General conditions
The local coal mines covered 1,800 hectares across the cities of Akabira and Utashinai, containing reserves of 400 million tons and a total of 23 coal seams. The cumulative gross coal seam thickness was 49.60 meters, and the cumulative net seam thickness was 37.20 meters. The maximum seam thickness was 9.5 meters, and the average was 2.15 meters. The mines produced high-quality coal for coking and other purposes, but the sharp inclination of most of the local coal seams placed major constraints on the mechanization of operations. However, the use of crushers to eliminate the need for immediate debris removal, the introduction of coal mining machinery designed for steep slopes, enhanced coal mining efficiency and other developments increased coalface production volumes, which came to exceed those from gently sloping seams. Production efficiency gradually improved, and the completion of a vertical shaft further enhanced output.
Significance of shaft sinking
nitially, a million tons of coal was produced annually using the inclined shaft method, primarily in areas above a horizontal crosscut at a depth of 350 meters. However, the Energy Revolution and deeper mining operations gave rise to the need for further rationalization involving a dramatic increase in carrying capacity using the vertical shaft method. The use of blind shafts from butt levels and the completion of conveyor belts for inclined shafts doubled annual production from one million to two million tons and boosted per-capita daily production from 30 to over 60 tons. Initial investment in the vertical shaft construction that was started in September 1959 was more than two billion yen. The project was completed in only three years and five months thanks to the all-out efforts of company management and engineering staff and the focused contribution of related parties.
The history of the city is inextricably linked to that of its coal mines. The affluent lives of local residents today are an extension of this history.
History of Akabira and its coal mines
| 1895 | Novelist and poet Doppo Kunikida visited an area near the Sorachi River. The number of settlers in the wilderness along the river increased. |
|---|---|
| 1901 | Coal mining efforts were made at the Takikawa Coal Mine and then at the Akama Coal Mine. These facilities were closed the following year. |
| 1911 | Construction of the Kamifurano Railway (later to become known as the Nemuro Line) began. |
| October 1913 | Railway services were introduced and came to play a major role in the region. |
| 1918 | Okura Mining Co., Ltd. opened the Moshiri Coal Mine – the first such facility in Akabira. |
| April 1, 1922 | Akabira Village was established with a population of 7,208. |
| 1923 | The Ohtani Coal Mine was opened. |
| 1924 | The New Akabira Coal Mine was opened in the Toyosato/Miyashita area. |
| 1925 | A national census showed that Akabira had a population of 6,759. |
| 1926 | Moshiri Station was opened. |
| 1937 | The Sino-Japanese War broke out. |
| 1937 | The Akama Coal Mine and the Toyosato Coal Mine were opened. |
| August 1938 | The coal mines were incorporated into the Business Startup Division of Sumitomo Coal Mining Co.’s Coal Mining Office (at the head office). |
| February 1939 | The East Inclined Shaft (later to become known as Shaft No. 1) was opened. |
| 1941 | Shaft No. 2 was opened. |
| 1944 | Shaft No. 3 was opened. |
| 1953 | Kamiutashinai Coal Mine was consolidated. |
| 1963 | Vertical Shaft No. 1 was completed. |
| 1970 | Coal mine development deeper than 550 meters below the surface was begun. |
| 1971 | The Central Vertical Ventilation Shaft was completed. |
| February 25, 1994 | The last mine was closed, bringing 55 years of operation to an end. |
