Long-distance, high-pressure tailings, water, and paste pipelines
Vale’s Voisey’s Bay mine site in Labrador required overland pipelines for the transport of thickened tailings, water, and high-pressure paste, respectively. Several challenges were associated with this design, including the environmental conditions (temperature and topography) high pressure, and highly abrasive media. The design also needed to mitigate the possibility of solids settling and freezing in the 2 kilometer long pipelines.
Halyard utilized the aid of CAESAR stress analysis software to determine the static and dynamic stresses expected during operation. 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.
Halyard also improved 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.