This accelerates the material through the crusher, allowing it to discharge at a rate suffi- cient to leave space for material entering above. This is arrested or free crushing as opposed to choked crushing, which occurs when the volume of material arriving at a particular cross-section is greater than that leaving. In arrested crushing, crushing is by the jaws only, whereas in choked crushing, particles break each other. This interpar- ticle comminution can lead to excessive production of fines, and if choking is severe can damage the crusher.