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Overview

ID番号 N53786 更新日 平成29年3月22日

Overview – The former Matsuo Mine

iwate map

The remains of the Matsuo Mine are located in the mountains of Hachimantai in northern Iwate. The mine is near the upper reaches of the Aka River, which in turn flows into the Kitakami River that runs all the way to the Pacific. For a time, the mine prospered from the production of sulfur, and it was known as a “paradise above the clouds”. However, cheaper sulfur started appearing in the market collected through desulfurizing heavy oil, and due to that among other things, business eventually slowed. Eventually, the rights to mine were renounced, and the mine closed in effect in 1972. Unfortunately, it left behind a huge societal issue. Highly acidic runoff from the mine drained into the Aka River, polluting the Kitakami River.

In response to this situation, in July 1971, the Iwate Prefectural Assembly petitioned the national government to establish permanent measures that would stop the pollution of the Kitakami River. In November of the same year, a Liaison Committee for Measures to Stop  Pollution of the Kitakami River was formed by the Forestry Agency, Ministry of International Trade and Industry (currently the Ministry of Economy, Trade and Industry), Ministry of Construction (currently the Ministry of Land, Infrastructure, Transport and Tourism), Ministry of Home Affairs (currently the Ministry of Internal Affairs and Communications) and the Environment Agency (currently the Ministry of the Environment). In essence, it was a committee made up of 5 government ministries and agencies, and they worked to come up with measures that would stop the pollution.

 

Starting in May 1972, the Ministry of Construction started interim treatments to neutralize the runoff at the site, and in 1976, the Liaison Committee decided to construct a new neutralization treatment facility. Iwate Prefecture received a subsidy from the Ministry of International Trade and Industry (currently the Ministry of Economy, Trade and Industry) to build the facility, and it commenced maintenance operations starting in April 1972.

Matsuo Mine when it was open

Matsuo Mine when it was open

Apartment buildings of the former Matsuo Mine and the sulfur production factory

Apartment buildings of the former Matsuo Mine and the sulfur production factory

Pollution of the Aka River (around 1974) 1

The Aka River flowing from Matsuo to Tairadate, Hachimantai (left) and the Aka River flowing  near Kitamori Station on the JR Hanawa Line in Matsuo, Hachimantai (right)
The Aka River flowing from Matsuo to Tairadate, Hachimantai (left) and the Aka River flowing near Kitamori Station on the JR Hanawa Line in Matsuo, Hachimantai (right)

Pollution of the Aka River (around 1974) 2

The Aka River merging with the Osanai River in Matsuo, Hachimantai (left) and the point at which the Matsu River and Kitakami River merge (right)
The Aka River merging with the Osanai River in Matsuo, Hachimantai (left) and the point at which the Matsu River and Kitakami River merge (right)

Neutralization Treatment in the Interim

The existing equipment and facilities at the former Matsuo Mine site were used by the Ministry of Construction to neutralize the runoff in the interim (left) and a neutralization agent (calcium carbonate) was put directly into the Aka River (right)
The existing equipment and facilities at the former Matsuo Mine site were used by the Ministry of Construction to neutralize the runoff in the interim (left) and a neutralization agent (calcium carbonate) was put directly into the Aka River (right)

Recent Developments

The Liaison Committee has met every year since 1999 in order to see that the purification and maintenance of the Kitakami River Project proceeds smoothly. Officials of the five involved ministries and agencies attend hoping to reach a common understanding of each separate issue and the results.

Between 2000 and 2004, energy efficient testing equipment for the new treatment facility were purchased and put in place, with everything up and running by 2006. Starting in 2007, a dispersal controller system was introduced which has resulted in more reliable wastewater treatment.

 

Not only is the quality of the water in the runoff much better thanks to work carried out at the source of pollution (1972-2000), the new equipment has also improved efficiency. Due to this, unit costs of water have reduced by about 40% compared to 1982, when treatment work started.  

このページに関するお問い合わせ

Mining and Water Resources Section (Mining), Environmental Preservation Division,
Department of Environment and Residential Life

(020-8570) 10-1 Uchimaru, Morioka, Iwate, JAPAN
T E L:019-629-5358 F A X:019-629-5364




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