• Besshi Copper Mines Heritage of Industrial Modernization

    Late Period (Electricity; Adit No. 3 (Tonaru) and Adit No. 4 (Hadeba))
    From 1902 to 1973

Adit No. 3 and Tonaru

This section introduces the gallery at the heart of the Besshi Copper Mines during the period of high output.

Shisakajima Smelter built on Shisakajima island in the Seto Inland Sea. Construction completed in 1904. The smelter was relocated to an island far away from the urban area because of the smoke problem (photographed in 1926). Photo courtesy of Sumitomo Historical Archives
Central Tonaru at the start of the Showa era. The long white structure is the roof of the platforms of the railway lines to and from Adit No. 3. On the stone-built upper levels were offices, a guardhouse, a public bath, and so on (photographed in 1926). Photo courtesy of Sumitomo Historical Archives

Center of the Besshi Copper Mines from the late Meiji era to the Taisho era


Mining was placed firmly on a modern footing in the late Meiji era with the completion of excavation of the Toen Inclined Shaft, a project that took almost two decades, and the introduction of state-of-the-art facilities. At the heart of the modernized Besshi Copper Mines was Tonaru, a district at an altitude of 750 meters to the north of the Copper Mine Pass. The 1,795-meter-long Adit No. 3 was excavated from Tonaru toward the bottom of the Toen Inclined Shaft. Tonaru was a mining community adjacent to the exit of Adit No. 3.

Adit No. 3: Major tunnel accelerating modernization of Besshi Copper Mines

Entrance to Adit No. 3 at Tonaru. The tramway track leading to the gallery remains.

The Toen Inclined Shaft, excavated along the axis of the mineral deposit toward the rich ore zone in Misuma, deep underground in the Besshi Copper Mines, was completed in 1895, 19 years after the project started. The excavation began from Toen at an altitude exceeding 1,100 meters. It was a major project connecting points with a 400-meter difference in altitude separated by a horizontal distance of 567 meters. The excavation was extremely laborious. Ventilation was so poor that the flames of the lamps often went out. Despite frequent suspension of excavation, construction of the Toen Inclined Shaft was eventually completed, making it possible to discharge the spring water that remained in the rich ore zone as a result of the major earthquake in 1854 and to start mining the rich ore, which was a long-cherished ambition.

In addition, construction of an adit (horizontal tunnel) from the bottom of the Toen Inclined Shaft was planned for the discharge of ore. Ore was previously smelted at Takahashi on the mountainside near Besshi and transported through Adit No. 1 and then via the upper railway. Completion of a smelter at Sobiraki in Niihama on the plain made it possible to transport ore directly from the mountain for smelting. Furthermore, opening a gallery at a low altitude would eliminate the need to hoist ore for several hundreds of meters before it could be discharged and would also make it possible to mine ore at a lower altitude.

Encouraged by the progress of the construction of the Toen Inclined Shaft, excavation of Adit No. 3 started in 1894. The entrance was located at Daisan in Tonaru at an altitude of 747 meters and the distance to the bottom of the Toen Inclined Shaft was 1,795 meters.

Thanks to the use of pneumatic rock drills and other machinery, Adit No, 3 Tunnel was completed in 1902, eight years after the launch of the project. With a width of 3.35 meters and a height of 3.73 meters, Adit No. 3 was roughly twice the size of Adit No. 1 (a width of 1.8 meters and a height of 2.7 meters).

Modernization of the Besshi Copper Mines got into full swing around the time of the opening of Adit No. 3. An ore sorting facility was newly established at Tonaru adjacent to the entrance and the latest ore crushers were introduced. Moreover, a tramway was opened in the tunnel to make the transportation of ore and other items much more efficient. In addition, a drainage channel was installed in the tunnel. Spring water in galleries had always been a headache but now the water accumulating at the bottom of the Toen Inclined Shaft was pumped out and the water dripping from above was disposed of via the drainage channel in Adit No. 3. The laborious task of removing water by manual labor, which had been the practice since the opening of the mines, was at long last consigned to history.

Tonaru: Mining community 750 meters above sea level deep in the mountains

Otoshi Bridge connecting Tonaru and Niihama. One of Japan’s oldest arch bridges made of steel, it was completed in 1905. (The suspension cables were installed subsequently for reinforcement.)

Tonaru, the location of the Mine Headquarters from 1916 to 1930, is often described as the Machu Picchu of the Orient. Deep in the mountains, imposing remnants of stone ramparts and brick buildings make one think of the mines in their glorious heyday, prompting fanciful comparisons with the magnificent ruins in the Andes.

In Tonaru, in addition to mine-related facilities, a hospital, an elementary school/junior high school, a post office, a social center, and many other amenities supported and enriched the way of life. Tonaru was a mining town with a population of 3,700 at its peak.

Among the many remains are those of the ore sorting yard and the ore storehouse. The massive three-tier stone-built terraces on the slope resemble the defensive perimeter of a mighty castle. Here, ore discharged via Adit No. 3 was sorted and stored temporarily. The ore was then transported by the aerial cableway directly down to Kuroishi Station (later changed to Hadeba Station) on the lower railway from where it was transported to Niihama and then by boat to the Shisakajima Smelter.

Adit No. 4 was subsequently completed and the Mine Headquarters was relocated to Hadeba in 1930. Nevertheless, Tonaru remained the center of the Besshi Copper Mines. The use of the Tonaru Adit was terminated in 1968 because of depletion of the deposit. After the miners left, Tonaru fell into ruin and were engulfed by vegetation.

Now, Tonaru is managed by Minetopia-Besshi as one of a cluster of industrial heritage sites in the Tonaru Zone open to the public. At the Tonaru Historical Museum visitors can learn about the way of life in Tonaru when it was a flourishing mining community.

Adit No. 4, Hadeba, and Hoshigoe

This section introduces the history of Besshi from the Taisho to the Showa era, from prosperity to the closure of the mines

The Hoshigoe Station opened in 1925 in line with the completion of the Niihama Ore Sorting Yard. This is the sole station building on the lower railway remaining today. Employees living in Sumitomo’s Yamada Corporate Housing built in 1929 used the station (photographed in 2013). Photo courtesy of Sumitomo Historical Archives (owned by Sumitomo Metal Mining Co., Ltd.)
Tramway carrying workers from the entrance to Adit No. 4. The double track was for efficiency (photographed in 1926). Photo courtesy of Sumitomo Historical Archives (owned by Sumitomo Metal Mining Co., Ltd.)

End of the Besshi Copper Mines’ 300-year history

Photo courtesy of Sumitomo Historical Archives (owned by Sumitomo Metal Mining Co., Ltd.)

Following completion of Adit No. 4 in 1915, Hadeba’s development got into full swing. With the relocation of the Mine Headquarters to Hadeba in 1930, Hadeba became the center of Besshi Copper Mines. As ore output from Adit No. 4 increased, so did the pace of Niihama’s development, transforming it into a bustling town. But eventually, as mining went deeper and deeper, the quality of the ore deteriorated. The Besshi Copper Mines closed in 1973, as a rising tide of imports of low-cost ore reached Japan from overseas.

Adit No. 4: Artery sustaining the Besshi Copper Mines in the Taisho and Showa eras


Situated on flat land demarcated by two valleys at an altitude of 156 meters, Hadeba is not far from the center of Niihama. Hadeba’s development took off in 1893 when it became the terminus of the Besshi Mines’ lower railway connecting Sobiraki in Niihama. Connected by the aerial cableway with Ishigasanjyo Station, the terminus of the upper railway, Hadeba played an important role as a base for the transshipment of goods.

In 1910, with mining at the Besshi Copper Mines going deeper and deeper, it became necessary to establish an adit for transportation far below Adit No. 3 in Tonaru (at an altitude of 750 meters). Therefore, excavation of Adit No. 4 started in Hadeba. In November 1911, excavation of Oodatekou, a vertical shaft connecting Adit No. 3 and Adit No. 4, started.

Although this was a major project involving excavations with a total length of 4,596 meters, progress outstripped the schedule, thanks to newly introduced rock drills and handy drills, and it was completed in September 1915. Whereas excavation of the 1,795-meter-long Adit No. 3 opened in 1902 took eight years and seven months, Adit No. 4, with a length 2.4 times that of Adit No. 3, was completed in about two-thirds of the time it took to complete Adit No. 3.

At the arch-shaped entrance was a signboard bearing the name “Adit No. 4” by the brush of Tomoito, the 15th head of the House of Sumitomo. Small shrines dedicated to Oyamatsumi, the principal deity of the Oyamazumi Shrine, were placed at the entrance, as was the custom for all mine entrances constructed since the Edo period. Adit No. 4 served as an artery sustaining development of the Besshi Copper Mines in the Taisho and Showa eras. The Hadeba entrance of Adit No. 4 witnessed the entry and exit of around 1,000 people every day for about 60 years until the closure of the Besshi Copper Mines in 1973.


Upon completion of Adit No. 4, the Mine Headquarters was relocated in 1916 from Toen (at an altitude of 1,150 meters) in Kyubesshi near the mountain peak to Tonaru (at an altitude of 760 meters) on the mountainside. At that time, the center of gravity of mining operations had already started to shift to Tonaru and the opening of Adit No. 4 made it clear that Hadeba, at a far lower altitude than Tonaru, was where the action would be from now on. Therefore, taking this opportunity, a decision was made to concentrate the functions of Besshi Mine at Hadeba. In line with this relocation, miners who lived in Kyubesshi moved to Tonaru or Hadeba. Branches of the departments at Kyubesshi were abolished and everything was relocated apart from certain facilities of the Forestry Department and the Brewery Department.

On the other hand, Hadeba developed rapidly from then on. In 1917, company housing was built in Uchiyoke and Shikamori, and the Shikamori Branch of the Sobiraki Elementary School/Junior High School (a private school established by Sumitomo), the Hadeba Clinic of the Sumitomo Hospital (private hospital), and other facilities necessary for everyday life were established. Upon completion of the ore sorting yard in Hadeba in 1927, ore, which under the previous system would have been transported to Tonaru, were concentrated at Hadeba. Upon relocation of the Mine Headquarters to Hadeba in 1930, the ore sorting yard in Tonaru was closed. In line with the concentration of the mining business in Hadeba, it became the center of the Besshi Copper Mines.

Subsequently, mining at Besshi encountered difficulties owing to unrealistically high production targets during the Second World War. However, from 1955 onward, buoyed by the post-war recovery, production at Besshi recovered to the level before the end of the war. Moreover, a large inclined shaft from Hadeba to a gallery 1,000 meters below sea level was completed in 1968 and entered full-scale operation in January 1969.

However, with the temperature hitting 50 degrees centigrade and humidity exceeding 95%, production efficiency at the deepest area of the shaft remained low. In addition, there was a risk of rock bursts owing to the pressure of the bedrock. The deeper the excavation, the lower the copper content of the ore. The Besshi Copper Mines were reaching their limits in terms of ore grade, ore quantity, and working environment. Furthermore, with a rising tide of low-cost imports of copper ore heading for Japan, Sumitomo decided to close the Besshi Copper Mines. The 293 years of the history of the Besshi Copper Mines ended in 1973.

Nowadays, Hadeba is managed by Minetopia-Besshi as a cluster of industrial heritage sites in the Hadeba Zone open to the public. Among the numerous points of interest are Adit No. 4, Hadeba Hydroelectric Power Plant, the remains of the ore storehouse, the iron bridge on the lower railway, the water channel, the large inclined shaft, and the remains of company housing. All serve to remind visitors of Hadeba’s former prosperity.

Hadeba Hydroelectric Power Plant: A large power plant with the greatest head in the Orient

On entering service in 1912 Photo courtesy of Sumitomo Historical Archives

Hadeba Hydroelectric Power Plant is a brick building that can be seen across the Kokuryo River from Minetopia-Besshi’s Hadeba Zone. You might never guess that this meticulously designed elegant building was a power station.

From the middle to late years of the Meiji era, electrification of the Besshi Copper Mines progressed, including electrification of transportation facilities, introduction of rock drills, and replacement of gas and oil lamps with electric lighting. To satisfy the rising demand for electricity, Sumitomo rapidly expanded power generation facilities. Having started by constructing a small-scale thermal power generation facility in Hadeba in 1897, Sumitomo went on to construct Hadeba Thermal Electric Power Plant (90 kW) in 1902, Otoshi Hydroelectric Power Plant (90 kW) in 1904, and Niihama Thermal Electric Power Plant (360 kW) in 1905. Hadeba Hydroelectric Power Plant, opened in 1912, was the first large-scale power plant supplying the Besshi Copper Mines.

With output of 3,000 kW, Hadeba Hydroelectric Power Plant was one of the largest-capacity power plants supplying mines in Japan. Water from the nearby Dozan River was collected at Hiura at an altitude of 747 meters and channeled via Adit No. 3 to a reservoir in Ishigasanjyo, the terminus of the upper railway. The water dropped from the reservoir via a high-pressure steel pipe in one go to turn the turbine generators made by Siemens.

Fed via a steel pipeline with a drop of 597 meters from top to bottom, Hadeba Hydroelectric Power Plant’s had the greatest head in the Orient and attracted much interest. The opening of Hadeba Hydroelectric Power Plant laid the foundation for introduction of the latest facilities and equipment, facilitating modernization of the Besshi Copper Mines.

Subsequently, output was increased to 4,800 kW and Hadeba Hydroelectric Power Plant remained in operation until 1970. Still housed in the magnificent building are the turbine generators that had been in use ever since the power plant entered service.

Yamane Stadium bleachers

Past and present of a stadium built for employee welfare

Large stadium built for employees


Yamane, situated in the south of Niihama City at the foot of the Besshi Copper Mines, used to be a bustling community of miners and their families. Although Yamane lost vigor in the mid-Meiji era because of the closure of the Yamane Smelter, it regained its dynamism in the Showa era with the relocation of the Oyamazumi Shrine, home of the tutelary deity of the mines, and the construction of company housing. The bleachers of the Yamane Stadium (currently Yamane Civic Ground) are a link with the past. Constructed in 1928 for employees, the Yamane Stadium was a venue for sporting events and festivals.

Bleachers constructed of stone characteristic of the Besshi Copper Mines district


The Yamane Smelter, which started operation in 1888, also served as a research facility for promising new businesses, such as the manufacture of sulfuric acid and other chemical products, and for investigating the possibility making iron use low-grade ores with little copper content. In 1893, with the opening of the Besshi Mine Railway, Itanomoto Station became a base for transportation of people and goods, and smelting in Yamane went into full swing as large quantities of low-grade ore were transported to Yamane from the mountain.

However, smoke pollution caused by sulfurous acid gas emitted from the chimney damaged agricultural produce. The local residents started to express resentment. Moreover, the anticipated demand for sulfuric acid did not materialize. Thus, the Yamane Smelter closed in 1895, having been in operation for just seven years.

In 1928, the Oyamazumi Shrine was moved to the site of the former Yamane Smelter and the Yamane Stadium was constructed at a location with a view of the shrine. The 14,500m2 Yamane Stadium was a welfare facility for employees of Sumitomo companies. Such lavish employee welfare facilities were unusual in Japan in those days.

Entering the stadium, you cannot miss the impressive stone bleachers. Taking advantage of the slope of the Shoji Mountain to the south, the bleachers rise to a maximum of 27 steps to accommodate spectators. Viewed from the oval track, the bleachers constructed using the local stone present a magnificent vista.

The bleachers are made of chlorite schist, a stone widely quarried in the region. Many remains of mining facilities on Besshiyama mountain are made of chlorite schist, indicating the connection between the stadium and the copper mine. Long after the center of gravity of the mining operations had shifted to Hadeba and people no longer lived in the mountainous area, veteran employees cherished memories of their life in the mountains, retaining the view of the stadium’s stone bleachers in their mind’s eye.

The bleachers were constructed by employees of Sumitomo companies who volunteered for the task on public holidays under the leadership of Kageji Washio, who became the Managing Director of Sumitomo Besshi Mine in 1927. Although they were not construction workers by profession, their experience and skills as miners enabled them to do an outstanding job.

Nowadays, the stadium, renamed Yamane Civic Ground, is managed by Niihama City. It is a multipurpose facility used for the community association’s sports day, baseball and soccer games, events promoting the health of the people of Niihama City, and as a venue for local festivals.


This section introduces activities to restore the natural beauty of the mountainous Besshi landscape denuded by mining.

A pioneer in environmental protection measures


As well as systematically modernizing its mining and smelting operations, Sumitomo Besshi Mine was also a pioneer in environmental protection measures. In order to restore the mountainous landscape denuded by logging and the smoke pollution associated with copper smelting, Sumitomo launched a large-scale afforestation project as early as the mid-Meiji era. The natural beauty of the Besshi mountains has long been restored.

Restore the Besshi mountains to their original verdant state


The Besshi mountains before afforestation and with their slopes once again clad in flourishing forest greenery. Forest conservation activities continue to this day.
Photos courtesy of Sumitomo Historical Archives (top) and Sumitomo Forestry Co., Ltd. (bottom)

Since the opening of the Besshi Copper Mines, afforestation has of necessity been pursued. Because charcoal was used as a fuel in refining and smelting, trees on the mountains near smelters were logged. Continuous afforestation was needed to compensate for the logging.

Meanwhile, smoke pollution became a major issue. Sulfurous acid gas emitted from the smelter caused acid rain that killed trees. Great tracts of Besshi mountains had become denuded owing to operation of the copper mines for over 200 years.

As a result, a typhoon that struck the region in 1899 triggered major landslides because the mountains stripped of their vegetation were unable to retain water. Mining facilities in the Besshi mountains were devastated and many people perished in the disaster.

On viewing the ravaged mountains, Teigo Iba, who was appointed manager of the Besshi Copper Mines in 1894, resolved to “restore the Besshi mountains to their original verdant state, and thus restore the natural order.” He launched a major afforestation project.

He hired a technical expert and formulated an afforestation plan. Fundamental measures were implemented: ore was no longer sintered and smelted at sites in the Besshi mountains and coal was used as fuel instead of charcoal. At the same time, a tree-planting project was launched in which over one million saplings were planted in the Besshi mountains annually. At the project’s peak, two million saplings were planted in a single year. The Besshi mountains were gradually restored to their original state.

If you hike the Besshi mountains now, you would never know that they used to be virtually devoid of trees. Since the Edo period, the physical legacy of mining operations has been largely concealed by the encroaching forest, making it difficult to imagine that where a forest now stands there used to be a bustling mining town. The Besshi Copper Mines are now part of the historical record, but Sumitomo companies have inherited the principle that all business should ultimately be for the benefit of society and people—a principle that the Besshi Copper Mines cultivated throughout their many years in operation.

Editorial supervisors for the articles on the Besshi Copper Mines

Osamu Goto, Director of Kogakuin University
Osamu Goto
Director of Kogakuin University
Professor of the Department of Architectural Design, School of Architecture. Born in 1960. Graduated from the School of Engineering, The University of Tokyo. After serving as Senior Cultural Properties Specialist, Architecture Division, Cultural Properties Protection Department, Agency for Cultural Affairs, he became professor of the Department of Architectural Urban Design, Faculty of Engineering, Kogakuin University, in 2005. His numerous publications include “The Basics of Architecture (Vol. 6) Japanese Architectural History” (Kyoritsu Shuppan), “Before Losing the Memory of the City” (co-author, Hakuyosha), and “Heritage of Modernization of Japan with Illustrations” (co-editor, Kawaide Shobo Shinsha).
Teruaki Sueoka
Teruaki Sueoka
Deputy Director of Sumitomo Historical Archives. Born in 1955 in Nagasaki Prefecture. Graduated from the Department of History, Faculty of Letters, Kokugakuin University, in 1978. Joined the predecessor of Sumitomo Historical Archives in 1978, became a Chief Researcher, and then Deputy Director. Since 1997, concurrently serving as Honorary President and Special Advisor of Hirose Memorial Museum in Niihama City. He has commented extensively on the historical significance of the former Hirose Residence, Sumitomo Kakkien, and the industrial heritage of the Besshi Copper Mines in reports on cultural assets. He is an expert on the history of Sumitomo. His numerous publications include “History of Sumitomo” (co-author, Shibunkaku), “History of Sumitomo Besshi Mine” (co-author, Sumitomo Metal Mining Co., Ltd.), and “The Environment and Development in the Early Modern Period” (co-editor, Shibunkaku).