FUNDAMENTALS

longwall mining
 

equipment
   

cutting machines - coal ploughes
 

Equipment

Cutting Machines - Coal Ploughes

Plough operating on a longwall face Coal Ploughs have had little application in Australia, and their main use has been in Europe, particularly in Germany where they were first developed. Essentially a plough is a large mass of steel, usually of a more or less triangular shape when viewed from the coal face or goaf sides, fitted with large "picks" (more like small agricultural plough blade tips) angled from the steel body towards the coal face. The plough height is the working height in the seam being mined (possibly a bit lower if the coal tops can be guaranteed to fall once the coal below is cut. These "picks" act in a fashion similar to chisels and break a narrow web of coal off the face (of the order of 300-400mm thick). In most cases there are no moving parts on a coal plough.

The plough itself is mounted on the front of the AFC and is pushed into the face by push cylinders mounted in the supports. The plough has an endless chain haulage attached to the rear, and is driven through sprockets on electric drive(s) at the face end(s).

The main advantages of ploughs compared to shearers are:

  • Cheap

  • Simple (no moving parts on the cutting machine itself)

  • Relatively low dust make

  • Able to keep exposed roof area very small (but a large number of chock movements would be required to maintain this)

Though only a small web is taken, in the right conditions production rates can be comparable to a shearer as the plough is operated at a relatively fast speed along the face.

Some disadvantages are:

  • Cutting height is fixed

  • Ability to cut stone is limited

  • With increasing cutting height, machine stability becomes more problematic

  • Grading can only be done using the AFC angle

  • There are safety implications with an exposed chain haulage.

DBTFocuses on Automation at Longwall USA 2005 – magazine extract with illustration of plough