Geology
The quarry is situated on the highest point of the landscape in an ancient glacial
bed which overlooks the Blackwood river. Most people are surprised when they find out it
is dug from the top of a hill and not out of the river. The deposit is the result of an ancient
glacier that was moved here from possibly from what is now Antarctica. The stones are rounded
and smooth, initially from being pushed along by a glacier then later due to the action of enormous
volumes of water running over them as a result of melting ice. The glacier bed is considered to be
one of the major drainage basins for the South west at that time running from south of the Stirling
Ranges to off the Darling Scarp near Kirup.
The stone is embedded in kaolin clay which is a very fine white clay used for porcelain making and
whitening paper. Kaolin is formed by the weathering of feldspar. Due to the harsh actions of the tumbling
stones and massive glacial fluvial flows that occurred, no fossils have been found and not likely to.
This has made it very hard to pin an exact date on the formation however the late cretaceous,
65 mya (the end of the Dinosaurs era) seems to be the favoured estimate. The formation stretches
for some 80 km however is buried quite deeply for most of this except on this patch of private
property where the Blackwood River has cut through the hill exposing the stone.
The quarrying process begins with the stone and clay being dug out by an excavator and
being tipped over a grizzley screen to separate the stone from the clay. The stone is
then screened into various sizes and then washed to remove any residual clay in a
large scrubber. The final product is then either placed into 1t bulka bags or
trucked out in bulk . The larger stone is hand picked to remove
broken stone.
