In a major step towards the construction of Mumbai’s first underground Metro, the first Tunnel Boring Machine (TBM) for the Metro 3 began its drive from Nayanagar launching shaft in Mahim on Thursday. Addressing the media, Ashwini Bhide, Managing Director, Mumbai Metro Rail Corporation (MMRC), said, “With this, tunnelling for the underground corridor has begun in the city. This TBM will tunnel up to Dadar. Since it is hard rock, the machine will travel a distance of 8-14 metres per day.”
The machine was lowered into the shaft on September 21 and after most of its parts were assembled, it began tunnelling. The TBM is expected to travel a distance of 2.5 km and reach the retrieval shaft in Dadar by September 2018. Twin tunnelling for the 33.5-km Colaba-Bandra-SEEPZ corridor (Metro 3) will require 17 TBMs. With a target of completing the Phase I (Aarey-BKC) by June 2021 and Phase II (BKC-Colaba) by December 2021, the MMRC plans to have all the TBMs in the city by March 2018.
“Currently, five TBMs have reached here. Of them, three have been lowered and two more will be lowered by next month. While one of them has begun tunneling, the other TBM should begin in a month. Seven more TBMs are in transit, while the Factory Acceptance Test (FAT) for five more TBMs are pending. However, all 17 should be in the city by March next year,” added Bhide.
Speaking on the risk to buildings during the tunnelling process, Bhide said, “The TBM will be travelling only through hard basalt rock 20-30 metres underground. So, there is no danger to the buildings.” Further commenting on the challenges of underground Metro construction in Mumbai compared to other cities in the country, Bhide said, “Mumbai is a linear city and so there are not too many alternate roads to divert traffic.”