MTR blasting is so quiet tai chi classes can go on

A new technique using water to dampen the impact of underground blasting for a new MTR station has ensured people exercising and practising tai chi up above every morning in King George V Memorial Park, in Sai Ying Pun, on Hong Kong Island, have been left - literally - unmoved.

Every week since last August, the MTR has carried out two or three underground explosions - as part of plans to blast about 400 small holes alongside the park to help build a shaft for the new Sai Ying Pun station.

Yet Walter Lam Wai-tak, MTR senior construction engineer for West Island Line, said the new technique of using water - instead of old tyres and sand - to absorb and cushion the effect of vibrations and dust had proved so successful that people up above in the park had been hardly able to feel the impact of the blast. 'We put a glass of water on the ground the other day during the blasting; we thought there might be some ripples, but there was none,' Lam said. 'The best thing about using water is that, except for noise, it greatly reduces dust and dirt, which mix in the water for easy discharge.'

He said the new blast-dampening method cost about the same as old methods. But blasting, which would finish next month, took 21/2 hours to fill the shaft with water, and 11 hours to pump out the water afterwards.

Reuben Chu Pui-kwan, president of the Hong Kong Institution of Engineers, said: 'Contractors are struggling to come up with environmentally-friendly construction methods when they bid for the contracts; they can't cost too expensive either; the market is now very price-sensitive.'