Yanahara Mine is located in Kume-gun, western part of Okayama Prefecture, and produces iron sulfide ore. Total annual production is 132, 000 tons of crude ore. The number of mine personnel is 92 in all, and separated to two divisions; the mining division and the administrative service division. The mining division consists of four sections; mining, maintenance, concentra-tion and water treatment. The operations are proceeded in day shifts.The orebodies are bedded deposits, and their main iron mineral is a high grade pyrite. They lay in volcaniclastic rocks and slate of permian. The hanging wall is slate and the foot wall is diabase and quartz-diorite. The orebodies extend in an area of approximately 2, 000m×400m with an average thickness of 60 meters.Yanahara Mine has two main shafts. One is used for mine service, another is used for ore transportation. Level drifts are generally located at 15 meter intervals from L+6 to L-60, while several sublevels are prepared among them. The orebody being mined is divided into the northern block and the southern block. A central pillar runs between them from east to west. The mining method applied is a sublevel stoping, and the mined space is filled with waste rocks. The primary stoping has been finished, and regular band pillars are currently being mined.All the ore mined are crushed by a jaw crusher located at L-32, and wound up through the shaft to the gravity concentration plant. To meet the market's needs, the concentrates are classified to several brands according to their size and grade. The main usages of products are high grade iron oxide, sulfuric acid and heavy concrete.