An apparatus for pre-loading a mechanical constant-resistance single prop includes a rhombic stretchable bracket, a screw rod, a first cylindrical sleeve ring, and a second cylindrical sleeve ring. The screw rod is connected to two opposite apex corners of the rhombic stretchable bracket. A tail end of the screw rod is fixedly connected to one apex corner of the rhombic stretchable bracket. An end head of the screw rod passes through another apex corner of the rhombic stretchable bracket. The remaining two opposite apex corners of the rhombic stretchable bracket are respectively fixedly connected to edges of the first cylindrical sleeve ring and the second cylindrical sleeve ring through connecting rods. The screw rod is threadedly connected to the apex corner of the rhombic stretchable bracket through which the screw rod passes. A method for pre-loading a mechanical constant-resistance single prop is also provided.

An apparatus for pre-loading a mechanical constant-resistance single prop includes a rhombic stretchable bracket, a screw rod, a first cylindrical sleeve ring, and a second cylindrical sleeve ring. The screw rod is connected to two opposite apex corners of the rhombic stretchable bracket. A tail end of the screw rod is fixedly connected to one apex corner of the rhombic stretchable bracket. An end head of the screw rod passes through another apex corner of the rhombic stretchable bracket. The remaining two opposite apex corners of the rhombic stretchable bracket are respectively fixedly connected to edges of the first cylindrical sleeve ring and the second cylindrical sleeve ring through connecting rods. The screw rod is threadedly connected to the apex corner of the rhombic stretchable bracket through which the screw rod passes. A method for pre-loading a mechanical constant-resistance single prop is also provided.

An equipment system for a self-retaining mining method mainly comprises a transition support, an end support, a following support, and a fast-retracting support. Working face gateroads do not need to advance in mining, and a coal mining machine may be used to cut a neat coal wall at the end of a district. The entry rib is automatically formed after roof caving, thus forming a gateroad in a re-mining process. The coal mining machine is under digital control when its end cuts the coal, automatically enabling the end to laterally cut the coal wall to form a vertical straight line, which is used as the entry rib of the gateroad. A scrapper conveyor works in coordination with an arc-shaped coal grabbing plate of the coal mining machine to clean up float coal at the end as much as possible.

An equipment system for a self-retaining mining method mainly comprises a transition support, an end support, a following support, and a fast-retracting support. Working face gateroads do not need to advance in mining, and a coal mining machine may be used to cut a neat coal wall at the end of a district. The entry rib is automatically formed after roof caving, thus forming a gateroad in a re-mining process. The coal mining machine is under digital control when its end cuts the coal, automatically enabling the end to laterally cut the coal wall to form a vertical straight line, which is used as the entry rib of the gateroad. A scrapper conveyor works in coordination with an arc-shaped coal grabbing plate of the coal mining machine to clean up float coal at the end as much as possible.

A yielding mine roof support is provided which is made in the form of a hollow tube made from an epoxy, phenolic, or polyester fiberglass composite.

A yielding mine roof support is provided which is made in the form of a hollow tube made from an epoxy, phenolic, or polyester fiberglass composite.