KUANTAN: The relaunch of the East Coast Rail Link (ECRL) project on July 25 has kick-started the construction of the longest rail tunnel along the 223km line between Dungun in Terengganu and Mentakab in Pahang.
The 2.8km Kuantan Tunnel, located in Jabor, near here, is the longest among the three tunnels of the ECRL in Section B, which includes the 1.1km Paka Tunnel and 871m Dungun Tunnel, both in Terengganu.
While the excavation and earthwork had begun in July, the drilling and blasting work for the 11.8m diameter tunnel project, which is scheduled to be completed in March 2022, officially began on Oct 7.
An ECRL project spokesman said the Kuantan Tunnel adopted the New Austrian Tunnelling Method (NTAM), which is the world’s most widely used underground construction method.
He said NTAM was used for modern tunnel design and construction, whereby it did not set a standard excavation and support technique, and was referred to as a “design as you go” approach.
The spokesman said the project utilised the Swedish-manufactured double-arm jumbo drilling machine, whereby tunnelling work commenced from both directions, and would meet in the middle.
“Currently, we have started work on one side, while work on the other end will begin soon (after finalising the land acquisition process). We have two units of the jumbo drilling machine to ensure that work progressed according to schedule,” he said as he took the New Straits Times reporter and photographer for a site tour.
“At the moment, 73m of the 2.8km tunnel have been excavated and general work is being carried out around the clock.
“To date, we chart our progress at about 25 metres a month,” he said, adding that explosives were used for blasting work when there were rocks along the path.
On the tunnel construction method, the spokesman said although they had compiled a geology profile of the soil, rocks, minerals and others at the site, geology mapping would continue to be conducted to ensure that tunnelling work progressed smoothly.
“We do the geology mapping every 30m (as work progresses) for the purpose of counter-checking. It will allow us to identify which section of the rock to drill or install explosives.
“Before installing the explosives, we will identify a weak section of the rock, which will be suitable to blast. Tunnel blasting is done to clear rocks along the stretch. Alternatively, we conduct excavation on the soft sections of the earth.”
He said ventilation was a vital aspect to provide fresh air for the workers.
Elaborating on security, the spokesman said closed-circuit television cameras were installed on site, including inside the tunnel, to monitor the workers’ movement and ensure safety.
“In future, a microchip will be fixed on the workers’ safety helmet to allow us to monitor their movements and track their locations inside the tunnel, especially when the excavation gets deeper.
“We are in the midst of installing a face recognition system for security purposes,” he said.
The spokesman also said blasting work was conducted with permission from the police, Mineral and Geoscience Department and the Occupational Safety and Health Department, having fulfilled all requirements on safety issues, including on permissible levels of vibration and sound.
At the ECRL site in Sungai Air Jernih, Kemaman, work to demolish a section of a concrete bridge along the now-abandoned Kerteh-Kuantan Port railway line had commenced on Oct 8.
The spokesman said the 185m rail bridge, which once connected the Petronas oil refinery in Kerteh, Terengganu, to Kuantan Port would be demolished to make way for the ECRL railway tracks.
“A new railway line will be built with requirements and specifications that meet ECRL standards,” he said.
The 223km Dungun-Mentakab main line is also known as Section B while the other sections of the improved 640km stretch include Kota Bharu to Dungun (Section A) and Mentakab to Port Klang (Section C).