Screening Conveyor

The screening conveyor in this photograph is what remains of the processing infrastructure that turned raw dolerite into blue metal aggregate. Its steel frame has oxidised to a deep rust across every surface, the joints and brackets holding their shape while the finish has long since gone. The quarry floor and exposed rock walls surround it, the scale of the void visible beyond the structure. Nothing in the frame is operational. Everything is fixed in the state it was left when quarrying ceased. Hornsby Quarry operated from around 1905, when the Higgins family began extracting dolerite from the volcanic neck beneath Old Mans Valley. The site passed to Hornsby Shire Council in 1912, then to Hornsby Blue Metal Limited in 1924, before Farley and Lewers acquired it in 1959. CSR Limited took over Farley and Lewers in 1980, consolidating into CSR Construction Materials by the time operations wound down. Annual extraction averaged approximately 110,000 tonnes of crushed dolerite, destined for road base and aggregate across northern Sydney. The quarry ran for nearly a century before extraction ceased in 2002. The rock beneath the machinery is no ordinary substrate. The Hornsby diatreme is a Jurassic volcanic neck, 146 to 200 million years old, the largest of its kind in the Sydney area. Quarrying cut more than 100 metres through it, exposing a cross-section that geologists have since classified as internationally significant. The dolerite that fed conveyors like this one is the same material that made the site worth quarrying at all, and the same material that drew researchers to the exposed face long after the machinery stopped. Hornsby Shire Council acquired the site in 2003 for $26,508,771.28, the figure determined by the NSW Land and Environment Court. The remnant crusher plant buildings, including structures associated with conveyors and processing equipment, are noted in the Hornsby Park master plan as heritage features to be retained. This photograph, made in 2015, records the conveyor before the rehabilitation works that followed.