During its peak production period, from around 1615 to 1645, the mines on Sado produced an estimated 400 kilograms of gold and 37.5 tons of silver per year, making Sado one of the largest producers of gold and silver in the world. =perations were reduced by a large scale in 1952. The final mining operations were stopped on March 31, 1989. (more information in English https://en.wikipedia.org/wiki/Sado_mine )