The Hosokura mine was located in the Ōu Mountains the northwest part of Miyagi prefecture. The mine extended for about 5 kilometers east-west and about 3 kilometers north and south and had ten major veins and over 150 minor veins of mineral deposits, with the vein width ranging from 12 meters to 15 meters at maximum, but on average 1.3 meters. Major minerals include galena, zinc blende and pyrite, along with smaller amounts of silver, copper, bismuth, cadmium, and gold.