WORK has resumed on the $850 million redevelopment of the Hongkong Stadium after the Urban Council returned it to contractors Dragages et Travaux Publics yesterday. But the turf that played host to Western Samoa's win in the Hongkong Sevens and South China's triumph in the Viceroy Cup is being ripped up to turn the stadium back into a building site. The grass has to be removed to allow heavy machinery to return. Though tens of thousands of people were admitted to the ground to watch the rugby and soccer matches, the project is still only half-completed. Everything that was installed especially for two of the territory's leading sporting events has to be removed. The temporary plastic seating installed in the Rugby Sevens patrons' boxes has to go, as do the fixtures and fittings in the food and drink booths and toilets. The next big change to the appearance of the stadium will be the raising of steel structures that will support a Teflon roof. The huge frame will be assembled on the ground before being lifted into place by crane. The project, financed by the Royal Hongkong Jockey Club, will be completed in time for the 1994 Rugby Sevens next spring.