In order to meet specified Particle Size Distribution (PSD) requirements of the end-users specifications, raw materials are reduced in size and graded to ensure consistency. This is typically achieved though Crushing and Screening. The selection of the types of crushers to be used will depend on multiple factors such as geology, raw feed, productivity, and end user specifications.
A Jaw Crusher is typically used as a "primary crusher" in reducing raw feed to maximise the productivity of secondary crushers. A compression crusher, typically used as a "secondary and tertiary crushers" in reducing raw feed to a size and gradation suitable for screening or additional crushing.
Screening is the process of mechanically grading materials to achieve a desired fraction of the materials introduced. This fraction will be "cut and sized" using screens made of woven wire in unbound pavement production.