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 machine

Tunnel boring machine

A tunnel boring machine 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 can bore through anything from hard rock to sand. Tunnel diameters can range from a metre to almost 16 metres to date...

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 priapic miner for exploitation of small seam, close walled deposits, typically in wet conditions.

Types

Cutting Heads:

• Transversal - rotates parallel to the cutter boom axis
• Longitudinal - rotates perpendicular to boom axis

Uses

Roadheaders are used in tunneling

Tunneling

Tunneling may refer to:* Digging tunnels * Quantum tunneling, the quantum-mechanical effect where a particle crosses through a classically-forbidden potential energy barrier...

 both for mining

Mining

Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

 and municipal government projects, in building wine cave

Wine cave

Wine caves are subterranean structures for the storage and aging of wine. They are an integral component of the wine industry world wide. The design and construction of wine caves represents a unique application of underground construction techniques....

s, and to build cave homes such as those found in the Coober Pedy area of Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

.

Projects utilizing roadheaders

• Boston's Big Dig
• Ground Zero Cleanup
  World Trade Center site
  The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...
  
  
• Addison Airport
  Addison Airport
  -Accidents and incidents:The following involved flights departing or arriving at the airport:*July 19, 1986: All 4 occupants of a Cessna 421, registration number N6VR, were killed when the aircraft suffered an apparent right-hand engine failure, rolled over, and dived into a vacant lot immediately...
  
   Tunnel Project
• Fourth bore of Caldecott Tunnel
  Caldecott Tunnel
  The Caldecott Tunnel is a three bore highway tunnel between Oakland, California and Contra Costa County, California. The east-west tunnel is signed as a part of State Route 24, which is also known as the William Byron Rumford...
  
  
• Malmö City Tunnel
  City Tunnel, Malmö
  The City Tunnel is a 17-kilometre rail link in Malmö, Sweden, running between Malmö Central Station and the Öresund Line . The tunnel portion of the project extends for a length of six kilometres under the city centre...
  
  

External links

• An article on underground home design and construction, with a section on use of roadheader machines.
• Ripping head roadheader Video