Mumbai, Nov 30 (PTI) The tunnelling work of the Colaba-Bandra-SEEPZ Metro-3 corridor was completed 100 per cent on Wednesday while the overall project is 76.6 per cent complete, the Mumbai Metro Rail Corporation (MMRC) said here.The tunnelling work was completed after the final breakthrough at the Mumbai Central Metro Station.The line 3 of Mumbai Metro which will have a 33.5 km underground route will connect south Mumbai with the western suburbs, and is expected to reduce the burden on the suburban local trains.Robbins-made TBM Tansa-1 machine completed its most challenging drive of 837 meters from Mahalaxmi Metro Station to Mumbai Central Metro Station up line in 243 days using 558 concrete rings, an official release stated.“It was with great pleasure that I witnessed the final breakthrough today. It marks 100 per cent tunnelling of Metro-3 corridor," said Ashwini Bhide, managing director of MMRC.The tunnelling below Mumbai"s heritage precincts, in close proximity of old dilapidated buildings and the existing Metro line, railway lines and water bodies with different and sometimes difficult geological conditions has been a daunting task, the release said.S K Gupta, director (projects) of MMRC said the company used advanced technology without compromising on the safety of workers. PTI KK KRK KRK