To balance the risks of slope instabilities versus efficient ore recovery and financial return in oil sands mining operations, the Observational Method was applied to the final pitwall design at the Suncor North Steepbank Extension Mine. This design approach provides flexibility for Suncor to economically mine the ore body while effectively managing their risk of pitwall instability. The risk management framework adopted for the final pitwall design includes an Alert Level Offset between the Operational Pit Limit and the Infrastructure Limit. Hazard zoning outlines areas with increased risk of potential block-slides and provides guidelines to pit slope safe mining operations. Performance monitoring provides opportunities to monitor and assess the final pitwall performance, provides advance warning of a potential pitwall movement and triggers the implementation of stabilization measures to minimize the risk to personnel and equipment and the impacts on mine production. The final pitwall performance so far demonstrates that the advantages of mining and effectively managing the risk of steeper pitwall slopes provide benefits that outweigh the occasional occurrence of relatively large but operationally manageable pit slope movements.
Chen, H.J., R. Charron, D. Hepp, J. MacLean, J. Chen and S. MacNeil. 2016. “Pitwall Design and Performance at Suncor North Steepbank Extension Mine,” in GeoVancouver 2016: 69th Canadian Geotechnical Conference, Vancouver, BC, October 2-5, 2016. Canadian Geotechnical Society.