Raw Material Conveyor

A raw material conveyor runs into the Tsudō Ore-Dressing Plant at Ashio, the ore-processing facility inside the wider Ashio Copper Mine surface complex in Tochigi Prefecture. The conveyor carried ore from the receiving area into the plant to be broken down. The steelwork is weathered and the line is standing still. The dressing plant handled the first half of the process: crushing, ball-mill pulverisation, then froth flotation to bring the copper up into a concentrate for the smelter. A conveyor like this one sat at the front of that sequence, feeding rock in at the rate the mills below could take it.

Ashio was worked from the sixteenth century by traditional accounts and entered its modern era in 1877, when Furukawa Ichibei took over management with financial backing from Shibusawa Eiichi. At its peak the mine produced around a quarter of Japan's copper. The consolidated dressing plant dates from 1922, with ball mills and froth flotation cells installed from 1918 under the modernisation programme of 1918 to 1922. The same expansion produced the Ashio Copper Mine Pollution Incident, which peaked in 1896 and contaminated roughly 40,000 hectares across five prefectures. The mine's Excavation Department closed in 1973 and the dressing plant closed with it. The Honzan smelter kept working imported ore until the late 1980s. This conveyor has carried nothing since 1973.