A reinforced lightweight mine door for installation in a mine passageway. The mine door includes a generally rectangular sheet metal door panel having four sides and four corners, and a reinforcing structure projecting from a face of the door panel. The reinforcing structure has a central section and a plurality of channel sections extending from the central section toward respective sides or corners of the door panel. A mine door including at least one hinge arrangement having unique reversibility features is also disclosed.

A mine door system which includes a mine door having a door leaf, and a door-moving mechanism that articulates between a first configuration in which the mechanism applies a relatively smaller door-moving force to the door leaf and moves it at a first speed and a second configuration in which the mechanism applies a larger door-moving force to the door leaf and moves it at a second speed less than the first speed.

A mine door system which includes a mine door having a door leaf, and a door-moving mechanism that articulates between a first configuration in which the mechanism applies a relatively smaller door-moving force to the door leaf and moves it at a first speed and a second configuration in which the mechanism applies a larger door-moving force to the door leaf and moves it at a second speed less than the first speed.

A mine stopping panel is disclosed. The panel includes first and second channel-shaped panel members having a telescoping sliding fit one inside the other. An elongate end cap is fitted in the first panel member. One or more louver connections between the first panel member and the end cap hold the end cap against movement relative to the first panel member when an extending force is applied to the end cap tending to telescopically extend the first panel member relative to the second panel member.

A mine stopping panel is disclosed. The panel includes first and second channel-shaped panel members having a telescoping sliding fit one inside the other. An elongate end cap is fitted in the first panel member. One or more louver connections between the first panel member and the end cap hold the end cap against movement relative to the first panel member when an extending force is applied to the end cap tending to telescopically extend the first panel member relative to the second panel member.

A longitudinally yieldable support for underground roof support includes first and second outer shell portions having a first wall thickness and a third outer shell portion having a second wall thickness that is greater than the first wall thickness. The support is filled with a solid compressible filler material. At least one air ventilation tube extends between opposite sides of the third outer shell portion to allow a flow of air through the support as the first and second outer shell portions and filler material therein yield under load.

A ventilation method for a high gas working face based on alternating intake and air return in a mine gallery is provided. In this method, an isolated island working face is divided into several sections along a strike direction. A coal pillar is alternately set as a conventional section and a gas-drainage section. Opposite coal pillars in the two mine galleries within the same section are respectively used as the conventional section and the gas-drainage section. Two mine galleries on both sides of the isolated island working face are alternately used as an intake gallery and a return gallery. The coal pillar at the side of the mine gallery as the return gallery is the gas-drainage section. A gas-drainage hole communicating a goaf is provided in the gas-drainage section, so that gas in the goafs at two sides of the isolated island working face can be extracted alternately.

A ventilation method for a high gas working face based on alternating intake and air return in a mine gallery is provided. In this method, an isolated island working face is divided into several sections along a strike direction. A coal pillar is alternately set as a conventional section and a gas-drainage section. Opposite coal pillars in the two mine galleries within the same section are respectively used as the conventional section and the gas-drainage section. Two mine galleries on both sides of the isolated island working face are alternately used as an intake gallery and a return gallery. The coal pillar at the side of the mine gallery as the return gallery is the gas-drainage section. A gas-drainage hole communicating a goaf is provided in the gas-drainage section, so that gas in the goafs at two sides of the isolated island working face can be extracted alternately.

A longitudinally yieldable support for underground roof support includes first and second outer shell portions having a first wall thickness and a third outer shell portion having a second wall thickness that is greater than the first wall thickness. The support is filled with a solid compressible filler material. At least one air ventilation tube extends between opposite sides of the third outer shell portion to allow a flow of air through the support as the first and second outer shell portions and filler material therein yield under load.

A ventilation method for a high gas working face based on alternating intake and air return in a mine gallery is provided. In this method, an isolated island working face is divided into several sections along a strike direction. A coal pillar is alternately set as a conventional section and a gas-drainage section. Opposite coal pillars in the two mine galleries within the same section are respectively used as the conventional section and the gas-drainage section. Two mine galleries on both sides of the isolated island working face are alternately used as an intake gallery and a return gallery. The coal pillar at the side of the mine gallery as the return gallery is the gas-drainage section. A gas-drainage hole communicating a goaf is provided in the gas-drainage section, so that gas in the goafs at two sides of the isolated island working face can be extracted alternately.