Tar sand, methane gas could spike cost of L.A.’s Purple Line extension

LA Metro’s success with the Purple Line extension has commuters asking for more tunnel projects.

L.A. Metro

The tar sand geography underneath the city of Los Angeles appears to have gooped up any hopes of avoiding cost overruns on the tunnel boring section of the Purple Line extension.

Through January the project was in line to meeting cost and schedule projections, but a May report indicated a potential cost overrun. The $2.8 billion, 3.9-mile WPLE1 section opened for construction in 2014, with twin tunnel boring machines arriving on the scene in mid-2018. The boring has covered 3 miles from Western Avenue and Fairfax Avenue. La Cienega Boulevard is the final destination.

However, tar sands and methane pockets are slowing down the process. Construction processes were supposed to account for methane gas dangers, but the tunnel boring machines have been shutting down due to gas detection in the tunnels.

The city of Beverly Hills and its construction restrictions also are driving up the cost of the project, as is a requirement for air scrubbers to comply with revised Southern California Air Quality Management District hydrogen sulfide regulations.

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