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.

[1] It was invented as a remote operated miner for exploitation of small seam, close walled deposits, typically in wet conditions.

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.

[4] 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.