Future outlook

Finally, as we continue to assess current operations, practice ongoing continual environmental improvement, develop and implement decommissioning plans, and work on forecasting environmental performance for new facilities, a number of wider issues will have to be addressed. In no particular order of importance, they can be summarized as follows:

Environmental effects monitoring. As documented in this report, there appears to be a shift in regulatory assessment, away from the more conventional measurements of environmental performance such as adherence to a predetermined set of chemically-based performance criteria and the effluent’s acute toxicity to fish. The esoteric nature of more wide-ranging environmental effects monitoring has been well demonstrated. What is unknown is how such analysis can (or should) be used to regulate the uranium mining and milling industry. Clearly if one examines any effluent in enough detail, one will find some measure of impact. To bring manageable scope to the process, the environmental effects monitoring requirement must be defined in terms of such things as class(es) of organisms to be studied (i.e., fish, benthos, zooplankton, phytoplankton, macrophytes and/or bacteria), sampling methodology to be

employed, the structural levels to be studied in each selected class of organism (i.e., intracellular, tissue, population and/or community level) and the end point of the work. End points could range from such things as developing a database on current performance for future reference, defining the zone of influence of the operation’s effluent, documenting sublethal toxicity impacts of effluents, or to effect a higher level of regulatory control.

Detectable change, in and by itself, is insufficient grounds for performance improvements. In Canada, there is a wide range of opinion on such matters. The debate also delves into the area of cumulative effects monitoring. Specifically, accumulative effects of a single operation over time and/or possible overlapping effects of several operations at a particular location in any given time. It is our view that these studies should focus on higher trophic levels, and deal with population-based impacts.

Sediment-based ecological assessment. Effluent systems can operate within an accepted standard of performance, yet over time, create enhanced concentrations of metallic impurities in the sediment of near-field receiving waters. The biological impact of elevated metal levels in sediment during operation and upon decommissioning is a topic which is difficult to assess.

Intuitively, it seems unlikely that the biochemical/geochemical/physical processes which lead to sediment enrichment will be completely reversed once the operation ceases. However, the long-term fate of these sediment-based metals, involving bio-mineralization, geochemical immobilization and biological/chemical cycling to and from the sediment matrix are difficult to assess. Basic research, most likely site-specific, is needed to effectively address these issues, provided a case can be made that these enriched sediments create important, long-term effects. This is a debatable point. The issue is to what extent these “research” questions should impact the regulatory licensing/de-licensing process.

Potentially incompatible environmental goals. Current Canadian engineering thinking on the best way to handle disposal of problematic waste rock and tailings involves subaqueous disposal, provided the resulting drop in oxidation rate of contaminants has net environmental benefit. Deeper water disposal can also provide contaminant isolation, depending upon the water body’s limnological characteristics. However, subaqueous waste disposal can also affect fish habitat and increase the risk of interaction between the waste material and aquatic organisms, all in the name of reducing overall impact. Some favour isolation in a sterile ecological compartment. Others favour integration into the natural environment, within the

“carrying capacity” of that environment. To this list of potential incompatible goals could be added the inherent conflict between initiatives to reduce water use and the use of performance indicators such as concentration limits and end-of-pipe toxicity criteria. A compromise between these polar positions is routinely needed to advance the licensing process.

Application point for environmental performance standards. During operations, effluents must meet chemical performance standards that represent a compromise between what is achievable, size of the negotiated “mixing zone”, cost, and environmental consequence. Upon decommissioning, the reference point and performance standard must be redefined. There is clear expectation that the environmental loadings from a facility should be less upon close-out than those accepted during operation. In Canada, surface water quality objectives have been established, typically based on such concepts as lowest observable effect concentration. The location at which the performance of the facility will be judged against either current or future surface water quality objectives can have pronounced effect on the scope of decommissioning.

For example, simple accumulations of surface deposited piles of sub-economic grades of waste rock (typically 300–500 Pg U/g in Saskatchewan) are unlikely to be compatible with surface water quality objectives for most metallic and radiological parameters, if judged at

seeps from the toe of the waste rock pile. An impervious cap over the entire pile would be required in this instance. Site-specific negotiation of the location of the performance monitoring stations is a critical component in any decommissioning plan, probably requiring some re-negotiation once actual close-out performance can be measured.

Conservatism in establishing environmental performance standards. One of the federal regulators, Environment Canada, is in the process of assessing radionuclide releases under the Canadian Environmental Protection Act (CEPA). In it’s recently published draft assessment report, Environment Canada have proposed that uranium generally, and radionuclides from uranium mines and mills specifically, be considered toxic elements with respect to “non-human biota”. As such, they would warrant additional risk assessment to determine if additional controls are necessary. The CEPA process is a structured evaluation process which initially uses “hyperconservative” analysis. As the process evolves, the layers of conservatism are meant to be moderated. We have developed a number of concerns with this methodology:

— The approach of building conservatism upon conservatism in developing criteria puts the industry in a defensive position. One can well imagine how this leads to ever-lower criteria and ever-evolving research programmes;

— It is far from clear what we should be studying and what the criteria should be based on - which trophic level, and at what biological organization level (cellular, individual or population); and

— By starting with ultra-conservatism, one can easily be convinced to retain multiple margins of safety, following the “precautionary principle” promoted by some.

The approach being taken to assess radionuclides is being used elsewhere. In 1997, the Canadian Water Quality Guideline to protect freshwater life from arsenic was lowered from 50 to 5 Pg/L. Arsenic toxicity data were found for 21 species of fish, 14 species of invertebrates and 14 species of plants. The most sensitive organism tested was described in a 1980 study of phytoplankton which showed 14-d EC-50 (growth) values of 0.05–30.76 mg/L for As (V). EC-50 refers to the concentration which produced 50% of the control response, as measured by chlorophyll-a concentration. The lower bound value was multiplied by a safety factor of 0.1, generating the new objective of 5 Pg/L. This is likely too conservative for most applications, yet generates an onus to prove that this factor of safety is not needed, rather than an onus to prove that this level of conservatism is in fact needed.

Balanced regulation of non-radiological parameters. In many countries, Canada included, specialized regulatory agencies, or departments of more general environmental agencies are established to oversee nuclear facilities. The required expertise in these matters formed the basis for this regulatory specialization, and is both a strength of the system and a potential weakness in regulating the non-radiological aspects of the operation. For example, it is now quite apparent that arsenic and nickel control rather than uranium and radium control will be the main driver in decommissioning planning for the Key Lake Operation. It is important that the level of control afforded nickel at Key Lake is compatible with that applied to a nickel mine elsewhere in the country. The use of 10,000 year modelling by nuclear regulators versus simpler performance criteria in conventional mining is a good example of different approaches to a common issue.

Impact assessment of decommissioning works. Experience has shown that the process of disturbing identified problem areas in a reclamation programme (excavation, recontouring) can have significant to mid-term impacts on environmental performance. These short-term negatives must be weighed against potential longer-short-term benefits.

Forward-looking regulatory approval process. Canada has produced an effective, thorough environmental assessment and licensing process for uranium developments. As time goes on, there is undoubtedly merit in judging modifications to a project against original predictions.

However, there must be room to evolve within this regulatory environment in an efficient manner. Only significant modifications should warrant detailed examination and comparison to past assessment/licensing decisions to generate a time-efficient regulatory process.

As we look into the future, we expect that we will eventually develop consensus on the ecological assessments for major contaminants of concerns like arsenic, nickel, Ra-226 and uranium. We will also complete study on the next tier of contaminants of concern, which currently include molybdenum and selenium. Finally, the focus will likely shift to the impact of relatively benign constituents of effluent, specifically, the principle components of total dissolved solids loading. Mill effluents are at, or close to, being saturated gypsum solutions.

Total dissolved solids levels are typically about 3000 mg/L with the major ions being SO4 and Ca along with some Na, Mg, K and Cl in that order. We expect to eventually be asked to study this impact on the aquatic environment, as a precursor to discussions on the pros and cons and technical feasibility of lower TDS levels.

One comes to the conclusion that any enterprise, if studied in sufficient detail, will demonstrate some level of impact identification. In dealing with these issues, the question correctly becomes one of balancing the costs of studies and the costs and benefits of potential solutions against the relative degree of environmental risk. What seems lacking at this point is an effective cost-benefit methodology.

There is much left to study and undoubtedly we are further along the path of sustainable mine development as a result of these efforts.

REFERENCES

[1] CAMECO CORPORATION, Effects of Nickel on the McDonald Lake Drainage Basin, Phase II – Proposed Nickel Discharge Limits, (1993).

[2] TERRESTRIAL & AQUATIC ENVIRONMENTAL MANAGERS Ltd., Outlet Creek Aquatic Baseline and McDonald Lake Basin Operational Impact Assessment, (1996).

[3] CONOR PACIFIC ENVIRONMENTAL TECHNOLOGIES Inc., Additional Impact Assessment of Elevated Nickel Concentrations in the McDonald Lake Drainage Basin (1998).

[4] PYLE, GREGORY G., The Toxicity and Bioavailability of Nickel and Molybdenum to Standard Toxicity–Test Fish Species and Fish Species Found in Northern Canadian Lakes. University of Saskatchewan Department of Biology Ph.D. Thesis, (2000).

[5] CONOR PACIFIC ENVIRONMENTAL TECHNOLOGIES Inc., McArthur River Pre-Milling Baseline for the Key Lake Study Area, 1998/1999, (2000).

[6] CONOR PACIFIC ENVIRONMENTAL TECHNOLOGIES Inc., Three Year Non-Fatal Fish Disease Monitoring Programme for the Key Lake Project Area, (2000).

[7] CONOR PACIFIC ENVIRONMENTAL TECHNOLOGIES Inc., Raven Lake Study Programme: Pre-Sewage Removal Baseline, (2000).

[8] HOLBIRD, SCOTT (CAMECO Key Lake RO Supervisor), Overview of RO Plant Operation and Experience, (1999).

[9] CONOR PACIFIC ENVIRONMENTAL TECHNOLOGIES Inc., Key Lake State of the Environment Report Assessment Period 1993–1998, (2000).

Study on the technology for the development of macroporous resin