Roadheader

A roadheader, also called a boom-type roadheader, road header machine, road header or just header machine, is a piece of excavating equipment consisting of a boom-mounted cutting head, a loading device usually involving a conveyor, and a crawler travelling track to move the entire machine forward into the rock face.
The cutting head can be a general purpose rotating drum mounted in line or perpendicular to the boom, or can be special function heads such as jack-hammer like spikes, compression fracture micro-wheel heads like those on larger tunnel boring machines, a slicer head like a gigantic chain saw for dicing up rock, or simple jaw-like buckets of traditional excavators.
History.
The first roadheader patent was applied for by Dr. Z. Ajtay in Hungary, in 1949. It was invented as a remote operated miner for exploitation of small seam, close walled deposits, typically in wet conditions.
Types.
Cutting Heads:
Uses.
Roadheaders were initially utilized in coal mining applications. The first use of a roadheader in a civil engineering project was the construction of the Melbourne Underground Rail Loop in the 1970s, where the machines enabled around 80% of excavation to be performed mechanically.
They are now used in a broad range of applications including but not limited to tunneling both for mining and municipal government projects, building wine caves, and building cave homes such as those found in the Coober Pedy area of Australia.
On February 21, 2014, Waller Street, just south of Laurier Avenue collapsed into an 8m-wide and 12m-deep sink-hole where a roadheader was excavating the eastern entrance to Ottawa's LRT O-Train tunnel. A similar incident occurred in June 2016, when a sink-hole opened up in Rideau Street during further construction of the tunnel, and filled with water up to a depth of three metres. The CBC reported that one of Rideau Transit Group’s 135-tonne roadheaders was in a part of the tunnel where the flooding was the deepest. Three roadheaders were used in the construction of the O-Train.