Spirals are gravity concentrators and separate minerals of different specific gravity according to their relative movement in response to gravity, centrifugal force and other forces in the fluid medium. It has extremely good performance and effects in processing placer of beach, riverside, seashore and stream. 
"LEILI Machinery" Spirals are made of polyurethane lined fiber glass with wearable corundum inner surface.
Generally there are 5 turns in one start, single, twin, triple and quad starts available per column to suit capacity requirements.