History

1874	The Mitsui Clan acquires Jabarabira pit at Kamioka Mine and begins mining operations.
1892	Mitsui Mining Limited Partnership is established.
1911	Reorganized as Mitsui Mining Co., Ltd.
1913	The first zinc is produced from Horizontal Distillation Furnace No. 1 at Omuta Zinc Smelting Plant (Asamuta).
1914	Operations commence as Omuta Zinc Smelting Plant affiliated with the Kamioka Mine of Mitsui Mining Co., Ltd.
1928	Hikoshima Zinc Smelting Plant (currently Hikoshima Smelting Co., Ltd.) is acquired from Suzuki Shoten.
1943	Hibi Smelting Plant (currently Hibi Smelter) and Takehara Refinery Plant (currently Takehara Refinery) are acquired from Showa Mining Co., Ltd. and Hibi Smelter is created.
1944	Takehara Refinery Plant is separated from Hibi Smelter, and Takehara Refinery is created.
1950	Mitsui Mining Co., Ltd. spins off its metals division to establish Kamioka Mining and Smelting Co., Ltd. (The predecessor company of Mitsui Mining & Smelting Co., Ltd.). Kamioka Mining and Smelting Co., Ltd. is listed on the First Section of the Tokyo Stock Exchange.
1951	Tokyo Laboratory (currently Materials Analysis & Exploration Center/R&D Center) is created.
1952	Kamioka Mining and Smelting Co., Ltd. is renamed Mitsui Mining & Smelting Co., Ltd.
1962	Ohji Metals Co., Ltd. and Showa Die-cast Co., Ltd. are merged into Mitsui Mining & Smelting Co., Ltd, and Rolled Copper & Zinc Division and Die-casting Division are created.
1964	Kushikino Mining is separated and Mitsui Kushikino Mining Co., Ltd. is established. The purchase of all shares of Compania Minera Santa Luisa S.A. is completed.
1967	Hachinohe Smelting Co., Ltd. is established.
1968	Huanzala Mine (Peru) began its full-scale operations. Hibi Kyodo Smelting Co., Ltd. is established.
1974	Mitsui Grinding Wheel Co., Ltd. is established.
1976	Oak-Mitsui Inc. is established in the USA.
1980	Mitsui Metal Foil Co., Ltd. and Sankin Rare Earth Co., Ltd. are merged into Mitsui Mining & Smelting Co., Ltd. Ageo Metal Foil Plant (currently Ageo Copper Foil Plant) and Miike Rare Metal Plant are created. Taiwan Copper Foil Co., Ltd. is established in Taiwan.
1982	Mitsui Mining & Smelting Co., Ltd. becomes a profit center organization.
1983	Okuaizu Geothermal Co., Ltd. is established.
1986	Kamioka Mining and Hikoshima Refinery are separated and reestablished as Kamioka Mining & Smelting Co., Ltd. and Hikoshima Smelting Co., Ltd. Miike Smelting Co., Ltd. is established.
1987	GECOM Corp. is established in the USA.
1989	Mitsui Copper Foil (Malaysia) Sdn. Bhd. is established in Malaysia, YOURSOFT Inc. is established. MCS, Inc. is established.
1990	Three companies, Tokyo Koukyu Rozai (TKR) Co., Ltd., Mitsui Kinzoku Perlite Co., Ltd., and Dicalite Orient Co., Ltd., are merged into Mitsui Mining & Smelting Co., Ltd. TKR Division (currently Ceramics Division) and Perlite Division are created. A unified common name, Mitsui Kinzoku, is introduced and a new corporate symbol is adopted.
1995	Mitsui Siam Components Co., Ltd. is established in Thailand.
1998	Mitsui Copper Foil (Hong Kong) Co., Ltd. is established in Hong Kong.
1999	The Head Office is moved to Osaki, Shinagawa-ku, Tokyo. Mitsui Components Europe Ltd. is established in England.
2000	Mitsui Electronic Materials Co., Ltd. is established in Taiwan. Pan Pacific Copper Co., Ltd. is established as a joint investment with Nippon Mining & Metals Co., Ltd. (currently JX Nippon Mining & Metals Corporation)
2001	Mitsui Copper Foil (Guangdong) Co., Ltd. is established in China.
2002	Mitsui Components Guangdong Co., Ltd. is established in China. MS Zinc Co., Ltd. is established as a joint investment with Sumitomo Metal Mining Co., Ltd. Mitsui Micro Circuits Taiwan Co., Ltd. is established in Taiwan.
2003	Ohi Seisakusho Co., Ltd. becomes a wholly owned subsidiary of Mitsui Mining & Smelting Co., Ltd. through a share exchange.
2005	Mitsui Kinzoku Trading (Shanghai) Co., Ltd. is established in China. Mitsui Kinzoku Components India Private Limited is established in India. Mitsui Kinzoku Korea Co., Ltd. is established in Korea.
2006	Palka Mine (Peru) begins full-scale operations. Shanghai Mitsui Xin Yun Precious and Rare Metal Recycle Co., Ltd. are established in China. Mitsui Kinzoku Catalyst Zhuhai Co., Ltd. is established in China.
2007	Mitsui Kinzoku (Shanghai) Management Co., Ltd. is established in China.
2010	Sumitomo Metal Mining Co., Ltd. and Rolled Copper & Zinc Division are integrated and reestablished as Mitsui Sumitomo Metal Mining Brass & Copper Co., Ltd. Automotive Parts & Components Division and Ohi Seisakusho Co., Ltd. are integrated to form MITSUI KINZOKU ACT CORPORATION.
2011	AUTOMOTIVE COMPONENTS TECHNOLOGY INDIA PVT. LTD. is established in India.
2012	PT. MITSUI KINZOKU CATALYSTS JAKARTA is established in Indonesia. MITSUI KINZOKU ACT (SHANGHAI) MANAGEMENT CO., LTD. is established in China. Mitsui Kinzoku Advanced Ceramics (Suzhou) Co., Ltd. is established in China. MITSUI KINZOKU ACT MEXICANA, S.A. de C.V. is established in Mexico. Instrumentation Systems Division and Mitsui Kinzoku Kyusyu Engineering Co., Ltd. are integrated to form Mitsui Kinzoku Instrumentations Technology Corporation. Mitsui Kinzoku has sold Mitsui Zinc Powder LLC to Horsehead Corporation.
2013	Mitsui Kinzoku Catalysts (Thailand) Co., Ltd. is established in Thailand. Mitsui Kinzoku Catalysts Vietnam Co., Ltd. is established in Vietnam. MCS, Inc. is dissolved. PT. MITSUI KINZOKU ACT INDONESIA is established in Indonesia. Mitsui Micro Circuits Taiwan Co., Ltd. is dissolved. Mitsui Copper Foil (Guangdong) Co., Ltd. is dissolved. Mitsui Kinzoku Catalysts America, Inc. is established in the USA.
2014	Die-Casting Division is separated and Mitsui Kinzoku Die-Casting Technology Co., Ltd. is established.
2016	Solar power plant begins operation at Hikoshima Smelting Co., Ltd.
2018	Mitsui Kinzoku USA Inc. is established MITSUI KINZOKU ACT TANGER MAROC SARL is established in Kingdom of Morocco
2019	Kamioka Mining & Smelting Co., Ltd.started selling electricity from seven hydraulic power plants.
2020	Hibi Smelting Co., Ltd. is established. Nippon Caserones Resources Co., Ltd. is established as a joint investment with JX Nippon Mining & Metals Corporation Oak-Mitsui Inc. is transferred
2022	Perlite Division is separated and Mitsui Kinzoku Perlite Co., LTD. is established.
2023	Kamioka Components Co., Ltd. are merged into Mitsui Kinzoku Die-Casting Technology Co., Ltd.