A team of experts from Himachal Pradesh's Bhakra Nangal hydro power project on Wednesday started a search for four persons in Kopili hydro project in Assam's Dima Hasao district, who went missing after a water pipeline raptured on Monday.

However, the four including a junior engineer, who were stationed at the power station, remained traceless even on Wednesday.

Vinod Kumar Singh, Chief Managing Director of North East Electric Power Corporation (NEEPCO), the public sector company running the project said the experts from Bhakra Nangal project and those from National Hydro Electric Power Corporation (NHPC) were called to the site to plug the damage in the pipeline and carry out the search for the four missing persons.

Sources said the National Disaster Response Force (NDRF) personnel, who reached the site could not carry our the search as they are not trained to deal with mishaps in hydro power projects.

Water fountain, which was formed after the explosion in the pipeline continued to flow out water as engineers struggled to plug it on Wednesday.

Water coming out of the pipeline, that carried water from the reservoir of the Kopili river to the power station had inundated the power house and other installation, in which 10 staffs got stucked. Six of them, however, managed to flee. 

Singh, however, called the incident as sheer accident, while denying charges of negligence causing the incident. 

NEEPCO opened all the gates of the reservoir to release excess water and reduce the pressure. The pipeline carries nearly 12,000 litres of water per second. 

Located on the Kopili river in the hilly Dima Hasao district sharing a border with Meghalaya, the Kopili Hydro Electric Project has installed capacity to generate 275 MW electricity