Blasting at dam construction of Mangdechhu Hydroelectric Project did not cause cracks on the wall of Trongsa and Ta Dzongs, study finds out.
The two-week-long study was carried out in December after cracks were noticed on the walls of Trongsa Dzong and the Ta Dzong. The dam site of the Mangdechhu Hydroelectric Project lies just 1.6 km below the Dzong.
Seismographs were placed around Dzongs to measure the velocity of the blasts being carried out at the Mangdechhu Hydroelectric Project dam construction site.
The National Institute of Rock Mechanics from India that carried out the study said the blasts at dam site did not trigger the seismographs and that the velocity of the blasts had not exceeded the threshold limit.
However, cracks have appeared on the glasses placed on the walls of Dzong. The glasses were placed on the walls of Trongsa Dzong in December.
BBS reporter, Surja Man Thapa, said it is yet to be established if the blasts at Mangdechhu Hydroelectric Project dam site, caused the glasses to break.
The Management of the Mangdechhu Hydroelectric Project said they are in the process of procuring instruments to measure the velocity and strength of the blasts.
The Chief Engineer of Dam Complex, Karma Chopel, said surface blasting can cause major vibrations in future. He said strict measures will be put in place to monitor tremor.
The contract agreement between the dam construction contractor Jaypee and the Mangdechhu Hydroelectric Project clearly mentions that the responsibility of any damages to life and properties lies with the contractor.
The detailed project report that was prepared in 2007 to study the impacts of blasting on the Dzongs also clearly states that the use of explosive should be limited to 200 kilograms to ensure the velocity of the blasts are less than two millimetre per seconds.
Apart from the Dzongs, a few residential houses have also developed cracks.
