The Toyoha mine is one of the largest lead and zinc mines in Japan.[1] The mine is located in northern Japan in Hokkaido.[1] The mine has reserves amounting to 13 million tonnes of ore grading 2.1% lead, 7% zinc and 51.6 million oz of silver.[1] It is located 30 km SW of Sapporo and is very close to an active hydrothermal system.