Roadheaders are crawler-type excavating machines with a boom-mounted cutting drum that were first used for tunneling projects and coal mining operations. Then models were developed for use above ground in place of regular excavators. Like all complicated treaded construction machinery rigs, roadheaders can be fitted with various excavation attachments, including shovels, conveyors, booms, and roof bolters. Also, a roadheader can be just a cutting drum attachment on a boom arm mounted on another piece of construction machinery.
Usually the cutting drums are electrically powered, up to 400 kw or 530 hp. They are more effective than the hydraulically powered versions and are more suitable to underground applications. Electric motors allow for all the power to be directly applied to the cutting tool(s). Also underground rigs are usually smaller and have some sort of conveyor hopper and belt arrangement near the bottom so they can also move the cut rock debris to the back of the machine. While above ground models sometimes have these as well, it is not as important. Above-ground roadheaders have the room to back up or move aside easily to let a bucket rig or a payloader scoop up the debris.
A full blown roadheader rig is a complicated machine. It has to not only cut the rock, but move the cut-up rock debris to its rear. Also, crew comfort and safety is a real concern, especially if used underground. The right type of cutting head has to be chosen and mounted for the rock to be cut. As well as the cutting head has to be checked periodically for wear. In underground situations, the integrity of the tunnel it is cutting has to be monitored to avoid cave-ins.
The main points to keep in mind in choosing a roadheader are:
- To choose between a boom attachment or a dedicated machine. Booms are usually used above ground
- Longitudinal or Transverse mounted drum cutting heads.
- Under or above ground usage.
- The type of roadheader cutting drum drive power. The choice is usually between electric or hydraulic. Also the power needed, which can go up to 530 hp or 400 kw. Higher powered models & underground roadheaders usually have electrically powered cutting drums.
- Type of roadheader drum, or cutting head style. This is very important since cutting into coal seams underground is far different than cutting into granite above ground, This is the actual tool the rest of the machine is made to use.