Multi-bucket excavators

There are two important types of continuous excava- tor, the bucket-chain and the bucket-wheel. Mounted upon crawler undercarriage or rails the excavator has mobility. The material dug by the buckets is transferred to a conveyor belt which carries the material away. The figure shows a bucket-chain excavator although the bucket-wheel is more common. This type of excavator is not suitable for strong, consolidated rocks but has been applied to unconsolidated soils and overburden, sands, clays, chalk and, especially, brown coal (lignite).