Maharashtra chief minister Uddhav Thackeray has launched the largest tunnel boring machine (TBM) for the Mumbai Coastal Road project at Priyadarshini Park, in Malabar Hill area of South Mumbai.

Called Mavala, the TBM having the largest diameter and the first of its size to be used in the country, will be used to bore twin sea tunnels between Priyadarshini Park to Chotta Chowpatty. The tunnels will run both ways; up towards south Mumbai and down towards Worli end.

Mumbai suburban guardian minister and state environment minister Aaditya Thackeray, BMC commissioner Iqbal Singh Chahal, additional municipal commissioner ES, Ashwini Bhide, and principal secretary to the chief minister, Vikas Kharage, were also present at the event on Monday.

The Shiv Sena-led BMC’s ambitious 10.58 km coastal road is being constructed from Princess Street flyover to South end of Bandra Worli Sea Link. It is being constructed in 4+4 lane configuration consisting of roads build on reclaimed land, bridges, elevated roads and tunnels.

The project is being executed in three packages: Package I consist of stretch between Priyadarshini Park to Baroda Palace, Package II from Baroda Palace to south end of Bandra Worli Sea Link and Package IV from Princess Street Flyover to Priyadarshini Park. Package IV is 4.05 km, Package II is 2.71 km and Package I is 3.82 km.

Package IV mainly has twin tunnels between Priyadarshini Park to Chotta (Girgaum) Chowpatty which will be bored through TBM. Each tunnel will be 2.07 km long with outer diameter of 12.9 metres and finished diameter of 11 metres. Both tunnels will have a clear distance of 12 metres and constructed 10 metres to 70 metres below ground level. Each tunnel will require approximately nine months of boring work.   

Further, each tunnel will have three lanes and 11 cross passages to interconnect both tunnels in case of emergency. There will be emergency control room buildings in both tunnels for emergency operations with self-automated and Saccardo system of ventilation in line with international Code Standards.

Larsen and Toubro are the contractors for Package I and Package IV, and HCC-HDC are the contractors for Package II. Separate project management consultants are handling each project. AECOM Engineering Company has been appointed as the employer’s representative and general consultant of the contract.

BMC commissioner Iqbal Singh Chahal said that substantial work has been done in the couple of months till November 2020 with an expenditure of Rs 1,281 crore. “The coastal road will be functional in July 2023. About 175 acres of land has so far been reclaimed from the Arabian Sea for the project and another 102 acres is being reclaimed.”

BMC purchased the machine from China last year. It was taken to the site in dismantled parts on 17 trailer trucks after which it was assembled. The tunnelling work was pushed behind schedule due to the Covid-19 pandemic which delayed delivery of the TBM from China.   

Chahal also said that the Mumbai coastal road will reduce travel time, decongest existing roads, reduce air and noise pollution levels, improve public transport by a dedicated BRTS and also generate much needed additional green spaces. Post-construction of coastal Road motorists will be able to reach Worli from Nariman Point within minutes.