Raw Material Chutes

A set of raw-material chutes at Ashio Copper Mine drops crushed ore from the upper conveyors into the receiving hoppers below. Each chute is a riveted-steel funnel inverted at an angle to its lower partner, the assembly forming a stepped descent across two levels of the processing building. The steel is darkened with ore residue along the lower edges of each section, where the falling ore wore the surface back over decades. Wear plates have been bolted into the high-impact zones of several chutes; some are original to the build, others have been replaced. The chute walls vibrate when the building is touched. Light here is thin, coming through small dust-coated windows on the side wall.

Chutes do the gravity work in a processing plant: where the ore needs to drop from one level to the next, a chute carries it without using power. The arrangement at Ashio used gravity wherever it could, then used the conveyors only on the horizontal runs. The chutes carried ore through the works for the operational life of the plant under Furukawa, from the 1877 modernisation through to the Excavation Department's closure in 1973. They have been still since. The wear pattern in the steel is the record of every shift that passed material through them.