Powered roof supports are used to support the roof at the face.They work in several steps mostly in the immediate forward support (IFS) type in order to support the newly exposed roof as soon as possible. In normal supporting condition the canopy of the support is set tightly against the roof strata,by the supporting resistances of the hydraulic legs. When the cutting machine cuts and passes several support units beyond the support in question, the support legs are lowered and pulled forward for a distance equal to the width of cut (web) by retracting the hydraulic advancing ram. The advancing ram acts against the face conveyor panline, whose position is held unchanged by the advancing rams, forces of the supports that are set on both sides of the support to be advanced. As soon as the support has been advanced to the designed position, the support is immediately reset against the roof. Finally, the advancing ram of the support in question is extended to push the conveyor forward and becomes ready for the next cut.
