AJV between Neilson and EBC, both leading Canadian contractors, has won the contract to build a 1.8km long single-bore twin-track tunnel as part of the US $239M Montreal Metro Line 2 extension, the tunnel alignment takes it under the River des Prairies for a length of 700m.
Initially, there was talk of a possible re-bid, after over inflated cost estimates were submitted. However, discussions between the client AMT (Agence Métropolitaine de Transport) and the JV were positive and tunnelling is scheduled to start at the end of this month.
The winning bid was US$53M, which beat off interest from Janin Atlas (US$56.8M), Herve Pomerleau (US$59.1M), and Kiewit (US$62.4M).
Known as the “Henri-Bourassa Section” this is the third contract to be awarded on this 5.2km long project, and considered to be the most difficult. A pilot tunnel will be bored first, which will be widened to an 8m diameter, using two Voest Alpine reamers. The geology, which has been subject to several geotechnical analyses, is made up of limestone with fossiliferous and crystalline layers and some shale. Other tunnelling work on this contract will be with roadheaders and cut and cover.
The aim of the project is to extend Line 2 of the metro east from Henri-Bourassa station towards the suburb of Laval, providing access to the existing metro system for commuters faced with congestion on the bridges that cross between the islands.
EBC and Neilson are already working on separate contracts on the Line 2 extension, both opting for different tunnelling methods. EBC opted for drill and blast. While it raised complaints from some local residents, and experienced some problems with fractures in the bedding planes at the top of the arch, it was the swiftest method, with advance rates up to 3.5m per day. Neilson has advanced more slowly with a Voest Alpine roadheader, but did not report any problems.
Tunnelling is scheduled for completion by the end of January 2005.
