Demolition experts on Thursday were continuing to set explosives that will later this week create a massive explosion to demolish the last cofferdam protecting the just-completed Three Gorges Dam.

Dubbed the world's toughest demolition job, 192 tons of dynamite will be used to completely destroy the cofferdam, said a senior engineer with the demolition squad.

"Such a demolition operation is unprecedented in the world and requires high precision techniques in order to demolish the temporary cofferdam without damaging the main dam," said Zhou Guisong, deputy chief engineer of the Chongqing Gezhouba Yipuli Chemical Co. Ltd..

Zhou told Xinhua that half the explosives had been set as of Wednesday night.

The cofferdam which has been in use since 2003, is situated 114 meters upstream of the Three Gorges Dam.

The cofferdam is 580 meters long, 140 meters high. Zhou said that the water level behind the dam will reach 139 meters when the explosion is set on June 6. Explosives have been set in holes that were drilled 38 meters underwater.

The Three Gorges Dam located in China's Hubei Province was completed on May 20, and with the demolition of the cofferdam means the mammoth project will formally begin its role in flood control, two years ahead of the schedule.

The China Three Gorges Project Corporation said last month that the dam will protect the river's middle and lower reaches from major floods.

The water level in the Three Gorges reservoir is expected to rise to 156 meters above sea level after the summer flood season this year.

The 185-meter-high Three Gorges dam will be capable of holding 22.15 billion cubic meters of water and the water level will normally be kept at 175 meters when it is fully completed by the end of 2008.

Source: Xinhua