Fan

A large industrial fan at Ashio Copper Mine sits in a steel housing along the upper level of the processing building, its drive motor mounted on the same frame and connected to the impeller shaft through a flexible coupling. The housing is a riveted-steel volute, the inlet open to one side and the discharge ducting rising out of the top through the wall above. The impeller inside has been visible at some point in the building's history through an inspection door, now closed and bolted. The motor end carries a manufacturer's plate in Japanese, painted onto the casing. Stains from decades of dust-laden air run down the housing along the gasket lines.

Fans in a mineral processing plant move air for two main jobs: pulling exhaust gases away from the kilns, smelters, and flotation cells, and feeding ventilation into spaces where workers needed clear air. At Ashio, fans like this one ran continuously through the working shifts. The Furukawa-era plant produced copper from 1877 onwards; the Excavation Department closed in 1973. The fan in this photograph stopped at the same time and has not been started since. The motor's bearings have settled in place; the impeller behind the inspection door is still where the last shift left it.