A mine safety system is provided for preventing coal dust explosions in an underground coal mine. The system comprises a reservoir, for storing an inerting agent; a compressor, for providing compressed air; and a mixer, coupled to the reservoir and the compressor, for mixing the inerting agent and compressed air and providing the mixture to the underground coal mine. The reservoir is located outside of the coal mine.

Described are a test apparatus and a test method for the wetted perimeter of coal seam water injection. In the test apparatus, a columnar insulator is provided between an upper electrode and a lower electrode, circular insulating tapes are located at the outer edges of the upper electrode and the lower electrode, a circular reverse osmosis membrane is provided at the middle of the circular insulating tape, the upper electrode, lower electrode, circular insulating tapes and circular reverse osmosis membrane form an enclosed chamber which is filled with solid sodium chloride, and cotton yarns are packed among the upper resin backing plate, lower resin backing plate, circular insulating tapes and the inner walls of water permeable perforated pipes. The upper electrode is provided with an electrode lead which passes through the columnar insulator, the lower electrode and the lower resin backing plate and goes out from the tail connecting end.

Described are a test apparatus and a test method for the wetted perimeter of coal seam water injection. In the test apparatus, a columnar insulator is provided between an upper electrode and a lower electrode, circular insulating tapes are located at the outer edges of the upper electrode and the lower electrode, a circular reverse osmosis membrane is provided at the middle of the circular insulating tape, the upper electrode, lower electrode, circular insulating tapes and circular reverse osmosis membrane form an enclosed chamber which is filled with solid sodium chloride, and cotton yarns are packed among the upper resin backing plate, lower resin backing plate, circular insulating tapes and the inner walls of water permeable perforated pipes. The upper electrode is provided with an electrode lead which passes through the columnar insulator, the lower electrode and the lower resin backing plate and goes out from the tail connecting end.

A mining machine includes a chassis, a cutting assembly coupled to the chassis, and a spray arm coupled to the chassis and positioned proximate the cutting assembly. The chassis includes a first end, a second end, and a chassis axis extending between the first end and the second end. The chassis is movable in a direction parallel to the chassis axis. The cutting assembly includes an arm and a rotatable cutting drum having a plurality of cutting elements. The spray arm includes a first portion, a second portion pivotably coupled to the first portion, and at least one spray nozzle for emitting a fluid spray in a region adjacent the cutting assembly. The first portion is coupled to the chassis and extends away from the chassis along a spray arm axis. The second portion is pivotable relative to the first portion about a wrist axis.

A mining machine includes a chassis, a cutting assembly coupled to the chassis, and a spray arm coupled to the chassis and positioned proximate the cutting assembly. The chassis includes a first end, a second end, and a chassis axis extending between the first end and the second end. The chassis is movable in a direction parallel to the chassis axis. The cutting assembly includes an arm and a rotatable cutting drum having a plurality of cutting elements. The spray arm includes a first portion, a second portion pivotably coupled to the first portion, and at least one spray nozzle for emitting a fluid spray in a region adjacent the cutting assembly. The first portion is coupled to the chassis and extends away from the chassis along a spray arm axis. The second portion is pivotable relative to the first portion about a wrist axis.

A method for the suppression of coal seam fires provides for the location and determination of the boundaries of a coal seam fire, directing access to the coal seam, preparation of the coal seam prior to suppression and the suppression of the fire within the coal seam using a foam mixture, the method providing minimal impact and disruption to the surface above the coal seam fire.

Systems and methods for controlling dust. One method includes automatically detecting an operating status of a mining machine. The method also includes automatically, with an electronic processor, adjusting operation of a dust suppression system based on the operating status of the mining machine.

Systems and methods for controlling dust. One method includes automatically detecting an operating status of a mining machine. The method also includes automatically, with an electronic processor, adjusting operation of a dust suppression system based on the operating status of the mining machine.

A fluid spray for an underground roof support includes a first housing portion, a spray outlet, a second housing portion formed integrally with the first housing portion, and a service port. The first housing portion includes an elongated shaft having a first end, a second end, and a first fluid passage extending between the first end and the second end. The spray outlet is positioned adjacent the second end of the shaft. The second housing portion is positioned adjacent the first end of the shaft. The second housing portion includes at least one port and a second fluid passage between the at least one port and the first fluid passage. The service port is aligned with the first fluid passage, and the service port is selectively opened to provide access to the first fluid passage from the first end of the first housing portion.

A fluid spray for an underground roof support includes a first housing portion, a spray outlet, a second housing portion formed integrally with the first housing portion, and a service port. The first housing portion includes an elongated shaft having a first end, a second end, and a first fluid passage extending between the first end and the second end. The spray outlet is positioned adjacent the second end of the shaft. The second housing portion is positioned adjacent the first end of the shaft. The second housing portion includes at least one port and a second fluid passage between the at least one port and the first fluid passage. The service port is aligned with the first fluid passage, and the service port is selectively opened to provide access to the first fluid passage from the first end of the first housing portion.