Limesand
Limesand is mined from coastal sand dunes found in various places along the south-west coast (Figure 1 and 2). It is entirely different from the silica sand that is found on beaches around Perth. Limesand is comprised mostly of shell and coral fragments from marine organisms; predominantly calcium carbonate with some magnesium carbonate.
The limesand dunes, which are approximately 10 000 years old, were formed by wind action when sea levels dropped and the exposed limesand was moved inland. The fineness, types of shell and purity varies between deposits. Limesand may be screened at the pit, but this is not necessary with some particularly pure deposits.
Figure 1 Limesand mine near Dongara
Figure 2 Close-up of agricultural limesand from a pit near Dongara