Guwahati: The strategic Sela Tunnel Project, which is set to provide all-weather connectivity to Tawang in Arunachal Pradesh, will be inaugurated only after a third-party safety audit, a BRO official said.

The audit is expected to be completed by mid-February this year, following which Prime Minister Narendra Modi is likely to inaugurate the tunnel, Border Roads Organisation (BRO) Additional Director General (East) P K H Singh said in an interview with PTI.

"The construction work for the tunnel, situated at an elevation of 13,000 feet, is nearing completion, while physical and environmental audits, already provisioned in the contract, have been conducted and positive results have been received," he said.

Following the Silkyara tunnel incident in Uttarakhand, however, the BRO DG had ordered a third-party audit of the Sela tunnel as it is strategically important due to its proximity to the Line of Actual Control (LAC), Singh said.

The tunnel, located near Sela Pass, was necessitated as the Balipara-Charidwar-Tawang Road remains closed for an extended period due to snowfall and landslides caused by heavy rainfall, he pointed out.

"The tunnel is aimed at enhancing the army's capabilities at the LAC," he added.

It will ensure speedy deployment of troops, weapons and machinery to the forward areas along the India-China border, Singh said.

The foundation of the project was laid by the prime minister in February 2019, with a cost estimation of ₹697 crore, but work got delayed due to various reasons, including the COVID pandemic.

Construction work had started in April 2019 and the first blast took place at tunnel 2 portal 4 on Oct 31 of the same year, he said.

The project comprises two tunnels, with the first being a single-tube tunnel of 980 metres in length, and the second being 1.5-km-long with an escape tube for emergencies, Singh said.

The BRO is engaged in constructing 7.1 km of approach roads to tunnel 1, 340 metres of approach roads to tunnel 2 and 1.3 km of roads between the two tunnels.

The Sela tunnel has been constructed with the New Austrian Tunnelling Method (NATM) and the final breakthrough in tunnel 1 was recorded on January 22.

"When the tunnel was being constructed, in the final phases of installations, a major cloudburst took place in the higher reaches in July last year, delaying the construction of the approach roads and thereby, the expected time frame for completion of the project," the official said.

The BRO will also construct a 100-metre-long departmental tunnel on the Sela-Chhabrela-Banga Janga Gompa (BJG) axis for the organisation's use to transport men, materials and machines, he said.

There is also a proposal to construct a ₹10,000-crore underwater tunnel under Brahmaputra River from Tezpur but the project is still under consideration by the Union government and a final decision is yet to be taken, Singh said.

The BRO has also constructed the now operational Nechiphu tunnel in West Kameng district of the state at an altitude of 1,630 metres. It was inaugurated by Defence Minister Rajnath Singh in September last year.

This double-lane 500-metre long-tube tunnel is located in an area where traffic used to be severely affected due to dense fog but after becoming operational, it has not only reduced travelling time but also provides a safe route to travellers, including defence personnel, Singh said.