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 jackhammer-like spikes, compression fracture micro-wheel heads like those on larger

tunnel boring machine A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore thro ...

s, 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: * Transverse - rotates parallel to the cutter boom axis * Longitudinal - rotates perpendicular to boom axis

Uses

Roadheaders were initially used in coal mines. The first use in a civil engineering project was the construction of the

City Loop The City Loop (originally called the Melbourne Underground Rail Loop or MURL) is a mostly-underground and partly surface-level subway and rail system in the central business district (CBD) of Melbourne, Victoria, Australia. The Loop includes t ...

(then called the Melbourne Underground Rail Loop) in the 1970s, where the machines enabled around 80% of the excavation to be performed mechanically. They are now widely used in such as tunneling both for

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econom ...

and municipal government projects, building wine caves, and building cave homes such as those in

Coober Pedy Coober Pedy () is a town in northern South Australia, north of Adelaide on the Stuart Highway. The town is sometimes referred to as the "opal capital of the world" because of the quantity of precious opals that are mined there. Coober Pedy ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

. 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 Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the c ...

's LRT

O-Train The O-Train is a light metro transit system in Ottawa, Ontario, Canada, operated by OC Transpo. The O-Train system has two lines, the electrically-operated Confederation Line (Line 1) and the diesel-operated Trillium Line (Line 2). Since May ...

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 Rideau (French for "curtain") may refer to: In or near Ottawa, Ontario, Canada Geographical features *Rideau Canal *Rideau Falls *Rideau River *Rideau Trail Towns and places *Rideau Ferry, Ontario * Rideau Lakes, Ontario *Rideau Street *Ridea ...

’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.

Projects utilizing roadheaders

* Boston's Big Dig * Ground Zero Cleanup * Addison Airport Toll Tunnel * Fourth bore of

Caldecott Tunnel The Caldecott Tunnel is an east–west highway tunnel through the Berkeley Hills between Oakland and Orinda, California. Its four bores carry California State Route 24. Named after Thomas E. Caldecott, former mayor of Berkeley, it opened in 19 ...

* Malmö City Tunnel * Confederation Line, Ottawa

References

External links

{{Commons category, Roadheaders
An article on underground home design and construction, with a section on use of roadheader machines

Ripping head roadheader Video
Engineering vehicles Mining equipment Excavating equipment