Work on first Metro tunnel under Mithi River complete

The city officially has a Metro line under water now. In its 27th tunnel breakthrough on Wednesday, the Mumbai Metro Rail Corporation (MMRC) completed one of the

The city officially has a Metro line under water now. In its 27th tunnel breakthrough on Wednesday, the Mumbai Metro Rail Corporation (MMRC) completed one of the twin tunnels passing under the city’s Mithi River.

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A tunnel breakthrough is when the tunnel completes its pre-determined length. The 33.5-km underground Metro-3 (Colaba-Bandra-Seepz) has 32 tunnel breakthroughs in total.

The tunnel-boring machine (TBM) Godavari-3 covered a length of 1,500.80m between Bandra-Kurla Complex (BKC) and Dharavi metro stations. The Terratec-manufactured TBM started its initial drive in July 2019.

SK Gupta, director (projects) said, “Tunnelling under the Mithi was a challenging task as the geology was weak and fractured; with a water body above. Hence, we had to deploy earth-pressure balance TBM and taken other necessary technical measures and expertise. We are happy to successfully complete one of the two tunnels.”

The tunnels are almost 12.5m below Mithi River. The second up-line tunnel is expected to be completed by end of March. In fact, of the total 7.97-km package, 7.56-km has been completed till date. Apart from Mumbai, Kolkata is also building a Metro under the Hooghly river, while Chennai has an operational line under water.