Mavala, the largest tunnel boring machine to ever be deployed in India, today made its first breakthrough at Girgaum’s Chowpatty for Mumbai’s 29.2 km Coastal Road (Western Freeway) project.
Larsen & Toubro had commissioned this 80m long CRCHI slurry machine (DZ636) in January 2021 to build the first of two 2,070m tunnels between Priyadarshini Park Launch Ramp and Chowpatty. The machine has a cool Indian-flag themed cutterhead with a diameter of 12.19m which obviously wore off during excavation.
The TBM operated 75 meters below Malabar Hill and bored through complex geological conditions that include basalt, breccia and shale – more details can be viewed here.
The first southbound tunnel built on this section (MCRP’s 3.93 km Package-4) is 12 meters wide and consists of two lanes and one emergency lane.
Back in 2021, L&T was hoping to excavate 9 meters/day and complete both tunnels by their internal deadline of June 2022 – but that just won’t be possible. The machine will now be dismantled and taken back to PDP Launch Ramp for its 2nd assignment, and I see it getting recommissioned no sooner than March-end.