In a hydraulic shield support system, a plurality of pressure intensifiers are respectively provided for a plurality of hydraulic props. Each pressure intensifier is operated to increase a system pressure to an increased pressure for supplying fluid at the increased pressure to a pressure chamber of the associated hydraulic prop. The plurality of pressure sensors measure the pressures of the fluid supplied to the respective hydraulic props. A control unit sets a plurality of desired pressures for the plurality of hydraulic props, and stops operation of the respective pressure intensifiers when the set desired pressure has been reached.

In a hydraulic shield support system, a plurality of pressure intensifiers are respectively provided for a plurality of hydraulic props. Each pressure intensifier is operated to increase a system pressure to an increased pressure for supplying fluid at the increased pressure to a pressure chamber of the associated hydraulic prop. The plurality of pressure sensors measure the pressures of the fluid supplied to the respective hydraulic props. A control unit sets a plurality of desired pressures for the plurality of hydraulic props, and stops operation of the respective pressure intensifiers when the set desired pressure has been reached.

An apparatus for protecting a roof tray when a gob-side entry retaining end support migrates is provided. The apparatus is mounted at a top end position of a hydraulic support, and includes a movable bearing mechanism, an automatic expansion/contraction connecting groove mechanism, and an active reset mechanism. The movable bearing mechanism includes two parallel belts and a plurality of rollers supporting the belts, and the rollers are mounted on and supported by a bearing mechanism. The automatic expansion/contraction connecting groove mechanism is two concave base plates fixed between the two belts, and the two concave base plates are spaced by a distance. The active reset mechanism includes two telescopic rods and reset springs sleeved on the telescopic rods, and the telescopic rod is connected to an end portion of the reset spring to form a synchronous mechanism.

A mobile canopy (or rapid advance shield) for use in a tunnel, comprising: first and second opposing and spaced walls; a curved roof coupled between the first and second walls; first and second skis mounted to respective bottoms of the first and second walls, the skis adapted to slide the mobile canopy about a floor of the tunnel; wherein the curved roof slopes downward from a front end of the mobile canopy toward a back end of the mobile canopy, the front end of the mobile canopy for positioning adjacent to a face of the tunnel; wherein the curved roof is movable between a first position proximate a tunnel roof and a second position spaced from the tunnel roof; and, wherein the first and second walls are movable between respective first positions proximate respective tunnel walls and respective second positions spaced from the tunnel walls.