Basement

Beneath the main level of Hornsby Quarry, a concrete basement sits in near-darkness. Dry straw and debris have collected across the floor and landings. A multi-level steel staircase, eaten through with rust, stands against bare concrete walls tagged with spray paint, the metal framework casting hard shadows. Nothing moves. Hornsby Quarry sits within Old Mans Valley, in Hornsby, NSW. The site is a Jurassic diatreme, a volcanic neck pushed through Sydney Basin sandstone between 146 and 200 million years ago. The dolerite it produced, hard and dense, was the material that built the road network across northern Sydney for close to a century. Quarrying began around 1905, when the Higgins family, the valley's first European settlers, began extracting dolerite from the diatreme. Hornsby Shire Council purchased the operation in 1912, recognising the strategic value of the local volcanic material for road construction and maintenance. Hornsby Blue Metal Limited took over in 1924 and operated until 1932. Farley and Lewers arrived in 1959, acquiring the quarry through a subsidiary. CSR Limited absorbed Farley and Lewers in 1980, eventually operating as CSR Construction Materials until the quarry closed in 2002. The quarry void reaches approximately 120 m deep at the southern face. The walls expose a cross-section through the volcanic neck that geologists now classify as internationally significant. Above this subterranean space, the remnant crusher plant buildings stand on the quarry floor, noted in the Hornsby Park master plan as heritage features. This photograph was made in 2015. At that point the quarry had been idle for around 13 years. The straw and the rust were not recent damage; they were simply what happens to a concrete space left to its own devices. By 2019, more than one million cubic metres of NorthConnex tunnel spoil had been delivered into the quarry void. By February 2025, bulk earthworks across the site were complete. The basement recorded here exists now in a landscape being remade from the ground up.