The mishap has led to suspension of construction work at the site as four of the workers were injured and a similar number are currently missing.
A survey is currently underway to assess damage and reasons for the leakage and subsequent collapse, reported US News.
Police chief Maj. Theang Leng remarked that the excess water in the dam was the key reason for the devastation of the plant.
Construction of the 120MW project was scheduled to be completed in May 2013 with the company expected to operate the $255m plant under a build-operate-transfer concession for 30 years.
