Over the period between 2023 and 2024, the Civil Engineering and Development Department and its project team (hereafter as "the Project Team") under works Contract No. GE/2022/23 transformed the abandoned lead mine into an open museum. In planning and designing the revitalisation project at the Lin Ma Hang Lead Mine, the project team strived to strike a balance between enhancing the stability of the caverns and preserving the natural landscape. Preliminary site investigation and stability analysis carried out by the Project Team revealed that stability enhancement works at the lead mine were necessary. Concrete buttresses were installed to reinforce existing rock pillars which provided direct support to the roof. Other stability enhancement works such as rock dowels, wire mesh and grout strengthening works were installed as necessary. To facilitate blending of man-made structures with natural surroundings, rock decorative panels were installed to conceal the concrete (Fig. 1 & 2). Moreover, to enhance safety and visitor experience, a series of revitalisation works were carried out between 2023 and 2024 in the adit, including reinforcement of adit walls and rock block, improvement of drainage and installation of a solar-powered lighting system. fter revitalisation, the adit was transformed into the "Mine Adit Adventure", to let visitors to have an immersive experience of the mine adit (Fig. 3 & 4).

Fig. 1. Rock Dowel and Wire Mesh	Fig. 2. Concrete Buttress and Artificial Rock Cladding
Fig. 3. Mine Adit Adventure	Fig. 4. Solar-powered lighting

During World War II, the Japanese military inspected industrial facilities in Hong Kong after the occupation. They found that the mine produced lead, which was an important military resource at that time. The Japanese took over the mine and forced villagers to work there. Lin Ma Hang villagers joined forces with the Anti-Japanese guerrillas, trying to damage the mine and attack the Japanese forces. In the third attempt, the villagers and guerrillas successfully drove away the Japanese and damaged the mine. This series of anti-Japanese attacks are known as "Three Raids at Lin Ma Hang Lead Mine".

Fig. 5. Inspection report of Hong Kong by the Japanese Military (Japan Center for Asian Historical Records)

The natural landforms in Lin Ma Hang area have been shaped by regional tectonic activity, weathering and fluvial erosion. The once existed mining activities followed Pb-Zn-Ag (lead-zinc-silver) mineralisation enriched by faulting events and metamorphism in Lin Ma Hang area.

The major rock type in the area is coarse ash crystal tuff of the Tai Mo Shan Formation (Fig. 6). During some violent volcanic eruptions in the Middle Jurassic Period about 165 million years ago, large volumes of volcanic ash, comprising predominantly broken crystals, were ejected, deposited in the area, and cooled down quickly.

Regional metamorphism with faulting is evident in the volcanic terrain. The faulting events might be associated with increased hydrothermal activities, ultimately allowing enrichment of Pb-Zn-Ag mineralisation along vein systems. In addition, here is a fault zone that spans several hundred metres. The rock layers on either side of the fault have shifted and rubbed against one another, leading to intense fragmentation and shearing of the rocks within the fault zone, which formed mylonitised fault breccia (Fig. 7).

The major ore mineral is galena (lead (II) sulphide) and there are minor sphalerite (zinc sulphide) and silver. The ore body found here had high economic value as the grade of lead contains up to 10%-12% by weight and 2 to 3 oz (i.e. around 57 to 85 g) of silver per tonne in average.

Fig. 6. Tai Mo Shan Formation

Fig. 7. 1. Coarse ash crystal tuff 2. Mylonitised fault breccia 3. Stabilisation Works Arrow: The fault