Cumulative Effects Assessment Practitioners' Guide

Northern Saskatchewan Uranium Mines: Case Study Highlights

VECs: Air quality, groundwater, surface water, vegetation, wildlife, human health

Issues: Exposure to radiation

Approaches: Network diagrams

Lessons learned: Acknowledgement of poor understanding of cause-effect relationships, need for long-term monitoring supported by many stakeholders


A joint federal-provincial panel was formed in 1991 to review and assess the environmental effects of five uranium mining proposals in Northern Saskatchewan. Two additional proposals were added to its mandate in 1992 and 1994. An independent team of consultants were hired to help the panel foresee significant impacts that may arise from interactions among the projects (Ecologistic 1992), an initiative that took a more regional view than the project specific impacts examined in the three Environmental Impact Statements (EISs) originally submitted.

In its January, 1993 report (Lee et al. 1993a), the panel recommended approval for exploration at one mine (McArthur River). In its October, 1993 report (Lee et al. 1993b), the panel recommended: 1) conditional approval for an extension of an existing operation (Dominique-Janine, at the Cluff Lake operation); 2) a conditional approval of a new mine (McClean Lake), with one of the conditions being a five-year delay; 3) and rejection of a third proposal (Midwest Joint Venture) because the risks to the environment and human health were judged to outweigh the benefits. In its February, 1997 report (Lee et al. 1997a), the panel recommended conditional approval for the McArthur River mining proposal. Later in 1997 (Lee et al. 1997b), the panel recommended conditional approval for the Cigar Lake and Midwest proposals.

The McArthur River mining proposal uses a mill and tailings disposal site at an existing operation at Key Lake. The Cigar Lake and Midwest proposals will share a milling and tailings disposal site at McClean Lake. The custom milling and tailings proposals, whereby five mines share two mills and tailings disposal areas, are recognized to offer significant benefit by reducing the amount of land disturbance in northern Saskatchewan.

Assessment Approach

The study area for the assessment was half of the province. The principal cumulative effects issues identified were: transfer of radionuclides and stable heavy metals through the pathways of surface water, groundwater and vegetation; effects due to ingestion or inhalation by humans, wildlife and fish; and various socio-economic effects such as effects on public health and native lifestyles.

An Environmental Transfer Pathway model (i.e., network diagram) was used to assess cumulative effects (these diagrams convey some of the function of Pathway Diagrams as used in Impact Models). The model defined physical and chemical linkages or pathways that connected impacts to effects, and zones of influence that identified the areal extent of those linkages. The diagrams were useful as aids to illustrate complex linkages. Results were tabulated for various VECs, which included an assessment of the significance of effects (by areal extent, frequency and duration, and certainty in prediction) and the potential for significant cumulative effects. An effect was considered significant if it was regional in extent, long-term and if there was a degree of uncertainty in the prediction.

Recommendations by the panel for mitigation of cumulative effects included the monitoring of key biological components and processes, epidemiological studies on all Saskatchewan uranium miners (past, present and future), use of this data to predict future risks and mitigation measures, long-term monitoring of worker exposure to airborne dust and gas contaminants, phasing of proposals, and education and training of residents to ensure long-term employment and avoidance of a "boom-bust" cycle. Monitoring plans for each project were mandatory to fulfill the proponent's licensing requirements, which are reviewed annually by the Canadian Atomic Energy Control Board and Saskatchewan Environment.

The federal and provincial governments are cooperating on a cumulative effects monitoring program, and a site-specific and regional cumulative effects model has been developed

Lessons Learned

  • The assessment attempted to clearly define an organizational and jurisdictional framework in which CEA could be conducted, responsibilities of the stakeholders plainly stated, and collaboration encouraged for the collection of data.
  • The specialist's study identified various problems typically encountered in CEA, such as "limited knowledge about cause and effect relationships, jurisdictional conflicts and confusion, poor coordination and cooperation among institutions, and conflicting societal values and expectations of the environmental assessment process and the varied status of environmental laws and regulations enforced and implemented by various levels of government".