International Dredging Review

International Dredging Review

Last year Quebec-headquartered Ocean performed a maintenance contract for the Port of Sept-Îles using its clamshell dredge Ocean Borromée Verreault. Sept-Îles is on the north shore of the St. Lawrence River 325 miles east of Quebec City. The project included dredging the multi-users wharf #35 at Pointe Noire.

Working from August 6 to October 15 the dredge removed 350000 cubic yards of material using a 16-cubic-yard CableArm environmental bucket with a 15-foot by 16-foot open footprint. The bucket was designed with an open center to increase lowering speed. The material was a clean plastic clay which could be placed in an in-water site a half mile from the dredge. The round trip was about 20 minutes.

The OBV dredge is Liebherr 895 crane mounted on a 140-foot by 45-foot barge. The dredge has three 100-foot spuds two welding machines two compressors a Hiab deck crane used to load equipment and the small 20 by six-foot tender boat. There are two drum winches to handle the anchors. One of Ocean's 4000-hp tugs with Z-drive moves and positions the dredge.

Ocean used its two self-propelled 225-cubic-yard 250 hp bottom dump scows on the project. Each scow has a bow and stern thruster driven by a 180 hp engine and can achieve up to eight knots.

The Bay of Sept-Îles is shaped like a horseshoe with Pointe-Aux-Basques and Pointe a la Marmite forming its two points. Its entrance protected by the seven islands can be accessed by three channels (the eastern western and the middle channel).