Trans Mountain Expansion Project will construct an underground tunnel to connect Burnaby Terminal and Westridge Marine Terminal, avoiding impacts on residents and existing infrastructure. Trans Mountain’s contractor will use a tunnel-boring machine to construct a 2.6-km tunnel through Burnaby Mountain.

The new tunnel, at least four metres in diameter, will be large enough to contain three 30-inch delivery pipelines to load vessels at Westridge. The existing 24-inch pipeline between the two terminals is not part of the Expansion Project. Under a separate application, Trans Mountain is currently seeking approval from the National Energy Board NEB to relocate this existing delivery pipeline from Burnaby streets to the Burnaby Mountain Tunnel and increase the diameter to 30 inches. Trans Mountain will also apply to the NEB to decommission the existing 24-inch delivery pipeline at a future date. Construction of the tunnel will involve use of earth-moving equipment, drills and other motorized equipment.

This work will be completed under a Burnaby Mountain Tunnel Environmental Protection Plan

Work Hours

Tunnel construction will occur 24/7. Trans Mountain plans tunnel preparation and work on the tunnel portals to be conducted in a single shift per day, Monday to Friday from 7 am to 8 pm. When required, maintenance work may be performed on Saturdays from 9 am to 8 pm. Tunnelling will be conducted in double shifts of 10 hours each, between 7 am and 3 am, seven days a week. Between 3 am and 7 am, cleaning and maintenance activities will be performed within the tunnel.

Managing Impacts


Trans Mountain has developed noise management and mitigation measures according to federal and provincial guidelines and best practices. These measures include actions such as enclosing noisy equipment and using baffles where and when feasible to limit the transmission of noise beyond the construction site.

Existing sound levels have been established for the neighborhoods surrounding the terminal sites. Construction sound levels will be monitored to verify selected controls are effective and if additional controls are needed. 
There are also mitigation measures proposed to address potential construction impacts such as light, dust and disposal of waste rock from the tunnel excavation. 

Some examples:

Light - Light mitigation will be implemented where work is in proximity to public roadways and/or residential areas. An example of light mitigation includes directed lighting.

Waste Management - Waste rock will be disposed of at an appropriate facility according to applicable regulations. 

Air and Dust - Vehicles and equipment must observe air emissions management plans which limit idling and the types of fuels and equipment that can be used on-site. Water or an approved tackifier will be applied if necessary to soil piles to prevent wind erosion and applied to disturbed areas if traffic and wind conditions result in excessive dust. The frequency of dust abatement measures will be increased during periods of high wind.