The mine began in 1906, when Sir Paul Chater — one of colonial Hong Kong's most influential merchants and co-founder of Hongkong Land — put the Hong Kong Iron Mining Co. Ltd. to work on the Ma On Shan hillside. The first method was open-cut: surface rock stripped away, ore scooped from exposed seams. For over two decades, this opencast operation ran under Chater's company. After a gap in operations in the 1930s, a succession of operators kept the workings going through the chaos of the 1940s, including the years of the Japanese occupation from 1942 to 1945, when extraction continued under different management. The hillside held iron, and whoever controlled Hong Kong found a reason to dig.

In 1949, the Mutual Trust Co. Ltd. took over, and within four years they had fundamentally changed the character of the mine. Starting in 1953, the tunnels went horizontal, then deeper. By 1959, all mining had moved underground entirely. A joint venture with Japan's Nittetsu Mining Company began that same decade, creating a direct economic thread from the hillside in the New Territories to the Japanese steel industry. The tunnels multiplied. Miners spent their shifts underground in conditions that left their lungs full of dust and their bodies marked by hard physical labor in confined, dark spaces. Above ground, their families lived in Ma On Shan Village, which swelled to over 10,000 inhabitants at its peak — a community shaped entirely by what happened beneath the hill.

Mining communities carry a particular kind of solidarity forged by shared risk. The men who went down into the Ma On Shan tunnels each day understood that the mountain held dangers no surface farmer ever faced. Two churches — the Lutheran Yan Kwong Church and St. Joseph's Catholic Church, both inaugurated in 1952 — gave the village its social anchors. Schools were built, a clinic established. The community had its own small universe on the hillside, separated from the city below by distance and by the rhythm of shift work. When the mine faltered and then stopped, the social fabric went with it. The primary school closed in 1976. The Catholic church held its last regular Sunday service in 1981. By 1999 it was abandoned entirely.

The mine's end was shaped by forces thousands of miles away. In the 1970s, Japan restructured its heavy industry, shifting resources toward building supertankers rather than refining iron into steel. Demand for iron ore from Ma On Shan collapsed. The 1973 oil crisis compounded the pressure on global shipping and manufacturing, squeezing margins further. The Nittetsu joint venture became uneconomic. The government mining lease survived until 1981, but the real closure came five years earlier, in 1976, when the last workers walked out of the tunnels and 400 jobs ceased to exist. Estimates suggest that even after seventy years of extraction, 30,000 tonnes of iron ore remained in the rock — ore that was simply not worth the cost of reaching.

The structures left behind have gradually earned recognition. In April 2016, Hong Kong's Antiquities Advisory Board graded several mine remnants: the exterior walls of the 240 ML and 110 ML tunnel entrances achieved Grade 2 status; the Mineral Preparation Plant and the Site Structures at the Mining Settlement both received Grade 3 listings. These grades mark them as historically significant, requiring documentation and some form of preservation. Engineers have also proposed that the abandoned tunnels could serve a new purpose entirely — as underground chambers for compressed-air energy storage, a technology that captures surplus electricity as pressurized air and releases it on demand. The mountain that once fed Japan's steel mills might yet power Hong Kong's grid.