May 11 Opening Keynote – 9:00 – 10:00 am

Closing Mines Opening Minds
Terry I. Mudder, Ph. D, Managing Director, TIMES Limited

People regardless of economic or social status need and demand products produced from mining of metals and minerals to sustain their lifestyles. However, mining has periodically caused unacceptable environmental and economic impacts requiring large unexpected public capital expenditures to facilitate their remediation. Rising environmental concerns and development costs prompted the dramatic transformation into a global industry causing many companies to consolidate and abandon historical settings. The transition encountered many unexpected technical obstacles and unfamiliar social issues such as sustainability and poverty alleviation. Although not devoid of risk and impact, the global mining industry over time made meaningful strides toward improving its image through stewardship and technical advancement. Yet, the industry received minimal acceptance based on these improvements with continued criticism and opposition from a well-funded international anti-mining movement. The legacy associated with environmental damage arising from abandoned mines still plagues the modern industry’s image, with the protracted process of remediation programs at times contributing to that image. This presentation examines the ramifications of the phenomenal growth of the international mining industry in order to open minds to the possibilities for satisfying societal expectations while facilitating future demands for metals and minerals.

May 12 Gala Evening – 6:00 – 10:00 pm

Keynote
Stopping Contamination at the Source:
International and Philosophical Developments
Holly Dressel

Holly Dressel and David Suzuki’s latest book More Good News, out just this month, reviews how the EU is dealing with toxic waste management, and how these methods can be economically applied here. In this keynote speech, Holly applies wildlife conservation’s revolutionary new approach, Adaptive Management, to our dealings with toxins. She makes some radical suggestions on how the disposal of hazardous waste must be linked to recently discovered natural systems, and even shows how some very traditional approaches can make this integration work.

May 13 Closing Keynote – 12:30 – 1:15 pm

Contaminated Site Assessment and Remediation: Consideration of the American Experience
and Implications for Canada
John A. Cherry, Ph.D., P. Eng., FRSC, School of Engineering, University of Guelph

Efforts directed at contaminated site assessment and remediation, now starting to increase in Canada, began intensely in the United States in the early 1980’s driven by US federal legislation: the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, commonly known as Superfund; 1980) and the Resource Conservation and Recovery Act (RCRA; 1976). The American regulatory framework for contaminated sites continues to be driven by this legislation and billions of dollars have been spent; however, relatively few sites have attained final remediation or restoration. We (Cherry and Parker) began involvement in contaminated site assessment and remediation in the United States in the mid 1980’s, and in this presentation we examine the American experience over the last thirty years for implications most relevant to Canada.

When the CERCLA and RCRA framework was created, little was known concerning the nature and number of sites that would be encompassed. The expectation was that sites would be quickly identified, assessed, and then remediation achieved efficiently to closure; however, experience rapidly proved otherwise. Unexpectedly, the majority of tens of thousands of sites identified fit into a category that became known as DNAPL (dense non-aqueous phase liquids), which includes halogenated organic compounds mostly represented by chlorinated solvents, such as TCE , PCE, and TCA[Cmnt:GB1], creosote, coal tar, and some mixed organic industrial wastes. Importantly, groundwater contamination is commonly present at DNAPL sites, and contaminant penetration is so deep due to the high organic liquid density that excavation is not a viable remediation option. Experience in the USA in the 1980’s demonstrated DNAPL type sites are, in general, immensely more difficult to assess and remediate than sites contaminated by other chemicals, such as petroleum compounds, inorganic contaminants, and most other types of organic compounds. In the 1990’s, the futility of pump-and-treat for restoring DNAPL sites (but not for containing plumes) was fully recognized and many new and improved methods for in situ remediation of DNAPL sites were applied. However, although considerable engineering and financial resources were expended, few sites were successfully remediated and most of the new methods (e.g., air sparging, surfactant flushing, some types of bioremediation) were found ineffective for achieving restoration and were eventually rejected as viable options. In the next decade (2000-present), the continued large effort in the USA directed at site restoration combined with past experience established much understanding of, and appreciation for, site hydrogeologic complexities, in particular the difficulties and limitations to contaminant mass removal or destruction imposed by substantial contaminant mass residing in the low permeability zones (e.g., silty, clayey aquitards, and matrix blocks between fractures) common at many sites. For example, permeable zones can be successfully remediated; however, back-diffusion (i.e., reverse diffusion, often the cause of rebound in contaminant concentrations ) causes slow release of contaminants from the low permeability zones, causing recontamination of the previously cleaned permeable zones.

For Canada to benefit from the American experience concerning contaminated site assessment and remediation, and thereby minimize inappropriate and unsuccessful remediation attempts and cost ineffective activities, it will be necessary to:

1. Recognize the essential differences between site characterization and site monitoring—these should be separate goals using different methods;
2. Distinguish those remediation methods now “proven” for engineering use based on successful experience from those unproven and therefore still in research or experimental stages. Premature engineering application of unproven remediation technologies has resulted in considerable ineffectiveness and inefficiency in the United States, and has greatly impeded effective research and increased engineering failure;
3. Acknowledge the need for much longer than normal time frames to assess success of engineering endeavours in subsurface remediation (e.g., decades versus years). This is important in the context of moving towards environmental sustainability;
4. Recognize the essential value of conducting rigorous site monitoring to assess the progress and performance of remediation actions so that adjustments can be made during the course of the projects (e.g., similar to the observational method used in geotechnical engineering);
5. Recognize that site" restoration" to pristine conditions is not feasible and even remediation to the degree that the groundwater zone achieves drinking water standards is for most sites an immense challenge and therefore lesser goals that can be viewed as site" renovation" can be worthy of application. This requires addressing difficult and non-prescriptive issues concerning the environmental and/or water resource benefits and risk reduction achieved by various degrees of partial mass removal;
6. Identify conditions that make a site technically impracticable for restoration, and not engage in futile remediation attempts; in these cases, site stabilization or control options are most relevant. Good intentions cannot be a substitute for the limitations of our present-day technology and engineering infeasibility.

The American experience with contaminated site assessment and remediation has consumed huge financial resources, employed very diverse methods, and been conducted over a long time. This affords Canada exceptionally good opportunities for avoiding ineffective paths and focusing on cost-effective and environmentally appropriate options. To benefit strongly from the American experience would require a focused Canadian effort to avoid repeating mistakes. However, it is not evident that taking this path is a Canadian priority. This talk will expand on this framework, using case examples from the USA and Canada concerning successes and failures, and identify processes and principals that commonly make remediation of sites with groundwater contamination an exceptionally difficult endeavour.