A mine roof support comprises two or more frusto-conical, tubular sections, the sections each flared outwardly from an upper end to a lower end thereof, a skirt portion of a section being received and secured within a neck portion of a section below in a frictional fit to define a continuous, interior volume of the mine roof support. A continuous, solid, compressible, load-bearing material is located within the interior volume. An uppermost section is closed at an upper end thereof, and a lowermost section is closed at a lower end thereof. Methods of installing a mine roof support and a pre-installation assembly for a mine roof support are also disclosed.

A mine roof support comprises two or more frusto-conical, tubular sections, the sections each flared outwardly from an upper end to a lower end thereof, a skirt portion of a section being received and secured within a neck portion of a section below in a frictional fit to define a continuous, interior volume of the mine roof support. A continuous, solid, compressible, load-bearing material is located within the interior volume. An uppermost section is closed at an upper end thereof, and a lowermost section is closed at a lower end thereof. Methods of installing a mine roof support and a pre-installation assembly for a mine roof support are also disclosed.

A mine roof support comprises two or more frusto-conical, tubular sections, the sections each flared outwardly from an upper end to a lower end thereof, a skirt portion of a section being received and secured within a neck portion of a section below in a frictional fit to define an interior volume of the mine roof support. A solid, compressible, load-bearing material is located within the volume. Methods of installing a mine roof support and a pre-installation assembly for a mine roof support are also disclosed.

A mine roof support comprises two or more frusto-conical, tubular sections, the sections each flared outwardly from an upper end to a lower end thereof, a skirt portion of a section being received and secured within a neck portion of a section below in a frictional fit to define a continuous, interior volume of the mine roof support. A continuous, solid, compressible, load-bearing material is located within the interior volume. An uppermost section is closed at an upper end thereof, and a lowermost section is closed at a lower end thereof. Methods of installing a mine roof support and a pre-installation assembly for a mine roof support are also disclosed.

A mine roof support comprises two or more frusto-conical, tubular sections, the sections each flared outwardly from an upper end to a lower end thereof, a skirt portion of a section being received and secured within a neck portion of a section below in a frictional fit to define a continuous, interior volume of the mine roof support. A continuous, solid, compressible, load-bearing material is located within the interior volume. An uppermost section is closed at an upper end thereof, and a lowermost section is closed at a lower end thereof. Methods of installing a mine roof support and a pre-installation assembly for a mine roof support are also disclosed.

A mine roof support comprises two or more frusto-conical, tubular sections, the sections each flared outwardly from an upper end to a lower end thereof, a skirt portion of a section being received and secured within a neck portion of a section below in a frictional fit to define an interior volume of the mine roof support. A solid, compressible, load-bearing material is located within the volume. Methods of installing a mine roof support and a pre-installation assembly for a mine roof support are also disclosed.

A telescopic device includes a first U-shaped connector with a plurality sets of adjustment slots defined in two sides thereof and arranged along an adjustment direction; a second U-shaped connector defining first through holes in two sides thereof, the second U-shaped connector being inserted into the first U-shaped connector with U-shaped openings thereof opposite to each other to define an accommodating space; a first spring located in the accommodating space and abutting against the first and second U-shaped connectors, respectively; an elastic pin with two ends thereof extending through the first through holes and engaging into one of the plurality sets of adjustment slots; and an initial fixing pin being detachably connected to the first and second U-shaped connectors. A telescopic annular tunnel steel arch includes an upper arch, two lower arches and two telescopic devices connecting two ends of the upper arch to the two lower arches, respectively.

A mine prop includes a first pipe having a first end and a second end, a second pipe having a first end and a second end, and a yield member secured to the second pipe. The second pipe is slidably received in the first pipe. The yield member is configured to yield before the first and second pipes when the mine prop is placed under a predetermined load.

A support comprising an outer casing having a main axis, the outer casing comprising a first casing part and a second casing part, the first casing part being at least partially receivable within the second casing part to enable relative movement therebetween in the axial direction, the casing parts having a cavity therein at least one of which has a core that includes a compressible medium, the support further including a pressure responsive system configured so that under the influence of pressure it can cause the relative displacement or movement between the first and second casing parts.

A support comprising an outer casing having a main axis, the outer casing comprising a first casing part and a second casing part, the first casing part being at least partially receivable within the second casing part to enable relative movement therebetween in the axial direction, the casing parts having a cavity therein at least one of which has a core that includes a compressible medium, the support further including a pressure responsive system configured so that under the influence of pressure it can cause the relative displacement or movement between the first and second casing parts.