Crescent sprays. Crescent sprays (Figure 3-13) can be located on each ranging arm and are typically oriented inward toward the cutting drum. These sprays are located on the top and end of the ranging arm. It is important that these sprays be aimed inward toward the cutting drum and appropriately spaced to provide uniform wetting of the entire cutting zone. Crescent sprays on the headgate ranging arm should be used with caution. Sprays on the end of the headgate ranging arm are oriented into the face airflow, which can create turbulence that forces dust toward the walkway [Colinet et al. 1997].