Entering the Gate End When cutting out at the endgate, the shearer needs to reach a reference point so that the program knows the shearer is ready to change directions and go to the next turn point. For the headgate, this reference point is set by parameter “HG Turn Point”. Setting this parameter to 7 means the shearer position has to reach shield 7 or less every time it cuts out at the headgate.
Parameter "HG Turn Point”
For the tailgate, this reference point is set by parameter “TG Turn Point from TG”. Setting this parameter to 5 means the shearer position has to reach the 5 th shield from the end of the face every time it cuts out at the tailgate.
Parameter "TG Turn Point from TG”
The best way to determine these values is to tram the shearer to the stop points at each end and then set the parameter 2-3 shields towards mid-face. For example, when going into the head gate, if the shearer reaches number 7, then set the “HG Turn Point” to 9. This way the turn point will always be reached. When the SRB position reaches the HG or TG Turn Point, then the shield system is ready for the shearer to travel back to the next turn point in the mining cycle. The next turn point will be the double cut setting when in Bidirectional mode or the turn point at the other endgate in the unidirectional mode. The picture below represents the tailgate of 175 shield face. Several things can be seen in this picture: ● Parameter “TG Turn Point from TG” is set to 5 which positions the turn point at shield 171. The shearer has actually gone one shield farther then necessary to shield 172 so the shield system is ready for the shearer to turn around and go back the other direction. ● Parameter “Auto HG Safe Zone” is set to 6 so the closest shield that has advanced is #165, leaving the Primepoint at shield 166. ● Parameter “TG Cleanup Area” is set to 8; when the shearer turns around and leaves the cleanup area (i.e., position becomes 167) the system will begin trying to advance the tailgate shields. If parameter “Auto TG Safe Zone” is set to 6 also, then shields 173 through 161 will be in the shearer zone when the position is at shield 167; this means that initially only 175 and 174 will be triggered to advance.
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