Serlui-B Hydropower Project is the largest hydro plant in Mizoram. The site is near Bilkhawthlir Village in Kolasib district. The DPR was approved in Feb 1999 and a turnkey contract was awarded to BHEL and Mecon in Dec 2003. Serlui-B has a 293m long, 51m high earthfill dam a 415m headrace tunnel, a 135m pressure tunnel, and a semi-underground powerhouse. The project cost Rs 191cr  Construction began in 1998 but it was halted in 2004 because of 'unfavourable geological conditions at the dam site, technical reasons, high compensation for crops and law and order situation'. In 2011, the project cost was revised to Rs 913.23 crore, almost triple its original estimate of Rs 369  Nearly 5,100 villagers of Ratu, Mawchar, Saipum, Palsang, N. Khawdungsei, Serzawl, Lungmuat, Bukpui, Saiphai, Hlimen, Darlawn, Khawruhlian, N Chaltlang, Nisapui and Thingtherh will be affected by the dam . The Hydel Project submerged Builum village and the affected villagers were rehabilitated on a new site Bawktlang near Kolasib  The Serlui B project has the dubious distinction of creating the state's first 'dam refugees' who are still fighting for proper rehabilitation and in case of Tuirial project, the people and experts are questioning its legality as no public hearing was ever held. Experts said the affected villagers of Tuirial could move court .