The size of a roadheader would depend on the dimensions of its major parts. The excavating machine consists of a cutting head mounted on a boom, a set of wheels or tracks, and a loading device often with a conveyor. It comes in two types of cutting heads: transverse cutting heads that rotate parallel to the cutter boom axis; and longitudinal cutting heads that rotate perpendicular to boom axis.
Sandvik Mining and Construction developed MT520, a tunneling roadheader with an eight-meter cutting height module. The cutting height extension module makes the machine highly suitable for large road tunnels. The size of a roadheader weighing 115 tons would fall into the large and heavy-duty class. The entire vehicle measures 15.7 meters in length and 4.9 meters in height. Its transverse cutter head is powered by 315 kilowatts and makes a maximum cutting width of 10.3 meters (10.8 meters with extension module).
Rock Crusher
A heavier and larger roadheader developed by the same company is MR620. The size of a roadheader weighing 128 tons makes it capable of cutting through hard and abrasive rock formations. The machine measures 15520 millimeters in length, 6400 to 7200 mm. in width (over loading table), and 4046 mm. in height. The transverse cutter head can bore a tunnel at a speed of 1.4 meters per second.
Aker Solutions ASA has developed a roadheader close to the weight of Sandvik’s MR620. Its Aker Wirth T3.20 has an approximate weight of 120 tons. The size of a roadheader with a 300 kilowatt installed cutting power was designed for boring and cutting through medium to hard rock of 120 megapascals (MPa.) to 150 Mpa. compressive strength. The machine can excavate tunnels reaching 7.69 m. in height and 8.96 m. in width from one central position.
Dosco Overseas Engineering, however, focused in developing compact roadheaders. Its MK2A weighs under 24 tons. The size of a roadheader with 58 kilowatt axial cutting boom would be suited for excavating surfaces with a comprehensive strength of 103 Mpa. or 15,000 per square inch (PSI). Close to a thousand units of the lightweight machine were built. The entire machine measures 7160 mm. x 2910 mm. (maximum) x 1640 mm. It has a maximum cutting height of 4040 mm. and a maximum cutting width of 5560 mm.
The size of a roadheader required for mining and road construction would depend on the strength of the surface for cutting or tunneling. Roadheaders will continue to be used in building wine caves, as well as, cave homes such as those found in the Coober Pedy area of Australia.
Roadheaders for Different Rock Formations