JUST 46 weeks into the 31/2-year Site Preparation Contract, the Chek Lap Kok airport project is racing ahead, easily exceeding construction targets. More than 270 hectares of new land has been added to the site in a construction process that moves about 800,000 tonnes of material each day. A total of 938 hectares of land will, eventually, be reclaimed. Speaking at an Airport Projects seminar organised by the Hong Kong Institution of Engineers and the Provisional Airport Authority, PAA project director Doug Oakervee said 34.6 per cent of the necessary excavation had been completed and the work was aheadof schedule. The airport island of Chek Lap Kok employed 1,700 people, he said. By mid-1996 - when the Site Preparation Contract is completed - more than 310 hectares of land will have been excavated at Chek Lap Kok and Lantau island. A total of 85 million cubic metres of material needs to be excavated. When work started, the contractors had to move 28 million cubic metres by October 17 - they achieved 29 million. A total of 65 million cubic metres of marine mud needs to be removed from the airport footprint. The October target was 34 million cubic metres, but the world's largest fleet of trailer suction hopper dredges removed 44 million cubic metres - 68 per cent of the project total. In July, marine sand depositing began and more than 7.5 million cubic metres of the total of 76.5 million cubic metres has already been deposited. More than 13 kilometres of sea walls need to be formed at Chek Lap Kok between now and late 1995. While most of the sea walls are sloping, almost two kilometres of vertical walls are required for the unloading of sea-borne construction materials. This is necessary because the island will not be accessible by road or rail until the airport project is nearly completed. The pre-fabricated terminal building and other airport facilities will need to be unloaded from ships. Concrete blocks for the vertical sea walls are cast on site, and stacked by derrick on the sea bed. When the blocks are in place, the area behind the wall will be filled and compacted. And Mr Oakervee said the terminal building was in the final stages of design. ''In construction terms, the passenger terminal will be our next major milestone,'' he said. Contracts for the cargo, fuel, maintenance and catering facilities would be awarded by the end of 1993, he said. ''Each company is now preparing a draft business plan, and we would like to begin the awards of the first of these licences later this year,'' he said. Mr Oakervee said the Ground Transportation Centre, the design of which was awarded to a consortium that included Ove Arup, Parsons Brinckerhoff, Foster Asia, and Anthony Ng, was crucial to the success of the airport. ''Passengers need to move easily and efficiently,'' he said. ''They will be able to move through passenger terminals, arrival and departure halls, to their choice of ground transport, through the service centre without having to leave the air-conditioned environment. ''The passenger terminal itself will contain retail opportunities which we estimated will generate a revenue of $5.4 billion in the airport's first year of operation.'' Chek Lap Kok will have 150 shops compared to Kai Tak's 35. Mr Oakervee said the development of Chek Lap Kok would provide an ongoing economic boost. He said the Authority would be responsible for an estimated annual turnover of $10 billion, and would employ 28,000 people, including downstream activities. He also pointed out that the airport would continue its construction activities with funding from the government while agreement was being sought with China. ''Until agreement is reached on the final form of the airport financing plans, the government continues to fund our necessary activities on a step-by-step basis,'' he said.