Visitors stand near Doyu no Warito, symbolic remain of the Sado Gold Mine, in Sado, Niigata prefecture, Japan, Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

Mayor of Sado City Ryugo Watanabe delivers a speech during a memorial ceremony for the Sado Island Gold Mine in Sado, Niigata prefecture, Japan, Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

Guests offer a flower during a memorial ceremony for the Sado Island Gold Mine in Sado, Niigata prefecture, Japan, as several seats reserved for South Korean guests remained empty Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

Visitors stroll one of the industrial heritages Kitazawa Flotation Plant, a processing gold ore plant in Sado, Niigata prefecture, Japan Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

Guests offer a moment of silence during a memorial ceremony for the Sado Island Gold Mine in Sado, Niigata prefecture, Japan, as several seats reserved for South Korean guests remained empty Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

A visitor tries to pick up a gold bar at Sado Kinzan Gold Mine historic site in Sado, Niigata prefecture, Japan, Saturday, Nov. 23, 2024. (AP Photo/Eugene Hoshiko)

A staff walks through a tunnel at Sado Kinzan Gold Mine historic site in Sado, Niigata prefecture, Japan, Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

Guests offer a moment of silence during a memorial ceremony for the Sado Island Gold Mine in Sado, Niigata prefecture, Japan, Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

One of the industrial heritages Kitazawa Flotation Plant, a processing gold ore plant, is seen in Sado, Niigata prefecture, Japan Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

Stone statues are placed near the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

Visitors look at display at Sado Kinzan Gold Mine historic site in Sado, Niigata prefecture, Japan, Saturday, Nov. 23, 2024. (AP Photo/Eugene Hoshiko)

A visitor walk through tunnels at Sado Kinzan Gold Mine historic site in Sado, Niigata prefecture, Japan, Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

One of the industrial heritages Kitazawa Flotation Plant, a processing gold ore plant, is seen in Sado, Niigata prefecture, Japan Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)