July 28, 1939: The management of the company was left to Oye-yama Nickel Mining Company, which was merged into its parent company Nippon Yakin Kogyo Co., Ltd. in 1943.
1939年（昭和14年）7月28日：大江山ニッケル鉱業（1943年に親会社の日本冶金工業に合併）に経営を委ねる