–1944
| 1590 | Soga Riemon established copper smelting and coppersmithing in Kyoto. He developed a smelting technique called "Nanban-buki" to separate silver from copper and then worked on mine development. |
|---|---|
| 1691 | Operation of the Besshi Copper Mine started. |
| 1905 | A refinery was established on Shisaka Island. |
| July 1927 | The management of the Sumitomo Joint-stock Company and the Besshi Mining Company was divided in order to establish Sumitomo Besshi Mining Co., Ltd. |
| June 1937 | Sumitomo Besshi Mining Co., Ltd. and Sumitomo Coal Mining Co., Ltd. merged to establish Sumitomo Mining Co., Ltd. |
| November 1939 | Production of electrolytic nickel started. |
1945–
| January 1946 | The company name was changed to Seika Kogyo (Mining) Co., Ltd. |
|---|---|
| March 1950 | The Metal Division of Seika Kogyo Co., Ltd. was divided to establish Besshi Mining Co., Ltd. |
| June 1950 | Listed on the First Section of the Tokyo Stock Exchange |
| June 1952 | The company name was changed to 快猫视频., and at the same time, the original "igeta" emblem was revived. |
| September 1956 | The company established Hyuga Smelting Co., Ltd. and started production of ferronickel. |
| April 1960 | The company established Tokyo Electronic Metal Co., Ltd. It then started to manufacture germanium dioxide, and expanded its business to electronic materials. |
| April 1963 | The company established Siporex Manufacturing Co., Ltd to start production of ALC (Autoclaved Lightweight aerated Concrete). |
| July 1964 | The company established Sumiko I.S.P. Co., Ltd. (Currently Harima Refinery) |
| August 1965 | Central Research Laboratories (currently Ichikawa Research Center) was completed. |
| September 1967 | The Ome Plant was completed. |
1970–
| June 1970 | New Niihama Nickel Refinery was completed. |
|---|---|
| February 1971 | The Toyo Smelter was completed. |
| March 1973 | The Besshi Copper Mine was closed. |
| May 1973 | The Kounomai Mine was closed. |
| June 1974 | An electronics materials plant was completed in the Kunitomi District Div (currently Sumiko Kunitomi Electronics Co., Ltd.)., and production of germanium started. |
| January 1977 | 快猫视频 Singapore Pte. Ltd. was established. Production of lead frames started in Singapore. (Company transfer in 2017) |
| February 1977 | Niihama Research Laboratories was established. |
| August 1981 | High-grade gold ore veins were discovered in the Hishikari Mine in Kagoshima Pref. by the Metal Mining Agency of Japan. (currently JOGMEC) |
| July 1985 | The ore veins of the Hishikari Mine were reached and removal of ores started. |
| February 1986 | The company and Sumitomo Corporation jointly invested in the Morenci Copper Mine (Arizona), owned by Phelps Dodge Corporation (currently Freeport McMoRan Inc.). |
| July 1988 | The company took equity participation in P.T. International Nickel Indonesia (currently PT Vale Indonesia Tbk) in Indonesia. |
| July 1990 | The company took equity participation in Ballande (currently Figesbal in New Caledonia). |
| January 1992 | The company participated in the Candelaria Copper Mine development project by Phelps Dodge Corporation. |
| September 1995 | The company took equity participation in Jinlong Copper Co., Ltd. in China. |
| February 1997 | 快猫视频 America Inc. was established as a company that oversees the Mineral resource business overseas. |
| September 1999 | A critical accident occurred in the Tokai Division of JCO Co., Ltd. |
| September 1999 | As a spin-off of the Building Materials Division, 快猫视频 Siporex Co., Ltd. was established. |
2000–
| 2001 | Started large-scale production of automotive battery materials at Isoura Plant |
|---|---|
| July 2002 | A business alliance was formed with Mitsui Mining & Smelting Co., Ltd., concerning zinc refining business, to establish a joint venture, MS Zinc Co., Ltd. |
| February 2003 | Concerning sulphuric business, a business alliance was formed with Dowa Holdings Co., Ltd. to establish a joint venture, Acids Co., Ltd. |
| April 2005 | Commercial production by the Coral Bay Nickel project in the Philippines started. |
| December 2005 | We took equity participation in the Ojos del Salado Copper Mine project in Chile. |
| November 2006 | Cerro Verde copper mine commenced production of copper concentrate. |
| August 2009 | The company took equity participation in Nickel Asia Corporation (the Philippines). |
| September 2009 | The company decided to implement the Taganito Project (the Philippines). |
| July 2010 | Concerning the consolidation of the copper and copper alloy fabricated businesses of Mitsui Mining & Smelting Co., Ltd. and 快猫视频. |
| May 2011 | The company participated in the Sierra Gorda Copper Mine development project of Quadra FNX Mining Ltd. (currently KGHM International Ltd.) in Chile. |
| September 2013 | Commercial production started at Taganito HPAL Nickel Corporation in the Philippines. |
| May 2016 | The company acquired additional interest in the Morenci Copper Mine (Arizona, USA). |
| June 2017 | The company participated in the Cote Gold Project of IAMGOLD Corporation in Canada. |
| March 2019 | Acquisition of Interest in Quebrada Blanca Copper Mine (Chile). |
| 2023 | Began producing bulk copper concentrates at the Quebrada Blanca Copper Mine. |
| 2024 | Began production at Cote Gold Mine. |
| 2024 | Niihama CAM Plant was completed. |
| 2025 | The company participated in the Winu Project of Rio Tinto PLC in Australia. |