The present invention discloses a combined automatic anti-explosion method for a gas drainage pipeline, comprising specific steps of: preparation of an anti-explosion installation piping; connection of the installation piping and the gas drainage pipeline; assembly of a porous foam material and an automatic control valve; installation of an automatic powder-spraying device and a signal analyzer; installation of a temperature sensor and a pressure sensor; and signal processing and automatic anti-explosion. According to the present invention, the porous foam material is located in a bottom groove of an arched pipeline when no gas explosion occurs in the gas drainage pipeline, without affecting the extraction effect of the gas drainage pipeline. If a gas explosion occurs, the present invention blocks the pipeline with the porous foam material due to its fire resistance and pressure reduction performances, and the automatic powder-spraying device sprays a certain amount of a dry powder explosion suppressant to reduce the explosion overpressure generated in the gas explosion process and isolate the propagation of flame, so that the safety performance of the gas drainage pipeline is ensured, and thus the safety production of coal mines can be ensured.

A liquid nitrogen cyclic freeze-thaw permeability-improvement gas drainage method based on horizontal directional boreholes comprises: first constructing a main borehole at an intake roadway or a return roadway, a low-level roadway and a high-level roadway, after a drill bit reaches a pre-set target position of a coal bed, uniformly and directionally constructing a plurality of branch boreholes along a horizontal direction of the coal bed, injecting water to the coal bed, opening a valve, filling the main boreholes with liquid nitrogen, rapidly freezing the water injected into the branch boreholes and the periphery of the coal bed, and stopping injecting the nitrogen when an average temperature of a pre-permeability-improvement area monitored by a temperature measuring hole is lowered to 2 C. or lower.

A liquid nitrogen cyclic freeze-thaw permeability-improvement gas drainage method based on horizontal directional boreholes comprises: first constructing a main borehole at an intake roadway or a return roadway, a low-level roadway and a high-level roadway, after a drill bit reaches a pre-set target position of a coal bed, uniformly and directionally constructing a plurality of branch boreholes along a horizontal direction of the coal bed, injecting water to the coal bed, opening a valve, filling the main boreholes with liquid nitrogen, rapidly freezing the water injected into the branch boreholes and the periphery of the coal bed, and stopping injecting the nitrogen when an average temperature of a pre-permeability-improvement area monitored by a temperature measuring hole is lowered to 2 C. or lower.

The present invention discloses a combined automatic anti-explosion method for a gas drainage pipeline, comprising specific steps of: preparation of an anti-explosion installation piping; connection of the installation piping and the gas drainage pipeline; assembly of a porous foam material and an automatic control valve; installation of an automatic powder-spraying device and a signal analyzer; installation of a temperature sensor and a pressure sensor; and signal processing and automatic anti-explosion. According to the present invention, the porous foam material is located in a bottom groove of an arched pipeline when no gas explosion occurs in the gas drainage pipeline, without affecting the extraction effect of the gas drainage pipeline. If a gas explosion occurs, the present invention blocks the pipeline with the porous foam material due to its fire resistance and pressure reduction performances, and the automatic powder-spraying device sprays a certain amount of a dry powder explosion suppressant to reduce the explosion overpressure generated in the gas explosion process and isolate the propagation of flame, so that the safety performance of the gas drainage pipeline is ensured, and thus the safety production of coal mines can be ensured.

The present invention discloses a combined automatic anti-explosion method for a gas drainage pipeline, comprising specific steps of: preparation of an anti-explosion installation piping; connection of the installation piping and the gas drainage pipeline; assembly of a porous foam material and an automatic control valve; installation of an automatic powder-spraying device and a signal analyzer; installation of a temperature sensor and a pressure sensor; and signal processing and automatic anti-explosion. According to the present invention, the porous foam material is located in a bottom groove of an arched pipeline when no gas explosion occurs in the gas drainage pipeline, without affecting the extraction effect of the gas drainage pipeline. If a gas explosion occurs, the present invention blocks the pipeline with the porous foam material due to its fire resistance and pressure reduction performances, and the automatic powder-spraying device sprays a certain amount of a dry powder explosion suppressant to reduce the explosion overpressure generated in the gas explosion process and isolate the propagation of flame, so that the safety performance of the gas drainage pipeline is ensured, and thus the safety production of coal mines can be ensured.

A portable monitor used to measure landfill gas and landfill well parameters. The portable monitor includes a control unit and a measuring unit that can communicate wirelessly with one another. The control unit and/or measuring unit can include a heating arrangement to increase the temperature of one or more components in the control unit and/or measuring unit in cold environments.

A method for dynamic water feeding and hole sealing using high water-absorbent resin is applicable to sealing of a borehole on which extraction has a great impact. Two ends of a hole-sealed section of the borehole are sealed. Fine mixed high water-absorbent resin powder wrapped in a piece of cotton cloth is disposed in the hole-sealed section of the borehole, a water injection pipe and a gas extraction pipe are inserted in the borehole, and an automatic feed water valve is used to inject water into the hole-sealed section. The fine mixed high water-absorbent resin powder that fills the hole-sealed section and surrounding cracks with the water flow rapidly swells up after soaking up water to fill the hole-sealed section, and maintains at a swelling pressure. After the powder swells up and hole sealing is completed, the extraction pipe is connected to an extraction apparatus to perform gas extraction. This method has advantages such as tight hole sealing, high automation degree, and dynamic hole sealing, thus effectively solving problems that pores around the borehole are poorly sealed, it is difficult to seal cracks newly produced by extraction and so on. Moreover, the powder for hole sealing is low in price, and therefore the hole sealing cost is low.

A method for constructing networked preferential gas migration pathways and diverting and extracting gas. The method proposes that a fracture generation hole, a fracture guidance and development hole, a lateral rupture hole, and a fracture connection hole are respectively constructed in a roof in roadways on two sides of a working face in advance of an advance stress change area. Artificial guided fractures are actively constructed and formed inside the hard roof. Under a mining-induced stress effect, the artificial guided fractures and mining-induced fractures intersect with and are connected to each other to form networked preferential gas migration pathways. Meanwhile, boreholes for artificial guided fractures accelerate roof fracturing to form a rupture bed separation fracture area in a roof. Gas flows and migrates in a timely and efficient manner along networked fracture pathways and concentrates in the rupture bed separation fracture area in the roof.

A method for constructing networked preferential gas migration pathways and diverting and extracting gas. The method proposes that a fracture generation hole, a fracture guidance and development hole, a lateral rupture hole, and a fracture connection hole are respectively constructed in a roof in roadways on two sides of a working face in advance of an advance stress change area. Artificial guided fractures are actively constructed and formed inside the hard roof. Under a mining-induced stress effect, the artificial guided fractures and mining-induced fractures intersect with and are connected to each other to form networked preferential gas migration pathways. Meanwhile, boreholes for artificial guided fractures accelerate roof fracturing to form a rupture bed separation fracture area in a roof. Gas flows and migrates in a timely and efficient manner along networked fracture pathways and concentrates in the rupture bed separation fracture area in the roof.

A method for stepwise construction of a preferential gas migration pathway at a stope in a coal seam. First, a gas migration pathway is preliminarily formed at a stope depending on a mining effect of mining in a first mined seam. construction and stabilization method of gob-side entry retaining in deep strata, and a method of manual-guided pre-fracturing boreholes are then used to perform active construction respectively in external space and the outside of coal-rock mass to form preferential gas migration pathways. Eventually, under the effect of mining-induced stress, a system of preferential gas migration pathways connected to each other at the stope is further formed.