MORE than a dozen minor landslides at Kwun Lung Lau Estate since Saturday night have hampered the search for four people thought to be buried under the tonnes of mud and rock, a senior fire officer said yesterday. Western divisional officer Tong Koon-ngai said slides were happening ''all the time'' and officers feared another major landslide. ''When these landslides occur everybody stops working for a few minutes to check the situation. Small landslides may carry forward major landslides,'' he said. Despite the delay, the search continued yesterday for those believed to be still under the rubble. Mr Tong said it was doubtful, however, that anyone would be found alive. ''We have heard nobody shouting for help and according to our heat detection systems there are no signs of life,'' he said. Yesterday morning, rescue officials said they were relieved when a man and a woman thought to have been buried under the debris were found alive - albeit nowhere near the site. Families of Lin Loy-heung and Chan Kwok-wah telephoned police to say they were safe. Ms Lin had been singing at a karaoke club and was unaware that she was feared missing. Mr Chan was found in the Shek Tong Tsui temporary housing shelter. Police Chief Superintendent Mike Horner, district commander of Western, said there were also indications that two of the remaining four may be in China. However, Mr Tong said his men were still working on the assumption they were searching for four people. By late last night an estimated 250 tonnes of mud and rock had been removed from the site by 25 fire officers who were working ''round the clock''. Excavation work was held up on Sunday by heavy rain, leaving geotechnical engineers unsure whether the area was safe to continue work. At 9 pm on Sunday they cordoned off 10 metres by five metres of mud and declared it a ''safety zone'' for fire officers to work. The rest of the 20 metres by 30 metres of mud was still considered prone to further slides. ''It is still very unstable there,'' Mr Tong said. He said the work was moving slowly because of the continuing rain, the uncertain safety situation at the site and the fact that bodies were thought to be submerged. He said more manpower would be brought in to aid in the excavation once the conditions were further stabilised. Government engineers confirmed that the housing estate above was secure and dismissed speculation that it could collapse. But an unstable staircase was still a worry, engineers said.