Panel Report

Northerners are adamant that activities such as mining not interfere with their sustainable use of the land. It is, therefore, important to assess the impacts of mining on the local as well as the regional environment, looking both at the effects observed during the operational phase of the mine as well as any residual effects after decommissioning.

...if we do not use the land properly, we do not have a future.

G. Ross, Mayor of Pinehouse, Transcript of Cigar Lake and McArthur River Public Hearings, Pinehouse, Saskatchewan, October 7, 1996, p. 129.

The Cigar Lake mine would impact the environment in many ways. First, from the mine itself would come minewater discharge and aerial emissions of dust and gases. Secondly, the disposal of mine waste rock, with its potential to be acid-generating, would have an impact on the surrounding environment. Thirdly, milling at the McClean Lake mill and deposition of tailings in the JEB TMF would contribute to the impacts at the McClean Lake site.

The effects of mill effluent are not considered independently in this report; the reader is referred to a discussion on the monitoring of mill and minewater effluent from the McClean Lake mine in our earlier 1993 report, [D.G. Lee, J.F. Archibald, J. Dantouze, R. Neal and A. Yassi, Dominique-Janine Extension, McClean Lake Project, and Midwest Joint Venture, Supply and Services Canada, October, 1993, Section 5.3.] and some additional comments in our 1997 report on the Midwest mine. [D.G. Lee, J.F. Archibald, and R. Neal, Midwest Uranium Mine Project, Supply and Services Canada, 1997, Section 10.1.] As well, these effects are included in an assessment of the cumulative effects of the Cigar Lake mine and the other uranium mines in the eastern region of the Athabasca Basin (see Section 9.4).

9.1 Monitoring of Aerial Emissions and Minewater Discharge

Predictions presented in the EIS indicate that the atmospheric emissions from the mine and ore preparation facility, and the discharge of treated minewater effluent would have little impact on the environment surrounding Cigar Lake. This is so because of the way in which the mine has been designed, and the fact that the ore will be milled, and the tailings disposed of, at McClean Lake.

9.1.1 Aerial Emissions

The Cigar Lake Mining Corporation predicts that aerial emissions would be low and would likely have very minor impacts. [The Cigar Lake Project Environmental Impact Statement, Main Document, Cigar Lake Mining Corporation, July, 1995, Section 5.3.1.] We agree with this assessment. The emissions from the mine ventilation system and the ore preparation facility are predicted to increase the radon concentration by an average of approximately 1 Bq/m³ within a 2 km radius of the mine, compared to an average background concentration of 6 Bq/m³. These emissions would be low compared to those of most other uranium mines because the use of ground freezing at Cigar Lake would limit the movement of radon into the mine. In addition, the ore stream would be contained, from extraction to transportation. For similar reasons, the predictions for emissions of other long-lived radioactive dusts are also low.

The concentrations of total suspended particulates (TSP) from the mining operation are predicted to be very low because of the wet process proposed for ore preparation. The predominant source of TSP would be road dust which is not radioactive and is largely chemically inert.

Finally, the production of oxides of sulphur and nitrogen from the exhaust gases of mine and surface equipment would be low because much of the equipment is electrically operated.

The proposed monitoring program for air, soil, and vegetation (lichens, blueberries, alder, and willow) is adequate and the locations of the various sampling stations are appropriate. However, the monitoring program should be extended to include a terrestrial vertebrate to ensure that transfers along the food chain, as predicted by pathways analysis (see Section 9.4), can be assessed.

9.1.2 Impacts of Minewater Discharge

The proposed use of freezing and grouting would significantly reduce the amount of water entering the mine, and some of the water that does enter the mine would be used in the preparation of the ore slurry. The volume of treated minewater effluent, predicted to average approximately 684 m³/day, [The Cigar Lake Project Environmental Impact Statement, Additional Information, Cigar Lake Mining Corporation, March, 1996, p. 1-52.] is consequently much lower than at any of the present Saskatchewan uranium mines.

The treated effluent would also be considerably lower in dissolved salts and other contaminants compared to the effluent released from milling operations. It would be released into a muskeg which first drains into Aline Lake and, eventually, into Waterbury Lake. Based on hydrological measurements during test mining between 1986 and 1992, there would be a ninefold dilution, at least, of the effluent at the exit of Aline Lake. The water would then drain along Aline Creek for about 1500 m before exiting into Seru Bay of Waterbury Lake. It is predicted that the concentrations of key contaminants in Aline Lake would only reach 10 to 50 per cent of the Saskatchewan Surface Water Quality Objectives, even with a worst-case assumption showing no contaminants removed in the muskeg area. [The Cigar Lake Project Environmental Impact Statement, Additional Information, Cigar Lake Mining Corporation, March, 1996, Section 1.3.2.]

Waterbury Lake supports a productive sports fishing operation that is an important resource to protect. However, it appears that the risk to fish and other aquatic organisms is acceptable, given the low volume of effluent to be released.

In general, the aquatic monitoring program proposed to assess the impacts of treated minewater discharge is acceptable. There remains a need to identify appropriate control sites where no mine-related impacts are predicted. In particular, a small lake to match Aline Lake should be identified. In addition, the method of sampling sediments could be improved (see Section 9.4).

9.2 Monitoring of Waste Rock

As described in Chapter 6, mining would produce 2.6 million tonnes of potentially acid-generating waste rock that would require appropriate disposal. There would appear to be at least two viable disposal sites: the mined-out Sue C pit at McClean Lake; and Lake 497, located on the Thin River drainage system approximately 6 km west of Cigar Lake. The monitoring requirements for these two options would obviously be very different.

In some respects, monitoring for the Sue C pit option would be similar to the monitoring required for tailings management facilities. There would be a need to monitor and understand the movement of groundwater through and around the pit, to measure the solubility of contaminants in the waste rock under the conditions in the pit, and to monitor the spread of contaminants from the pit via the groundwater into nearby surface waters. In addition, if the remainder of the Sue C pit above the waste rock were allowed to fill with water, the levels of contaminants in the pit water would also require monitoring.

Monitoring for the Lake 497 option would require a standard monitoring program for the surface waters impacted by mining activities, similar to that which the proponent has described for assessing the impacts of minewater discharge. Thus, water chemistry, the rate of water flow, sediment chemistry, aquatic macrophytes, benthic invertebrates, and fish would require monitoring in Lake 497 and at one or more points downstream. In addition, a suitable control lake should be identified as a reference point.

It would be the responsibility of the regulatory agencies to enforce an appropriate monitoring program for whichever site is selected for the disposal of waste rock. The main outstanding issue is how long monitoring should continue in the postdecommissioning period. If the waste rock is placed in Lake 497, there will be a need to check periodically to see if the rock is covered with sufficient water to prevent oxidation and the production of acid. The water chemistry of the lake should also be measured during these checks. This form of monitoring should continue indefinitely because the potential for this type of rock to produce acid does not decrease with time. If deposition is in the Sue C pit, long-term monitoring for contaminants in the groundwater downstream from the pit would also be required. For either option selected, mitigation possibilities for the most likely causes of unfavourable environmental impacts should be identified in advance.

9.3 Monitoring of the JEB Tailings Management Facility

As described in Section 7.2, the proposed method for disposal of tailings from the McClean Lake mill would involve placing them in the JEB pit, where it is predicted they would consolidate until their permeability becomes much less than that of the surrounding rock. If this were to occur, ground water would flow preferentially around the tailings decreasing the risk of contamination to surrounding surface waters.

However, evidence was presented which suggests that the source terms used in arriving at these predictions may not have been conservative. [R. Swider, The Cigar Lake and Midwest Projects Tailings Disposal, Richard C. Swider Consulting Engineers Limited, Toronto, Ontario, August 21, 1997.]

This concept, therefore, needs to be confirmed by detailed field observations during the operating, decommissioning and postdecommissioning phases, if this facility is approved. These observations are prescribed by the licensing procedure. Thus, the construction licence for the JEB Tailings Management Facility required the operator to measure the characteristics, including the permeability, of the overburden and various layers of rock forming the pit wall. Similarly, the operating licence would prescribe how the tailings, the groundwater, the water in the pond overlying the tailings, and the water collected in the drainage sump beneath the tailings would be monitored. Subsequently, the licence for the decommissioning phase would require the monitoring of the final consolidation of the tailings, the settlement of the cover, and restoration of the groundwater. The proposed monitoring program for the various phases has been described by the proponent [The Cigar Lake Project Environmental Impact Statement, Addendum, Cigar Lake Mining Corporation, September, 1996, Section 3.7 and Section 8.] and it would be the responsibility of the regulatory agencies to enforce an appropriate monitoring program for the facility.

If the tailings management facility is approved, one outstanding issue to be addressed is how long it should be monitored after the pumps are shut off and the water table restored. Local people deserve to know that contaminants are being contained within the facility and to be assured that, in the long term, any unacceptable leakage of contaminants would be mitigated before organisms were harmed. Since modelling predicts that it would take about 8000 to 9000 years for the maximum concentration of contaminants to reach the nearest water body, Fox Lake, [The Cigar Lake Project Environmental Impact Statement, Tailings Management -- Additional Information, Cigar Lake Mining Corporation, April, 1997, Section 11.3.] it would be necessary to continue monitoring at some level for the foreseeable future. The panel believes, therefore, that the only way in which the people of the region can be assured of environmental protection is to monitor the facility indefinitely; it is not possible to guarantee a walk-away, zero-risk storage facility. The details of the monitoring program, possible maintenance of the facility, and ability to respond to any contingencies will require careful thought and appropriate funding.

If properly constructed, tailings management facilities should not require expensive maintenance and there should be little likelihood of incurring large costs for mitigating future problems. Nevertheless, it is apparent that the environmental risks associated with uranium tailings disposal facilities will require periodic monitoring for as long as can be foreseen. The idea that it might be possible in a few years to walk away from a site that contains millions of tonnes of material that is both toxic and radioactive is not realistic. Instead, provisions should be made for continuous monitoring of all of the existing Saskatchewan tailings disposal areas, as well as the underground excavations that will eventually be filled. The word "decommissioned", when used in connection with uranium tailings management facilities, means that the site should be left in a condition that will require only infrequent monitoring and minimal maintenance; it does not mean that the site can be abandoned and forgotten about.

Decommissioning costs would be covered by financial guarantees from the mining companies as legislated by the federal and provincial governments. However, postdecommissioning costs for the perpetual maintenance and monitoring of tailings management facilities, as well as costs of any contingencies which might arise, should be derived from a dedicated permanent fund controlled by an authority appointed to oversee these activities. The fund might be called the Uranium Mining Contingency Fund (see Section 10.4).

9.4 Pathways Modelling and Cumulative Effects

The proponent has used pathways analysis to predict the movement of contaminants in the environment and the dose to biota and human receptors at different locations. By necessity, the models used in these analyses are complex because they integrate contaminant inputs from a variety of sources, and follow their movement along different pathways to human receptors. The purpose of this type of modelling is to assess the magnitude of risk to humans, not to produce exact predictions. The latter is not possible because contaminant concentrations vary in both time and space, and because animals of any one species do not all have identical diets, resulting in a transfer of contaminants that is not constant.

Modelling reported in the EIS predicts that semi-aquatic animals, such as moose, beaver and scaup, would receive the highest radiation doses because they receive both aquatic and atmospheric impacts. [The Cigar Lake Project Environmental Impact Statement, Supporting Document No. 2, Cigar Lake Mining Corporation, July, 1995, Section 6.7.] Even so, the highest predicted dose, 32 µGy/hour (to a scaup residing on Aline Creek), is still less than the 1 per cent Response Threshold for the most sensitive life stages of a mammal (125 µGy/hour). The average dose for most organisms was 1.25 µGy/hour or less. It was concluded that there would be no harmful radiological effects to animals at the Cigar Lake site.

The proponent used pathways analysis to estimate the radiological dose to humans living close to the mine site both during operations and after decommissioning. [The Cigar Lake Project Environmental Impact Statement, Supporting Document No. 2, Cigar Lake Mining Corporation, July, 1995, Sections 6.8 and 7.3.] During the operational period, Jackson's Lodge on Waterbury Lake, located about 5 km east of the mine, was chosen as a suitable location for a hypothetical human population. It was assumed that persons lived at the lodge for four months during the summer (similar to the current pattern of use) and obtained all of their food and water from the immediate area during their period of residence. The model predicted a peak exposure of 0.108 mSv/yr, which occurred towards the end of the operational period. This compares favourably to the current ICRP guideline of 1 mSv/yr.

For the period after decommissioning, the hypothetical human population was assumed to live in the permanent residence at the mine throughout the year and subsist entirely on local country foods and local water. The residence would be located approximately 3.5 km northeast of the mine site. In this case, the model predicted peak exposure rates immediately after closure with dose rates at least 100 times less than the value reported for the Jackson Lodge population.

The cumulative effects of all the mines in the eastern part of the Athabasca Basin were assessed for residents of Wollaston Lake, Hatchet Lake and Black Lake. The estimated doses were well below regulatory limits and approximately 1 per cent or less of the natural background dose. The Atomic Energy Control Board made an independent modelling assessment of dose estimates and obtained comparable values. [L. Chamney, Atomic Energy Control Board, Regulatory Review of the Radiological Impact of Cigar Lake and McArthur River Uranium Projects, Submission to the McArthur River and Cigar Lake Public Hearings, Saskatoon, Saskatchewan, September 16, 1996.]

9.5 Conclusions and Recommendations

On the basis of available evidence, it can be concluded that the potential radiological impact of the Cigar Lake mine on the biota and humans, now and in the future, would be acceptably low.

Monitoring will be required over a much longer time span than suggested in the Environmental Impact Statement. The JEB Tailings Management Facility, if it is approved, and the mine waste rock site, when it has been selected, will require perpetual monitoring.