The Mumbai Metro Rail Corporation has received the first Tunnel Boring Machine (TBM) that would be used to drill twin tunnels for the 33.5km Colaba-Bandra-SEEPZ Metro-3 line. Sixteen more highly-mechanised TBMs will arrive in the city in the period of next two years to drill 51km of tunnels.

Procured from German major Herrenknecht AG, from its manufacturing facility in Guangzhou, China, the TBM will be lowered from launching shaft in Naya Nagar, Mahim using cranes with heavy gantry of capacity of 135 tonnes.

According to MMRC, the TBM will be assembled in the next 45 days and then deployed for construction of 6.08-km twin tunnels between Siddhivinayak and Dharavi. The tunnelling is expected to start in October. The Earth Pressure Balance (EPB) device will be used to construct tunnels in circular cross section some 20 meters to 25 meters below the surface.

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