The crushed material is then screened through the circular vibrating screen for coarse sand, medium sand, fine sand and other specifications. Sand Washing. To meet the strict requirements, we need to add the sand washing machine behind fine sand.Crushed Rock. We have extensive experience in the design and delivery of wet processing plants for a variety of rock types including • Limestone. • Granite. • Gabbro. • Tillite. These processing plants include material from across our portfolio which can be introduced throughout the process • Feeding. •.