Mumbai, May 30 (IANS): Marking a significant progress, the 'breakthrough' was achieved on the second arm of the 2.07 kms long twin-tunnel of the upcoming Mumbai Coast Road Project being built by the Brihanmumbai Municipal Corporation (BMC), officials said here on Tuesday.

Chief Minister Eknath Shinde, Deputy CM Devendra Fadnavis, BMC Commissioner I.S. Chahal and other dignitaries witnessed the moment when the country's biggest tunnel boring machine (TBM) ripped through the final few feet of the rocky bed to complete the digging works this evening.

A thunderous round of cheers and claps greeted the TBM blades rotating to gnaw away the final obstacle to open up the tunnel for thoroughfare with a cloud of dust, as the project raced to meet its proposed completion target date of November 2023.

The first phase of the Coastal Road will run 10.65 kms from the Princess Street Flyover (Marine Lines) to the southern end of the Bandra-Worli Sea Link.

This 8-lane Coastal Road portion comprises a complex achievement of reclamation of land from the Arabian Sea (4.35 kms), sea-wall, bridges, twin-tunnels under the sea and the Malabar Hill, including 6-lanes inside the tunnels.

There will be four underground car parks with a capacity of 1,856 vehicles and 70 hectares of open green spaces en route.

The project will have three interchanges with a total length of 15.66 kms and the sea-wall will be constructed for 7.47 kms.

The total project cost is around Rs 12,720 crore, and construction cost is Rs 8,429 crore and the work on it started in October 2018 from the southern side.

The work on digging the first tunnel was taken up on January 11, 2021 and 'breakthrough' notched on January 10, 2022, in exactly a year, while the second tunnel work started on April 26, 2022 and achieved 'breakthrough' after around 13 months on Tuesday.

With this, the total project progress is given as 75 per cent including 100 per cent tunnel works done, 95 per cent reclamation completed and 84 per cent of the sea-walls built.

The coastal road will bring a slew of benefits by reducing the commute time on that sector by 70 per cent, fuel savings of around 34 per cent, dedicated bus lanes to help decongest traffic snarls, etc.

The project has several firsts in India to its credit - the biggest (12.19 metre) TBM deployed for the tunnels, Saccardo Ventilation System in the tunnels, a Monopile Foundation bridge, and a single project will have reclamation, sea-walls, bridges, interchanges, tunnels, parking lots and green/open spaces.