CENTRAL MANIC 2 (BAIE COMEAU)

The Jean-Lesage generating station, formerly known as Manic-2, is a dam located 22 km from Baie-Comeau and is built on Manicouagan River. Following a series of minor rockfall events, a geomechanical rock slope investigation and analysis was undertaken by Hydro Quebec in order to assess the condition and stability of the near vertical rock cuts around the generating station infrastructure.

Following the results of the analysis and investigation, it was determined by Hydro Quebec that a rockfall drapery system would be required to mitigate the rockfall hazards. Maccaferri SteelGrid HR30 was ultimately selected as the most appropriate drapery system. The Class A Zn/Al galvanisation was important to achieve the required design life for the project. Additionally, the geocomposite nature of Steelgrid HR30 was deemed to mean that the mesh could be installed more efficiently than a conventional mesh+cables installation. Steelgrid HR30 was installed on the 120m long rock slope, with runs of mesh covering the slope for heights of up to 40m. HR-Link connectors were used for the selvedge-selvedge (beta) connection - at nominal 160mm spacing in accordance with the manufacturer’s instructions. The Steelgrid® HR system is a new woven steel geocomposite mesh for geotechnical, rockfall mitigation and slope stabilisation applications. The Class A Zinc-5% Aluminium alloy coated ropes and wires offer a considerable extension in design life even in adverse environments.