Colombo South Port Project Encounters Rocky Patch
- Rock blasting to go on till August
By Mandana Ismail Abeywickrema
The Colombo South Port Development Project is currently engaged in blasting a patch of rock in the seabed near Galle Face.
The Sri Lanka Ports Authority (SLPA) says the rock blasting that commenced early this month will continue for another two or three months. The tremors felt in the Colombo Fort area last Friday have been attributed by authorities to the blasting of one of the rocks in the Colombo port expansion project. Last Friday’s rock blasting, according to the SLPA, is the 11th instance when rocks in the Colombo Port had been blasted. A similar rock blasting took place last year at the newly built Hambantota Port costing the government millions of rupees.
The patch of rock in the Colombo South Port Development Project is located where the quay wall of the container terminal is located.
SLPA Chairman, Dr. Priyath Bandu Wickrema said that rock blasting was likely to be completed by August.
Dr. Wickrema said he was unable to give the volume of the rock patch.
He said the rock patch is located 14 metres below the surface in the the seabed and the foundation is to be laid 19 metres below the surface in the sea bed.
“The rock blasting is being carried out according to the standards set by the Geological Survey and Mines Bureau (GSMB),” Dr. Wickrema said.
“The rock patch blasting is carried out by the construction company and the SLPA does not have to incur any expense for it,” Dr. Wickrema noted. The construction work is being carried out by China Merchants Holding (International) Company Limited.
The Chairman added that the GSMB was monitoring the blasting of the rock patch and has even set up monitoring units in several buildings in the Fort area.
Chairman of the GSMB, Dr. N. P. Wijayananda confirmed that the GSMB has set up six monitoring units in buildings in the Fort area including the World Trade Center and the Central Bank.
He explained that the GSMB focused on the vibration velocity and that it has recommended to the Colombo South Port Development Project to ensure that the vibration velocity when blasting rocks is 3 mm per second. “The vibration velocity should not exceed this amount,” he said.
However, Dr. Wijayananda maintained that the vibration velocity recorded during last Friday’s blast was less that 2 mm per second. When asked for the reason behind the tremor felt in the Fort area, Dr. Wijayananda observed that it could have been due to the depth of the rock and proximity to the land.