Stone crushers are classified according to the fineness with which they fragment the starting material. There are primary crushing, secondary (intermediate) crushing and Fine (tertiary) crushing. Some production lines may include a single crushing stages，the most common production lines involve at least two or three crushing stages.

1. Primary Crushing

As the first stage during a crushing circuit following extraction from a mine site, primary crushing reduces material to a size and shape which will be handled by the secondary crusher. The duty of the first crusher is to form it possible to move material on a conveyer belt . In most aggregate crushing plants, primary crushing is administered during a jaw crusher, although a gyratory crusher could also be used. If material is definitely crushed and not excessively abrasive, an impression crusher could even be the simplest choice as a primary crusher.

2. Secondary (Intermediate) Crushing

In secondary crushing, reduction ratios become an important consideration. Knowing just how fine you would like your final output to be, along side the feed requirements of your tertiary or final reduction crushing station, will assist you determine what proportion reduction must happen within this stage.

Cone crushers are often placed within the secondary crushing station because they're versatile in terms of feed, closed side setting, speed, and throw. With cone crushers, though, it's essential to work them at consistent choked settings to stay productivity up.

3. Fine (Tertiary) Crushing

In this crushing stage, the standard and quantity of fine products are determined. Quality requirements are often stringent for the ultimate products, especially within the mixture industry. Customer requirements common to both the mixture and mining industries are capacities and quality (fraction/particle size). the mixture industry has additional quality demands like soundness and particle shape (cubicity).