Suspended or Abandoned Mines
Dealing with Suspended or Abandoned Mines
The main suspended or abandoned mines managed by the Furukawa Company Group are the Ani Mine (Akita Prefecture), Ashio Mine (Tochigi Prefecture), and Iimori Mine (Wakayama Prefecture).
In mines where minerals were extracted, drainage containing heavy metals continues to be generated from the shafts and tailing dams*1 even after closure due to rainwater and other factors, resulting in mine run-off *2.
- 1Regular patrols and inspections
We conduct regular patrols, inspections, and water quality monitoring of mining facilities (including mine run-off treatment facilities and tailing dams) to ensure early detection of abnormalities.
- 2Water quality monitoring
We regularly monitor the water quality in surrounding and downstream areas, continuously assessing its impact on the environment.
- 3Resilience enhancement
To prepare for unexpected events, such as heavy rainfall or earthquakes, we are working on preventive measures, including strengthening our mine run-off treatment capacity, enhancing backup facilities, and stabilizing tailing dams.
- *1Tailing dams (final disposal sites): Facilities for the final disposal of mining waste, such as waste rock with no inherent value extracted from former mines, waste generated in the smelting process at ore dressing plants and smelters, and neutralized sludge generated from the treatment of mine run-off. We use the term “tailing dam” for such facilities.
- *2Mine run-off: Groundwater (“mine water”) that seeps from excavated mines and infiltrated water (“wastewater”) generated from tailing dams.
Specific mining pollution prevention measures implemented by the Company and the applicable laws and regulations
| Applicable laws and regulations | Measures taken |
|---|---|
| Special Measures Law for Pollution Control in the Metal Mining Industry (Pollution Control Special Measures Law) | Mine run-off treatment work at tunnels and decommissioned tailing dams |
| Mine Safety Act | Reinforcement and mine run-off treatment work at active tailing dams |
In addition to the aforementioned legal frameworks, the Group has signed pollution prevention agreements with neighboring municipalities. As a result, we manage inactive mines based on stricter standards than those set by the national government.
Mine Run-Off Treatment System
To treat mine run-off, we use the “neutralization method,” in which an alkaline agent (such as lime) is added to the mine water emanating from the shaft and the wastewater emanating from the tailing dam (both of which are acidic and contain heavy metals). With the neutralization method, the treatment process results in purified supernatant water (treated water that meets discharge standards) and neutralized sludge, which is heavy metal hydroxide that has been settled and separated.
The supernatant water is discharged into rivers after being treated to meet regulatory standards. The neutralized sludge is either accumulated in Company-managed tailing dams or disposed of as industrial waste.
Ashio Mine: Mine run-off treatment system
Resilience Enhancement Initiatives
Following its fundamental policy of ensuring safe operations in the management of suspended or abandoned mines, the Furukawa Company Group has developed a medium- to long-term plan for its mining facilities. These plans include implementing preventive maintenance measures and strengthening resilience (disaster response capabilities) in a systematic manner.
Capital investments related to suspended or abandoned mines (results)
From 2000 to March 2024, the Group made total capital investments of approximately ¥5.7 billion on the management of suspended or abandoned mines. In addition, we spend roughly ¥300 million per year on maintenance and management, including facility repairs, disaster recovery work, and purchase of chemicals (such as lime).
| Tailing dams | Mine run-off treatment | Shafts | Heavy machinery & telecommunications |
|---|---|---|---|
| Approx. ¥3.4 billion | Approx. ¥1.7 billion | Approx. ¥400 million | Approx. ¥200 billion |
Main project examples
Location: Nakasai water purification plant
Details: Inlet channel and stone masonry reinforcement work
Construction period: FY2021–2023
Location: Ushigoya tailing dam
Details: Stabilization work
Construction period: FY2015–2017
Ensuring sustainable and stable financial resources for management of suspended or abandoned mines
To fulfill our ongoing responsibility for managing suspended or abandoned mines, it is important that we continue our Real Estate business, which generates stable and long-term cash flows.
Managing suspended or abandoned mines is a core social responsibility of the Furukawa Company Group. To prepare for future obligations, we aim to maintain a stable asset base, with our Real Estate business serving as a key anchor for financial stability.
We will manage suspended or abandoned mines using funds from our Real Estate business, which we operate separately from our other activities, namely, reinforcing the earnings of our core businesses (Machinery and Materials) and investing in M&As and new businesses.
Greening Activities
Greening of Mine Facilities
When the mines were operational, large-scale deforestation occurred due to the need for significant amounts of timber as fuel in ore smelting, construction materials for housing, and tunnel support structures. At the time, moreover, there were no established technologies to mitigate sulfur dioxide gas emissions from smelters, leading to the destruction of surrounding forests. Accordingly, the Furukawa Company Group has since worked to address pollution issues*3 and promote continuous reforestation efforts on these lands. Today, these lands serve as protected forests and play a vital role in water source conservation, preventing soil erosion and other natural disasters, and preserving and shaping people’s living environment.
We have also covered decommissioned tailing dams with soil to promote reforestation and have continued applying fertilizers and conducting regular inspections to ensure proper maintenance and long-term sustainability.
- ※3As a measure to control sulfur dioxide gas emissions from smelters, in 1956 we established the Furukawa–Outokumpu flash smelting technology (patented), successfully achieving both sulfur dioxide gas capture and cost reduction. This technology was subsequently recognized both domestically and internationally and adopted by numerous smelters, thus helping reduce environmental impact.
Cherry Tree-Planting Activities
The Furukawa Company Group formed the Ashio Cherry Tree-Planting Drive, which aims to plant 1,000 cherry tree saplings on Company-owned land in Ashio-machi (Nikko City, Tochigi Prefecture) as part of its own greening activities. Since the first event in March 2009, we have held tree-planting drives every year. In April 2024, we held our 12th tree-planting event, which was attended by 73 people, including Group employees and their families. This year, we planted 60 Somei-Yoshino cherry trees, bringing the total number of trees planted to date to 660.
Also in April 2024, we held the seventh Furukawa-no-mori Tree-Planting Drive (organized by the Tochigi Furukawa Association*4) on Company-owned land in the Matsuki area of Ashio-machi. A total of 78 members from 19 Tochigi Furukawa Association member companies participated, planting 40 Somei-Yoshino cherry trees. We will continue hosting both events in the future.
- ※4Organization of companies in the Furukawa Company Group in Tochigi Prefecture