INNOVATION July-August 2016

New Acid Tower for Chile NORAM Engineering & Constructors Ltd engineered an extensive upgrade of a sulphuric acid plant for a Chilean copper smelter. The 1,300-tonne/day double-absorption plant treats off-gas from Teniente and Peirce Smith converters. A new NORAM final acid tower, capable of increased gas throughput and a lower pressure drop, allows treatment of up to 150,000 Nm 3 /h of metallurgical gases to capture essentially all sulphur trioxide gas and to produce commercial sulphuric acid of 98.5 percent purity. Environmental performance of the plant improved significantly, with a greater than 95 percent reduction in sulphur trioxide and acid mist emissions. NORAM provided basic design, detailed engineering, site services, fabrication advisory services, and start-up assistance. Specialised equipment, including some tower internals and acid distributors, was custom manufactured in BC for shipment to site.

Extraordinary Load Move Across North–Central BC Lee Peltz, P.Eng., Chris Grant, P.Eng, RPF, and Glenn Stanker, P.Eng. , assisted Heavy Metal Heavy Haul Tall Totem Transport 1998 Ltd. in transporting two large rock trucks across north–central British Columbia. The 7.3-metre-wide loads required all public roadways to be closed to traffic while the loads were moving. The route was divided into 12 segments, and the loads were stopped after each segment to clear any queued public traffic. The sequential closures worked well, even in Fort St. James, where side streets had to be closed to prevent traffic from entering the roadway while the loads were moving. Four bridges required inspection and monitoring while the loads crossed. Chris Grant, P.Eng., RPF, traveled to Endako Mine and Fort St. James six times to weigh the vehicles and monitor the bridge crossings. In the process, he developed a new method for weighing axle loads for tridem axles. Stabilisation of Eroded Cedar Creek Headwaters The BC Lower Mainland's Cedar Creek headwaters were severely eroded following two recent significant rainfall events. During the events, creek substrates were breached, exposing highly erodible sands, which caused major slope failures and transported large amounts of sediment downstream near the sensitive aquatic habitat upstream of Burnaby Lake. This failure also put at risk an existing sanitary sewer west of the creek and caused substantial tree loss. Urban Systems, along with Thurber Engineering and Hatfield Consultants, completed slope stabilisation by importing more than 15,000 tonnes of material, restoring the baseflow channel and slopes to the natural creek profile, and completing a significant planting and restoration program. To manage erosive storm flows, a high-flow bypass diversion and a custom energy-dissipation structure were installed to safely convey peak flows to a lower-energy reach of the creek. APEGBC members, Urban Systems: Spencer Thompson, P.Eng., Simpson Hong, P.Eng.

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