Abstract: This invention aims to provide a gas-hydrate extracting device and method whereby a high-performance jet fluid is injected from a nozzle at the tip of an extraction pipe inserted into a gas-hydrate stratum, and whereby said jet fluid breaks said stratum so as to form a gas-hydrate mixed fluid that is transferred to surface of the earth, and whereby the void resulting from the removal of said gas hydrate is filled with the components of said high-performance jet fluid and a void-refilling fluid.

Abstract: A drum-type miner having a plurality of water jet nozzles which cut independently of the mechanical bits is disclosed. The drum-type miner may configured in either a hard-head or a ripper-chain design. The unique combination of mechanical and hydraulic cutting results in higher rates of penetration and improved productivity. The nozzles in one embodiment are supplied on a transversely mounted strut and are supplied with high-pressure fluid through two independent water channels in the strut. The nozzles may be configured in different directions, such that the high-pressure fluid may be directed in several directions simultaneously, or configured to direct the high-pressure fluid in one direction only. Moreover, because the mining face is pre-scored by the water jets, the amount of wear on both the mechanical bits and the motors may be significantly reduced.

Abstract: A portable apparatus for exploration and sampling of placers which is capable of being disassembled for transport into areas not accessible to traditional sampling methods. The sampling unit operates on a principle of power augering and water jetting a sampling pipe to bedrock while concurrently recovering ¾″ minus materials, including particles and nuggets of valuable minerals and gemstones, through a concentric center pipe, such recovery powered by a ring jet venturi and supplemented by a sample hole plug to increase the water pressure in the sampling hole.

Abstract: A method and system is disclosed for extending the depth of a subterranean borehole that uses heated aqueous fluid to dissolve rock of the subterranean formation. The heated aqueous fluid comprises water and hydroxides of Group I elements of The Periodic Table of Elements and mixtures thereof. The drilling system comprises means for delivering aqueous fluid and heating the aqueous fluid prior to contacting rock of a subsurface formation.

Abstract: A Borehole Mining method comprising driving a borehole, into a production zone under a low-degree angle &agr; (0<&agr;<35°), installation in said borehole a mining device with a hydromonitor and eductor, water-jet cutting of rock, pumping-out a slurry, and creating a cavity. Said tool is positioned such that the hydromonitor is oriented at an angle &bgr; to the horizontal plane. The projection on said plane of the water-jet equals to the desired span of the driven cavity. The borehole may be driven sinking or raising. The BHM tool is inserted/removed from the borehole while mining without rotation, extending said cavity along the borehole. Said borehole can be driven from a land or water surface trough the mother-well drilled vertically and then deviated. It also may be driven straight from an underground mine or open pit floor. After a creation of said cavity, it may back-filled with a waste or hardening material.

Abstract: The invention comprises a high pressure fluid barrier forming an enclosure boundary with respect to overburden and floor strata separated by one or more production strata containing desirable fluidizable deposits and/or potential reaction materials. A centrally located Super Daisy Shaft delivers a highest pressure fluid to the enclosure boundary by way of envelope conduits extending laterally horizontal and/or downward from the Super Daisy Shaft (or a trench from which such conduits may also extend) into the production strata.

Abstract: A jet nozzle is provided for drilling holes through the earth, such as drainholes around a well. The nozzle may include orifices for discharging fluid to drive the nozzle forward and includes a disk or other device having orifices to produce a swirling motion to fluid in the body of the nozzle. Swirling fluid is discharged from a front orifice and an extension is placed forward of the front orifice to confine the swirling fluid in a radial direction.

Abstract: The present invention is a lance for removing dirt or other substances from an underground hole, by the use of air and water under high pressure. The water is used as an abrading material or lance to loosen dirt in a hole or to pick or chip off substances which are attached to a pipe. A limited amount of water is used during the operation of the apparatus, to prevent the formation of wet mud.

Abstract: This invention relates to apparatuses and methods for subsurface mining, and more particularly to apparatuses and methods for relocating (including dredging, mining, filling, reverse-layering, replenishment) subsurface strata.

Abstract: The claimed invention is a method, system and apparatus for solution-mining of subterranean materials such as trona, nahcolite, thermonatrite, pirssonite, natron, dawsonite, wegscheiderite, gaylussite, shortite, halite, and other salts, minerals, and so forth. The method comprises injecting a fluid into an elbow well, the fluid forming a subterranean mixture with the subterranean material, and collecting the subterranean mixture from the elbow well. The system comprises a means for injecting a fluid into an elbow well, the fluid forming a subterranean mixture with the subterranean material, and a means for collecting the subterranean mixture from the elbow well. The apparatus further comprises a production casing, wherein the production casing has a production casing inner diameter of sufficient size to allow for production of a subterranean mixture of the fluid and the subterranean material between an outer surface of the injection tube and an inner surface of the production casing.

Abstract: A drum-type miner having a plurality of water jet nozzles which cut independently of the mechanical bits is disclosed. The drum-type miner may configured in either a hard-head or a ripper-chain design. The unique combination of mechanical and hydraulic cutting results in higher rates of penetration and improved productivity. The nozzles in one embodiment are supplied on a transversely mounted strut and are supplied with high-pressure fluid through two independent water channels in the strut. The nozzles may be configured in different directions, such that the high-pressure fluid may be directed in several directions simultaneously, or configured to direct the high-pressure fluid in one direction only. Moreover, because the mining face is pre-scored by the water jets, the amount of wear on both the mechanical bits and the motors may be significantly reduced.

Abstract: A self-advancing drilling system comprising a drilling apparatus, the drilling apparatus having at least one leading fluid cutting nozzle, means on the drilling apparatus to provide forward movement to the drilling apparatus, the drilling system further comprising a drill string formed from a recoverable flexible hose.

Abstract: A borehole mining tool comprising a drill string having an inner pipe column and an outer pipe column. Water is forced under high pressure down an annulus between the outer pipe and inner pipe. A hydromonitor is attached to the end of the drill string. A nozzle in the hydromonitor directs the pressurized water into a stope or work area, thereby loosening the material to be mined. The slurry is educted from the mined area by the action of a venturi attached downstream of the hydromonitor. Water flow through the venturi creates a vacuum which draws the pregnant slurry from the work area up through the inner pipe to the surface. A plurality of tools may be attached to the hydromonitor by a connection comprising a gasket having an interference fit. The gasket allows quick connection and removal of a plurality of tools from the hydromonitor. A radar is include to provide an image of the stope being worked.

Abstract: Apparatus for the hydrodemolition of concrete layer including a movable vehicle, a bed having a guideway extending transversely to a direction of movement of the vehicle, a nozzle assembly having a guide slidably engaging the guideway and a plurality of nozzles spaced apart in a direction transverse to the guideway, separate fluid flow controllers coupled between a pressurized source of fluid and respective nozzles, the nozzles being oriented to spray a fluid jet onto the concrete surface and means for moving the nozzle assembly along the guideway transversely across the direction of travel.

Abstract: A drum-type miner having a plurality of water jet nozzles which cut independently of the mechanical bits is disclosed. The drum-type miner may configured in either a hard-head or a ripper-chain design. The unique combination of mechanical and hydraulic cutting results in higher rates of penetration and improved productivity. Moreover, because the mining face is pre-scored by the water jets, the amount of wear on both the mechanical bits and the motors may be significantly reduced.

Abstract: Cutting heads, cutting head systems, and methods for creating an excavation in a mineral seam. A preferred cutting head includes a first body having a manifold for containing high pressure fluid and an axis of rotation generally parallel to the borehole, a first plurality of mechanical bits disposed on the first body, a first plurality of nozzles disposed around the axis of rotation for spraying the high pressure fluid, and a plurality of tubes fluidly coupling the manifold and the first plurality of nozzles. On supplying high pressure fluid to the manifold and rotating the cutting head about the axis of rotation, the nozzles create a generally circular, overlapping pattern of high pressure fluid in front of the cutting head, the pattern of high pressure fluid being directed to cut the borehole independently of the mechanical bits.

Abstract: A self-advancing drilling system comprising a drilling apparatus, the drilling apparatus, the drilling apparatus having at least one leading fluid cutting nozzle, means on the drilling apparatus to provide forward movement to the drilling apparatus, the drilling system further comprising a drill string formed from recoverable flexible hose.

Abstract: An excavator including a center shaft rotatably provided in a shield body in concentric relation to an outer cone. An inner cone for crushing excavated materials in cooperation with the outer cone is eccentrically provided on the center shaft. A cutter head provided in front of the inner cone is mounted on the center shaft. An internally-toothed gear is secured to the inner cone in concentric relation to the center shaft. A plurality of externally-toothed gears rotated by driving motors whose rotational speed and torque are variably controllable are internally meshed with the internally-toothed gear. Rotation of the externally-toothed gears causes the center shaft to rotate through the inner cone. A plurality of water jet spray nozzles are provided on the cutter head. The spray pressure is switched between high pressure and low pressure.

Abstract: An excavating device configured to form a channel of predetermined cross section in the ground in an excavation direction. The excavating device includes an assembly of jet excavating units which together define the cross section of the channel and are each provided with at least one jet device. The excavating device also includes at least one sensor which is connected to at least one of the jet excavating units for measuring a force which is exerted on the jet excavating units by the ground substantially parallel to the excavation direction. A controller is provided for controlling the excavation by the excavating device on the basis of the force measured by the at least one sensor. The controller is adapted to set a flow rate of jet liquid which is used in at least one jet device.

Abstract: A preferred cutting head includes a first body having a manifold for containing high pressure fluid and an axis of rotation generally parallel to the borehole, a first plurality of mechanical bits disposed on the first body, a first plurality of nozzles disposed around the axis of rotation for spraying the high pressure fluid, and a plurality of tubes fluidly coupling the manifold and the first plurality of nozzles. On supplying high pressure fluid to the manifold and rotating the cutting head about the axis of rotation, the nozzles create a generally circular, overlapping pattern of high pressure fluid in front of the cutting head, the pattern of high pressure fluid being directed to cut the borehole independently of the mechanical bits.

Abstract: A hydrovac wand is provided with a crossfire nozzle arrangement that reduces thrust to the wand operator, and that has a spray pattern that eliminates spray back. A pair of jets erode a hole while two other jets push the debris back to a suction hose. Two high pressure swivels are provided at the end of the wand to allow the wand to rotate in all directions without binding. Boom controls are placed on the wand to maximize digging rates.

Abstract: Apparatus for the hydrodemolition of concrete layer including a movable vehicle, a bed having a guideway extending transversely to a direction of movement of the vehicle, a nozzle assembly having a guide slidably engaging the guideway and a plurality of nozzles spaced apart in a direction transverse to the guideway, separate fluid flow controllers coupled between a pressurized source of fluid and respective nozzles, the nozzles being oriented to spray a fluid jet onto the concrete surface and means for moving the nozzle assembly along the guideway transversely across the direction of travel.

Abstract: Apparatus for the hydrodemolition of concrete layer including a movable vehicle, a bed having a guideway extending transversely to a direction of movement of the vehicle, a nozzle assembly having a guide slidably engaging the guideway and a plurality of nozzles spaced apart in a direction transverse to the guideway, separate fluid flow controllers coupled between a pressurized source of fluid and respective nozzles, the nozzles being oriented to spray a fluid jet onto the concrete surface and on actuator for moving the nozzle assembly back and forth along the guideway.

Abstract: A method and apparatus for mining of hydrocarbons from a hydrocarbon-containing clathrate such as is found on the ocean floor. The hydrocarbon containing clathrate is disaggregated from sediment by first disrupting clathrate-containing strata using continuous mining means such as a rotary tilling drum, a fluid injector, or a drill. The clathrate-rich portion of sediment thus disrupted from the sea floor strata are carried through the apparatus to regions of relative lower pressure and/or relative higher temperature where the clathrate further dissociates into component hydrocarbons and water. The hydrocarbon is recovered with the assistance of a gas that is injected and buoys the hydrocarbon containing clathrate helping it to rise to regions of lower pressure and temperature where hydrocarbon is released. The sediment separated from the hydrocarbon returns to the ocean floor.

Abstract: A device and a method for moving an object are based on the fact that the object (8) is pivotable in relation to a base portion (7) about an axis. There is an arrangement (18) for displacing, during pivoting motion of the object, the object substantially parallel to its pivoting plane for the purpose of causing a point of the object to describe a motion in substantially one and the same plane as a consequence of the combined pivoting/displacing.

Abstract: This invention provides an excavator 1 for crushing a matter to be excavated, existing in an excavating hole in which a discharge liquid is fed, by electric discharge between a plurality of electrodes generated by high-voltage pulses. The excavator comprises a high-voltage pulse generator 2; a plurality of electrodes 17, 18, at least one of which is given a high voltage from the high-voltage pulse generator 2; discharge liquid circulating system 3, 4, 5a, 5b; and optimum condition setting devices 13, 14, 15, 16. Also, this invention provides an excavation method in which at least one of the parameters for excavation efficiency of i) load voltage required for crushing the matter to be excavated; ii) single pulse energy; and iii) quantity of discharge liquid, is optimized for minimization of power consumption required for excavation by using the excavator of this invention.

Abstract: Slurryable ore where the overburden is unstable and subject to collapse is mined from substantially parallel elongated main trenches connected by a perpendicular trench at the bottom of the mineral seam. A plurality of softwall mining devices supported by face equipment is placed in the perpendicular trench. The devices slurry the mineral material and move into the mineral seam as the overburden sloughs behind the mining devices. The subsided overburden is supplemented as necessary with injected material. Slurried mineral flows to the parallel trenches for removal to the surface. After the softwall devices have advanced the length of the parallel trenches, the devices are withdrawn and placed in additionally developed trenches elsewhere in the ore reserve.

Abstract: A method for stimulating a wellbore penetrating a solid carbonaceous subterranean formation by positioning a hydrajet in an uncased portion of the wellbore penetrating the formation; perforating the formation with the hydrajet; and producing carbonaceous fluids and particulates from the formation through the wellbore and, thereby, forming a cavity in the formation surrounding the wellbore.

Abstract: A drilling apparatus includes a drill string, a drilling head located at a first end of the drill string, a drilling fluid pump located at a second end of the drill string, wherein the drilling fluid pump pumps a drilling fluid along the length of the drill string to the drilling head, and a traveling wave generator coupled to the drill string at a location downstream of the drilling fluid pump, wherein the traveling wave generator generates a series of ramped pressure pulses that are applied to the drilling fluid. The ramped pressure pulses are compressed by a reduction of the cross-sectional area of the drill string, and further by time compression caused by varying propagation rates of different portions of the pressure pulses pressure pulse if substantially formed at a surface of a drilling substrate. A shock wave associated with the compressed pressure pulse is generated substantially at the location of a surface of a drilling substrate.

Abstract: A horizontal remote mining system comprising a water jet cutting head, down hole crusher, jet pump, and guidance system for orchestrating select excavation of a horizontal borehole. The system is assembled on the end of a drill string comprised of multiple compartments accommodating various water pressures and functions in association with the remote excavation process. Selective tubing is also utilized to facilitate movement of air and ventilation of the borehole. In this manner, relatively thin coal seams can be economically mined.

Abstract: A method and apparatus for penetrating a well casing (12) and surrounding earth strata includes the insertion of a flexible shaft (24) having a ball cutter (22) on an end thereof into upset tubing (18) within a well casing. The upset tubing is provided with an elbow (20) at its lower extremity for receiving the ball cutter therein. The flexible shaft is then rotated and the ball cutter cuts a hole in the well casing and is then moved horizontally a distance, usually less than 12 inches (30.5 cm). The flexible shaft and ball cutter are then removed and a flexible tube (48) having a nozzle blaster (46) on an end thereof is then inserted into the upset tubing in the channel. A fluid of surfactant and water at high pressure is then pumped into the tube wherein the high pressure fluid passes through orifice in the spiral drill thereby cutting an extension into the previously cut channel. The tube is continually fed into the channel as the high pressure fluid continues to blast away the earth's strata.

Abstract: A method and apparatus for horizontal channeling into a mountain of granite automatically have been developed in which a water jet nozzle contained in a rigid lance assembly advances in and out of the mountain to the depth of the lance in a horizontal plane along a line of cut predetermined by the setup of the apparatus and the original drilled hole. The jet oscillates back and forth in a transverse fashion, cleaving the crystal formation of the granite through the application of high pressure water pulsing at the appropriate angle of penetration to achieve the correct spalling of the granite surface in slightly upward direction such that the channel remains free of chips and grit for easy movement of the feed system. The machine advances incrementally just prior to the lance entering the channel, maintaining standoff distances to properly erode channel corners.

Abstract: Methods of fracturing subterranean formations are provided. The methods basically comprise positioning a hydrajetting tool having at least one fluid jet forming nozzle in the well bore adjacent the formation to be fractured and jetting fluid through the nozzle against the formation at a pressure sufficient to form a fracture in the formation.

Abstract: A jet boring pre-assembly for excavating an underground area susceptible to disaggregation and for control from a working gallery below the area includes a cutting head for the top of the assembly, the cutting head having separate conduits for delivery of high pressure cutting fluid to high pressure nozzles, and a low pressure flushing fluid to flushing nozzles. A dual conduit drilling rod is located in a borehole beneath the cutting head, the rod having separate conduits for delivery of the high pressure and low pressure fluids to the cutting head. A preventor box below the cutting head seals the borehole and transmits slurry of excavated material to an outlet.

Abstract: An underground method and apparatus for recovery of mineral deposits from sloping seams including high pressure water jet mineral dislodgement from underground deposits and water borne transport of dislodged mineral to an underground recovery site, and compressed air injection for transport of water borne mineral deposits from the underground recovery site to the surface.

Abstract: The invention relates to an excavator for suction material, particularly for removing soil from underground pipes. The excavator has a pneumatic elephant trunk for removing the suctioned material and which issues into a storage tank for the suctioned material and to which is connected an exhaust fan. In the storage tank the suctioned material is separated from the suction air flow and is subsequently passed through a filter positioned between an elephant trunk opening and the exhaust fan. In order to ensure a good separation on the part of the filter for a long period of time, the filter is formed by a coarse filter and a fine filter connected to the latter. The coarse filter is formed by a labyrinth or cascade-like flow channel, which is bounded by reciprocally displaced partitions and whose flow cross-section increases in the flow direction.

Abstract: A method and apparatus for penetrating a well casing and surrounding earth strata includes the insertion of a flexible shaft having a ball cutter on an end thereof into upset tubing within a well casing. The upset tubing is provided with an elbow at its lower extremity for receiving the ball cutter therein. The flexible shaft is then rotated and the ball cutter cuts a hole in the well casing and is then moved horizontally a distance, usually less than 30". The flexible shaft and ball cutter are then removed and a flexible tube having a nozzle blaster on an end thereof is then inserted into the upset tubing in the channel. A fluid of surfactant and water at high pressure is then pumped into the tube wherein the high pressure fluid passes through orifice in the spiral drill thereby cutting an extension into the previously cut channel. The tube is continually feed into the channel as the high pressure fluid continues to blast away the earth's strata.

Abstract: A method and system for cutting kerfs in rock is shown and described. In one embodiment, a single fan jet is mounted in ultrahigh-pressure tubing. In an alternative embodiment, a manifold in which two fan jets are mounted is coupled to a manifold in which two round jets are mounted, such that the twin fan jets are directed so as to cover the entire width of the kerf and the round jets are directed towards the edges of the kerf to cut out a well defined kerf. In another alternative embodiment, an angled fan nozzle is mounted in ultrahigh-pressure tubing and combined in a system with another angled fan nozzle mounted in ultrahigh-pressure tubing such that the angled fan jets may be directed at opposite walls of a kerf to carve out a well defined kerf of a desired depth.

Abstract: An hydraulic device for forming a cavity in a borehole. The device includes generally the following modular sections: a hub section for connection to a drill pipe; hydromonitor (cutting nozzle); hydroelevator (eductor); and drill bit box. Through each section, except the drill bit box, extends first and second concentric pipelines for delivering fluid into the device and directing slurry out of the device. Only the drill pipe extends to the surface to receive standard well blowout prevention equipment. The second pipeline releases slurry into a casing which channels, in cooperation with an upper portion of the first pipeline and the drill pipe, the slurry to the surface. The hydromonitor includes a nozzle which is hydraulically associated with the first pipeline, and extends through the second pipeline, for delivering fluid into the borehole to form the cavity. The eductor pulls spent cutting fluid, coal fines, etc., out of the cavity as the slurry.

Abstract: A process and apparatus for high pressure drilling are disclosed. The apparatus comprises an essentially solid drill head with horizontally extendable nozzle arms hingedly connected by shear pins thereto. Flow of high pressure fluid both extends the nozzle arms and flows through the nozzle arms, thereby fracturing and shearing material surrounding the drill head. Cessation of fluid flow returns the arms to the vertical position.

Abstract: In a method of mining coal seams using a ploughing cutter, a longwall conveyor extending along the coal face is moved forwards by the extension of self-advancing cylinders, the advance being controlled in dependence on a piston stroke of a respective self-advancing cylinder and being made in individual defined partial strokes using travel-measuring signals generated at each partial stroke. The distance covered by the partial strokes corresponds to the preset depth of cutting and is increased by an amount sufficient to compensate an average mechanical clearance at the pivot points of the self-advancing cylinders. In addition, a defined face line is fixed with respect to a center of rotation on the side of a main or auxiliary drive of the cutter so as to form a straight line through the center of rotation, the straight line being pivoted through an angle <90.degree. so that a circular segment is mined.

Abstract: Apparatus for cutting erosive materials such as stone and the like includes a high-velocity, high-pressure water lance which can be raised and lowered as necessary. The lower end of the water lance carries a cutting head in the form of a nozzle assembly able to be rotated about the longitudinal axis of the water lance. The water lance is mounted upon a carriage which can be propelled in directions at right angles to each other and the water lance may be supported by a vertically-disposed truss, which itself may be relocatable about the longitudinal axis of the lance.

Abstract: An excavation apparatus includes a tank partitioned into two isolated chambers. One of the chambers is adapted to hold fresh water and communicates with a flexible wand to be carried by operating personnel. The other chamber is adapted to hold excavated material and communicates with a flexible hose also to be carried by operating personnel. A single, positive displacement vacuum pump driven by a motor is selectively connectable to one or both chambers through a series of valves and hoses. Depending on the valve positions, either the intake or exhaust port of the vacuum pump is in communication with one or both the chambers. The vacuum pump can therefore by used to fill the front chamber with fresh water as well as to pressurize the front chamber so that the water held therein can be discharged through the wand under pressure sufficient to dislodge earth at the excavation site. The vacuum pump can then be used to draw the dislodged earth and discharged water into the other chamber.

Abstract: A method of working coal seams to a defined preset cutting depth during ploughing with a cutter, a face conveyor moving along a face behind the cutter being advanced by the defined preset cutting depth and this advance being made by extension of self-advancing cylinders pivotally attached at one end to the face conveyor and at the other end to face supports disposed parallel to the face conveyor. The advance is controlled in dependence upon the piston stroke of the self-advancing cylinders, carried out in dependence upon individually defined partial strokes corresponding to the preset depth of cutting. After a predetermined maximum total piston stroke has been reached, the face support connected to the respective self-advancing cylinder is automatically disengaged, advanced by the maximum total piston stroke and then re-set (self-advancing process).

Abstract: Hydraulic drilling apparatus and method in which a drill head is driven toward the formation being drilled by the force of the drilling fluid, and the rate of advancement or penetration of the drill head is controlled by entrapping a fluid in a chamber to resist advancement of the drill head and allowing a controlled amount of the entrapped fluid to pass out of the chamber through an orifice to permit the drill head to advance at a controlled rate.

Abstract: In particular for cutting working of especially hard rock such as granite, an additional cooling medium is supplied to a pressure medium which is at a high pressure of especially more than 1500 bar. The pressure medium is ejected particularly in the form of discrete narrow jets from a nozzle head (5) and the directional jet (5g) of the cooling medium is directed towards at least some of the jets (5b) of the bundle of jets of the pressure medium so that together with the pressure medium a cooling effect is caused on the object to be worked, thus resulting in an improved crushing effect.

Abstract: A borehole mining process for recovery of petroleum from unconsolidated heavy oil formations. The process consists of drilling a borehole in the unconsolidated heavy oil reservoir, which is formed from sand particles aggregated by heavy oil, and positioning a casing and a first and second tubing string within the borehole. At least one nozzle is positioned on the lower end of the second tubing string and is oriented for fluid emission generally radially outwardly from the second tubing string. Fluid is then flowed downwardly through the second tubing string and outwardly through the nozzle, thereby eroding a cavity in the reservoir and forming a slurry consisting of the fluid, the heavy oil, and the particles from the reservoir. The slurry is flowed upwardly through the annulus between the first and second tubing strings to the upper end of the borehole for recovery of the heavy oil.

Abstract: Evaporite mineral solution mining process and apparatus comprising the steps of undercutting a bed or massive deposit by in-air jetting with an aqueous solution followed by solution mining of the mineral above the undercut with monitoring and control to cease the solution mining when the roof rock is adequately exposed to maintain a stable roof and stable pillar support. The resulting cavity exhibits steeply angled, nearly vertical sidewalls, flared upwardly and outwardly only 10.degree. to 15.degree. from the vertical plane normal to the edges of the undercut as compared to 45.degree. typical for morning glory cavities. A first plan vertical production well is drilled with a sump provided substantially adjacent to the floor rock. A second horizontal well is developed up dip to intersect and communicate with the production well. The air jet tool mechanism provides horizontal, slightly upwardly inclined jets (0.degree.-15.degree.

Abstract: A cutting machine for mining minerals from a seam thereof, the machine executing reciprocal movements parallel to the face of the seam and being provided with switches for generating signals indicative of the direction of movement of the machine for controlling the removal of protective bumpers on support structures located forwardly of the machine and for moving support structures against the face of the seam and relocating bumpers rearwardly of the machine.

Abstract: A soft excavator (10, 90, 110, 130) is disclosed which utilizes a jet of high velocity fluid flow such as air or water flow, preferably supersonic, through a nozzle (48, 92, 112) to excavate a material, such as the ground. A second passage for air flow is provided which is directed by an evacuator skirt (52, 102) in a direction along the excavator generally opposite the direction of discharge of the high velocity excavating flow to entrain the material excavated for disposal.