The best place for a landfill
Kate Valley was chosen for the Landfill because the underlying geology makes the site an ideal location. Beneath the topsoil is a layer of a low permeable material called Tokama Siltstone that extends down to depths of 200 metres. Low permeability simply means that water isn’t able to soak through the ground. With no known aquifers beneath the site the potential for water from within the Landfill mixing with groundwater is non-existent.
The greatest environmental protection
Even with excellent ground conditions providing natural containment, a multi-layered synthetic liner is also used in the Landfill. Construction of the Landfill begins with shaping and compacting of the siltstone to form a smooth natural liner. The synthetic liner is laid on top of this surface. It consists of upper and lower layers of high-density polyethylene, on either side of a layer of geo-synthetic clay lining. On top of this liner is placed a 10mm thick fabric layer to protect the liner. Then a 500mm permeable gravel leachate drainage blanket is applied on top of the liner to allow the flow of leachate out of the Landfill (see section below). Finally 3 metres of uncompacted waste are laid on top to further cushion the liners. Together these liners and layers provide Kate Valley Landfill with a containment system superior to the standards used in both the European Union and the USA for municipal waste landfills.