JICA EPP Training Review (1) The Ashio Copper Mine P ollution Case

1. JICA EPP Training Review (1)The Ashio Copper Mine Pollution Case October 2011 JEMAI Kenzo OHOKA

2. The Ashio Copper mine history • The original Ashiocopper mine was discovered in 1550 • New copper lode was discovered in 1610 and the Government owned and operated the copper mine • Ashio mine had been the property of the Government, Tokugawa shogunate since then • Ashio copper was utilized for Edo castle roofing and for Nikko Toshogu Shrine roofing in 1651 • Annual copper production had been 1,300 ton ~1,500 ton during 1676 - 1688 • Annual copper production 1600s was gradually decreased. • Annual production declined and became 150 ton in 1700 • To save the local workers they strikes 20 million coins for 5 years from 1742 • The mine was temporarily closed in 1817

3. The Ashio Copper mine history • Edo period finished and the Meiji era started (1867) • Ichibei Furukawa owned the mine in 1877 and he dramatically redeveloped the mine in Meiji era • Thanks to the additional mine discoveries in 1881 and 1884, the copper production increased very rapidly • He introduced advanced technologies • Ashio became the mine with the highest copper output in Japan, producing 68 per cent of the Japanese total amount in 1884 Ichibei Furukawa (1832～1903）

4. Technical improvement and Mine pollution • Ichibei Furukawa; More efficient output by introducing new techniques and equipment • Ore-digging and crushing equipment (a steam-operated pumping method etc.) • The horizontal mining method • In September 1885 when the Ashio mine was flooded, the technical limitations were revealed but recovered the mine operation within three years • Hydraulic power plant was built in 1890 • An electric railway was built between the mine and the refining area • Mine pollution occurred by flooding and the local paper put news articles about the pollution in 1890

5. Bessemer Smelter and Mine Pollution • The discovery of the additional large copper ore lode 1880s More production  more pollution generated • The entirety of the once-forested areas around the Ashio refinery had been destroyed by the end of 1884 • Deforestation (mine lumber and fuel etc.) and pollution • In 1893 Furukawa installed a Bessemer smelter • Refinery processing time was reduced from 32 days to 2 days • The Ashio copper mine became the leading copper producer in Japan

6. Bessemer process • The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron • The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855 • The process had also been used outside of Europe for hundreds of years, but not on an industrial scale • The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron • The oxidation also raises the temperature of the iron mass and keeps it molten • The oxidation process removes impurities such as silicon, manganese, and carbon as oxides. These oxides either escape as gas or form a solid slag

7. Two major pollution sources in Ashio • Smoke • Fuel burning gas (combustion) • Smelting gas Sulfurous acid gas, SOx; sulfur dioxide etc. • Waste water • Process water • Leachate out of mine tailings • Flood overflow waste water Cupper compounds, iron compounds, and sulfuric acid were identified out of the river water in 1892

8. Frequent flooding in 1896 • After modern technology systems had been installed, several floods occurred in 1890 -1896 • The Watarase river basin, and about 1,600 hectares of farmland and 28 towns and villages downstream in Tochigi and Gunma prefectures were heavily damaged by the floodwater, which contained mine poisons from the Ashio mine • Headwaters of Watarase river had no trees and no plantsin 1960s

9. Floods & Catchment (Watarase river basin) • After modern technology systems had been installed, several floods occurred in 1890 -1896, especially in 1896 • The Watarase river basin, and 1,600 hectares of farmland and 28 towns and villages downstream in Tochigi and Gunma prefectures were heavily damaged by the floodwater, which contained mine poisons from the Ashio mine • The Watarase drainage basin • Used to be flowing to Tokyo • Changed to the pacific ocean Figure: WataraseRiver Office

10. Ashio water-borne poisons • The destruction of agricultural ecosystems by the Ashio water-borne poisons became very serious [accumulation] • In October 1890, local people asked the prefectural hospital to do some tests for water-borne poisons • They published the results of soil analysis and other surveys related to the Ashio mine poisons. carried out by Professor of the Agricultural University, but the book was immediately confiscated by the authorities ‘Industrial pollution in Japan’, Edited by Jun Ui, The United Nations University, 1992 • In December 1890, the residents of Azuma Village, Tochigi Prefecture, appealed to the governor of the prefecture to call a halt to the mining operations • The first appeals and the movements against pollution • Other municipalities both in Tochigi & Gunma followed the Azuma village

11. Stream and its drainage basin • Tributary streams • Flowing downhill through mountainous area • Erosion and sediment transportation • Carries gravel with the finer sediments • Mid-stream area • Deposition of sediments start • Watarase Reservoir area • Deposition of sand and fine sediments (Mine pollutant settles in this area)

12. Longitudinal profile of Watarase River ‘The past and present problems of Geo-Environment for the Ashio Copper Mine and the Watarase Reservoir’ Guides: Y. Momikura, N. Wada, and K. Takashima (2002 International Geo-pollution workshop)

13. Shozo Tanaka • Sulfurous acid gas (Ashio refinery) • Forest dieback (killing trees, some used as fuel) • Lumber and/or deforestation (wood for the mining operation such as mine timbers) • Soil erosion, then, increased runoff water, flooding • Crops deterioration etc. • Local people including downstream area asked Shozo Tanaka, a member of the Lower House to solve the pollution problems

14. Shozo Tanaka • 1891 • He submitted questions to the Imperial Parliament (Diet) about the mine poisonsof Ashio • 1901 • He tried to appeal the mine poison case to the emperor but failed • All village people (Matsuki-mura) sent a claim letter to the Imperial parliament • 1902 • Four villages including Matsuki-mura were abolished because of heavy air pollution from the refinery

15. Shozo Tanaka • In December 1891 Shozo Tanaka, a member of the Lower House from Tochigi Prefecture, demanded that mining at Ashio should be stopped, drawing on Article 27 of the Imperial Constitution which guaranteed the inalienable right of petition and pointing out the fact that Japan's Mining Laws stipulated a withdrawal of the right to mine if mining operations damaged public welfare • Along with this action Tanaka requested that Mutsu, who was then Minister of Agriculture and Business, take complete responsibility for the damage done to the agricultural sector by the mine-related poisoning

16. Shozo Tanaka • However, before any action could be taken in this regard, the second Diet session was dissolved over budgetary issue confrontations between the government and opposition parties. • The government's answers to Tanaka's questions and demands appeared in Kanpo, the government newsletter. which said that the causes of the damage to the agricultural systems in the areas around the Ashio mine were unknown and were under investigation; the company would be reprimanded for the discharge of poisons from the mine and ordered to install pulverized ore-dust collection equipment so as to prevent the outflow of poisons.

17. Massive flood in 1896 • In September 1896 a massive flood, larger than the one attacked on the area in July of the same year, was caused by torrential heavy rains, and the Watarase River overflowed their banks downstream • Mine tailings including heavy metals were washed away and transported, then, spread over the farmland through broken banks in Tochigi and Gunma prefectures

18. Meiji Government’s order for improvement Pollution prevention countermeasures (1st ) • Removal of potential pollutant at the mine site • Step by step countermeasures including beneficiation/dressing (ore sorting) • More efficient methods to remove fine powder ore in the waste water, should be introduced • Removal of potential pollutant especially soluble copper and free acid etc. • Mine tailings must be piled higher places having no flood risks

19. Mine tailings There are 14 tailing piles in Ashio town

20. Meiji Government’s order for improvement Pollution prevention countermeasures (2nd) • The Government ordered Ahio Mine to use a settling pond for waste water in 1896 • Some settling basins are under operation now

21. NakasaiJosuijo

22. Meiji Government’s order for improvement Pollution prevention countermeasures (3rd) • Smokestack must be improved by • Off gas equipment (Sulfurous acid gas) • Location not at mountainside but at the mountaintop • Stacks must be higher than 24m (main) and 15m (Kotaki) (Sulfurous acid gas generated from refineries were collected and sulfuric acid was manufactured in 1960s)

23. Watarase flood control reservoir Watarase River used to flowing onto Tokyo bay. New channel was made and it now flow into Tone River . There was a possibility to cause pollution in Tokyo area. They decided to create a huge flood control reservoir . Figure: WataraseRiver Office

24. The outer circumference of all resorvoirs is about 30 km and the area is 3,300 ha. The volume of water storage will be about 26,400,000 m3.

25. Yellow area has highly contamination (1909 map)

26. They considered that the flood control would be the best solution to prevent future pollution in Tokyo area and started to make a huge reservoir in 1911 • Strong typhoon hit Watrasedrainage basin as shown in the left pictures and they utilized the reservoir in 1963 • The location was Yanaka village where all farmland was heavily contaminated by Ashio mine poisons.

27. Watarase flood control reservoir When it is flooding the reservoirs can contain lots of water as shown in left picture (2002). The circumference of the main reservoir is over 9 km.

29. Watarase flood control reservoir

30. Third resorvoir

31. Watarase River Officeinstructs how to check river water (Web) http://www.ktr.mlit.go.jp/watarase/wata/k_m_a/1516.htm