Mitsubishi Materials Corporation, headquartered in Tokyo, is one of the world’s largest materials companies. Its gold refining and bar production are carried out at the Naoshima Smelter in Kagawa, where operations moved in 1989 from the original Osaka Refinery. Founded in 1917, the Naoshima facility supports a company that now operates in over 20 countries across metals, cement, advanced materials, electronics, energy, and recycling.