Cement Mill Duct

A length of ductwork runs along one of the cement mill bays at Kandos Cement Works, carrying dust-laden air away from the grinding circuit. The duct is steel, riveted in long sections, painted pale grey over earlier coats that show through where the surface has worn. Where the duct enters the bag filter at the end of the run, the join has been wrapped in additional steel banding. Cement dust has settled along the upper surfaces and in the seams. Light from a clerestory above falls across the bend in the duct, picking up the pattern of the rivets. Smaller branch ducts run off the main line, each one feeding from a separate point on the mill below. The whole assembly sits inside a steel-framed bay, with walkways running underneath for access.

Cement mills generate a continuous stream of fine dust during operation. The ductwork was the plant's collection system: extraction fans pulled the dust through the ducts to a bank of bag filters, where the powder was caught and either returned to the cement stream or discarded. At Kandos the system ran whenever the mills were running, which was most of the time across the plant's 95-year operational life. The mill closed with the rest of the works in September 2011, and the ducts have held cement dust in suspension and on every surface since. Most of the steel is still where it was put.