Ishikari Coal Fields

Japan's largest coalfield, located in central Hokkaido. It occupies the western Yubari Mountains, stretching 80 km north to south and 25 km east to west, from the Sorachi River basin in the north to the Yubari River basin in the south, with reserves of 6.4 billion tons. It is sometimes divided into the Sorachi coalfield in the north and the Yubari coalfield in the south. The coal varies from caking coal to non-caking general coal, but the geological structure is complex, and mining high-quality coal from deep within the area poses a high risk of gas explosions, so many mines have been forced to close. By 1997, the large underground coal mines had disappeared, and only eight small mines that rely on outcrop coal remain in Ashibetsu, Akabira, Utashinai, Bibai, and other areas. The development of the Ishikari coalfield began with the opening of the Horonai coal mine (now Mikasa City) in the central part of the country, and in 1882 (Meiji 15), a railway was laid between Horonai and Temiya in Otaru, and coal transportation began. Initially, it was a government-run business that used prisoners from the Sorachi Penal Colony (now Mikasa City), resulting in many casualties. During the prefectural government era, management was transferred to the Hokkaido Colliery and Railway Company (Hokutan), and coal mines were developed in Utashinai in the north and Yubari in the south, and railway construction also progressed, connecting the area to Muroran in the south. Around the time of World War I, large capitalists from Honshu also began to develop coal mines, and the area was characterized by the four major capitalists, Hokutan, Mitsui, Mitsubishi, and Sumitomo, operating the major coal mines, and reached its peak after World War II, with the addition of small and medium-sized mines. It was during this period that many coal mining towns emerged. Since the 1960s, as Japan has switched to oil as an energy source and become dependent on imported coal, rationalization and closure of mines has progressed, and in 1997, annual coal production fell to 650,000 tons of exposed coal, almost all of which is used for electricity generation. However, coal is still a valuable resource in Japan, where domestic energy sources are scarce.

[Ichiro Kashimura]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

北海道中央部にある日本最大の炭田。南北80キロメートル、東西25キロメートル、北は空知(そらち)川流域から南は夕張(ゆうばり)川流域に及ぶ夕張山地西部を占め、埋蔵量64億トン。北の空知炭田と南の夕張炭田に分ける場合もある。炭質は粘結性原料炭から、非粘結性の一般炭まで種々あるが、地質構造が複雑で、深部良質炭の採炭はガス爆発の危険性が高いため閉山に追いやられた例も多い。1997年（平成9）には坑内採炭の大炭鉱は姿を消し、露頭炭依存の八つの小炭鉱が芦別(あしべつ)、赤平(あかびら)、歌志内(うたしない)、美唄(びばい)などに残るにすぎない。石狩炭田の開発は、中部の幌内炭山(ほろないたんざん)（現、三笠市）の開坑に始まり、1882年（明治15）に幌内と小樽(おたる)手宮間に鉄道が敷かれ、石炭輸送が始まった。当初は官営事業で空知集治監（監獄）（現、三笠市）の囚人を使い、多くの犠牲者を出した。道庁時代に入ると経営は北海道炭礦鉄道会社(ほっかいどうたんこうてつどうがいしゃ)（北炭）に移り、北の歌志内、南の夕張などに炭鉱が開発され、鉄道建設も進んで南の室蘭(むろらん)とも結ばれた。第一次世界大戦前後から本州大資本も炭鉱開発に乗り出し、北炭、三井、三菱(みつびし)、住友の四大資本が主要炭鉱を経営する点に特徴があり、中小炭鉱も加えて第二次世界大戦後には頂点に達した。多くの炭鉱都市の出現もこの時期である。1960年代以降、日本の石油エネルギーへの転換、海外輸入炭依存により、合理化や閉山が進んで、1997年（平成9）には年間出炭量も露頭炭65万トンにまで減少し、ほぼ全量が電力向けという状況にある。しかし国内エネルギー源の少ない日本では貴重な資源であることは確かである。

［柏村一郎］

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