Abstract: An auger support assembly for use with an augering system for mining which bores a pair of side-by-side holes through a coal seam using dual side-by-side augers. Each auger includes a drilling section which is followed by a series of auger flights for conveying the bored coal back out of the respective hole. The augers are connected together in axially aligned pairs and are supported by the auger support assembly. The auger support assembly includes a pair of bearing housings that are disposed on drive shafts which extend outwardly from the first ends of a first pair of parallel augers and are received within the second ends of a second pair of parallel augers. The bearing housings are connected to each other by a tie bar. A single support leg extends downwardly from approximately the mid-section of the tie bar to engage the ground ledge that is formed between the counter rotating augers.

Abstract: The present invention is directed generally to the combined use of slurry mining and hydrocyclones to recover hydrocarbons, such as bitumen, from hydrocarbon-containing materials, such as oil sands, and to selective mining of valuable materials, particularly hydrocarbon-containing materials, using a plurality of excavating devices and corresponding inputs for the excavated material. The excavated material captured by each input can be switched back-and-forth between two or more destinations depending on the value of the stream.

Abstract: An auger flight support for use with an augering systems for mining which bores a pair of side-by-side holes through the coal seam using respective augers. Each auger includes a drilling section which is followed by a series of auger flights for conveying the bored coal back out of the respective hole. The auger flight support includes a pair of thrust bearing and housing assemblies which are tied together and each supported by a respective leg which lowers the friction between the auger flight and the bottom of the bore. This significantly reduces the power required to rotate the augers.

Abstract: A tunnel excavating machine having an excavating machine body can be moved forward by shield jacks. A rotatable cutter head is mounted in a front portion of the excavating machine body. An erector device for assembling segments in a ring form is mounted in a rear portion of the excavating machine body. A rest extends rearward from the rear portion of the excavating machine body. A shape retainer for making pressurized contact with inner peripheral surfaces of the assembled segments to retain the segments in a predetermined shape is supported on the rest so as to be movable along a fore-and-aft direction. Also, a revolving frame is located between the erector device and the shape retainer, and supported on the rest so as to be movable along the fore-and-aft direction such that the revolving frame does not interfere with the erector device and the shape retainer. A cage is supported on the revolving frame so as to be revolvable in a circumferential direction of an existing tunnel.

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 tunnel excavator includes a pair of cutters arranged side by side at a front portion of a tunnel excavator main body. These cutters rotate in opposite directions for excavating the earth to form excavation and for causing the excavated earth to move toward a center area between the pair of cutters. The tunnel excavator further includes a screw cutter extending horizontally in a width direction of the tunnel excavator behind the pair of cutters at a lower level. The screw cutter has a pair of flights spiraling in opposite directions toward the center from opposite ends of the screw cutter for gathering the excavated earth to the center of the screw cutter. A soil plate generally extends along and behind the screw cutter and pushes the excavated earth as the tunnel excavator advances, but the soil plate has an outlet at a lower center area thereof for allowing the excavated earth to pass therethrough. A conveyor is provided behind the soil plate outlet.

Abstract: A mining machine (20) for combined entry and retreat cutting of material located in underground seams including, a movable mainframe (21), a wing (50, 51) extending ahead of the movable mainframe, a cutter assembly (100) positionable proximate the end of the wing for entry cutting a hole in the material when the wing is aligned with the direction of movement of the mainframe, a pivotal connection (130) between the mainframe and the wing for orienting the wing at an angle to the direction of the movement of the mainframe, and a carriage mechanism (80) for moving the cutter assembly along the wing for cutting of the material in proximity to the wing during retreat cutting of the material.

Abstract: An auger mining machine (10) including a cutter head (11) from which there extends an auger train (12) consisting of a plurality of axially aligned auger modules (13). The cutting head (11) includes a cutting assembly (21) driven by electric motors (38). The cutting assembly (21) is supported on a housing (22) for movement relative thereto to move the cutting assembly (21) into material being mined. There is further provided a launch vehicle (120) from which the auger train (12) extends. Said launch vehicle (120) is provided with a motor (113) to drive the auger train. The launch vehicle (120) has cylinders (123) which engage a mine face to retain the launch vehicle (120) in a desired position.

Abstract: A device for drilling into the ground for the in-situ production of columns of stabilized and compacted soil, which comprises at least two parallel shafts, each shaft driving in rotation one auger, each auger being fitted with a loosening drill head. The shafts and the shanks of the augers include a bore and at least one orifice for discharging a filler material, the augers having opposite hands and being driven in counterrotation, and which furthermore have a drive for reversing the direction of rotation of the augers, said device including an even number n, at least equal to 4, of augers and in that, as seen in cross-section, the axes of the augers are centered at the vertices of a regular n-sided polygon.

Abstract: A mining machine uses front cutters (barrel cutters) to cut into an area to be mined defining a first profile, and then expands rear cutters on the sides to cut a second, larger, profile during out-cutting. Cutter chains and drums of the rear cutter initially move cut material (e.g., coal) forward, and then through openings in the side frame of the machine onto a first, lowest, conveyance surface over which an endless conveyor chain with flights moves. A second conveyance surface above the first conveyance surface is also traversed by the chain with the flights to move material from the front cutters. A reversible motor powers the chains so that cut material is moved over the second conveyance surface during in-cutting, and over the first conveyance surface during out-cutting. The rear cutters are a sufficient distance above the mined floor formed during in-cutting that cut material tends to move onto (rather than under) the first conveyance surface.

Abstract: A mining machine for mining coal from outside a hill containing a coal seam wherein a plurality of cutter drums and rotary cutters are pivotally and detachably connected to a pan having an auger conveyor rotatably mounted therein. Certain cutter drums and the rotary cutters are movable in a vertical plane to allow the operator to control the direction of the hole being drilled, and to accommodate the machine to different seam thicknesses or hole heights. A plurality of thrust and torque transmitting units are connected end-to-end between the auger conveyor drive shaft and a prime mover positioned outside the seam tunnel for conveying the cut coal out of the tunnel.

Abstract: An apparatus for mining aggregate material from a seam includes a miner for cutting material from the seam and a conveyor for conveying the won aggregate material from the miner for recovery. The conveyor is formed by a series of individual conveyor units that are coupled or interconnected in series so as to form a train. The coupling comprises cooperating clevises and tongues interconnected by locking pins. Each unit includes a main frame supported on ground engaging wheels. A belt conveyor is supported in the main frame and a conveyor drive mechanism is provided on each unit. The apparatus also includes a launch vehicle. The launch vehicle includes a frame holding a conveyor for receiving won aggregate material from the conveyor train and for delivering that material to a discharge conveyor. Additionally, the launch vehicle includes a reciprocating drive assembly to aid in advancing the conveyor train and miner into the seam face.

Abstract: A launch vehicle is provided for a continuous mining system including modular conveyor units that may be connected together to form a conveyor train. The launch vehicle includes an elongated frame that holds a belt conveyor for conveying aggregate material that is received from the conveyor train. A drive assembly for selectively advancing and withdrawing the conveyor train is also provided on the launch vehicle. Additionally, the launch vehicle includes a mechanism for adding a modular conveyor unit to the conveyor train. More specifically, the conveyor train drive assembly includes a pair of cooperating tandem drive cylinders. Each drive cylinder includes a pusher arm unit that is adapted to engage one of the modular conveyor units of the conveyor train. The conveyor unit adding mechanism includes a positioning mechanism that holds and places a conveyor unit on the launch vehicle. A pusher cylinder is also provided to push the new conveyor unit into engagement with the rear of the conveyor train.

Abstract: A mining machine having a frame undercarriage having forward and rearward ends provided with a traction assembly for driving the frame undercarriage towards a seam face to be mined. A cutting assembly is provided which includes a plurality of rotatable outer elements each having a substantially horizontal rotation axis disposed perpendicularly to the seam face and an assembly for swinging the cutting assembly up and down with respect to the seam face about a horizontal swing axis parallel to the seam face. The swinging assembly is pivotally mounted on the forward end of the carriage to input pivotal movement of the cutting assembly about a vertical pivot axis.

Abstract: An apparatus for mining aggregate material from a seam includes a miner for cutting material from the seam and a conveyor for conveying the won aggregate material from the miner for recovery. The conveyor is formed by a series of individual conveyor units that are interconnected in series so as to form a train. Each unit includes a main frame supported on ground engaging wheels. A belt conveyor is supported in the main frame and a conveyor drive mechanism is provided on each unit. The apparatus also includes a launch vehicle. The launch vehicle includes a frame holding a conveyor for receiving won aggregate material from the conveyor train and for delivering that material to a discharge conveyor. The launch vehicle also includes a pair of spaced guide tracks adapted to receive and guide the wheels that support an end conveyor unit of the conveyor train. Additionally, the launch vehicle includes a reciprocating drive assembly to aid in advancing the conveyor train and miner into the seam face.

Abstract: The present invention is applicable to a shield tunneling method and a tunneling machine therefor which excavate a deformed section by rotating a plurality of circular cutters. There is provided a deformed shield tunneling method and a tunneling machine therefor which excavate a tunnel surface by rotating a plurality of circular cutters (4), (5) and (6) arranged in the front of a front casing (2) of a tunneling machine (1) and which cut soil in tangent portions (15a), (15b) and (15c) of circles formed between said circular cutters by rocking rocking cutters (17) attached opposite to the tangent portions in order to continue excavation while completely forming a predetermined deformed section in excavation of any combination of circular cutters regardless of the diameter of the circular cutters.

Abstract: A spiral conveyor section assembly for a mining machine includes a spiral conveyor mounted by a shaft for rotation about an axis, the shaft having first and second free ends each adapted to be connected to another shaft. A motor, gearing, and like power device effects rotation of the shaft about its axis. The power device is mounted directly in association with the spiral conveyor between the ends of the shaft. The power device has at least about 1/4-3/4 horsepower for each foot of spiral conveyor (e.g. about 32-36 inches in diameter). A second (or more) spiral conveyor can be provided mounted parallel to the first, with the power device effecting rotation of both, toward each other. A guard is mounted in association with each inner portion of the spiral section to prevent mined material from being flung from one spiral to the other. It is possible to convey mined material 1,000 feet or more utilizing spiral conveyor sections connected end to end.

Abstract: A mining machine and method allow coal or the like to be mined substantially as quickly during out cutting as in cutting. A front cutter is mounted at the front of the frame, and a first conveyor, which preferably comprises a chain conveyer, conveys cut coal from the front of the frame to the rear and ultimately out of the area being mined. A second conveyor is mounted in back of the front cutter for conveying cut coal from adjacent the rear of the frame towards the front, and ultimately to be deposited on the first conveyor. A rear cutter is located to the rear of the second conveyor for cutting material during out cutting to be moved to the second conveyor as the machine moves rearwardly. The rear cutter is movable from a first inoperative position within the volume cut by the front cutter, to a second, operative position outside the volume cut by the front cutter.

Abstract: A continuous mining machine comprising a forward cutter assembly connected for horizontal pivotal movements with respect to a rearward assembly mounted on the endless track assembly. The cutter assembly includes a central frame and a pair of said frames mounted on the central frame for independent pivotal movement about a pair of axes generally parallel with each other extending in a longitudinal direction corresponding generally to the forward direction of movement of the forward assembly with respect to the mine face. An elongated shaft is rotatalby mounted on each of the side frames so as to extend longitudinally from a position adjacent the rearward portion of the associated side frame forwardly thereof to an extent such that a forward end portion of each shaft extends forwardly of the associated side frame. A speed reducing units is mounted on each side frame between the associated shaft and the associated pivotal axis in driving relation with respect to the rearward portion of the associated shaft.

Abstract: The two ends of the luffable and swivelable arms of the gantry of an overburden excavator each have a horizontal bolt for a frame of the drive, on the axis of rotation or drive shaft of which is mounted a rotary cutter in the form of a cutter drum. The rotary cutters are disposed on both sides of a receiving conveyor. The axes of rotation of the shafts rotating the rotary cutters are oriented approximately parallel to the plane of symmetry (longitudinal axis) of the receiving conveyor belt. The angle of the rotary cutter axis can be adjusted in relation to the plane of the roadway by the length adjuster in the form of a hydraulic or pneumatic cylinder, which is located between a bearing lug of the arm and a bearing lug of the frame. The rotary cutters transport the material via transverse conveyors to the converyor belt.

Abstract: A movable cutting machine is subdivided into a front portion (1) and a rear portion (2) of the cutting machine, which portions are swingable around an approximately vertical pivotal axis (10) and are secured against a relative displacement in direction of this pivotal axis (10) by means of two joints (11, 12). The front portion (1) of the cutting machine has a caterpillar chassis (3) and carries a swivelling means (5) comprising as the cutting means a cutting arm (6) and two cutting heads (7). The rear portion (2) of the cutting machine has, as a support means against ground, equally a caterpillar chassis (4) and carries auxiliary equipment and/or a section of a conveying trough (13) equipped with a chain conveyer.

Abstract: Auger apparatus is disclosed adapted to utilize one or more augers each formed of a string of auger sections. The apparatus includes means for hoisting one or a plurality of auger sections simultaneously between a storage rack and a position for placement in an auger string. The hoist means includes bridge rails extending transversely of and above the machine, a trolley that travels on the bridge rails, lifting apparatus including a cable on the trolley and a carriage supported by the lifting apparatus and carrying a plurality of tongs for grasping auger sections. A safety connection is provided between the carriage and the lifting apparatus to prevent inadvertant release of a raised auger section. A collapsible and expandable assembly of multiple pairs of cross links pivotally joined at their midpoints is connected between the trolley and the tong carriage at two sides thereof to guide and stabilize the tong carriage and auger sections as they are moved.

Abstract: An excavatory machine for use in coal and other mining, has a pair of rotary cutters for simultaneous presentation to the work. The cutters are mounted on the ends of a medially fulcrumed lever which can be swung about its fulcrum so to increase the work ambit of the combined cutters. The fulcrum has means for raising and lowering it and holding it at selected elevation so to suit the height of the seam being worked. The cutter assembly is mounted on a saddle which is laterally slidable and drivable from side-to-side of a base slidable along the excavation floor in the direction the work is required to follow. This base is furnished with means enabling it to be nudged along in the said direction so to force the cutters into the work.The base is provided with conveyor means to take away excavated matter and also with mechanism by which the path followed by the base may be up-or down-trended.

Abstract: A shaft drilling machine has a circularly moving drilling head. The drilling head is angularly oriented with respect to the longitudinal axis of the shaft sought to be drilled. Loosened material is transported from the lower portion of the shaft by pickup means, moving with the drilling head, and taken to the upper portion of the angularly oriented bottom of the shaft, whereupon the loosened material or borings slide, by gravity, to a centrally located vertical conveyor mechanism for final removal of the material or borings from the shaft.

Abstract: A machine for mining hard material in-situ between adjacent auger holes in thin seams is disclosed which is suitable for being drivingly connected to a conventional mining apparatus, particularly an augar mining apparatus. The mining machine includes a rotating cutting apparatus with a longitudinal axis roughly parallel to the longitudinal axis of the auger holes. The rotating cutting machine is used for mechanically contacting and dislocating hard material in-situ between adjacent auger holes in thin seams. A power operated system is drivingly connected to the cutting apparatus for generating a cutting motion during the in-cutting operation. A guiding system is provided for maintaining the cutting apparatus in mechanical contact with hard material in-situ between the adjacent auger holes. In one embodiment of the invention a means are provided for collecting dislocated material which is transported from the position at which the material is mined to a remote location for deposit.

Abstract: A cutter assembly for a continuous miner adapted for use in the underground mining of coal. The cutter assembly includes a frame adapted to be pivotally supported by the continuous miner, a pair of spaced apart, generally longitudinally directed augers supported by the frame and a transverse auger extending generally between the longitudinally directed augers and rearwardly thereof. The longitudinally directed augers include cutters disposed at the forward end thereof which are adapted to be rotated into cutting engagement with a coal face or seam. A generally U-shaped pan supported by the frame is disposed below the longitudinally directed augers and the transverse auger and has an upwardly slopping rear wall which permits coal to be fed upward to a receiving belt. Drive means are provided for imparting a rotational force to the longitudinally directed augers and the transverse auger.

Abstract: A continuous mining machine comprising a cutter assembly including a cutter frame, a pair of oppositely pitched independently vertically movable auger cutters having their axes of rotation disposed generally parallel with respect to one another, a mobile assembly disposed rearwardly of the cutter assembly and including a mobile frame having a pair of parallel power driven endless track units mounted thereon for independent pivotal movement of each unit about a common generally transversely extending horizontal axis disposed adjacent to the forward portion of the track units, a yoke assembly between the mobile assembly and the cutter assembly including a yoke frame pivotally interconnected with the mobile frame for pivotal movement about an axis generally parallel with the common pivotal axis of the track units and pivotally interconnected with the cutter frame for pivotal movement about a generally upright axis extending generally perpendicularly to the pivotal axis of the yoke frame with the mobile frame, an

Abstract: A continuous mining apparatus and method for the underground mining of coal. The continuous mining apparatus includes a cutter assembly, conveyor assembly and base assembly. The base assembly is adapted to be maintained in a stationary position during a cutting operation. The cutter assembly is adapted to be projected outwardly from the stationary base assembly into the seam of coal for a substantial distance on the order of 80-100 feet. The conveyor assembly is positioned between the cutter assembly and the base assembly and, with the aid of telescoping members, provides two functions. First, the conveyor assembly provides for a variable length conveyor between the cutter assembly and the base assembly permitting the cutter assembly to project outwardly from the base assembly for varying distances of up to 80-100 feet. Second, the conveyor assembly serves as a means to crowd the cutter assembly into the coal seam without movement of the base assembly.

Abstract: The present invention relates to mining machinery and presents a new an improved machine, and components therefor, suitable for mining tar sands and other soft materials such as soft coal, oil shale and so forth. The machine can be used both above ground and below ground, and is particularly suitable for underground mining, to take advantages, for example, of the absence to exposure to inclement weather, excessive moisture, and for other reasons. Underground mining use of the machine is particularly suitable since the tar sands will not freeze up when the mining function is accomplished below-grade. The machine itself has a cutting face comprising a series of cutting heads that may be rotated in the same direction, revolve at the same speed, and inter-mesh so as to provide for an effective solid cutting surface. The machine is provided with air compressor means for blow cuttings rearwardly of the machine through a provided trough carried by such machine.

Abstract: A machine for mining hard material in-situ between adjacent auger holes is disclosed which is suitable for being drivingly connected to a conventional mining apparatus, particularly an auger mining apparatus. The mining machine includes cutting apparatus for mechanically contacting and dislocating hard material in-situ between adjacent auger holes. A power operated system is drivingly connected to the cutting apparatus for generating a cutting motion during the in-cutting operation. A guiding system is provided for maintaining the cutting apparatus in mechanical contact with hard material in-situ between the adjacent auger holes. In one embodiment of the invention a collection bin collects the dislocated material which is transported from the position at which the material is mined to a remote location for deposit.

Abstract: The mining machine has a body portion mounted on a pair of endless propelling tracks which advance the mining machine forwardly in the mine. Pairs of forwardly extending arm members are pivotally connected to the body portion and support at their end portions a skid plate which is positioned transversely across the body portion and arranged to rest on and slide over the mine floor. A first conveyor is supported by the skid plate and receives and directs dislodged material from the mine floor to a second conveyor connected to the end portion of the first conveyor. The second conveyor discharges the dislodged material to the rear of the body portion. A support frame is positioned on the skid plate and horizontally supports a pair of transverse guide rails at the front end of the body portion. A carriage is slidably mounted for transverse movement on the guide rails and includes a rotatable supporting shaft.

Abstract: A drag bit excavating device comprising a core extending along an axis; a bit carrier supported on the core; cutter bits supported by the carrier along a three dimensional spiral having constant pitch and increasing radius along at least a portion of the axis, the carrier being relieved to provide radially extending spaces between the turns of the spiral; a frame supporting the core, carrier, and bits for rotation about and advance along the axis; and a drive to provide rotation, whereby the bits slot the material to be excavated while the material between portions of the resulting slot extends into the spaces to be subsequently broken away.

Abstract: In a drag bit excavating device having a plurality of cutting elements, each element comprising a core extending along an axis; a bit carrier supported on the core; cutter bits supported by the carrier along a three dimensional spiral having constant pitch and increasing radius along at least a portion of the axis, the carrier being relieved to provide radially extending spaces between the turns of the spiral; a frame supporting the core, carrier, and bits for rotation about and advance along the axis; and a drive to provide rotation, whereby bits slot the material to be excavated while the material between portions of the resulting slot extends into the spaces to be subsequently broken away; support means for supporting the elements in an array sloping along a plane with their respective axes parallel to each other, the plane sloping in a direction transverse to the axes, the axes being spaced along the plane in the direction of slope, the elements having their drives arranged so that each core, carrier, and

Abstract: Apparatus for forming bores and coal seams and the like and enlarging preexisting bores. A mining machine includes a nonrotatable body member, a conveyor in line with the body member, a pilot head, and a pair of wing cutters mounted to the body member for pivotal movement with respect to the body member. Structure is provided for moving coal or the like cut by the wing cutters during out-cutting toward the sides of the bore, the structure including a pair of shields, one associated with each wing cutter and disposed between the wing cutter and the body member and pilot head, and a generally conical member coaxial with the shaft for rotation of the pilot head. Stabilization of the body member, etc., within the bore is provided by a pair of wheel sets spaced along the length of the conveyor, and a pair of right angle guide members vertically displaced from the wheel structure of one the wheel sets.

Abstract: In an auger mining system which forms an opening in the earth comprising a pair of axially aligned cylindrical holes and wherein the opening has a bottom, the system has a pair of side-by-side conveyors. Each auger conveyor has a shaft and a flight around the shaft which shafts are journaled through bearings at each end to a spacing member and where the spacing members are rigidly tied to each other by a longitudinal member having an underside. A supporting apparatus including a skid is attached to the auger pair and extending to the bottom of the opening. The skid may be attached either to the underside of the longitudinal member or to each of the bearings. If the skids are attached to the bearings, then skids which are on adjacent bearings of mating auger pairs are arcuately staggered to permit side-by-side positioning of the skids.

Abstract: A machine for excavating underground galleries, comprising a frame displaceable within a gallery, an arm pivotally connected to said frame, means for adjusting the orientation of said arm in a plurality of directions, said arm having a rotary tool carrier provided with cutting tools distributed over the periphery thereof located to operate in a plane perpendicular to the direction of the arm, the machine having means enabling the pivotal connection between the arm and the frame to occupy two distinct alternative positions, in each of which positions the means supporting said pivotal connection can be immobilized.

Abstract: A method and apparatus for forming bores in coal seams and the like and enlarging pre-existing bores. A mining machine includes a non-rotatable body member, a conveyor, such as an auger, in line with the body member, and a pair of wing cutters mounted on the body member for pivotal movement with respect thereto. The wing cutters are movable from a first position wherein they are generally in line with the body member and conveyor, to a second position wherein they are disposed outwardly with respect to the body member. The wing cutters will be in their first position during movement into a bore, and will be moved to and latched in a second position during movement out of the bore. A pilot cutting head in front of the body member may also be provided. The wing cutters may comprise rotatable drums driven by cutting chains, and the drums are normally powered to rotate outwardly from the body member, in directions opposite to each other.

Abstract: Material is continuously dislodged by a pair of conical cutters and displaced outwardly toward the ribs of the room as the mining machine advances. The dislodged material is picked up by a transversely extending spiral conveyor and conveyed inwardly from the ribs onto the bottom strand of a flexible belt. The flexible belt has one end portion coiled on a lower rotatable spindle at a fixed discharge station adjacent the room entry. The other end portion of the flexible belt is coiled on an upper rotatable spindle positioned above the lower rotatable spindle. The intermediate portion of the flexible belt forms a lower conveying strand portion extending from the lower coil around a cylindrical idler or turn around pulley and an upper strand portion extending from the upper spindle to the turn around pulley. The upper strand portion extends between a pair of driven compression rollers to pull the upper strand toward the mining machine from the upper spindle.

Abstract: Method of and apparatus for extracting oil from oil shale. An excavating unit is driven by supplying steam to a plurality of steam engines mounted in an annulus between stationary outer and inner casings. A hollow center column and apertured screw vane are mounted for rotation in the inner casing and helical screw sections are provided outwardly of the inner casing at both ends of the apparatus for directing material to and from the inner casing. Steam is supplied to the unit for driving the center column and helical screws, with the steam supplied to the center column emanating through openings in the screw vane mounted in the inner casing for separating the oil from the oil shale by pyrolysis. The oil is withdrawn in the form of a vapor product by means of a vacuum applied to the inner casing for separation and condensation at the surface. Following excavation, the unit can be withdrawn to the surface under its own power.