Unidirectional Cutting Cycle

To allow the tailgate shields to advance and push the pan so it is straight, the tailgate must be double-cut as shown in the following two pictures:

Setup – Double Cut Tail

Setup – Tail Double Cut Complete

The shearer is now in the tailgate and all shields are advanced and fully pushed. The system is now ready for the shearer to start cutting to the headgate in any of the unidirectional cycles.

Half-Web (or Partial) Cutting Cycle

In half-web cutting, a partial-web cut of coal, both top and bottom, is taken on both passes. On one pass, the shields are advanced behind the shearer and then the pan is partially pushed. On the next pass, as the shearer travels in the opposite direction, the shields do not move but the conveyor is pushed to full stroke. It is generally better to advance shields on the tail to head pass so that the operators are not in the dust generated by the shield advances. Below is a picture showing the initial position of the shields, conveyor, and shearer when the unidirectional cycle is started.