The HG shields that have not yet advanced will be triggered as the shearer leaves the HG Cleanup area and goes back into the partially pushed area on its way to the TG. This can be seen in the picture below. (Notice that the HG shields have not yet begun to push.) Half-Web Cycle – Step 3 – Cutting Head to Tail
As the shearer continues to move toward the TG, the conveyor will then start pushing to the stroke set by SRB parameter “H->T Push Stroke”, usually 98% or higher.
SRB Parameter “H->T Push Stroke”
The picture below shows the shearer in mid face with a conveyor push following it towards the tailgate. Half-Web Cycle – Step 4 – Still Cutting Head to Tail
The full push will follow the shearer all the way to the TG until the entire conveyor is pushed. The picture below shows the longwall state when the shearer reaches the tailgate. Half-Web Cycle – Step 5 – Shearer in Tailgate
The coal face has two snakes but the shields are straight and the conveyor is completely pushed on the entire face. The longwall is in the same state as the Initial Position picture shown previously. The system is ready for the shearer to go back to the headgate and repeat the entire cycle.
Shearer Cleanup Problems If the shearer does not clean-up sufficiently to allow the shields to push to a full 100% stroke, the parameter “H->T Push Stroke” can be set to a lower value, such as 90%. 88 © Caterpillar
