Hishikari Mine is located in the eastern part of the Hishikari district of Isa City, Kagoshima Prefecture. It is currently the only gold mine in Japan operating on a commercial scale. Historically, it has also been Japan’s largest gold producer in terms of both total gold output and estimated reserves. In addition to gold, the mine also produces silver.
The Hishikari area has been known as a gold-producing region since the Edo period (1603–1868). In the 1960s, the Metal Mining Agency of Japan, now part of the Japan Organization for Metals and Energy Security, began conducting gold exploration in the area.
In 1981 (Showa 56), a gold vein was discovered. Mining operations by Sumitomo Metal Mining began in 1985. The gold content of ore from Hishikari Mine is approximately eight times higher than that of ore from a typical gold mine. The mine accounts for more than 90 percent of Japan’s annual gold production.
Hishikari Mine’s estimated gold reserves are approximately 250 tonnes. This is greater than the combined reserves of all the other major gold mines in Japan.
In a drilling survey conducted by Sumitomo Metal Mining in 1982, all six boreholes reached gold-bearing veins, indicating the remarkable scale of the deposit. Subsequent surveys have continued to increase the estimated reserves.
In 1997 (Heisei 9), the mine’s cumulative gold production surpassed that of Sado Gold Mine, which had produced 83 tonnes before closing. Hishikari thus became Japan’s largest gold producer. In 2012 (Heisei 24), another gold vein was discovered, with estimated reserves of 30 tonnes and a market value of approximately 130 billion yen at the time.
Hishikari Mine continues to produce approximately 6 tonnes of gold annually, making it the only active gold mine operating on a commercial scale in Japan.
The mine is not open to the general public, and visitors are not permitted to enter the site. It also serves as a training facility for engineers employed by Sumitomo Metal Mining, with approximately 60 people working at the mine.
The underground tunnels extend for more than 100 kilometers in total. Although the mine entrance is located at an elevation of 265 meters above sea level, the tunnels reach depths as low as 50 meters below sea level.
As of March 2020, cumulative gold production had reached 248.2 tonnes.
One of the most remarkable characteristics of Hishikari Mine is the exceptionally high gold content of its ore.
Ordinary gold ore generally contains only a few grams of gold per tonne. At Hishikari, however, exploration drilling has recorded concentrations of up to 290 grams per tonne, while the mine’s average grade is approximately 40 grams per tonne.
This average is about ten times the global average, making Hishikari Mine one of the world’s highest-grade gold deposits.
After the mined ore is sorted, it is transported to Sumitomo Metal Mining’s Toyo Smelter and Refinery in Saijo City, Ehime Prefecture, where the gold is refined.
The gold is shipped after receiving conflict-free certification. This certification reflects the importance of responsible sourcing and the effort to ensure that the gold is not associated with the financing of armed conflict.
Many traditional mines used underground railways and small mine carts to transport ore. Hishikari Mine, by contrast, introduced a trackless mining system from the beginning of its operations.
Under this method, dump trucks travel through the underground tunnels to carry the mined ore out of the mine. The system allows ore to be transported efficiently and has helped modernize the mine’s operations.
Hot spring water at approximately 65°C emerges from underground within Hishikari Mine. Some of this water is supplied as a by-product to Yunoo Onsen, while the remaining water is cooled before being discharged into the Sendai River.
Before mining began, Yunoo Onsen was known for its geyser. However, the geyser dried up after mining operations started. Ground subsidence also occurred in the hot spring district, and the inns subsequently moved to other locations.
Today, the relocated hot spring inns operate using hot spring water supplied from the mine. This unusual connection between gold mining and hot spring bathing is one of the distinctive features of the area.
Hishikari Mine is expected to continue developing its mining technology in response to domestic and international demand for gold.
At the same time, sustainable operations require careful attention to environmental protection and cooperation with the surrounding community. The mine is expected to maintain its position as one of the world’s leading gold-producing sites while contributing to sustainable development.
Hishikari Mine is an extraordinary industrial site that has transformed the history of gold mining in Japan. Its discovery in 1981 led to the development of a deposit with enormous reserves and exceptionally high-grade ore.
Although the mine itself is not open to visitors, its scale and significance make it an important part of the modern history of Kagoshima. Its underground tunnels, advanced trackless mining system, and connection with Yunoo Onsen illustrate the many ways in which this remarkable gold deposit has shaped the region.