DOWA CSR Report 2019

Environment

The DOWA Group recognizes the impact of business activities on the environment, and we are working on it throughout the entire group with initiatives for the environment and society through our core business, and by positioning a reduction in the environmental impact of our business as an important issue for management.

Priority Measure - Reducing Environmental Impact & Risks
Safety Management of Suspended or Abandoned Mines and Tailing Dams

　　In the past, many mines were operating in Japan, but from around 1970, such things as the rapid appreciation of the yen reduced profitability, and forced many domestic mines to stop operating. At present, along with tailing dams that are adjoining facilities of these suspended or abandoned mines, under various mining laws and procedures such as the Mine Safety Act, they are strictly managed by the company or local government that ultimately held the right to operate the mine.
　We currently operate and manage more than 20 suspended or abandoned mines and more than 30 tailing dams, the majority of which have been suspended or abandoned. In addition, by managing with voluntary management standards that are stricter than mining laws and procedures, we are working to prevent mine pollution and maintain and improve safety.

Management of water resources

　In suspended or abandoned mines, as a result of excavated tunnels, some of the ore remaining in the mines comes into contact with groundwater and oxygen in the air, causing an oxidation reaction. There is the possibility that acidic water or mine water (pit water) containing heavy metals will flow out from the pithead. In addition, at tailing dams, leachate (wastewater) containing harmful heavy metals is discharged due to rainwater or groundwater, and there is the risk of it flowing into rivers, causing pollution of water quality and agricultural land.
　We have set up mine wastewater treatment plants near each facility, we monitor pit water and wastewater generated from tunnels and tailing dams 24 hours a day, 365 days a year, and perform appropriate treatment according to the quality. Through this, we are working to maintain healthy water circulation and a sustainable water use environment.

Maintaining Stability at Suspended or Abandoned Mines and Tailing Dams

　Most of the suspended or abandoned mines and tailing dams that we manage are facilities that had ceased operations by 1980. Mine wastewater treatment plants and tailing dam facilities are inspected on an irregular basis by public safety and inspection departments in each region. However, our tailing dams are mostly suspended or abandoned, with soil covering and mine pollution prevention work implemented, and greening by vegetation completed, so they are in a very stable condition. Including tailing dams still in use, we set the items for inspection and frequency for each location, with qualified people doing patrol inspections of such things as pitheads that have been blocked, and the slopes and culverts of tailing dams. We strive to maintain a stable condition by quickly detecting and repairing points of deterioration due to changes over time.

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Preparing for Natural Disasters

　In recent years, abnormal weather caused by climate change has continued in Japan, with localized heavy rains occurring at an unprecedented frequency. In addition, Japan is an earthquake-prone country, and preparing for large-scale earthquakes is essential.
　Together with building a mechanism to prevent mine wastewater from flowing out of the system even if heavy rain occurs, and by evaluating the stability of tailing dams against large-scale earthquakes, and systematically implementing reinforcement work as needed, we are enhancing our preparedness for the threat of natural disasters.

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Akitsu Mine Treatment Plant

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Esashi Mine Kuchizawa Dumping Site

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Nonami Mine Treatment Facility

VOICE

At Unekura Mining, which manages the suspended or abandoned mines of the DOWA Group and treats mine wastewater, we have introduced various technologies into the mine wastewater treatment process, such as labor-saving treatment facilities and a neutralization method using iron-oxidizing bacteria. In the future as well, we will pursue efficient treatment methods that have both low environmental impact and low cost, and we will work on safe and secure mine pollution prevention.

HAREYAMA Satoshi HAREYAMA Satoshi, Representative Executive Director, UNEKURA MINING
Environment

Progress of Activities

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