Catwalk

A steel catwalk at Ashio Copper Mine runs the length of one of the processing levels, suspended from the structural steel of the building above on threaded rods and held against the wall on a steel ledger. The walkway is steel grating, the kind that drains liquid and lets dust fall through. A handrail of mild steel pipe runs along the open side at standing height. The catwalk passes the inspection ports of the hoppers, the access doors of the conveyors, and the maintenance points of the flotation cells along its length. The decking is darkened from years of foot traffic and ore-dust accumulation. Daylight comes through the side windows in flat panels, falling across the grating in long stripes.

Catwalks are the working circulation of a mineral processing plant. Operators, fitters, and electricians walked these levels through every shift, checking the lights on the mimic-board against the conditions at each machine. At Ashio the plant ran on shift work from the 1877 modernisation onwards, with the catwalks carrying the foot traffic of a working copper mine across nearly a century. The Excavation Department closed in 1973. The catwalk has not carried a working shift since.