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)

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

Visitors look at the display 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, as several seats reserved for South Korean guests remained empty Sunday, Nov. 24, 2024. (AP Photo/Eugene Hoshiko)

People visit remains of a Sado gold mine are seen on Sado Island, northern Japan, on Aug. 26, 2024. (Yasufumi Fujita/Kyodo News via AP)

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)

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

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

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

Akiko Ikuina, Parliamentary Vice-Minister for Foreign Affairs, offer a flower on behalf of the government 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 illuminated in Sado, Niigata prefecture, Japan, Saturday, Nov. 23, 2024. (AP Photo/Eugene Hoshiko)

Mannequins enacting a mining scene are seen inside remains of the Sado gold mine on Sado Island, northern Japan, on July 4, 2024. (Atsushi Watanabe/Kyodo News via AP)

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

Remains of Japan’s Sado gold mine are seen on Sado Island, northern Japan, on Aug. 19, 2021. (Keiji Uesho/Kyodo News via AP)

One of the industrial heritages Kitazawa Flotation Plant, a processing gold ore plant, is illuminated in Sado, Niigata prefecture, Japan, Saturday, Nov. 23, 2024. (AP Photo/Eugene Hoshiko)

Akiko Ikuina, Parliamentary Vice-Minister for Foreign Affairs, offer a flower on behalf of the government 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 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 illuminated in Sado, Niigata prefecture, Japan, Saturday, Nov. 23, 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)