Miike coal mine explosion and disaster, Japan

The Mitsui Miike coal dust explosion on 9 November 1963 was the second deadliest coal mining disaster in Japan. 458 miners were killed in the accident and twice as many were permanently injured. Monetary compensation was small.


 A memorial ceremony was held on 9 November 2013 to mark the 50th anniversary of the country’s worst mine accident in the postwar era. [3] An explosion in 1963 at the Mitsui Miike coal mine in Omuta, Fukuoka Prefecture,  and Arao, Kumamoto Prefecture, which used to be one of the country’s largest, killed 458 workers. Another 839 suffered carbon monoxide poisoning.  The mine, which closed down in 1997, was operated by Mitsui Mining Co. On November 9, 1963, the explosion occurred in a mine tunnel roughly 500 meters below the mine ground-level entrance. The blast and flame caused roof fall in many areas in the tunnels, which then quickly filled with carbon monoxide.  It was the worst postwar mine disaster. Lack of safety provisions to prevent coal dust was the main cause. Coal dust was the cause. Coal-dust explosions are the worst type of explosion because there is a great amount of carbon monoxide produced. As a result of this, many mine workers continue to suffer from the long-term after-effects of carbon monoxide poisoning even if they are lucky enough to be rescued alive. Methane gas explosions create carbon monoxide when the density of the gas is high, but if there is not much gas it is more often than not dispersed in the air. However, in coal-dust explosions the story is a very different one. Coal dust, being a solid rather than a gas, does not burn completely, and high-density coal-dust clouds can be formed. This prevents adequate air circulation, contributing to the production of carbon monoxide. Even if a coal-dust explosion does not spread throughout the length and breadth of the mine, the resulting carbon monoxide gas does in fact spread in this way and all the workers are poisoned. The Miike mine explosion of 1963 was an example of this. [1]  It was common knowledge that maintaining the site clean and making the area moist by watering could prevent such explosions. These easy preventive measures had been in place on a routine basis. However, after a strong labour dispute  in 1960, the insufficient number of safety personnel, caused by the employer's productivity-first policy, failed to take those measures. In 1955 coal as a primary energy source provided 50 per cent of energy needs in Japan, but after the Miike labour dispute and mine explosion, the level decreased, dropping to 16.4 per cent by 1975, while the use of oil increased from 20.2 to 73.3 per cent. [1].  The accident was second worst in Japanese mining history and one of the worst ever recorded in the world, and resulted in a series of lawsuits that dragged on until 1987, when it is reported that each of the victims' families was awarded the modest sum of US$1,800.[2]

Basic Data
Name Miike coal mine explosion and disaster, Japan
Site Ōmuta
Accuracy of LocationMEDIUM regional level
Source of Conflict
Type of Conflict (1st level)Fossil Fuels and Climate Justice/Energy
Type of Conflict (2nd level)Coal extraction and processing
Specific CommoditiesCoal
Project Details and Actors
Project Details Coal production at the Miike mine was 14 tons per worker in June 1958, but this was increased to 44 tons as of October 1963. Mined coal was transported by a belt conveyor system, leading to an increase in coal production. In 1958 over 6,000 tons per day left the mine, rising to over 10,000 tons in 1962 and 13,000 tons by October 1963 at the time of the accident of 9 Nov. 1963 [1]

Coal-mine explosions can be sparked by methane gas filling certain areas that are not properly ventilated. Coal-dust explosions, however, present a particular problem, because coal dust is something that is produced at every point in the mining process and accumulates, through the movement of air and the transportation of coal, on the floors, walls, and ceilings of the mine, all the way from the mine entrance to the deepest shafts. Therefore, when a small explosion occurs somewhere in the mine, it is followed by a chain reaction fuelled by the coal dust, and the resulting explosion envelops the entire mine infrastructure.

According to the UNU publication [1], as regards compensation, "the loss of life and health cannot be compensated with money or other material goods. But for those who are victimized by the system, it is necessary to provide living expenses and to guarantee medical treatment. In the case of the Mitsui Miike coal-mine explosion the victims received very poor compensation. For the 458 deaths, compensation was set at 500,000 yen ($1,400 at an exchange rate of 360 yen to the dollar at the time), i.e. 400,000 yen ($1,120) for condolence money and 100,000 yen ($480) for the funeral costs. The initial proposal by the company was 100,000 yen ($480) per death, but the Miike mine labour union demanded one million yen ($2,800), and the negotiations concluded at the 400,000 yen ($1,120) level.

Up to that time the mining companies had not paid any money to victims' families when a death occurred. This understanding among mine-owners was brought into question when the Miike mine union demanded compensation. The executives of the union thought that the one million yen ($2,800) demand was rather high, as did the Sohyo (National Organization of Labour Unions), and in this regard the Miike mine workers were heavily criticized even by their own union organizations. This is a reflection of just how cheap life is when it comes to the profit-oriented use of working people."
Type of PopulationUrban
Potential Affected Population1400 dead and wounded
Start Date09/11/1963
Company Names or State EnterprisesMitsui & Co Ltd from Japan
Environmental justice organisations and other supportersSohyo (National Organization of Labour Unions)
The Conflict and the Mobilization
Intensity of Conflict (at highest level)LOW (some local organising)
When did the mobilization beginMobilization for reparations once impacts have been felt
Groups MobilizingIndustrial workers
Trade unions
Forms of MobilizationLawsuits, court cases, judicial activism
Refusal of compensation
There was a debate on the amount of compensation to be paid for loss of life and injuries.
Environmental ImpactsVisible: Fires, Other Environmental impacts, Air pollution
OtherCoal dust explosion
Health ImpactsVisible: Accidents, Occupational disease and accidents, Deaths
Socio-economic ImpactsVisible: Violations of human rights, Lack of work security, labour absenteeism, firings, unemployment, Loss of livelihood
Project StatusStopped
Pathways for conflict outcome / responseCompensation
Project cancelled
Development of AlternativesCoal mining stopped in Omuta in 1997 (years after the terrible accident), because of change in the energy matrix of Japan.
Do you consider this as a success?No
Why? Explain briefly.A major industrial disaster, the second largest coal mining explosion in Japan's history. Small compensations paid to families.
Sources and Materials

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A collection of the world's worst coal mining disasters. ("The Mitsui Miike coal mine explosion on 9 November 1963, was the second deadliest coal mining disaster in Japan after the Mitsubishi Hojyo Coal Mine Disaster in 1914").
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[1] The Miike coal-mine explosion (UN University publication on environmental problems in Japan, Takeshi Hayashi Project Co-ordinator)
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[3]The Japan Times, 9 Nov. 2013
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Media Links

Full report in The Japan Times of a historical film on the Miike coal mine made by Hiroko Kumagai, “Miike — Owaranai Yama no Monogatari” (“Echoes from the Miike Mine”)
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"This documentary by Hiroko Kumagai confronts the infamous Miike mine and 150 years of forced labor, strikes and explosions that modern Japan is still trying to forget."
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Other Documents

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Meta Information
ContributorJMA (suggested by Kenichi Matsui)
Last update23/12/2016