As part of the NorthConnex project's commitment to reuse materials where possible, about one million cubic metres of excavated rock and soil from tunnel excavation will be used to partially fill the Hornsby Quarry.

The Hornsby Quarry Road Construction Spoil Management Project will fill the quarry void with spoil to a level that will allow Hornsby Shire Council to start rehabilitating the site to a public recreation area benefiting the local community. 

The project involves hauling spoil from the NorthConnex tunnelling sites to the Hornsby Quarry using the existing road network. Entry and exit to the quarry will be via Bridge Road, which is being upgraded and sealed to provide all weather access for heavy vehicles to Old Mans Valley. Spoil will be unloaded from trucks and stockpiled before being transferred onto a conveyor system which will safely carry the spoil to the bottom of the void. At project completion, the site will be demobilised and rehabilitated in consultation with Council.