Switching Panel

A switching panel at Ashio Copper Mine is a wall-mounted control board fitted into one of the operations rooms, with rows of large knife switches, push-button starters, and amp meters arranged across its face. The panel is bakelite-fronted, the kind of electrical control gear that was standard in industrial plants from the 1920s through to the postwar decades. Each switch is labelled in Japanese above the handle: the lettering hand-painted, some labels still legible, others worn back to the bakelite. Two of the larger knife switches are in the up position. Cabling runs from the back of the panel down through the wall behind. The panel face is darker than the wall around it from years of being touched at the same points.

Switching panels of this kind ran the electrical distribution to the major motor loads of a processing plant: ball mills, conveyors, flotation cells, pumps. Each circuit was controlled separately from the panel, with the operator throwing the appropriate switch when starting or stopping a piece of equipment. At Ashio the panels controlled a plant that ran almost continuously under the Furukawa modernisation through to the Excavation Department's 1973 closure. The switches in this photograph have been in their current positions since that day. The labelling has remained as the last shift left it.