The present invention relates to a “drilling-flushing-slotting” coupled pressure relief and permeability increasing method for a high gas outburst coal seam, which is more particularly suitable for the pressure relief and permeability increasing when gas of a roadway band of the high gas outburst coal seam is pre-extracted through crossing boreholes. On the basis of the crossing borehole pre-extraction measures for the coal seam gas, the hydraulic flushing and the hydraulic slotting are reasonably combined, and a “drilling-flushing-slotting” dedicated device is utilized to implement the coupled operation of “low pressure drilling-medium pressure flushing-high pressure slotting” in a borehole, so that the coal in the pre-extraction area is deformed and moved to form network cracks, passages are provided to the desorption flow of the gas, and the gas is easier to extract. The method can enlarge the single-hole pressure relief influence range, increase the gas permeability of the coal seam, improve the gas extraction efficiency, reduce the number of pre-extraction boreholes, shorten the pre-extraction time and have good applicability to the coal seams in different occurrence states. The present invention can reduce the number of the crossing boreholes by 32.5% and can reduce the length of each crossing borehole by 42.9%, is remarkable in coal roadway regional outburst eliminating effect, and obviously increases the tunneling speed.

A fluid delivery system for a longwall shearer. The fluid delivery system includes a flow control device and an electronic processor. The flow control device is in fluid communication with a nozzle positioned on the shearer, and in fluid communication with a fluid source. The electronic processor is coupled to the flow control device. The electronic processor is configured to receive a measure of a capacity parameter, and determine a model fluid flow based on the measure of the capacity parameter. The capacity parameter corresponds to a position of the shearer along the mineral face. The electronic processor is further configured to set an operational parameter of the flow control device based on the model fluid flow, and operate the flow control device at the set operational parameter.

A method of performing coupled drilling, flushing, and slotting operations on a coal seam, which has a high gas content and prone to bursts, is described herein. The method is aimed to relieve pressure and increase permeability when drilling a through-seam borehole to pre-drain gas belts in a coal mine roadway. The pressure relief and permeation method of the present invention adjusts the water jet water inlet pressure in different stages according to the different positions of the drilling construction, and controls the water during drilling. At drilling stage, the jets are respectively subjected to low-pressure water flow drilling and medium-pressure water flow flushing. When withdraw drilling, the high-pressure water flow slotting is carried out. By doing so, the pressure is relieved in a low, medium, high stepwise manner.

A fluid delivery system for a longwall shearer. The fluid delivery system includes a flow control device and an electronic processor. The flow control device is in fluid communication with a nozzle positioned on the shearer, and in fluid communication with a fluid source. The electronic processor is coupled to the flow control device. The electronic processor is configured to receive a measure of a capacity parameter, and determine a model fluid flow based on the measure of the capacity parameter. The capacity parameter corresponds to a position of the shearer along the mineral face. The electronic processor is further configured to set an operational parameter of the flow control device based on the model fluid flow, and operate the flow control device at the set operational parameter.

An experimental apparatus for rock-breaking through vibration impact, including a confining pressure loading assembly, a drill bit, a drill rod, a drilling fluid circulation assembly, a rotary impact assembly and an axial impact assembly. The confining pressure loading assembly is configured to apply pressures to a core sample located in a core cavity in three directions perpendicular to each other. The drill bit is capable of inserting into the core cavity to drill the core sample. The drilling fluid circulation assembly includes a drilling fluid inlet, a drilling fluid outlet and a mud pump connected therebetween. The rotary impact assembly includes a hydraulic rotary motor and a hydraulic swing motor connected to the drill rod, respectively. The axial impact assembly includes a first hydraulic cylinder, and a servo linear actuator connected to the first hydraulic cylinder and the drill rod.

An experimental apparatus for rock-breaking through vibration impact, including a confining pressure loading assembly, a drill bit, a drill rod, a drilling fluid circulation assembly, a rotary impact assembly and an axial impact assembly. The confining pressure loading assembly is configured to apply pressures to a core sample located in a core cavity in three directions perpendicular to each other. The drill bit is capable of inserting into the core cavity to drill the core sample. The drilling fluid circulation assembly includes a drilling fluid inlet, a drilling fluid outlet and a mud pump connected therebetween. The rotary impact assembly includes a hydraulic rotary motor and a hydraulic swing motor connected to the drill rod, respectively. The axial impact assembly includes a first hydraulic cylinder, and a servo linear actuator connected to the first hydraulic cylinder and the drill rod.