New digging technique used for Kishanganga power project

Bandipora: In a first, a construction major has used a Tunnel Boring Machine (TBM) for digging nearly 15 kilometre long tunnel for Kishanganga hydroelectric power project here, a development which could help in providing all-weather connectivity in Jammu and Kashmir. The day-lighting of the 14.75 km long tunnel was achieved yesterday after the work started on it in May 2001. The 330 MW Kishanganga project, located on river Kishanganga, a tributary of river Jhelum, is being constructed by Hindustan Construction Company (HCC), in a joint venture with Halcrow Group Ltd for the National Hydroelectric Power Corporation Ltd. (NHPC). The breakthrough in the first phase of the tunnel with a diameter of 5.4 m from the powerhouse side was achieved by the TBM and rest of the 8.9 km, having six metre diameter from the dam side is being constructed using the conventional Drill and Blast Method. "It is a first such feat in the mighty Himalayan range and Jammu and Kashmir has taken the honour," Director Projects, HCC, J K Sharma told reporters. Officials said that TBMs can be used for digging in mountainous state in future for providing all-weather connectivity. Sharma said the TBM had never run successfully in the Himalayas and it was the first time that there was no problem in it. "It is for the first time that the TBM has run successfully in the Himalayas. We have achieved the progress in less time than we had targeted. We We had a target of 300 m in a month, but we achieved an average of 4400 m per month. We have created a record in the country by drilling 815 m in a month," he said. He said the success in the project here has given a lot of confidence to the NHPC to use the TBM in other projects in the country. The director said there were a lot of difficulties in executing the project as tunnelling was adversely affected by geological problems. "It passes through Andesite, phyllitic quartzite, meta siltstone and meta sandstone rock types through rock cover ranging from 400 m to 1407 m. Tunnelling in high rock cover zone to the extent of 1400 m is a real challenge due to squeezing and other geological problems," he said.

He said NHPC will install a 2 MW plant near the dam to benefit the local population. "Generally many casualties happen during the construction of any hydro-electric project. But in this case there were only few," he added. The project is run of the river scheme and involves transfer of water of Kishanganga River in Gurez valley to Bonar nallah near Bandipora. The contract of the project is on a turnkey basis valued at approximately Rs 2726.49 crore.