Abstract: The invention concerns a method and apparatus for providing yielding support for a hanging wall above a footwall in a mine working. A support assembly is installed between the hanging wall and the footwall, the assembly including a spacer (10), a pack (30) and a grout-inflatable bag (32). Grout is pumped into the bag (32) and is allowed to set to apply a vertical prestess force to the support assembly. The spacer (10) is substantially stiffer in compression than the pack (30), which is designed to yield under the compressive loading applied by the hanging wall. The use of a stiff spacer (10) serves to elevate the yielding pack to a suitble operative height without the allowable slenderness ratio for the pack to be exceeded.

Abstract: The mine prop headboard (10) is used to support an inflatable grout bag (44) and is located transversely on an end of an elongate mine prop (12) which is in use installed upright between a hanging wall and a footwall in a mine working. The headboard includes a chock assembly which is composed of parallel, elongate timber chocks (14). A steel reinforcement sheet is secured to and extends over the support surface of the chock assembly to provide tensile reinforcement a grout bag is placed on the headboard and is inflated with grout under pressure sufficient to apply a compressive axial force to the prop between the hanging wall and the footwall.

Abstract: The yieldable load support comprises a compressible support member in the form of an elongate timber pole. The load support or pole is asymmetrically modified at or near one end thereof in a manner to positively induce sideways brushing of the pole at the modified end, in a preferential direction transverse to the length of the pole, when the support member is placed under longitudinal compressive load of sufficient magnitude.

Abstract: The invention concerns a prop headboard (10) which is used in conjunction with an elongate mine prop. The headboard supports a preload bag (50) inflatable with a settable grout. The headboard is composed of a headboard member (12) and a pot (34). The headboard member includes a pressed steel sheet (14) having relatively higher end regions (16) and a relatively lower central region (22). The central region is formed with an opening (24). The headboard member also has bag retaining formations (30) which receive opposite ends of a preload bag located on the headboard member. The pot is engaged in the opening in the central region and receives the upper end of an elongate prop, thus supporting the headboard member on the prop with the headboard member extending transversely to the prop.

Abstract: The prop preloading apparatus comprises a frame and means for supporting the frame on an end of an elongate prop in a manner permitting at least limited swivelling movement of the frame relative to the prop about at least one axis transverse to the axis of the prop. The apparatus also includes a flexible preload bag which is inflatable with a settable substance and which is dimensioned to be supported by the frame.