KCB completed a report for the Mine Environment Neutral Drainage (MEND) program in 2015 in which we examined and compared alternatives to conventional slurry for tailings management (e.g., thickened, paste and filtered tailings). The MEND program was started in 1989 with a mandate to develop new technologies for preventing and controlling acidic drainage from mining. It is governed by a committee of representatives from the mining industry, non-governmental organizations, and Canadian provincial and federal governments.
This study included a review of the current use of tailings dewatering technologies in Canada and in other jurisdictions with similar climatic conditions. The strengths, limitations, and physical, chemical and environmental risks of alternative technologies were compared to those of conventional slurry across the life cycle of tailings facilities.
We applied the following approach:
- Conducted a survey to identify the current state-of-practice and projects that use alternative technologies in Canada.
- Evaluated the alternatives by comparing the tailings management technologies and costs identified with case study information from Canadian and international mine sites.
- Reviewed the advantages and disadvantages of each technology, assessed their applicability to Canadian mines, and identified knowledge gaps.
KCB looked at the technologies used to dewater tailings, how tailings are placed and managed, and evaluated their relative efficacy in addressing physical and geochemical risks. We also examined the strengths and limitations of tailings dewatering technologies and deposition practices, and how these choices apply to specific sites and mining projects compared to conventional practices.
The MEND report guides mine owners and operators on which technologies and strategies should be considered for a project, taking into account the site conditions, project constraints (e.g. production schedules), the physical and geochemical properties of tailings (such as grain size and plasticity) and the potential for metal leaching and acid rock drainage. In the report, we summarized the knowledge gaps and made recommendations for further work related to four categories: geochemistry, costs, closure, and other technologies.
Two of the authors of the report, Kate Patterson, M.Eng., P.Eng. and Lindsay Robertson, M.Sc., P.Geo., both Associates at KCB, recently presented a webinar about the study. Kate specializes in water resources engineering and tailings management and has worked on some of the largest mining operations in the world. Lindsay specializes in geochemistry and environmental soil sciences and has experience with the assessment of the environmental impacts of mining. In the webinar, Kate and Lindsay summarize the study approach and key lessons learned.