Construction of a deep-sea wharf in the Canadian arctic

The port facility in Deception Bay, located in the remote Nunavik region of the Canadian Arctic, has been operated by Xstrata Nickel for their Raglan Mine since 1998. The port was originally built in 1971 to service a former asbestos mining operation. In 2003, after 33 years of service, the wharf was identified as in need of a comprehensive repair program in order to maintain it in a safe and operational condition. However, the extent of deterioration was not apparent until a detailed inspection in the summer of 2005 revealed that the structure was suffering from an aggressive bacterial attack of the steel sheet piles and a localized collapse in the near term was a strong possibility. Emergency repair measures were designed and initiated and the planning for a complete wharf rehabilitation program implemented. Construction of a complete replacement of the wharf structure was scheduled for the summer of 2007. During the project planning phase, it became apparent that due to the global demand for nickel combined with the limited nickel concentrate storage capacity at Deception Bay, there was intense pressure from the owners to maintain shipping schedules. To avoid any possible disruption to operations, and with the added constraint of a four-month ice-free construction window, the conventional construction method of using steel sheet piles for Arctic deep-sea wharves, was no longer a feasible option. In order to meet all of the commercial and construction limitations and constraints, the only rehabilitation option considered possible within the timeframe was to construct new structures using concrete caissons. This paper presents an overview of the project approach taken and some of the unique features that were incorporated into the design to overcome the inherent problems of working in a remote location, and the project constraints related to a very short construction window and allowing the mine to continue shipping operations during construction. Copyright 2010 ASCE.