A non-human-entry method for extracting a desired subsurface material such as ore, wherein an access hole is drilled from surface downwardly to the material, a high-pressure fluid injection tool is lowered with or after the drill string to the material and injected outwardly to disaggregate the material and form a cavity, and the material is optionally ground to a desired size by a drill bit or other means to enable suction up production tubing with a carrier fluid to the surface. The injection tool and grinding means are preferably part of an integrated bottom hole assembly at the lowermost end of a drill string, which may include surveying equipment to measure the cavity dimensions at intervals during target material disaggregation to allow fluid injection adjustment to seek to achieve a desired cavity geometry. Deck cementing is optionally employed for ground support.

A non-human-entry method for extracting a desired subsurface material such as ore, wherein an access hole is drilled from surface downwardly to the material, a high-pressure fluid injection tool is lowered with or after the drill string to the material and injected outwardly to disaggregate the material and form a cavity, and the material is optionally ground to a desired size by a drill bit or other means to enable suction up production tubing with a carrier fluid to the surface. The injection tool and grinding means are preferably part of an integrated bottom hole assembly at the lowermost end of a drill string, which may include surveying equipment to measure the cavity dimensions at intervals during target material disaggregation to allow fluid injection adjustment to seek to achieve a desired cavity geometry. Deck cementing is optionally employed for ground support.

A method for underground mining in a rock body include drilling one or more service boreholes from at least one surface location into a subsurface rock body. A plurality of multilateral blast holes is drilled, branching from at least one of the one or more service boreholes into the subsurface rock body. The plurality of multilateral blast holes are each loaded with one or more explosive charges and one or more detonators. The one or more explosive charges and the one or more detonators are inserted from surface. The one or more explosive charges is detonated wirelessly to fragment the subsurface ore body. Fragmented rock is extracted via the one or more service boreholes, to surface.

Enhanced method for borehole mining comprising: drilling a borehole using a low-frequency pulsing sonic, hydraulic mining system including a pulsed jet assembly; inserting casing into the borehole above target deposit depth; inserting and rotating assembly into the casing with a sub-coupling and a shoe rock bit positioned below the casing; pumping fluid into the borehole; evaluating slurry at surface; fracturing and disaggregating materials at target deposit with pulsing jets from the sub-coupling and rock bit causing light slurry to flow upwardly to the annulus between the borehole casing and the downhole assembly, then upwardly through the annulus to the surface of the borehole thereby causing heavy slurry to concentrate in a sump, located below the pulse jet rock bit; continuing to form cavity at target location; removing pulsed jet assembly from borehole; running core barrel to extract heavy slurry from sump; analyzing slurry to determine whether to continue with operation.

Enhanced method for borehole mining comprising: drilling a borehole using a low-frequency pulsing sonic, hydraulic mining system including a pulsed jet assembly; inserting casing into the borehole above target deposit depth; inserting and rotating assembly into the casing with a sub-coupling and a shoe rock bit positioned below the casing; pumping fluid into the borehole; evaluating slurry at surface; fracturing and disaggregating materials at target deposit with pulsing jets from the sub-coupling and rock bit causing light slurry to flow upwardly to the annulus between the borehole casing and the downhole assembly, then upwardly through the annulus to the surface of the borehole thereby causing heavy slurry to concentrate in a sump, located below the pulse jet rock bit; continuing to form cavity at target location; removing pulsed jet assembly from borehole; running core barrel to extract heavy slurry from sump; analyzing slurry to determine whether to continue with operation.

An improvement to a sonic drilling system comprising a high-pressure, high-volume water pump connected to a fluid supply and a length of casing in a borehole; an elastic sonic rod string; an eductor coupling having an upwardly directed convergent nozzle; a transition rod; a sub-coupling having a laterally directed convergent nozzle; and a shoe rock bit having a downwardly directed convergent nozzle. The water pump provides fluid down the bore of the sonic rod string, the eductor, the transition rod, the sub-coupling and the rock bit whereby adjustable high-pressure, high-volume fluid is forced through the sonic rod string, the eductor, the transition rod, the sub-coupling and the rock bit to fracture, cut and agitate targeted mineral into slurry and whereby the light slurry is directed effectively upwardly through the annulus to the surface for extraction and heavy slurry gravitates into a sump trap and is recovered with a core barrel.

A method for permeability improvement for a downhole coal seam by directional fracturing with pulsed detonation waves, which is applicable to gas control in coal seam areas with high gas concentration and low air permeability. The permeability improvement method is as follows: first, drilling a pulsed detonation borehole and pulsed detonation guide boreholes from a coal roadway to a coal seam respectively; then, pushing a positive electrode connected to a positive output side of an explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation borehole and pushing a negative electrode connected to a negative output side of the explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation guide borehole; connecting the pulsed detonation borehole and the pulsed detonation guide boreholes to an extraction pipeline for gas extraction, after electrical pulsed detonation fracturing for the coal seam is carried out. The method disclosed in the present invention utilizes the high instantaneous energy provided by electrical pulsed detonation waves to fracture a coal mass, so as to form a fissure network in the coal mass between the pulsed detonation borehole and the pulsed detonation guide boreholes; thus, the air permeability coefficient of the coal mass can be increased by 200-400 times, the effective influence scope of gas extraction of a single borehole for gas extraction can be enlarged by 3-4 times, the extracted gas volume from the borehole can be increased by 3-8 times, and the coal seam gas pre-extraction time can be shortened effectively.

A method for permeability improvement for a downhole coal seam by directional fracturing with pulsed detonation waves, which is applicable to gas control in coal seam areas with high gas concentration and low air permeability. The permeability improvement method is as follows: first, drilling a pulsed detonation borehole and pulsed detonation guide boreholes from a coal roadway to a coal seam respectively; then, pushing a positive electrode connected to a positive output side of an explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation borehole and pushing a negative electrode connected to a negative output side of the explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation guide borehole; connecting the pulsed detonation borehole and the pulsed detonation guide boreholes to an extraction pipeline for gas extraction, after electrical pulsed detonation fracturing for the coal seam is carried out. The method disclosed in the present invention utilizes the high instantaneous energy provided by electrical pulsed detonation waves to fracture a coal mass, so as to form a fissure network in the coal mass between the pulsed detonation borehole and the pulsed detonation guide boreholes; thus, the air permeability coefficient of the coal mass can be increased by 200-400 times, the effective influence scope of gas extraction of a single borehole for gas extraction can be enlarged by 3-4 times, the extracted gas volume from the borehole can be increased by 3-8 times, and the coal seam gas pre-extraction time can be shortened effectively.

The invention relates to a control method for a hard roof of a coal mine, specifically to a method for over-pit and under-pit cooperative control of roofs of far and near fields of an extra-large stoping space. The method provided by the invention overcomes the problem of lack of comprehensive and cooperative control methods for hard roofs of far and near fields of an extra-large stoping space in the prior art. According to a technical scheme in the invention, the method comprises an over-pit vertical hole hydraulic fracturing method, an over-pit L-shaped hole hydraulic fracturing method, an over-pit highly-energy-gathered repetition pulse strong shock wave method, an under-pit water injection method, an under-pit layered blasting method and an under-pit hydraulic fracturing method. The method has the advantages that 1) the problem of great mine pressure of the extra-large stoping space is effectively controlled through over-pit and under-pit cooperative control of the hard roofs of far and near fields; 2) advantages of the variety of methods are given to full play and disadvantages of the variety of methods are mutually compensated, so weakening effect on the hard roofs is substantially improved; and 3) all the over-pit and under-pit holes can be used independently or be used in a shared way, so time, manpower, material resources and money used for hole perforation can be greatly reduced.

The invention relates to a control method for a hard roof of a coal mine, specifically to a method for over-pit and under-pit cooperative control of roofs of far and near fields of an extra-large stoping space. The method provided by the invention overcomes the problem of lack of comprehensive and cooperative control methods for hard roofs of far and near fields of an extra-large stoping space in the prior art. According to a technical scheme in the invention, the method comprises an over-pit vertical hole hydraulic fracturing method, an over-pit L-shaped hole hydraulic fracturing method, an over-pit highly-energy-gathered repetition pulse strong shock wave method, an under-pit water injection method, an under-pit layered blasting method and an under-pit hydraulic fracturing method. The method has the advantages that 1) the problem of great mine pressure of the extra-large stoping space is effectively controlled through over-pit and under-pit cooperative control of the hard roofs of far and near fields; 2) advantages of the variety of methods are given to full play and disadvantages of the variety of methods are mutually compensated, so weakening effect on the hard roofs is substantially improved; and 3) all the over-pit and under-pit holes can be used independently or be used in a shared way, so time, manpower, material resources and money used for hole perforation can be greatly reduced.