“We won’t go any further, it’s not safe,” says Chu, as the beam from his powerful torch illuminates a pile of granite boulders the size of large suitcases, which have fallen from the collapsed roof.

While working for a mining consultancy in Kazakhstan, Chu and a colleague, Jacky Chan Sik-lap, decided to write a book titled Hong Kong Mining History (2015). It was a labour of love rather than a commercial venture but they have sold more than 1,500 copies and the weekend group tours to disused mines Chu leads are usually oversubscribed.

Above Chu’s head, the large gap where the quartz vein once was rises to the upper reaches of a network of adits and shafts that extends for more than 3km, through Needle Hill, adjacent to the Lower Shing Mun Reservoir. The Shing Mun Tunnel Road passes within a metre of the bottom of the extensive mine network.

On this cold winter’s day, it is surprisingly warm and humid this far inside the mine. Chu says it remains about 18 to 20 degrees Celsius all year round as he searches for some of the dark grey wolframite mineral embedded in the mine walls, near the site of the quartz vein. Apart from Chu’s echoing voice, there is only the sound of dripping water.

“Yes, that’s it,” he says, shining his torch about 20cm from the adit ceiling as the mineral glints in the light.

During its operational peak, in the 1950s, when tungsten was in high demand for the armour-piercing munitions used in the Korean war, the mine employed more than 2,000 men. About 222 tonnes of wolframite concentrate was extracted annually.

On exiting the adit into blinding daylight, Chu points out the concrete shells of what were once ore-processing sheds, accommodation blocks and a canteen, now being reclaimed by vegetation. There was a good road here, too, which linked Needle Hill with Tsuen Wan, so that ore concentrate could be transported by truck for export.

Records show that the first mining permit for Needle Hill was issued in 1917 and a South China Morning Post report in June 1920 stated that, “The output from the Needle Hill mine averaged about 30 piculs [a unit of weight defined as a ‘shoulder load’] of wolfram ore per month [in 1919].”

Mining was sporadic during the 20s, because of unstable prices, and was restricted to traditional methods – shallow surface cuts and short adits – due to ventilation problems.

In 1935, while the Shing Mun Reservoir was under con­struction, resident engineer Gordon Gifford Hull spent a lunch break panning in a stream. He recognised wolframite-rich placer deposits (the accumulation of minerals formed by gravity separation during sedimentary processes) in sediment being excavated from the Upper Shing Mun River. This was of a higher grade than the wolframite that had so far been mined in the area and he traced the mineralisation to the quartz veins on Needle Hill.

Hull obtained a mining licence in the same year but the lease was subsequently transferred to Marsman Hong Kong (China).

“The agreement with the Hongkong Government which Mr J. H. Marsman signed on Monday grants to Marsman Investments Ltd a 21-years’ lease, on a royalty basis, to develop the wolfram deposits over an area of approximately 540 acres near Needle Hill and the Shing Mun River,” reads a May 13, 1936 Post report.

Jan Hendrik Marsman was a Dutch engineer and entrepre­neur who had extensive business interests in the Philippines. He successfully ran the Needle Hill mine until the Japanese invasion, in 1941. According to anecdotes from the time, Marsman missed his early morning call at the Peninsula hotel and thus the last Pan Am Clipper out of Hong Kong before the Japanese army arrived. He later escaped to the United States and wrote a book about his exploits.

Perhaps Marsman himself walked in this part of the mine during a tour of inspection, Chu suggests, pointing to a flood­ed shaft full of limpid water as a bat flutters past his head.

The Japanese worked the mine but left it in a state of acute disrepair. Marsman Hong Kong (China) was wound up in 1952. According to the Post report on the company’s demise, more mechanisation had been considered for Needle Hill, then dismissed “in view of the declining price of wolfram ore”.

The company had also been working the Castle Peak Mine, but that had been made untenable by an obstacle that has scuppered many a Hong Kong venture: uncoop­erative neighbours.

“Negotiations were entered into with the owners of the adjoining property to permit the passage of wheeled vehicles over their lots to gain access to the mine,” read the report. But the owners’ demands were “out of reason” and it was decided to defer any further capital expenditure.

Chu’s research reveals the Needle Hill mine was sub-leased to the Hoong Foo Mining Company from 1951 to 1955. It was then closed and reopened by the Yan Hing Mining Company.

Stephen Hui Sze-fun was the chief mining engineer and general manager of Yan Hing, working on the exploration of Needle Hill and Lin Fa Shan wolframite mine, in the northern New Territories. Yan Hing closed the Needle Hill mine for the final time in 1967, when tungsten prices were dropping and labour costs rising, but Hui went on to become a major influ­ence in local geology, amassing a comprehensive collection of minerals, which formed the basis of the first geological exhibition to be held in Hong Kong, in May 1976. He lends his name to the Geological Museum, at the University of Hong Kong, in Pok Fu Lam, to which he donated his collection.

Hui had been one of thousands employed in Hong Kong’s flourishing mining industry; Chu says he has found records of about 60 applications for mine licences between 1906 and 1980 and 20 known sites across Hong Kong are described in his book. In the years after the second world war, there were estimated to be more than 5,000 illegal miners in the New Territories.

Chu says that for such a small place, Hong Kong has extremely rich and diverse mineral resources, due largely to its location on an important old part of the Earth’s crust, known as the Cathaysia Block.

During the Mesozoic era (164-140 million years ago), Hong Kong lay on the Lianhuashan fault zone and experienced a lot of volcanic activity. This created enormous geological diversity and rocks and minerals would become one of the few commodities that Hong Kong could claim to be self-sufficient in. Tungsten, iron, lead, silver, beryl, graphite, quartz, feldspar and kaolin were all commercially exploited in Hong Kong before the 1980s, according to government records. Quarrying was also important and Hong Kong granite not only helped build this city, but was also used in the construction of notable buildings in other parts of the Pearl River Delta, including the Gothic French cathedral in Guangzhou.

Mining in Hong Kong did not begin in colonial times. The Map of the San-On District, compiled by Italian missionary Simeone Volonteri, in 1866, clearly shows a lead mine north­east of Shing Mun, the inspiration for the modern-day name Lead Mine Pass. Some think that mine was close to the Ng Tung Chai waterfalls, where there were 20th-century workings for zinc, copper and lead, but the exact location remains a mystery. And, according to Chu, the Portuguese were known to have mined galena (the mineral from which lead and silver can be extracted) at Lin Ma Hang, near the current boundary with the mainland, during the 1860s.

The Hong Kong mining boom of the 1950s and a corres­ponding increase in illegal digging was economically signi­ficant enough to persuade the government to pass special legislation. The Prospecting and Mining Ordinance had been passed in 1906 but, in 1951, the commissioner of labour suggested the time had come to put mining on a proper legal footing, not only in the interests of the health and safety of the workers engaged in the industry, but also in the interests of the economy. A beefed-up ordinance was passed in October 1954. Despite the paternalistic tone, this was principally about making money; as the official Legislative Council record notes, the total value of all minerals “won” in the year 1953 was nearly HK$4.4 million. The council’s considered view was that with the introduction of modern machinery and up-to-date methods, there were “good prospects of further development”.

The 1954 ordinance also created a Mines Department and a commissioner for mines and, perhaps surprisingly, 63 years after its formation and long after the last Hong Kong mine was shut down, the Civil Engineering and Development Department still has a mines division. What is more, there is also a commissioner for mines, Lorne Woodrow, chief geotechnical engineer/mines, who said he wanted to help with this article but unfortunately had “other urgent matters to handle”.

The Silvermine Cave, in Mui Wo, Lantau, is the only former mine recognised as a visitor attraction and its history can be traced back to the Ming dynasty.

It’s a pleasant 30-minute trek from the ferry pier but arrival at the cave can be something of an anticlimax. The scenic waterfall below the mine is obscured by a concrete barbecue area and the site is marred by a public toilet block resembling a Tang-dynasty space rocket plastered in lurid red tiles.

The entrance to what was the Mui O silver and lead mine extends for about 10 metres into the mountain, where pass­age is blocked by a concrete wall that allows access to about 1,000 resident bats but not curious humans. The interpret­ation panel near the mouth of the cave contains little infor­mation but, Chu says, the Man Mo temple in nearby Pak Ngan Heung (literally “white silver village”) is thought to date back to the late 1500s. Legend has it that the temple served as a venue for the settling of mining disputes between villagers. If true, that would make Mui Wo by far the oldest mining concern in Hong Kong and important evidence of early industrial activity in the region.

By 1888, Ho’s engineers had driven at least four adits, and a dam 600 metres up on the hillside supplied hydraulic power to the mine’s pumps and lifts. A ropeway took mined ore over rice fields and a hill to a smelting works near the seashore, some 900 metres away on the north side of Silvermine Bay. The processing plant, supplied by a British company called Robey & Co, was more than 70 metres long and designed to handle 40 tonnes of ore a day. The works’ 60-foot chimney was listed as a navigational aid for ships until the late 1930s but the mine ceased oper­a­ting sometime in the 1890s, when, it was rumoured, the abandoned adits became hideouts for pirates.

As many as 1,000 men were employed at any one time at the Ma On Shan iron mine, about 10km from Sha Tin, which operated from 1906 to 1976. In the later years, many were former Kuomintang soldiers and refugees from the Chinese civil war desperate for work.

The open pit in Ma On Shan remains, although it is mostly covered in vegetation, and the 5km of adits have been sealed off. Some locals have been trying for years to get support to turn their village into a mining heritage site.

Chu, who also leads tours to the Ma On Shan mine, as well as the Lin Ma Hang lead mine and the West Brother Island graphite mine, which produced crystalline carbon that was used to make the control rods of Britain’s nuclear power plants, admits he has been taken by surprise by the level of interest in this little-known aspect of Hong Kong’s industrial history.

“I think people are interested in the history and the geo­logy but I have noticed a big increase in interest in anything concerning Hong Kong’s past over the last five years or so,” he says.

Last month, Chu, along with artist and curator Vicky Ho Yim-ting, unveiled a small exhibition to celebrate the mining industry, at the TC2 café, in Prince Edward. The response – from people of all ages and backgrounds – has been so posi­tive, the café owner has extended the exhibition until the end of this month.

“I read Hong Kong Mining History and thought it would be perfect for a community arts project,” says Ho, pointing to mineral samples displayed on place mats with her original drawings repre­senting Hong Kong’s proud mining tradition. “Art lovers go to galleries and book lovers go to bookshops but, here, anyone can engage with this local story.”

Ho’s paintings of miners and their equipment, inspired by pictures from the time, adorn the walls of the café along with landscape photography of the mine areas, which many diners refuse to believe were taken in Hong Kong.

“It would be good to have a permanent exhibition to remember the industry but it’s very hard to find a suitable venue,” says Ho.

As revealed by place names such as Silvermine Bay, Lead Mine Pass and Quarry Bay, mining and quarrying are an integral part of the Hong Kong story. These abandoned mines and the stories of the people who worked them are a vital link in the city’s economic history. Because they are remote, the mines are not subject to the same development pressure as heritage sites in urban areas and they do not require multimillion-dollar restoration budgets. Yet, with the exception of Mui Wo, they remain forsaken and derelict.

“I strongly support the idea of turning mines into geological and historical trails, particularly those in more easily accessible locations,” says Chu. “Needle Hill would be ideal because it’s only 20 minutes’ walk from Shing Mun Reservoir.”