Ashio Copper Mine, Japan


This is a famous historical case in Japan that pitted two unequal forces against each other: the Furukawa Corporation and peasant protesters. Prior to the Ashio mining activities before 1880, the surrounding area was densely forested. The destruction of the trees caused by the concentrated sulphurous acid from the mines, caused the erosion of the topsoil, which allowed the rainwater to flow directly into the river. As a result, the Watarase River carried the poisons and affected the agricultural lands nearby. To further worsen the problem, the Ashio mine lacked storage facilities for the slag and untreated ores. Thus, these materials accumulated in the rice-fields through the irrigation systems and caused the topsoil to turn hard like cement. As the copper mining continued, damage to the agricultural lands increased, the farmers were forced to close the irrigation canal gates to keep out the poisons every time it rained. The poisons also affected the quality of drinking waters, which had a serious affect on the people’s health.

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Basic Data
NameAshio Copper Mine, Japan
ProvinceTochigi Prefecture
Accuracy of LocationMEDIUM regional level
Source of Conflict
Type of Conflict (1st level)Mineral Ores and Building Materials Extraction
Type of Conflict (2nd level)Tailings from mines
Mineral processing
Specific CommoditiesCopper
Project Details and Actors
Project DetailsAround 1900, between 8000 and 9000 tons of copper were produced per year. In 1890, during the first major flooding, 1600 hectares of farmland and 28 towns and villages in the Tochigi and Gunma prefectures were severely damaged.

In 1893, the conditions on the Ashio Area Mountains that were deforested was approximately 31,360 acres.

In 1899-1890, Shozo Tanaka created a survey of the birth to death ratio in order to show that the copper mine was responsible for murder. 12 villages in the Tochigi and Ibaragi Prefectures were surveyed for the years between 1894 - 1899. The results of the survey showed that the total number of the population is 6,182 in the 5 years whereby the deaths were about 939, and the births were 865. Tanaka also calculated the national average of deaths that took place in 1898 and compared to the areas that were affected by the tragedy, and found out that while the national birth rate was 3.21 and the deaths were 2.60, in the affected areas the births were 2.80, and the deaths were up to 4.12.

Since the copper mining incident affecte a whole different range of areas, people, animals, and crops, it is very difficult to figure out the extent of damage that was done by the mine poisons.
Project Area (in hectares)1600
Type of PopulationRural
Potential Affected Population25000
Start Date1895
End Date1973
Company Names or State EnterprisesIchibei Furukawa from Japan - Owner of the Ashio Copper Mine
Relevant government actorsEmperor of Japan, Prefecture of Tochigi
International and Financial InstitutionsJardine Matheson from China - signed a contract with Furukawa in 1886 - 1887, which allowed Furukawa to obtain technology for mining
Environmental justice organisations and other supportersShozo Tanaka, farmers´ organizer, member of the Diet
The Conflict and the Mobilization
Intensity of Conflict (at highest level)HIGH (widespread, mass mobilization, violence, arrests, etc...)
When did the mobilization beginMobilization for reparations once impacts have been felt
Groups MobilizingFarmers
Landless peasants
Local government/political parties
Fisher people
Forms of MobilizationMedia based activism/alternative media
Official complaint letters and petitions
Public campaigns
Referendum other local consultations
Street protest/marches
Appeals/recourse to economic valuation of the environment
Environmental ImpactsVisible: Air pollution, Biodiversity loss (wildlife, agro-diversity), Floods (river, coastal, mudflow), Food insecurity (crop damage), Loss of landscape/aesthetic degradation, Soil contamination, Soil erosion, Waste overflow, Deforestation and loss of vegetation cover, Surface water pollution / Decreasing water (physico-chemical, biological) quality, Groundwater pollution or depletion, Large-scale disturbance of hydro and geological systems, Mine tailing spills
Potential: Genetic contamination, Reduced ecological / hydrological connectivity
Health ImpactsVisible: Exposure to unknown or uncertain complex risks (radiation, etc…), Deaths
Potential: Malnutrition, Infectious diseases
Socio-economic ImpactsVisible: Increase in Corruption/Co-optation of different actors, Displacement, Lack of work security, labour absenteeism, firings, unemployment, Loss of livelihood, Loss of traditional knowledge/practices/cultures, Violations of human rights, Loss of landscape/sense of place
Project StatusStopped
Pathways for conflict outcome / responseCompensation
Environmental improvements, rehabilitation/restoration of area
Do you consider this as a success?No
Why? Explain briefly.There was mining for many decades. In the end, although these tragic events served as a motivation for the government to enact laws against industrial pollution, the environmental activists themselves did not achieve anything, since the people from the Yanaka village were still displaced and their original homes destroyed. The compensations were given to the farmers, but they were insufficient compared to the damage that was caused. The memory remained of Shozo Tanaka's movement.
Sources and Materials

Environmental Conflicts, Environmental Justice, and Valuation
[click to view]

Kenneth Strong, Ox Against the Storm: A Biography of Tanaka Shozo: Japan's Conservationist Pioneer, 1995


Institute of Developing Economies - Japan External Trade Organisations
[click to view]

United Nations University
[click to view]

Other Documents

Tanaka Shozu
[click to view]

Tanaka Shozu
[click to view]

Meta Information
ContributorYuki Sasaki
Last update26/03/2019