A hand held supersonic air knife with a supersonic variable flow nozzle yields a continuously variable power mass flow rate (CFM) and pressure over a selectable power range, responsive to rotations of the nozzle exterior sleeve or outer nozzle member. The maximum power position identified as one end position and a second end position as the lowest power. The exterior sleeve can be rotated to any axial or circumferential position between start (low) and end (high). The result will be an intermediate power position. Any intermediate position will also be a supersonic nozzle of varying parameters between the start and end positions. Thus, a variable flow supersonic nozzle is provided by the manual sleeve rotation by an operator or a remotely controlled positioning of the sleeve.

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 steeply inclined surface is hydrodemolished by providing a staging platform and a rig that includes a base frame defining a planar footprint within the frame. The rig is suspended from the platform by a cable such that frame is coplanar with the surface and the incline of the surface causes the rig to lean against it. Rails are provided on the surface to restrain spurious lateral movement of the rig. The rig is positioned on the surface and nozzles mounted on a trolley within a travelling carriage on the frame travel in two dimensions to hydrodemolish the surface within the footprint. The rig is moved vertically along the rails and laterally along the platform to reposition the rig to work a new section of the surface in conjunction with other rails that are also mounted on the surface.

A hand held supersonic air knife with a supersonic variable flow nozzle yields a continuously variable power mass flow rate (CFM) and pressure over a selectable power range, responsive to rotations of the nozzle exterior sleeve or outer nozzle member. The maximum power position identified as one end position and a second end position as the lowest power. The exterior sleeve can be rotated to any axial or circumferential position between start (low) and end (high). The result will be an intermediate power position. Any intermediate position will also be a supersonic nozzle of varying parameters between the start and end positions. Thus, a variable flow supersonic nozzle is provided by the manual sleeve rotation by an operator or a remotely controlled positioning of the sleeve.

Disclosed are an integrated mining method and an integrated mining system of coal breaking, coal extraction and water circulation in a U-well. The integrated mining system includes a first ground facility unit, a second ground facility unit, a jet unit and an extraction unit. The first ground facility unit is configured to transport jet fluid to the jet unit. The jet unit is configured to break a coal seam in a sub-segment to obtain broken cinders. The extraction unit is configured to extract a coal-water mixture. The second ground facility unit is configured to receive the coal-water mixture. In response to determining that an extraction of the sub-segment is complete, the jet unit and the extraction unit is configured to move to a next sub-segment using powers provided by the first ground facility unit and the second ground facility unit.

Disclosed are an integrated mining method and an integrated mining system of coal breaking, coal extraction and water circulation in a U-well. The integrated mining system includes a first ground facility unit, a second ground facility unit, a jet unit and an extraction unit. The first ground facility unit is configured to transport jet fluid to the jet unit. The jet unit is configured to break a coal seam in a sub-segment to obtain broken cinders. The extraction unit is configured to extract a coal-water mixture. The second ground facility unit is configured to receive the coal-water mixture. In response to determining that an extraction of the sub-segment is complete, the jet unit and the extraction unit is configured to move to a next sub-segment using powers provided by the first ground facility unit and the second ground facility unit.

The present invention relates to a high pressure water jet automatic drilling and cutting collaborative system and method for coal seams, and belongs to the field of coal seam gas control. The system comprises a drilling and cutting collaborative control platform, an automatically regulated slotting pump unit and an automatically regulated drill; the drilling and cutting collaborative control platform comprises a coalbed gas geology management system, a decision analysis system, a drilling and cutting collaborative execution system, a monitoring and feedback system, and an information management and evaluation system; construction operation parameter instructions issued by the drilling and cutting collaborative control platform are executed by the automatically regulated slotting pump unit and the automatically regulated drill; coal seam geological information is recorded by the coalbed gas geology management system, and reasonable drilling and cutting construction parameters are analyzed and formulated by the decision analysis system based on the coal seam geological information. Drilling and cutting collaborative construction, on-site operation construction parameter monitoring, and real-time feedback and adjustment are realized by the drilling and cutting collaborative execution system and the monitoring feedback system according to the operation parameter instructions. Coal seam outburst prevention and control effects in a drilling and cutting collaborative implementation area is evaluated by the information management and evaluation system. The present invention improves safety of on-site operators, and reduces personnel input and labor intensity.