A fourth sinkhole has slowed the progress of Evergreen Line tunnel construction but spokesperson Amanda Farrell said it's not a safety concern for the rapid transit project and noted the ground is being stabilized.
Farrell addressed safety concerns Tuesday after Port Moody Mayor Mike Clay raised the issue in media on the weekend after a sinkhole appeared in the middle of Clarke Road and the busy route had to be closed.
According to the contractors, EGRT Construction, the sinkhole was the result of ground material that entered a chamber where the tunnel boring machine was stopped for inspection and repairs.
The road was re-opened to traffic Sunday afternoon after repairs but there is still only one lane open in each direction and Farrell said that is likely to be the case for several more weeks while crews work to stabilize the ground and then do maintenance on the tunnel boring machine.
"It's not safe to put people in the front part of the machine until the ground is stable," Farrell said, adding that while the tunnel boring has been a challenge, the tunnel is being dug by a contractor with "world class" experience, and when it's finished, the tunnel will be completely safe.
Concrete rings will line the tunnel and extra reinforcements put in where necessary.
"We would expect that certainly that will be done and there will be a longer-term warranty," Farrell said, adding that the contractor's work is being monitored and the final product will be thoroughly surveyed.
She said she plans to speak to Mayor Clay to talk about any concerns. Clay has just returned from a trip to the Federation of Canadian Municipalities' convention in Alberta but on the weekend, he expressed concerns about the finished rapid transit project.
Farrell said the tunnel progress slowed because of the unstable soil conditions but the tunnel boring is now more than 50% complete, with rest of the $1.4-billion Evergreen Line project 60% complete. She said the guideway is nearly finished, the stations are coming together "very fast" and testing is slated to begin in July.
Meanwhile, a community meeting is being held Wednesday, June 17 on tunnelling operations in Coquitlam in anticipation of the tunnel boring machine moving to the area south of Robinson Street. The meeting is slated for 6 to 8 p.m. at Sir Frederick Banting middle school and Farrell said it will be an opportunity for Coquitlam residents to get the latest information on the tunnel boring operation.
