Roadheader is a type of excavator with a cutting head mounted on a boom. The roadheader is mounted on crawling tracks and has a conveyor system for removal of material. The cutting head on the roadheader can be general purpose such as rotating drum or jaw like buckets or with special features such as jack hammer with spikes.
Pipe jacking is a trenchless construction method that uses roadheaders to cut through differing geological conditions such as loose soil or hard rock.
Roadheaders come with an operating weight of 13 tons to 135 tons and cutting power up to 400 kW. The largest units can be used to cut through hard rock with high unconfined compressive strength. Roadheaders are now designed to meet differing geological conditions as encountered in trenchless projects.
Any given roadheader can be used to mount different types of cutter heads, can be operated with varying cutting speeds and can be equipped with regular bucket with teeth or a hydraulic breaker. This partial-face excavation method has the advantage of controlling the excavation precisely because the distance between the operator and the tunnel face is just a few meters allowing for swift reaction to change in geology and taking remedial measures.