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Early prospecting and extraction attempts

Early attempts from prospecting to extraction at MOS were carried out not quite smoothly. On the one hand, extraction at that time relied on primitive manual work and was unproductive. On the other hand, iron ores extracted could hardly find their market due to high transportation cost. Some small amount of iron ores was sold to the local Green Island Cement Company after Sino-Japanese War broke out which affected the importation of raw materials from China. After Canton (Guangzhou) was occupied by Japanese army, some businessmen considered developing smelting industry in Hong Kong but their plan was never materialised as Hong Kong soon came under occupation of the Japanese as well.

MOS was found to contain iron ores.
Hong Kong Iron Mining Company (HKIM) under the leadership of Sir Paul Chater, a powerful businessman cum politician in the colony, was granted a prospecting and a mining license, and thus planned to operate at MOS and develop a steelwork in Hong Kong.
Sir Paul Chater passed away. HKIM ceased its development plan and surrendered the mining lot.
New Territories Iron Company (NTMC) was granted a lease of mining for 50 years.
Japanese military occupied Hong Kong. It was said that the Japanese hired about 1500 workers to extract iron ores from MOS for military supply.
Mining right was subleased to South China Iron Smelters (SCIS).


Operation by Mutual Trust Company

After the end of World War II, the international arena experienced tremendous political and economic changes, transforming the fate of the MOS Iron Mine. A trading company, Mutual Trust Company (later renamed as Mutual Mining and Trade Company, MMTC) took over the operation of the MOS Iron Mine and started to earn foreign exchange through shipping the extracted iron ores to Japan. Hong Kong also received a large amount of refugees from mainland China due to the Chinese Civil War, and some of them became miners in MOS. The worsening of the Cold War forced the US-led ally power to withdraw from Japan and support the recovery and revitalisation of its economy in order to resist the expansion of communism in Asia. Japan’s demands for raw materials, therefore, increased drastically as its economy regained strength, especially during the period of the Korean War. The trade embargo placed on mainland China, which used to one of the major sources of Japan’s raw materials, forced Japan to turn to other places for iron ores.


The currency and trade conflicts between Japan and UK added another factor for Japan to seek purchases from British Colonies in Southeast Asia such as Hong Kong to use their British pound reserve (that faced the threat of devaluation). These macro factors provided a window for the MOS Iron Mine’s post-war development.


The quantity and quality of iron ores extracted by open-pit mining at the MOS Iron Mine could not satisfy the Japanese buyers.The Japanese steel makers entrusted a Japanese mining company, Nittetsu Mining Corporation, to conduct some investigation works at MOS. The positive result indicated the existence of a reasonable amount of iron ores and their grade could be improved if underground mining and ore dressing technique practised at Nittetsu’s Kamaishi Mine could be adopted. This resulted in an agreement between Mutual Trust Company and the Japanese company, allowing Japanese steel makers to continue their purchase of iron ores from the MOS Iron Mine under the condition that Nittetsu Mining Corporation provided technological investment and operational support. The MOS Iron Mine entered a new era.

Mutual Trust Company signed a contract with SCIS who lacked capital at the time and started its operation at MOS.
Three students studying at the Lutheran Theological Seminary visited MOS and started their missionary work.
Nittetsu Mining Corporation sent eight technical staff to MOS.
The Catholic Church was completed.
The Evangelical Lutheran Church was established at MOS.
Nittetsu Mining Corporation and Mutual Trust Company signed an agreement on their cooperation.


Japanese investment and mechanisation of the Mine

Nittetsu Mining Corporation set up their Hong Kong branch office formally at the beginning of 1954 and started its operation at MOS. This office was also the first overseas branch of a Japanese firm after WWII. Since then, iron ore extraction at MOS gradually moved from open pit to  underground stoping. Tunnels were dug at various levels and made into grids to reach the ore body, which was divided into different levels following a vertical direction and sub-divided into different cube blocks at the same level. Iron ore body was exploded into smaller pieces and these crude ores dropped through vertical chutes all the way to the lowest level where they were transported out by electric locomotive from the tunnel.


Two ore dressing plants were constructed with equipment imported from Japan to improve the grade of these crude ores before they were shipped to Japan from the pier. These improvements mechanised the MOS Iron Mine and led to the increase of its output and scale.

Nittetsu Mining Corporation established Hong Kong branch office. Ore dressing plant started construction and completed by the end of the year.
Underground tunnels from 240ML to 268ML were completed and iron ores started being extracted from underground.
All extraction went underground.
Prospecting investigation found more iron ores below 240ML and the construction of 110ML transport tunnel facilitated the extraction of the ore body at the lower part.
underground tunnel.png
110ML tunnel was completed, which marked the MOS Iron Mine’s mechanisation and entry into a stable production period.


From stable production to gradual loss of advantages and closing down

Output, all shipped to Japan, stepped up gradually after the Mine shifted to underground extraction, from an annual production of 120,000 tons in the late 1950s to over 170,000 tons by the end of 1960s and peaked at 189,000 tons per year in 1971.


It, however, did not last too long. Japan’s rapid economic growth in the 1960s resulted in increasing demand for raw materials and the rapid development of Japan’s shipping industry and lowering marine transportation costs facilitated their import of raw materials from more overseas destinations. Main source of iron ores during this period shifted from Southeast Asia to South America and Australia. Hong Kong lost its advantage in its proximate location and low unit price in comparison to these large overseas sites with much cheaper ore production.


After the first oil crisis in 1973, production of iron and steel slowed down and Japan’s stock of iron ores exceeded its demand. Given all these factors, the MOS Iron Mine was finally shut down in 1976.

Mining activities have contributed to environmental impacts and landscape changes. Trenches left behind by prospecting can be found in MOS. Open-pit mining also created benches and steep cliffs, destabilising slopes, leading to frequent landslides.


Transportation and waste dumping also caused soil and water pollution then. Expanding production activities also brought more workers and their families to the site, changed the landscape, polluted the environment, and also affected indigenous villagers’ agricultural activities.



The environmental impacts are mainly brought by the extraction of crude ferrous rocks and the evolved transportation system throughout the open-pit and underground mining operations. Surface and stope mining had caused topographical changes and landslides while transportation of the crude ore by trucks had caused air pollution, threatening people’s life and livelihood. The dumping of waste also contributed to topographic changes.


Iron Ore Processing

No poisonous chemicals were required during the ore dressing process in the MOS Iron Mine due to its special magnetic property. However, the soil surrounding the dressing plant was contaminated with different amounts of heavy metals and the main source of dust was from the dressing plant during operation. Ore dressing processes had resulted in re-distribution of the metallic elements, through waste stones dumping, polluting the natural environment.


Lived Communities

Communities living near the hilly and rugged the MOS Iron Mine faced many environmental changes such as recurrent hill fire that destroyed vegetation annually and flash floods in typhoon seasons, which could cause serious casualties and property loss. People living in MOS had adapted to local conditions through the construction of necessary structures on their own such as the Ping On Bridge linking the mining area and the surrounding settlements. While people had overcome the challenges, they also left their footprints on the landscape.

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