Beckley, WV (Vocus) June 3, 2008
Terex SHM recently signed a contract with Tacoa Minerals, LLC in Alabama for the delivery of a highwall mining system. This will be the first miner to go out of the Terex SHM facility to Alabama. It will mine high grade metallurgical coal seams starting in the Thompson Seam.
The highwall mining system is fully adapted to work in dipping conditions, and is supplied with a Terex SHM- Joy 14CM15 cutterhead. It is also equipped with a newly developed steep-dip mining package to enable the highwall miner to work in seams with more than a 12 degree dip.
Now in its second generation, Terex® SHM’s highwall miner is a self-contained, remotely operated mining system. Designed for safety, a three or four-man team can operate and maintain this highwall miner from the surface. No crewmember is ever required to go underground thus giving the operator a clear view of the operation. This promotes a safe working environment for employees. Depending on the height of the seam being recovered, each machine can produce an average of 40,000-120,000 short tons of coal per month. In terms of resource recovery, it can extract up to 70% of the in-situ coal, while operating on contour benches or in trench-mining applications.
The Terex SHM base-frame vehicle is carried on four hydraulically powered crawler units that give 360-degree mobility and allow the machine to be positioned precisely in front of each entry, even if the highwall is irregular. Interchangeable electric cutterhead modules mine coal-seam heights ranging from 28 in. to 15 ft. The cutterhead advances by sumping (pushing forward). The sumping force is supplied by two hydraulically powered cylinders mounted on the base frame that generate 190 tons of force.
The sumping force is transmitted to the cutterhead by means of 20 ft. long fully enclosed pushbeams. As the cutterhead pushes into the seam, the cut coal is carried by a pair of 18 in. diameter conveying augers that run inside the pushbeams, a major advantage of this system being that any rock that falls from the entry roof lands on top of the pushbeam and cannot contaminate the coal being transported inside it. Once the cut coal arrives back at the base frame, it discharges either directly into waiting haulers or to a stockpile for subsequent load out.
In addition to providing the drive transfer and transporting the cut coal, the enclosed pushbeams play one further vital role. The service connections from the base frame to the cutterhead - electrical power, control, water and hydraulic lines, as well as methane sensor links - are contained within an armored cable that is automatically unwound from a large-diameter drum on the base frame as each pushbeam is added. Resting in a groove in the top of the pushbeam, the cables and hoses are completely protected from falling roof rock, and are rewound onto the drum once an entry is mined out and the cutterhead is being recovered.
The power available on the Terex SHM base frame unit is sufficient to allow the machine to mine entries over 1,000 ft. in depth. In addition, the fact that - although they are firmly secured to each other - the pushbeams have vertical flexibility at each joint means that the system can work in seams that pitch and roll, with the cutterhead following the floor and roof of the seam and the pushbeams following its path regardless of the floor conditions. Indeed, the machine’s low ground-bearing pressure means that seams with soft floors can be mined as effectively as those with a hard stone base.
Terex Corporation is a diversified global manufacturer with 2007 net sales of more than $9.1 billion. Terex operates in five business segments: Terex Aerial Work Platforms, Terex Construction, Terex Cranes, Terex Materials Processing & Mining, and Terex Roadbuilding, Utility Products and Other. Terex manufactures a broad range of equipment for use in various industries, including the construction, infrastructure, quarrying, mining, shipping, transportation, refining, and utility industries. Terex offers a complete line of financial products and services to assist in the acquisition of Terex equipment through Terex Financial Services. More information on Terex can be found at http://www.terex.com.