Study of Current State-of-Practice on Tailings Management Technologies

by Kate Patterson, Wednesday, January 24, 2018

KCB completed a study examining and comparing dewatering technologies (e.g., thickened, paste and filtered tailings) to conventional slurry for the management of tailings (e.g., thickened, paste and filtered tailings) currently used in Canada. The strengths, limitations, and physical and environmental risks of these alternative technologies were compared to those of conventional slurry.  Strengths, limitations and physical and chemical risks were considered across the entire life cycle of tailings facilities, from design and construction through to long-term post-closure.

The study applied the following approach:

  1. Conduct a survey to identify the current state-of-practice, and projects that use alternative technologies in Canada.
  2. Evaluate the alternatives, comparing tailings management technologies and costs using the information obtained in 1., along with case study information provided by select Canadian and international mine sites.
  3. Review advantages and disadvantages of the technologies, assess applicability to Canadian mines, and identify knowledge gaps. 

The main conclusion from the study is that there is NO one-size-fits-all technology or management strategy and no technology should replace best practices in design, operations and closure of a tailings facility. This presentation will give high-level review of the study and present a snapshot of the current state-of-practice in the Canadian mining industry and key conclusions.

vgs-tac new year's Talk - Landslide Risk Reduction in guatemala for homeowners in under-privileged areas

by Lauren Hutchinson, Tuesday, January 9, 2018

This meeting is being held in the Uber Room of the Steamworks Pub next to Waterfront Station (375 Water Street).  Doors at 1730, talk begins at 1815.

BGC teamed up with two grad students to go to Guatemala and teach the local communities about rainfall induced landslides. Simple classification techniques (adding up some points to get a risk level) and mitigation options were taught to local NGOs and communities to assess the area.   A short article about the work can be found here.

Probability Approach for Ground and Structure Response to GSC 2015 Seismic Hazard Including Crustal and Subduction Earthquake Sources

by Guoxi Wu, Tuesday, November 14, 2017

This presentation will provide an overview on how to make use of crustal, in-slab, and interface subduction hazard values from the 2015 GSC Model for the 13148 grid points (10 km by 10 km) in southwestern Canada (southern BC and western Alberta). USH spectra for crustal/in-slab earthquakes and USH spectra for Cascadia subduction interface earthquake can be derived at a couple of probability levels. Structure performance assessment can then be determined separately for the two main earthquake sources at a couple of probability levels. The overall probability at a given performance level (displacement, liquefaction or others) can then be determined by adding the probabilities from each of the two individual performance hazard curves.  The overall performance (displacement, liquefaction or others) at a target probability level (e.g., 2%/50 years) is then determined from the overall combined performance hazard curve. Examples for determining seismic slope displacements from empirical equations (Bray and Travasarou 2007, Macedo et al. 2017) and for assessing site response and liquefaction using nonlinear finite element time history analyses (VERSAT, Wutec 2016) will be shown to illustrate the proposed procedure. 

The presentation slides are available here.

Advances in Dam Design - 2017 Fall Cross Canada Lecture

by Jean-Marie Konrad, Wednesday, October 25, 2017

Embankment dam performance and life span are closely related to the hydric, thermal and mechanical behaviour of materials used during its construction. The apparent simplicity of embankment dams hides complex and often poorly known behaviours resulting from thermo-hydro-mechanical coupling phenomena. Understanding the different behaviours as well as their interrelationships is of paramount importance to optimize the life cycle of these structures.

Hydro-Québec Production obtained the necessary approvals to build a 1,550-MW hydroelectric complex on the Rivière Romaine, north of the municipality of Havre-Saint-Pierre on the north shore of the St. Lawrence. The complex will consist of four hydropower generating stations with average annual output of 8.0 TWh.

Construction of the Romaine-2 development began in 2009. Romaine-2 was commissioned in 2014 and the Romaine-1 development was commissioned in 2015. Work on the Romaine-3 and Romaine-4 developments, which will be operational in 2017 and 2020, respectively is underway.

Since 2009, the NSERC/HQ industrial research chair in Life Cycle Optimization for Embankment Dams contributed to the advancement of various aspects in dam design.  Major developments for seepage induced erosion are presented.  The use of centrifuge testing for predicting deformation of Romaine 2 are discussed.  Rockfill properties are viewed from a fractal perspective.


by Ali Azizian, September 20, 2017

The 11 km long alignment of the Evergreen Line Rapid Transit (ELRT) project through Burnaby, Coquitlam and Port Moody consists of elevated and at-grade guideway sections as well as cut-and-cover and bored tunnels. Because of the high seismicity of the region, liquefiable and soft soils posed the main challenges for the design of structures. A performance-based design approach with varying levels of performance requirements were specified for the project. Several deep foundation and ground improvement solutions were used to meet the design objectives, while satisfying cost, schedule and site constraints. Foundation types included drilled shafts and driven steel pipe piles. Ground improvement solutions included Cement Deep Soil Mixing (CDSM) and driven timber piles. The presentation will provide an overview of the subsurface ground conditions along the alignment, seismic analyses (e.g. FLAC modelling), selected foundation or ground improvement types for each section, and some of the challenges faced during construction.