The Punatsangchu Hydroelectric Project Authority (PHPA) Managing Director R.N Khazanchi has said that the total cost of the right bank stabilization work for P I and the surge shaft stabilization work in P II could cost up to Nu 2.5 bn.
In P I, Khazanchi said that though the exact estimates are still yet to be arrived at it would be under Nu 1 bn and he said in P II it would cost around Nu 1.5 bn.
The additional cost in P I comes as the Norwegian Geological Institute (NGI) was hired from February 2017 after the P I right bank slide kept sliding even after a three phase and ongoing expensive rectification measures and also after the collapse of the roof of the cavern in the surge chamber in P II.
The NGI in P I has asked PHPA to excavate large amounts of soil and rocks from a much higher place of 150 to 200 meters from the current point of excavation and stabilization. This would lead to less pressure on the slope from above but would also lead to a gentler slope.
Khazanchi said that the project felt that it can simultaneously do the rectification measures on top and also do the dam construction activity.
The consultants WAPCOS and CWC had done the engineering proposal for P I slope which has been submitted to NGI. The NGI is expected to get back soon on the issue.
Khazanchi said that the delay so far was due to the fact that work had to be halted at the dam site for around four months while NGI was doing its study. He said the project would aim to complete by December 2021 though in case of delays it would go into the first quarter of 2022.
On P II the MD said that the three independent reports by CWC, NGI and IIT Delhi came to almost similar conclusions. He said the project would essentially build a wall on each side of the internal cavern collapse and then pump in cement from the surface and so seal and stabilize the area. He said to make for the loss of that space around three or four smaller tunnels would be made. He said strengthening works will also need to be done in the internal powerhouse.
The total sanctioned cost of the project is Nu 93.75 bn for P I and Nu 72.90 bn for P II. The MD said that India’s Minister for External Affairs has the financial authority to authorize five to six percent of the project cost and so it would come in that. Otherwise he explained it would have to go through RGoB, GoI agencies, standing committee in Power Ministry, Public Investment Board and finally the Indian cabinet. He said the P II project would be done by December 2019.