Kathmandu, December 14

Struggling with the class-V rocks, the Melamchi Water Supply Project is finally inching closer to tunnel breakthrough.

According to Melamchi Water Supply Development Board, 97.5 per cent tunnel work has been completed so far with only 700 metres remaining to be excavated.  It said of the 27,854.5 metres, 26884.5 metres had already been dug.

MWSDB Executive Director Ramchandra Devkota said the project was maintaining the average tunnel construction speed of around 16 metres per day to meet the water delivery target.

“Although we have been struggling with class-V rocks, we have been maintaining the tunnel construction speed as weak rocks have been appearing on both sides of the Gyalthum-Sindhu stretch,” Devkota told The Himalayan Times, adding, “Of the remaining 700 metres, 150-metre Ambathan-Gyalthum stretch will be completed this month and if class-XI rocks don’t appear, we will complete the remaining 550-metre Gyalthum-Sindhu stretch by 2018 January.”

The 27.5 km tunnel comprises three stretches — Sundarijal-Sindhu, Sindhu-Gyalthum and Gyalthum-Ambathan. Three stretches cover 9.5 km, 8 km and 9 km respectively. Of the three adit tunnels, the longest stretch Sundarijal-Sindhu, which covers 9.5 km, was completed on December 28 last year.

Meanwhile, the government has imported eight transit mixers from Bangalore of India for tunnel invert lining. The board said that although the mixers arrived at Birgunj customs prior to the recently held provincial and parliamentary elections, they have not reached the project site due to delay in customs clearance.

Transit mixer is equipment that is used for transporting concrete-mortar or ready mix material from a concrete batching plant directly to the site where it is to be utilised. Transit mixer is loaded with dry material and water. The interior of the transit drum is fitted with a spiral blade.

It has been said that after the mixers’ arrival tunnel concreting will be done at the rate of 200 metres per day.