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  "company_name": "住石ホールディングス",
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  "updated": "2026-08-21",
  "license": "© 2026 Yutaka Sugiura. All rights reserved.",
  "attribution": "The社史 (the-shashi.com) — https://the-shashi.com/tse/1503/",
  "source": {
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      "有価証券報告書"
    ],
    "extraction": "有価証券報告書の沿革を基礎に、社史・報道で補完",
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    {
      "date": "1893/11",
      "importance": 2,
      "event": "庄司砿（九州）を入手し石炭業に着手",
      "source": "有価証券報告書"
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      "date": "1894/4",
      "importance": 1,
      "event": "忠隈砿（九州）を入手",
      "source": "有価証券報告書"
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    {
      "date": "1924/10",
      "importance": 2,
      "event": "坂炭砿（北海道）の経営に参加",
      "source": "有価証券報告書"
    },
    {
      "date": "1927/6",
      "importance": 2,
      "event": "住友別子鉱山を設立（設立登記日）",
      "source": "有価証券報告書"
    },
    {
      "date": "1928/6",
      "importance": 1,
      "event": "住友九州炭砿を設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1930/4",
      "importance": 2,
      "event": "住友坂炭砿と住友九州炭砿が合併し住友炭砿を設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1937/6",
      "importance": 2,
      "event": "住友別子鉱山と合併し商号を住友鉱業に変更",
      "source": "有価証券報告書"
    },
    {
      "date": "1946/1",
      "importance": 2,
      "event": "商号を井華鉱業に変更",
      "source": "有価証券報告書"
    },
    {
      "date": "1949/10",
      "importance": 1,
      "event": "東京・大阪両証券取引所に株式を上場",
      "source": "有価証券報告書"
    },
    {
      "date": "1950/2",
      "importance": 1,
      "event": "本社を大阪市から東京都に移転",
      "source": "有価証券報告書"
    },
    {
      "date": "1950/3",
      "importance": 3,
      "event": "過度経済力集中排除法により金属鉱山部門・土木部門・調度部門を分離",
      "source": "有価証券報告書"
    },
    {
      "date": "1952/7",
      "importance": 2,
      "event": "商号を住友石炭鉱業に変更",
      "source": "有価証券報告書"
    },
    {
      "date": "1971/10",
      "importance": 3,
      "event": "奔別砿・歌志内砿を閉山し赤平砿の一山体制に移行",
      "source": "有価証券報告書"
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      "date": "1979/10",
      "importance": 1,
      "event": "赤平炭砿を分離して住友石炭赤平炭砿を設立",
      "source": "有価証券報告書"
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    {
      "date": "1988/10",
      "importance": 2,
      "event": "豪州の炭鉱会社Wambo Mining Corporationに資本参加",
      "source": "有価証券報告書"
    },
    {
      "date": "1994/2",
      "importance": 3,
      "event": "赤平炭砿を閉山し国内炭鉱経営から撤退",
      "source": "有価証券報告書"
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    {
      "date": "1998/4",
      "importance": 1,
      "event": "泉山興業を買収",
      "source": "有価証券報告書"
    },
    {
      "date": "2001/1",
      "importance": 2,
      "event": "豪州の炭鉱会社Wambo Mining Corporationを売却",
      "source": "有価証券報告書"
    },
    {
      "date": "2008/10",
      "importance": 3,
      "event": "単独株式移転により持株会社住石ホールディングスを設立",
      "source": "有価証券報告書"
    },
    {
      "date": "2008/10",
      "importance": 1,
      "event": "住石ホールディングスが東京証券取引所に株式を上場",
      "source": "有価証券報告書"
    },
    {
      "date": "2008/10",
      "importance": 1,
      "event": "住友石炭鉱業が商号を住石マテリアルズに変更",
      "source": "有価証券報告書"
    },
    {
      "date": "2009/10",
      "importance": 1,
      "event": "住石マテリアルズの石炭事業部門を住石貿易に事業譲渡",
      "source": "有価証券報告書"
    },
    {
      "date": "2016/4",
      "importance": 2,
      "event": "新素材事業部門と採石事業部門を新設分割により分社",
      "source": "有価証券報告書"
    },
    {
      "date": "2021/5",
      "importance": 1,
      "event": "住石山陽採石を売却",
      "source": "有価証券報告書"
    },
    {
      "date": "2022/4",
      "importance": 1,
      "event": "東京証券取引所スタンダード市場に移行",
      "source": "有価証券報告書"
    }
  ]
}