As the working faces advance and every time the block reaches the rear of the working face, it is pushed into the gob side of the roadway by single hydraulic prop
. Finally, a certain thickness concrete mortar is sprayed onto the block to connect the wall with the roof of the roadway.
(3) With respect to entry-in reinforced support, a high-resistance-yielding individual hydraulic prop
should be adopted for the GER within a certain range behind the working face during backstopping to reinforce roof support.
The diagrams in the sidebar on the opposite page show how a typical non-feathering hydraulic prop
uses engine oil from the propeller governor to change the blades' position when increasing, decreasing or maintaining a pitch setting.
RMD Kwikform will also be introducing our Ground Shoring range to the Oman market which includes such equipment as heavy duty trench boxes, trench sheets and hydraulic props
for excavation works.
Calculation of the pressure that the working roof wall is to exert on hydraulic props
is essential for support design, both to ensure working global stability and to avoid prop punching on gables .
Both single-ended and double-ended ranging drum shearers, ploughs with hydraulic props
, friction props, etc.
Rapid yielding hydraulic props
were first implemented in the late 1960s as a support system designed to accommodate the rapid convergence of the hanging and footwalls which occurs during a rockburst, while still providing the required support.