste tailings to pressure should, therefore, be undertaken. If the application of pressure causes them to flow rather than to consolidate, a more acceptable method for decommissioning the pit should be developed. Until experimental evidence indicating that it can be successfully decommissioned has been provided, the JEB pit should not be licensed as a tailings management facility.

12.3 Financial Guarantees

The federal and provincial governments have introduced legislation requiring mining companies to provide financial guarantees, prior to mine start-up, that will be available to cover the costs of decommissioning activities. This financial security is intended to ensure that uranium mine and mill sites can be decommissioned at no cost to Canadian taxpayers even if a mining company is unable to meet its commitments because of financial difficulties. The amount of financial guarantee requested is based on the needs outlined in the conceptual decommissioning plan, which is subject to regular review and updating to ensure that it reflects existing site conditions.

12.4 Uranium Mining Contingency Fund

The financial guarantees for decommissioning costs outlined in Section 12.3 cover a period of, at most, a few decades after mining ceases. When contaminant concentrations have been reduced to acceptable levels, and the leakage of contaminants from tailings management areas, etc., have stabilized and are acceptable, the proponent can apply to abandon the site.

The decommissioned JEB Tailings Management Facility would be required to contain contaminants for millennia, during which time many aspects of both the biophysical and institutional environments will change. Some mechanism must be established to provide for regular investigation of the integrity of contaminant containment and the performance of mitigative measures, should they be required, in the period after institutional responsibility for the area has been transferred from the mining company back to the province.

For this reason, our report on the McArthur River Project [D.G. Lee, J.F. Archibald and R. Neal, McArthur River Uranium Mine Project, Minister of Public Works and Government and Services, 1997, p. 48.] recommended that a fund be established to provide for monitoring and any required mitigation after the responsibility for the sites is returned to the province. The Province of Saskatchewan, in its response, stated:

Recognizing its responsibility for long-term management of the site, the Province is investigating options, including a contingency fund as proposed by the Panel, for implementation of monitoring and the funding of possible mitigation, should it be required. [The Government's Position on Proposed Uranium Mining Developments in Northern Saskatchewan, McArthur River Project, Government of Saskatchewan, May 1997, p.21.]

It is recommended that Saskatchewan move as expeditiously as possible to implement this recommendation.

The value of the contingency fund should be sufficiently large to cover the full costs of long-term maintenance and monitoring of the JEB tailings management facility and the potential implementation of contingencies. Rather than establishing such a fund for each mine independently, there may be merit in considering the establishment of an industry-wide fund. Such a fund might provide better overall fiscal protection to future generations and cost the mining companies less in total. There could also be a single authority to manage and oversee the maintenance, monitoring, and mitigation activities at all mine sites.

12.5 Conclusions and Recommendations

Decommissioning, since it will take place in the future, is only described conceptually at this stage; the scrutiny and acceptance of specific details must be entrusted to the government regulatory agencies. These agencies should, however, ensure that they receive advice from local residents at each stage of the decommissioning process.

This project, and in particular the JEB tailings management facility, will require long-term monitoring and possible mitigative activities for some time in the future. Arrangements should be made to guarantee that monitoring and any required mitigation can occur without placing a financial burden on future generations.

JOINT FEDERAL-PROVINCIAL PANEL ON URANIUM MINING DEVELOPMENTS IN NORTHERN SASKATCHEWAN
-- MIDWEST PROJECT --

• Dr. Donald Lee, Chairperson
• Dr. James F. Archibald
• Dr. Richard Neal