SERVING LIKE AN intricate system of veins and arteries, a vast network of nearly 200km of tunnels keeps Hong Kong's lifeblood moving. Without it, there would be no MTR, the KCR couldn't function, and road traffic would grind to a standstill. In fact, local life would be much like it was in the days when there were no cross-harbour tunnels. Back then, Kowloon was only accessible from the island by ferry, while Sha Tin and the New Territories were still seen as distant farming outposts. Consider also that without today's storm water drains, floods would be far more common. And with no underground pipelines to deliver water and dispose of sewage, the modern urban environment could barely exist. Therefore, we should offer our heartfelt thanks to the people who build and maintain these tunnels, not least because of the hardships they endure. 'Tunnelling is nasty work. It's dark, dusty, noisy and hazardous,' said Sam Ho, who, as principal engineering geologist with Geotechnical Consulting Group (Asia), spends much of his working life underground. 'You are always working in very confined spaces, like being a miner. And you have to be very careful since safety is a key issue,' he added. As a specialist in rock formations, Mr Ho can determine exactly where engineers should place explosives to blast their way through, and that expertise puts him right in the front line when decisions are made about the ever-expanding tunnel system. Over the past 27 years, Mr Ho can justifiably claim to have reshaped Hong Kong. He was involved in all of the cross-harbour tunnels, as well as the excavation of the MTR's labyrinth and the sinking of countless miles of waste water pipes. Throughout, there have been daily challenges and risks. 'It is a risky job because I'm always the first one in after the explosives, along with the shot firer who plants them,' he said. 'I have to assess the immediate danger and ensure it is safe to continue operating. Many times rocks have collapsed all around me.' When working underground, the golden rule is to be extremely careful and to know how to respond quickly in different situations. 'I know a lot of workers who have been seriously hurt,' Mr Ho said. 'Only recently, two drainage workers died inside a manhole investigating a gas leak in Sha Tin. We are very sensitive to accidents like that because we don't want them to happen to us. I have avoided any major incident, but you really need experience to be aware of all the potential risks.' The usual hazards include rock subsidence and poisonous gas. Therefore, tunnel workers carry a gas detector, while wearing PPEs - personal protective equipment - soon becomes second nature. The standard gear is a safety helmet, metal-plated boots, a reflective jacket, a torch, and a mask to protect the lungs from dust. The latter item is especially important for geotechnical engineers who are inside blast boreholes well before ventilation systems are installed. When tunnelling through Hong Kong's granite and volcanic tuff hillsides, falling rocks are a constant threat, but conditions can be even more dangerous in the soft mud and silt beneath the harbour. 'The danger when working beneath the water is flooding,' Mr Ho said. 'You can't run from that no matter how fast you move.' Nowadays, many excavations are done with giant boring machines, which resemble a submarine with waterproof compartments for the operators. The general public rarely catches sight or sound of them, but one such machine is currently boring away about 20 metres beneath Canton Road and the West Kowloon reclamation, to complete a 3.5km link between the KCR, MTR and West Rail lines. When not underground, Mr Ho does other engineering projects which involve blasting slopes to create the foundations for new developments. Given the local terrain, many of Hong Kong's biggest apartment blocks sit on platforms cut from the surrounding hillsides. 'These involve a lot of slope studies and design investigations,' he said, noting that nobody wanted to see a repeat of the mudslides that resulted in disasters in the 1970s and '80s. 'Disasters like that always relate to the soil and rock, so our knowledge is the key to safe development.' Mr Ho originally graduated in earth science from a university in Taiwan, and noted that the University of Hong Kong only introduced a similar course five or six years ago. His first job on returning to Hong Kong was as a field technician for a British consultancy firm, which led to a focus on soil mechanics and, in time, to specialising in engineering geology. After steadily climbing the career ladder for 20 years, he realised that he had become tied to his desk. As associate director and head of the entire geotechnical engineering department, he had turned into a businessman and an administrator. 'Geologists normally work outdoors, but I was sitting in an office taking care of accounts and looking for business in China,' Mr Ho said. 'I realised that wasn't what I was interested in.' So when GCG, a small independent consultancy specialising in tunnels and ground investigations, knocked on his door five years ago, he jumped at the chance. 'We focus on especially difficult ground conditions and tricky engineering designs, so it was like being set free,' he said. 'Ever since joining, I have spent nearly all my time out on sites, which I really enjoy. It is a great sense of achievement when you start a project with nothing but a mountainside and finish it with a completed tunnel or viaduct.' Every decision is crucial, since any wrong judgment could ultimately cost millions of dollars. For this reason, an engineering geologist needs both technical expertise and a wealth of experience. 'Unlike in business, there is no fast track,' Mr Ho said. 'Most geologists in Hong Kong are middle-aged, and young university graduates must realise they can learn the theory, but can't do the job without the experience. They will also find it is not an easy working environment. You have to be fit, either to clamber up hillsides or escape from dangerous situations.' To keep in shape, Mr Ho spends his days off walking in the countryside and enjoys nothing more than collecting rocks and fossils as he goes. 'I keep buckets of them at home,' he said. 'You find a lot of geologists are rock hunters in their spare time. Even when I'm hiking, or taking part in the Trailwalker every year along the MacLehose Trail, I'm always looking at the rocks.' BEWARE Risks Collapsing rocks, flooding, poisonous gas and falling in the dark Protection Safety helmet, metal-plated boots, torch, gas mask and a lot of experience Injuries Minor ones are inevitable but Mr Ho has been lucky to avoid serious injuries Working conditions Dark, dusty, noisy and dangerous Back again This is the final article in this series. We hope you have enjoyed learning more about dangerous jobs performed every day in Hong Kong. From next Saturday, September 16, Classified Post brings back the Moving Up series to showcase individuals who are reaching new career heights and to share their tips on achieving career success.