NGI says it had warned about overburden slide at PI
January 26 | Kuensel
By Tashi Dema
The third-party expert the Punatsangchhu Hydroelectric Project I (PI) hired, the Norwegian Geological Institute (NGI), refuted allegations of the consultant failing to provide a concrete solution.
According to the technical lead, engineering geology and rockslide, Mahdi Shabanimashcool, NGI mentioned that the local slide at PI project, which recently failed, was unstable and could collapse soon in separate reports submitted by NGI in September 2018 and in November 2018.
“It was clearly mentioned that if excavations continue below the slide, then the slide would fail and this is exactly what has occurred,” he said in an email.
He said that in 2018, NGI suggested installing a slope monitoring radar for monitoring the movements of the right bank of the Puntasangchhu I project and the project authority procured the slope monitoring radar system from Italy, which was successfully installed in June 2018.
“According to NGI, this is one of a most appropriate systems for monitoring the movement of a slope as it monitors the movement in real time where the slope can be observed round the clock,” Mahdi Shabanimashcool said.
He said the slope is being monitored online by the project authority, NGI, WAPCOS and CWC.
Mahdi Shabanimashcool said that much of the right slope in the P1 project has been stabilised using 2m diameter piles after a major slide occurred in 2013. “At the moment, the major focus is on finding a long term solution of the whole of the right bank after the construction of the dam. This is where the expertise of NGI is warranted along with Water and Power Consultancy Services (WAPCOS) and Centre Water Commission (CWC).”
He also said that NGI in Oslo, Norway, was appointed as an expert advisor for the projects Punatsangchhu I and Punatsangchhu II in 2017.
“Witnessing a delay in the completion of both the projects, it was decided in a meeting between the Royal Government of Bhutan and the Government of India to appoint NGI to provide expert advisory services for both the projects in 2017,” he said.
NGI received a contract from WAPCOS to provide expertise in tackling the on-going challenges at the two project sites. “Since then NGI has been providing its services from time to time,” Mahdi Shabanimashcool said.