PROJECT: Voisey’s Bay Paste Plant Overland Pipelines
PROJECT TYPE: Brownfield
LOCATION: Newfoundland and Labrador, Canada
COMMODITY: Paste, Water and Slurry
SERVICE SCOPE: Engineering Design
Vale’s Voisey’s Bay mine site in Labrador and Newfoundland required long-distance, high-pressure tailings, water and paste pipelines for the transport of thickened tailings, water and paste, respectively. There were several challenges associated with this design including the environmental conditions (temperature and topography), high pressure pipelines, highly abrasive media in the pipelines as well as the mitigation of solids settling in the 2 kilometer long pipelines.
In addition to engineering a suitable pipe specification, Halyard was responsible for ensuring the solution was cost effective and designed with a minimum ten year design life.
Since there were variables to be taken into consideration when determining the specifications for the various pipelines, Halyard utilized the aid of pipeline stress analysis software to determine the static and dynamic stresses expected during operation.
In addition to the stresses on the pipelines, several wear resistant materials were considered for the difficult application of tailings slurry transport. Over 20 combinations of pipe and liner materials were considered and adjudicated for technical adequacy and cost effectiveness.
Upon finding an adequate combination of pipe and liner materials, the pipelines were designed to allow for foam insulation and wrapped in a hard HDPE casing to protect the lines from the elements.
In addition to the scope of engineering the pipelines, Halyard also improved upon other aspects of the design that were outside of the original scope. For example, it was determined that the expansion and contraction forces were too large on the pumps and diverter valves selected by others, therefore, an improvement to the anchor design was engineered to relieve stresses on these elements while still maintaining their ability to control pressure. Through iterative designs and stress analyses, a series of line stops that allowed movement between the concrete and steel were added to the overall system design while maintaining structural integrity. This exercise saved the client having to revisit the mechanical equipment previously selected.