Upward Tunneling

Abstract

A power tunneler is advanced upwardly by a thrust ram acting on a non-rotating sectional support column connected to the power tunneler from below. While sections are being added to or removed from the support column it is anchored to a holding table situated underground above the thrust ram. The thrust ram is pivotally mounted at its lower end so that it can be swung sideways to be used as a pipe loader.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method and mechanism for mechanically excavating a tunnel upwardly from an underground location.

2. Description of the Prior Art

It is old to mechanically bore a relatively large diameter hole or tunnel upwardly through an earth formation from an underground location. Rotary drilling machines for doing this are disclosed by Stoces, Bohuslav, D.Sc., Introduction to Mining, Vol. II, page 191, London: Lange, Maxwell & Springer Ltd.; and by U.S. Pat. Nos. 2,979,320 and 3,114,425. A disadvantage of these machines is that they all utilize a rotating drill stem which by necessity includes stabilizer sections of substantial size. To add a stabilizer section it is necessary to disassemble the mechanism used for collecting rock chips in order to make room for the stabilizer section. During these periods the workmen handling the drill stem sections are exposed to the hazards of an open raise. Also, the stabilizers drag against the bore wall as they rotate, increasing the torque requirements of the rotary drive mechanism. Further, it is never possible to bore a perfectly straight hole. The drill stem is always slightly curved despite the presence of stabilizers. As a result, the drill stem wobbles during rotation and the drill stem material is alternately subjected to tension and compression forces severely fatiguing such materials. Also, in such machines the mechanism for rotating the drill pipe must be advanced and retracted axially of tunnel. The apparatus required for doing this adds size to the underground machine.

Another type of machine for boring upwardly from an underground location is shown by U.S. Pat. No. 2,864,600. Such machine is supported by "gripper" mechanisms which make tight engagement with the tunnel wall rather than by drill pipe. A disadvantage of this type of system is that the gripper mechanisms require ideal ground conditions to be dependable and ideal ground conditions are not always present. U.S. Pat. No. 3,354,969 discloses a similar machine which includes an in hole power tunneler which is driven forwardly by powered drive wheels. This type of machine also requires ideal ground conditions.

U.S. Pat. No. 3,604,754 discloses an overhead boring machine of a type which utilizes both a gripper mechanism for engaging the bore wall and a sectional support column which is erected in the hole below the boring machine. In the system of this patent, the mined material or cuttings are delivered into the hollow interior of the support column. As a result, the machine at the underground site is quite complex because it requires a means for handling the column sections and advancing the column upwardly which must be constructed and positioned to not interfere with the discharge of the mined material out from the support pipe.

SUMMARY OF THE INVENTION

Basically, the overhead tunneling apparatus of this invention comprises a power tunneler which is supported from below by a sectional support column. The sectional support column comprises a tubular center portion and a plurality of radially extending stabilizer fins which brace the support column against bending. The tunneler delivers the mined material into the space between a pair of such stabilizer fins through which space the material falls to a hopper mechanism below. The tunneler and the support column are advanced upwardly by a central thrust ram which also doubles as a support column loader. The support column is moved upwardly through a sealed opening in the bottom of the hopper and the column sections are added to and removed from the column in the space below such hopper. The support column does not rotate so it is not subjected to severe fatigue forces. The bringing of the mined material down the hole between a pair of stabilizer fins makes the use of a central thrust ram possible. The use of a central thrust ram results in a shorter machine at the underground machine site. Also, since the thrust ram is used as a support column loader, an independent column loader is unnecessary.

Additional features and advantages of the overhead tunneling equipment of this invention will be apparent from the following description of the illustrated embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a portion of a preferred embodiment of the invention, shown in the process of being set up at an underground machine site;

FIG. 2 is a view like FIG. 3, showing a later stage of set-up;

FIG. 3 is an elevational view looking towards the right side of the equipment as pictured in FIG. 2;

FIG. 4 is an elevational view of a support column section, with lower foreground portions thereof cut away;

FIG. 5 is a top plan view of the support column section shown by FIG. 4;

FIG. 6 is a fragmentary cross-sectional view taken through a stabilizer fin, substantially along line 6--6 of FIG. 5;

FIG. 7 is a view taken from the same aspect as FIG. 3, but showing the power tunneler being advanced upwardly into the overhead ground material and the mined material being loaded into a mine car;

FIG. 8 is a sectional view taken substantially along line 8--8 of FIG. 7;

FIG. 9 is a sectional view taken substantially along line 9--9 of FIG. 7;

FIG. 10 is a sectional view taken substantially along line 10--10 of FIG. 7;

FIG. 11 is a view taken from the same aspect as FIGS. 1 and 2, with some parts in sections;

FIG. 12 is a fragmentary elevational view of a lower portion of the mechanism, looking towards the right side of the equipment as viewed in FIG. 11, with some parts cut away;

FIG. 13 is a cross-sectional view taken substantially along line 13--13 of FIG. 12;

FIG. 14 is an enlarged fragmentary view of an anchor pin station at the holding table;

FIG. 15 is a pictorial view of the lead-in portion of the mined material receiving hopper;

FIG. 16 is a top plan view of a typical underground machine site;

FIG. 17 is an elevational view of the underground site shown by FIG. 16; and

FIGS. 18-23 are a series of elevational views picturing the sequence of operation of the preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Basically, the overhead tunnel excavating equipment of this invention comprises an in-hole power tunneler 10; a sectional support column 12; advancing mechanism including a thrust ram 14, for forcing the sectional support column 12 upwardly to in that manner forcibly advance the power tunneler 10 into the overhead ground formation; a holding table 16 at the underground location above the thrust ram 14; and mechanism for collecting the mined material or cuttings, including a hopper 18.

Referring to FIG. 11 in particular, the power tunneler 10 may comprise a non-rotating frame 20 having a hollow interior and a tail section 22. A drive motor 24 is shown housed within the hollow interior. As will hereinafter be described in greater detail, the tail section 22 has an external cross-sectional configuration which matches the external cross-sectional configuration of the support column sections. Also, tail section 22 is connectable to the uppermost section of the support column 12 in the same manner that adjacent sections are connected together.

A drum-like boring head 26 is mounted for rotation relative to frame 20 by means of a plurality of roller bearings 28. Boring head 26 includes an upper portion which carries a plurality of roller-type rock cutters. In the preferred embodiment these cutters are in the nature of the disc cutters 30. The boring head 26 also includes an outer cylindrical wall portion 32 which carries a plurality of stepped roller cutters 34 of the carbide button type, which cutters are arranged to engage the lateral surface of the tunnel or raise. The disc cutters 30 cut a plurality of concentric kerfs in the hard ground formation and fracture the material between the kerfs. The roller cutters 34 establish the gauge of the tunnel or raise, and also stabilize the tunneler 10 to prevent undesired wobbling or other lateral movement. Thus, the outermost circumferential surface 35 of the cutters may be made without the carbide buttons thereon to enhance this stabilizing function by the flat surfaces 35 engaging the raise wall.

Drive motor 24 includes an output gear 36 which meshes with and drives a plurality of planetary gears 38 which are carried by a rotary carrier 40. The gears 38 also mesh with a stationary interior ring gear 42 located inside of a cylindrical housing 44. Housing 44 is a non-rotating part of the frame 20. The rotating carrier 40 is secured to an upper end wall portion 46 of the boring head 26. The cylindrical wall 32 which carries the gauge cutters 34 depends from the end wall 46. The roller bearings 28 are situated between walls 32 and 44.

Referring now to FIGS. 4 and 5 in particular, the support column sections 48 are shown to each comprise a tubular central portion 50 and a plurality (e.g., three) of radial stabilizer fins 52. When a column section 48 is in the tunnel T the outer radial boundaries of the fins 52 are contiguous the tunnel wall (FIG. 7). Each column section 48 is of composite construction. The illustrated embodiment is composed of a length of cylindrical tubing 54 to which a pair of cast end members 56, 58 are welded. Each end member 56, 58 is formed to include a short radial projection or ear 60, 62 for each stabilizer fin 52. A length of channel stock 64 extends axially along the cylindrical pipe section 54 between each related pair of ears 60, 62 and is rigidly affixed by welding to the pipe section 54. The ears 60, 62 extend radially beyond the channel members 64 and it is to these extensions that the fins 54 are attached.

Axial sockets 66 are provided in the end members 58 in position to receive axial locator pins 68 which are carried by the tail section 22 of the boring head frame 20, and by the lower end member 55 of each support column section 48. As shown by FIGS. 5 and 4, the radial projections 62 are formed to also include a connector pin opening 70 which extends laterally through its socket 66. Each locator pin 68 includes a complementary connector pin opening 72 which becomes aligned with pin openings 70 when such locator pin 68 is in socket 66. The pins and sockets 68, 66 serve to correctly orient the support column section 48 relative to each other or to the tail section 22 of the boring head frame 20 and to transmit torque. Connector pins 71 (FIG. 11), are inserted through the aligned openings 70, 72 to connect adjacent column sections 48 together, or to connect the upper column section 48 to the tail section 22 of the tunneler 10.

As will hereinafter be described in detail, the radial ears 60, 62 also include cross-openings 74, 76 which are provided for receiving anchor pins 77 (FIG. 14), serving to connect the column sections 48 to the holding table 16.

The holding table 16 includes an opening sized to closely surround the support column 12. In other words, such opening includes a central circular portion which is only slightly larger in diameter than the central portion 50 of the column section 48 and three equally spaced apart radial cut-outs which are only slightly larger in size than the stabilizer fins 52.

Referring to FIGS. 13 and 14, the holding table 16 is provided with a pair of brace plates 78, 80 at the base portion of each cut-out in the table 16 for a related channel section 64. During tunneling the torque transmitted back to the table 16 by the support column 12 is transferred from the channel sections 64 through the brace plates 78 and 80 to the table 16. The cut-outs for the fins 52 are large enough radially outward from the brace block 78, 80 so that the weaker outer portions of the stabilizer fins 52 are not in loading bearing contact with the side boundaries of the cut-outs. The brace blocks 78, 80 are provided with aligned openings 82, 84 which are alignable with the holding pin openings 74 in the support column sections 48 and at the lower end of the tail section 22. As shown by FIGS. 12 and 14, anchor pins 77 may be inserted through the aligned pin openings 82, 74, 84 for the purpose of firmly anchoring the tail section 22 or a support column section 52 to the holding table 16. This is something that is done while support column sections 52 are either being added to or removed from the support column 12.

In the preferred embodiment the holding table 16 is shown to be supported above a lower frame assembly 86 by means of a plurality of frame columns or posts 88. The lower frame assembly 86 may be provided with a mounting socket 90 for each column 88. The frame member 86 may also include a top plate 92 which is provided with a pair of upwardly extending, selectively usable mounting lugs 94, 96. According to the invention, a thrust ram base 98 is pivotally connected to either lug 94 or lug 96 by a pivot pin 100. In the illustrated embodiment the pivot pin 100 is shown to extend through openings in the lug 94 and also through openings in a pair of ears 102, 104 which are secured to the thrust ram base 98.

The lower end of a piston 106 is firmly secured to the thrust ram base 98. A piston head 108 is provided at the upper end of the piston 106. A cylinder 110 is mounted on the 106 for movement up and down therealong. The piston 106 and the cylinder 110 together define a double acting linear hydraulic motor, comprising a variable volume fluid chamber 112 located above the piston head 108 and a variable volume fluid chamber 114 located below the piston head 108. Chamber 114 is the annular space defined by and between the piston 106 and the side wall of the cylinder 110. The piston 106 and cylinder 110 comprise the thrust ram 14.

The hydraulic fluid may be introduced into and removed from the chambers 112, 114 in any number of ways. By way of typical and therefore non-limitive example, in FIG. 11 the fluid conduits 116, 118 are shown to be built into the piston 106. As will be apparent, hydraulic fluid is delivered into chamber 112 and is removed from chamber 114 to drive the cylinder upwardly, i.e., to extend the thrust ram 14. The direction of flow is reversed to retract the thrust ram 14.

The cylinder 110 is provided with a radial support flange 120 unto which the lower end of a support column section 48 can rest. This flange 120 is provided with ears 62, each ear 62 having an axial socket 66 to receive a related pin 68 from a column section 48 above, and a pin opening 70 by which a related pin 68 can be secured to the socket 66. The portions of the cylinder 110 which are above the flange 120 and engage upper and lower sections 58 and 56 of the column sections 48 are sized to be snugly received within the interior of the tubular center portion 54 of a support column section 48.

As will hereinafter be described in greater detail, the thrust ram 14 may be swung over about the axis of pin 100 into a substantially horizontal position. While the thrust ram 14 is in such position a support column section 48 is inserted onto the upper portion of the cylinder 110. The thrust ram 14 is then swung back upwardly into a position placing the base 98 into contact with the top plate 92, to align such support column section 48 with another section 48 of the support column 12 which is then pin connected to the holding table 16.

The thrust ram base 98, and hence the thrust ram 14 carried thereby, may be swung between horizontal and upstanding positions by means of a single double acting hydraulic linear motor 122 (FIGS. 1, 10, 18 and 23). In FIGS. 1, 10, 18 and 23 a crank arm 124 is shown rigidly affixed to the pivot pin 100. Pin 100 is in turn rigidly affixed to the ears 102, 104 and is loosely fitted within the opening in lug 94. One end of the linear hydraulic motor 122 is pivotally attached to the crank arm 124 at a location 126 spaced a substantial distance from the pin 100. The opposite end of the hydraulic linear motor 122 is pivotally attached to a lug 128 upstanding from the top plate 92. The linear hydraulic motor 122 is extended to rotate the crank arm 124 in a direction causing movement of the thrust ram 14 from its upright position towards its horizontal position. A retraction of the hydraulic linear motor 122 causes a reverse rotation of the crank arm 124 and hence movement of the thrust ram 14 from its horizontal position towards its upright position.

The base assembly 86 may be pivotally connected to a base structure B, such as by means of pivot pins 130. A pair of turnbuckles 132 may be interconnected between end portions of the base structure B and upstanding support plates 134 secured to the top plate 92. This mechanism provides a way in which the main portion of the machine can be adjusted relative to the base structure B. A plurality of spaced apart openings 140 are provided in upstanding side wall portions 138 of the base structure B for receiving connector pins 142 used to connect the lower ends of the turnbuckles 132 to the base structure B. A plurality of similar openings 136 are provided in the upstanding plates 134 to receive similar pins 144 used for connecting the upper ends of the turnbuckles 132 to such plates 134. As will be apparent, angular adjustment of the base member 86 and the drilling machine apparatus above it relative to the base structure B can be accomplished by both a change in length of the turnbuckles 132 and a change in the mounting holes 136, 140 for the turnbuckles 134.

In the illustrated embodiment the angular adjustment of the base member 86 and the drilling machine apparatus above it relative to the base structure B occurs at a right angle to the direction of swinging movement of the thrust ram 14.

The second lug 96 (FIG. 10) is provided so that the direction of sideways swinging movement of the thrust ram 14 can be reversed. A simple way of changing the mounting of the thrust ram base 98 from lug 94 to lug 96 will now be described. The cylinder 110 is moved upwardly until the ears 62 of its thrust flange 120 can be connected to thrust column locator pins 68 with connector pins 71. The thrust column 48 is in turn connected to holding table 16 by pins 77. Next, the pin 100 and the motor 122 are removed and the piston 106 is retracted upwardly into the cylinder 110. When the ears 102, 104 and the base member 98 are above the lug 94, the piston 106 is easily rotated about its axis relative to the cylinder 110 until the ears 102, 104 are above lug 96. Then, the piston 106 is extended until the pin openings in the lugs 102, 104 are aligned with the pin opening in the lug 96. Then, the cross-pin 100 is installed to pivotally connect the lugs 102, 104 to the lug 96 and the motor 122 is remounted at its new location.

As perhaps best shown by FIG. 11, the receptacle or hopper 18 for collecting the mined material or cuttings is shown to include outer and inner bottom walls 146, 148 formed to include an opening through which the tail section 22 and the sectional support column pipe 12 may pass. FIG. 9 is a sectional view taken through the hopper 18 and looking downwardly towards the inner bottom wall 148. The outer bottom wall 146 and the inner bottom wall 148 include openings which are similar in cross-sectional configuration to the tail section 22 and the support column sections 48. A laminated seal 150 is held between the two bottom walls 146, 148. As best shown by FIG. 9, this seal material 150 makes tight contact with the tail section 22 and the support column sections 48 as they move relatively through the hopper 18.

The hopper 18 is preferrably movable axially of the tunnel relative to the holding table 16. This movement may be accomplished by linear hydraulic motors interconnected between the table 16 and the hopper 18. In the illustrated embodiment the cylinder portions 152 of a pair of such linear hydraulic motors are attached to the holding table 16 on opposite sides of the machine. The piston rods 154 project outwardly from the cylinders 152 and at their outer ends are connected to the base of the hopper 18. Extension of these rods 154 causes the hopper 18 to move upwardly relative to the table 16. Retraction of these rods 154 causes movement of the hopper 18 towards the table 16.

As best shown by FIGS. 7 and 9, the hopper 18 is equipped with a discharge chute 156 which depends downwardly from a lower side portion of the hopper 18.

A preferred mode of operation of the illustrated embodiment will now be described:

Firstly, the tunnel is enlarged at the underground machine site in order to provide sufficient room for the machine, the various accessory equipment and the workmen. The base structure B is then put in place. It may comprise a concrete pad to which one or more metal base members are attached or it may be formed by metal base members attached directly to the floor of the tunnel. The base structure B may be surveyed in place so that when the machine proper is attached to it such machine will be properly placed relative to the drill line.

Referring to FIGS. 1 and 18, the machine may be brought to the underground site with its frame columns 88 removed. The tunneler 10 is secured to one column section 48, which is in turn secured to the cylinder 110 of the ram 14. For convenience of illustration this first column section 48 is shown in broken lines in FIGS. 1, 2, 3, 18, 19 and 20. The machine may be supported on its side until the lower frame assembly 86 is attached to the base structure B and the hydraulic motor assembly 122, 124, 126 is installed. Then, the linear motor 122 may be used for raising the thrust ram 14 and the machine parts connected thereto into an upright position (FIGS. 3 and 19). At this time the power tunneler 10 and the thrust ram 14 are in fixed position relative to the holding table 16 and the hopper 18. Next, the thrust ram 14 is extended a sufficient amount to permit installation of the columns 88 and such columns 88 are installed (FIG. 20).

The thrust ram 14 is extended, with support column sections 48 being added as needed, until the disc cutters 30 on the boring head 26 of the power tunneler 10 are in contact with the tunnel roof overhead. The drive motor 24 is then operated to rotate the boring head 26 while the power tunneler 10 is advanced upwardly by the thrust ram 14. Each time the lower end of a support column section 48 reaches the brace plates 78, 80 on the holding table 16, thrusting is temporarily stopped, pins 77 are inserted to secure such column section 48 to the work table 16, and the thrust ram cylinder 110 is retracted. Then the motor 122 is operated to swing the thrust ram 14 over on its side to receive another support column section 48 (FIG. 23).

After the overhead tunnel or raise has been excavated a sufficient amount to locate the power tunneler 10 therein, an upper section 158 is installed onto the hopper 18. This upper section 158 may be constructed in three parts 162 which may be bolted or otherwise firmly secured to the upper end of the hopper 18. Axial cut-outs 164 are provided between upstanding neck sections 160 of the parts 162. Following installation of the upper section 158 the entire hopper assembly is moved upwardly relative to the holding table 16 to place the neck members 160 snugly into the overhead raise or tunnel (FIG. 22). This raising of the hopper assembly 18, 158 is accomplished by extension of the hydraulic motors 152, 154. The cut-outs 164 are provided to provide clearance for the stabilizer fins 52 which, like the outer surface of the neck parts 160, are contiguous the wall of the overhead raise or tunnel. This upper section 158 effectively seals the lower end of the tunnel about the upper end of the hopper assembly 18, 158.

During the tunneling operation the rock chips or cuttings (i.e., the mined materials) are moved by the rotating boring head 26 towards the lower side of the tunnel and into the passageway 176, which is defined two fins 52 and the adjacent portion of the tunnel wall. Such mined material falls by gravity through this passageway 176 into the hopper 18 and from the hopper 18 through the discharge chute 156 into a mining car 178 positioned below. The mining car 178 is supported on rails 180 in conventional fashion.

As mentioned above, the tight fit of the neck portion 160 of the hopper's upper section 158 with the lower end of the tunnel wall results in all of the mined material being directed into the hopper 18. A cover plate 174 perpendicular to the tunnel axis and connected to the tail section 22 of the tunneler 10 provides an upper barrier which serves to direct the mined material into the chute 176.

Owing to the side placement of the discharge chute 176 a central thrust ram 14 may be used. The positioning of the discharge chute 176 also makes it possible to swing the thrust ram 14 so that it can double as a column section loader, making a separate loader unnecessary. Since the mined material is not dropped downwardly through the center of the support column it is not necessary to provide a way of removing the mined material from the support column at its lower end or to co-ordinate such means with the advance mechanism for the support column so that neither one of these mechanisms interferes with the other. It is believed that the side discharge of the mined material and the central thrust ram arrangement results in a size (and particularly a height) saving in the machine.

Another advantage of the overhead raise excavating machine of this invention is that the hollow center of the support column 12 can be used as a survey avenue during times when the thrust ram 14 is swung over on its side.

According to the invention, one of the outer portions 166 of a stabilizer fin 52 is removable so that the power lines 172 leading to the drive motor 24 may be housed within the passageway formed through an axial series of such housings 166 (FIG. 7). Each support column section 48 may be installed on the thrust ram 14 with its housing 166 removed so that the motor lines 172 can be properly placed relative to such section 48. Then, the housing 166 is installed while the pipe section 48 is in the position shown by FIG. 11, before such support column section 48 is moved upwardly. In the illustrated embodiment there are three motor lines 172. One is a supply line to the hydraulic motor 24, a second is a return line from such motor 24, and the third is a drain line which carries away hydraulic oil which is permitted to leak upwardly from the motor 24 into the region of the gearing 36, 38, 40, 42 and the bearings 28. Of course, in some other installation utilizing a different type of motor or dirve assembly the motor line requirements may be different.

Referring to FIGS. 5 and 6, a plurality of flanges 168 may be provided on the inner walls of each housing 166 to receive an elastomeric "rub" member 170. These "rub" members are provided as a means against which the motor lines 172 may contact or rub during their ascent and descent. As will be appreciated, this arrangement prevents such lines 172 from rubbing against sharp edges and metal parts which could in time damage them through chafing.

Claims

What is claimed is:

1. Mechanism for tunneling upwardly from an underground location, comprising:

a power tunneler; and

means for advancing said power tunneler upwardly into the ground, said means comprising a sectional support column below said power tunneler having at least one longitudinal external rib thereon, thrust ram means positionable at the underground location for forcing said sectional support column upwardly to in that manner forcibly advance the power tunneler upwardly, a holding table positionable at the underground location above said thrust ram means, said holding table including means for restraining said sectional support column against rotation during such advancement of said sectional support column and said power tunneler, said means including a fixed guide through which said external rib moves during advancement of said sectional support column, and means for securing said sectional support column to said holding table while a section is being added or removed from it.

2. Tunneling mechanism according to claim 1, wherein said support column comprises a tubular central portion which is substantially smaller in cross-section than the tunnel, so that a substantial space exists between said tubular portion and the tunnel wall, and a plurality of stabilizer fins spaced about and radiating outwardly from said tubular central portion, and wherein said power tunneler includes means for delivering the mined material into a space defined angularly between an adjacent pair of said stabilizer fins and radially between said central portion and the tunnel wall.

3. Tunneling mechanism according to claim 1, wherein a radial space exists between said sectional support column and the tunnel wall and said power tunneler includes means for delivering mined material into said space for travel downwardly therethrough to the underground location.

4. Tunneling mechanism according to claim 1, comprising:

lower frame means below said thrust ram means, and means pivotally connecting the lower end of the thrust ram means to such lower frame means, for pivotal movement between a first position generally in line with the sectional support column and a second position generally over on its side, so that the thrust ram means can be swung downwardly out of line with the sectional support column into said section position to receive a section of the column thereon and then be swung upwardly back into line with the sectional support column.

5. Mechanism for tunneling upwardly from an underground location, comprising:

a power tunneler; and

means for advancing said power tunneler upwardly into the ground, said means comprising a sectional support column below said power tunneler thrust ram means positionable at the underground location for forcing said sectional support column upwardly to in that manner forcibly advance the power tunneler upwardly, a holding table positionable at the underground location above said thrust ram means, said holding table including means for restraining said sectional support column against rotation during such advancement of said sectional support column and said power tunneler, and means for securing said sectional support column to said holding table while a section is being added to or removed from it, wherein a radial space exists between said sectional support column and the tunnel wall and said power tunneler includes means for delivering mined material into said space for travel downwardly therethrough to the underground location, said mechanism further comprising hopper means above the support table for receiving the mined material, said hopper means including a discharge chute through which the collected mined material can be discharged into a transporter.

6. Tunneling mechanism according to claim 5, wherein said hopper includes an upper portion sized to snugly fit within the tunnel so that substantially all of the mined material will have to fall into the hopper.

7. Tunneling mechanism according to claim 6, further including means for moving the hopper upwardly relatively to the support table.

8. Tunneling mechanism according to claim 5, wherein said hopper includes a bottom wall having an opening therein through which the sectional support column extends during advancement of the power tunneler, and seal means for sealing between said bottom wall and the sectional support column.

9. A section of a sectional support column used for supporting and applying an upward thrust to an upwardly advancing power tunneler, said section comprising:

a tubular body which is substantially smaller in cross-section than the tunnel in which it is to be used, and a plurality of stabilizer fins radiating outwardly from said body substantially to the diameter of the tunnel in which the section is employed, with at least one of said fins making a strong, rigid connection to said body throughout the full length of said body, so that at such location of connection it can support bracing against rotation, and connector means at each end of said section for use in connecting it to an end of a similar section of the sectional support column.

10. A support column section according to claim 9, wherein at least one of said fins is hollow and is defined by a housing which is removably secured to said tubular body, so that such housing can be placed about control line means and then be secured to said tubular body.

11. A sectional support column section according to claim 9, wherein the connector means at one end of the section comprises:

a plurality of axial sockets in said tubular body and the connector means at the opposite end of the section comprises a plurality of complementary locator pins for insertion into the sockets of a second section, and wherein the wall means defining such sockets includes a transverse passageway, and the locator pins also include transverse passageways alignable with the transverse passageways in the walls of its socket, so that a transverse locking pin can be inserted through such aligned passageways for locking adjacent support column sections together.

12. For use in a mechanism for tunneling upwardly from an underground location in which the tunneling is done by successively constructing a sectional support column below a power tunneler and by thrusting said support column upwardly, to in that manner forcibly advance the power tunneler, while restraining said support column against rotation;

a thrust ram means for forcing said sectional support column upwardly, said thrust ram means comprising a linear piston-cylinder hydraulic motor having a first end with means for end-wise engaging a section of the support column and a second end which is pivotally securable to a frame situated at the underground location below said sectional support column, for pivotal movement of the hydraulic motor between a thrusting position in which it is coaxial with the support column and a side position for pickup of a column section.

13. For use in a mechanism for tunneling upwardly from an underground location in which the tunneling is done by successively constructing a sectional support column below a power tunneler and by thrusting said support column upwardly, to in that manner forcibly advance the power tunneler, while restraining said support column against rotation;

a thrust ram means for forcing said sectional support column upwardly, said thrust ram means comprising a linear piston-cylinder hydraulic motor having a first end with means for end-wise engaging a section of the support column and a second end which is securable to a frame situated at the underground location below said sectional support column; and

support shoulder means at said first end for receiving a lower end portion of a support column section, and pin means at said first end insertable into the interior of said support column section.

14. For use in a mechanism for tunneling upwardly from an underground location in which the tunneling is done by successively constructing a sectional support column below a power tunneler and by thrusting said support column upwardly, to in that manner forcibly advance the power tunneler, while restraining said support column against rotation:

a thrust ram means for forcing said sectional support column upwardly, said thrust ram means comprising a first end adapted for engaging a section of the support column and a second end which is securable to a frame situated at the underground location below said support column, said first end including support shoulder means for receiving a lower end portion of the support column section, and means insertable into the interior of said support column section; and

means for pivotally connecting the second end of said thrust ram means to a frame member situated at the underground location, so that the thrust ram means when retracted, can be swung sideways out of line with the support column and into a position to receive a new section of the support column, so that the new section can be secured to the support column and the thrust ram means can again be used for advancing the support column and the power tunneler supported thereby.

15. A power tunneler which during use is progressively moved upwardly from an underground location by a sectional support column which is itself moved endwise upwardly by thrust ram means, said power tunneler comprising:

a non-rotating body portion securable to the support column, a rotary cutter carrier mounted on said body portion, cutters on said carrier, motor means mounted on said body portion, means drivenly connecting said motor means to said cutter carrier, and a tail section adapted for connection to the upper section of the sectional support column, said tail section comprising a tubular central portion which is substantially smaller in cross-section than the bore formed by the cutters, so that a substantial space will exist between said tubular portion and the bore wall, and a plurality of fins radiating outwardly from said tubular central portion, said power tunneler including means for directing the mined material into a space that is defined angularly between an adjacent pair of said fins and radially between said central portion and the tunnel wall.

16. A power tunneler which during use is progressively moved upwardly from an underground location by a sectional support column which is itself moved endwise upwardly by thrust ram means, said power tunneler comprising:

a non-rotating body securable to the support column, motor means mounted within said body, a rotary cutter carrier mounted on said body said cutter carrier comprising an end portion which is positioned endwise of said body and a side portion which extends about said body, cutters on said carrier including face cutters on said end portion and gage cutters on said side portion, means drivenly connecting said motor means to said cutter carrier, and a tail section extending rearwardly from said body which is adapted for connection to the upper section of the sectional support column.

17. A power tunneler according to claim 16, wherein said tail section includes a tubular central portion which is substantially smaller in cross-section than the bore formed by the cutters, so that a substantial space will exist between said tubular portion and the bore wall, and at least one fin which extends radially outwardly from said tubular central portion, and power supply lines for said motor extending from the motor through an opening in said tubular portion and into said fin.

18. A power tunneler according to claim 16, wherein said tail section includes means strong enough to withstand bracing imposed thereon for preventing rotation of said tail section and said body portion.

19. A power tunneler according to claim 16, wherein said tail section includes means for receiving a transverse pin which is used for affixing the tunneler in position relative to a fixed support table.

20. Mechanism according to claim 16, wherein said cutter carrier comprises an upper end portion which is positioned endwise of said body and a side portion which extends about said body, and wherein the cutters on said carrier include face cutters on said end portion and gage cutters on said side portion.

21. A power tunneler which during use is progressively moved upwardly from an underground location by a sectional support column which is itself moved endwise upwardly by thrust ram means, said power tunneler comprising:

a non-rotating body, motor means mounted on said body, a rotary cutter carrier mounted on said body, cutters on said carrier, means drivenly connecting said motor means to said carrier, and a tail section on said body including means for detachably connecting it to the upper section of the sectional support column, said tail section generally corresponding in cross sectional shape to the sectional support column with which it is used; and

hopper means for receiving the mined material, said hopper means including sidewall means and a bottom together defining an interior space which is large enough to receive a substantial portion of the tunneler, said bottom having an opening therein sized to receive the tail section of the tunneler, and seal means for sealing between said bottom and the tail section, said seal means accommodating axial movement of the tunneler relative to the hopper.

22. In mechanism for boring upwardly from an underground location, by use of a rotary cutterhead that is forced upwardly by means including a sectional support column which is moved axially upwardly as sections are added to it, said sections including longitudinal external ribs, wherein the mined material is dropped downwardly through a space between the support column and the bore wall, a material gathering hopper positionable at the underground location, comprising:

a bottom;

side wall means connected to the bottom and extending upwardly therefrom, to with the bottom form a receiving chamber for the mined material;

a support column passageway in said bottom, corresponding in cross-sectional shape to the sectional support column, through which said support column moves during boring; and

a discharge passageway from said hopper spaced laterally outwardly from said support column passageway.

23. Mechanism according to claim 22, including a holding table that is positionable at the underground location below the bottom of the hopper, said holding table comprising:

means defining an opening through which said support column moves as it is advanced upwardly, including a guide avenue for the longitudinal external ribs;

means adjacent said guide avenue for contacting said ribs during boring and restraining said support column against rotation; and

means for securing said sectional support column to said holding table while a section is being added to or removed from it.

24. Mechanism according to claim 23, comprising hydraulic cylinder means interconnected between the hopper and the support table, for adjusting the hopper in position relative to the support table and the entrance to the borer.

25. Mechanism according to claim 22, wherein the bottom of the hopper includes seal means surrounding the support column passageway, for sealing against substantial leakage of material from the hopper through such passageway.