Yieldable mine roof support

A method of installing a roof support in a mine passageway, said support comprising an upper telescoping containment member and a lower telescoping containment member freely telescopically movable relative to one another and a filler material pumpable into the containment members to form a yieldable column of material extending vertically in the passageway, the containment members defining an interior space for receiving said filler material, said method comprising the steps of:

• pumping a fluid, hardenable material into the telescoping containment members to cause the upper containment member to telescopically rise with respect to the lower containment member to form a column of material inside the containment members,
• allowing the hardenable material to form a yieldable set inside the containment members, and
• leaving the telescoping containment members with the hardened material therein permanently in place while allowing for freedom of movement between the telescoping members so that the yieldable material is capable of yielding while providing continued support and the telescoping containment members are capable of moving freely relative to one another to permit such yielding without damage to the support.

A mine roof support adapted to extend vertically in a mine passageway, said support comprising a containment structure having at least two tubular telescoping containment members freely telescopically movable relative to one another and defining an interior space inside said containment members, a yieldable cementitious material substantially filling said interior space to form a yieldable column of material extending vertically in the passageway, one of said containment members having an inlet port for filling the interior space with said cementitious material, said column being capable of yielding while providing continued support and the telescoping containment members being capable of moving freely relative to one another to permit such yielding without damage to the support.