Abstract:
An apparatus is provided for the drilling of a borehole and its simultaneous lining with cement or the like by the same apparatus. The apparatus comprises a combination spray bead and reamer head, a means to drive the reamer head through a borehole and a means for delivering cement to the spray head. Cement is fed to a rotatable spray disc or arms of the spray head, which is arranged to distribute the cement substantially evenly over the internal surface of the borehole created by the reamer head, The apparatus uses lined drill rods, as well as a lined reamer core with a double walled plastic tube. An air transfer assembly is used to connect an internal air source to an air passage contained in the plastic tube, such that the external air source remains stationary during rotation of the lined drill rods and attached reamer and spray beads.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. FIELD OF THE INVENTION  
           [0002]    The present invention relates to a method and apparatus for raise bore drilling and lining of a borehole, more specifically to bore holes drilled for use in the mining industry.  
           [0003]    2. DESCRIPTION OF THE PRIOR ART  
           [0004]    Raise bore drilling has been used in the mining industry for many years and has been successful in virtually all types of rock. Modern raise bore drilling machines are capable of boring a pilot hole of up to 1000 meters and then reaming the pilot hole out to between 3 and 20-|- feet. Prior to the drilling of the pilot hole, information relating to the bore bole (i.e. location, start and end co-ordinates, size of hole, start-and-break-through mine levels, and the type of rock) are required to determine the size of raise drilling machine required, size of reamer, length of hole, and the size and number of drill rods required to complete the bore hole formation. Once this information is ascertained, the layout of the drilling apparatus is calculated and the drilling station is set up.  
           [0005]    The first stage of borehole drilling involves the creation of a pilot hole. The piloting process generally begins by assembling a pilot bit, roller bit stabilizer, one or two ribbed stabilizers and loading the assembly into the raise drill. On drilling, the hole is flushed with a fluid medium, typically water, to flush cuttings away from the pilot bit. The resultant slurry is forced up through the drilled hole around the outside of the drill and is piped away from the raise drill by means known to one skilled in the art. Typically, a new drill rod is added after each live feet of drilling is completed, however lesser drill rod lengths are also used, The pilot process continues until the pilot bit breaks through at a lower level of the mine.  
           [0006]    The second stage involves the replacement of the pilot bit with a reamer to enlarge a portion of the pilot hole. Generally the reamer is positioned such that it is adjacent to the surface of the rock face and is loaded to the tension required to force the reamer cutters into the rock during rotation of the drill string. Typically, after each drill rod length of reaming is complete, a drill rod is removed and the process is repeated until the reamer is immediately below the raise drill set up rail, At this point the reamer is removed and the borehole is completed.  
           [0007]    The third stage involves lining of the borehole with a material such as cement to guard against the crosion and potential collapse of the borehole walls. Once the reamer and drilling equipment are removed, a lining delivery equipment is set up. Typically, this process involves the use of a separate device under remote control in order to avoid an operator having to descend into the boreholes. Several Systems exist for the application of this lining, such as preformed liner sleeves, shuttering, and a spray-on apparatus. However, each is an independent system to the apparatus used for the drilling of the borehole, This arrangement has disadvantages in that set-up time is required for both the drilling apparatus and lining delivery equipment. Accordingly, the use of two separate and independent systems in the creation of a borehole, one for drilling and one for lining, can require two crews and two sets of equipment. This method can be particularly time consuming and costly.  
           [0008]    In the art, Canadian Patent 1,308,249 describes a process for the lining or boreholes involving an apparatus for the remote spraying of cement on the walls of a bore hole. This patent focuses solely on the lining of the borehole once the borehole has been created. Canadian Patent 1251,475 teaches a raise bore mining method; however, the patent does not discuss the lining of the bore itself.  
           [0009]    It is an object of the present invention to provide a drilling system and method obviate or mitigate at least some of the above-mentioned disadvantages.  
         SUMMARY OF THE INVENTION  
         [0010]    The raise bore drilling and lining apparatus of the present invention comprises a raise boning drill for boring a raise into a pilot hole, using a drill string to create a bore hole; a reamer head affixed to one end of the drill string where the drill string and reamer have a passage defined there through which is generally coaxial with the drill string; and a spreader assembly for distributing a liner material on the wall of the bore hole, where the spreader assembly is affixed to the reamer at an end opposite to the drill string.  
           [0011]    The combined liner and drill apparatus enables a single system to both line add drill the bore hole and help improve the efficiency of the overall process, The reamer remains in the borehole during the distribution of the liner material on the wall of the borehole. Further, the reamer and spreader assembly is used to help provide a uniform thickness of liner material to the wall of the borehole.  
           [0012]    According to the present invention there is provided a raise bore drilling and lining apparatus for creation of a borehole. The apparatus comprising: a raise boring drill for boring a raise into a pilot hole using a drill string to create a bore hole; a reamer head affixed to one end of said drill string, the drill string and reamer having a passage there through generally coaxial with the drill string; and a spreader assembly for distributing a liner material on the wall of the bore hole, said assembly affixed to said reamer at an end opposite end to the drill string.  
           [0013]    According to a Further aspect of the present invention there is provided a method of drilling and lining a raise bore hole. The method comprising the steps of: boring a pilot hole using a conventional raise boring drill having a pilot bit; flushing said pilot hole to flush cutting away from said drill with a fluid medium; removing said pilot bit from said raise bore drill; attaching a drill string having a reamer affixed thereto, said drill string and said reamer having a passage defined there through; installing a spreader delivery tube within said passage; attaching a spreader assembly to said reamer at an opposite end to said drill string; lowering said drill string though said pilot hole; reaming said pilot hole for a specified distance to create a bore hole; and applying a liner medium to the wall of said bore hole using said spreader assembly.  
           [0014]    Other aspects of the invention can include a double walled drill rod and a spreader assembly. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    These and other features of the preferred embodiments of the invention will become more apparent in the following detailed description in which reference is made to the appended drawings wherein:  
         [0016]    [0016]FIG. 1 is a schematic representation of the sequence of steps used to create a raise bore.  
         [0017]    [0017]FIG. 2 is an enlarged view of a raise bore drilling and lining apparatus used in FIG. 1;  
         [0018]    [0018]FIG. 3 is a cross-sectional view of a drill rod of the apparatus of FIG. 1:  
         [0019]    [0019]FIG. 4 is an enlarged cross-sectional view of a pair of coupled rods of FIG. 3;  
         [0020]    [0020]FIG. 5 is a cross-sectional view similar to FIG. 3 of an alternative embodiment of drill rod;  
         [0021]    [0021]FIG. 6 is shows a sectional view of a drive arrangement of the drill string with the raise drill of FIG. 1;  
         [0022]    [0022]FIG. 7 is an enlarged sectional view of a component used in the drive of FIG. 6;  
         [0023]    [0023]FIG. 8 is a side view of a reamer assembly;  
         [0024]    [0024]FIG. 9 a sectional view on an enlarged scale of the reamer assembly of FIG. 8; 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    Referring firstly to FIG. 1, raise bore drilling apparatus generally indicated at  10  is located in al upper gallery G 1  of a mine at a position in which a vertical bore interconnecting the upper gallery G 1  and lower gallery G 2  is required. The raise bore drilling apparatus  10  includes a raise bore drill  18  to which is connected a drill string  12 . The drill string  12  is formed from interconnected drill rods  36  to which is connected a tool  13 .  
         [0026]    As shown in FIG. 1 a , the apparatus  12  is initially used with u pilot drill bit to drill a pilot hole  20  from the upper gallery G 1  to the lower gallery G 2 . During the drilling, the drill string  12  is advanced downwardly with additional lengths of drill rod  36  added as required. Upon completion of the pilot hole, the drill bit is removed and replaced with a reamer assembly  14  which is used to enlarge the pilot bole  20  to the required diameter as will be described more fully below. The details of the apparatus  10  as used with the reamer assembly  14 , is shown more fully in FIG. 2.  
         [0027]    The drill string  12  connected to reamer assembly  14  by a releasable coupling  15 . The drill string  12  is also connected by a coupling  51  to a raise bore drill  18 , which rotates the coupled drill string  12  and reamer assembly  14  to enlarge a pilot hole  20  for producing a bore hole  22 . The reamer assembly includes a reamer  17  and a spreader assembly  16  is fastened to the bottom of the reamer  17 , to provide for co-joint rotation between the reamer  17  and spreader assembly  16 . The drill string  12  and reamer  14  have an internal passage  23  there-through that contains ducts for supplying drilling fluid, bore hole liner material, typically referred to as shotcrete, and a drive fluid to the spreader assembly  16 . The spreader assembly  16  includes a rotating spreader wheel that is effective to apply the liner material  26  to the sides of the borehole  22 .  
         [0028]    Accordingly, as the reamer  17  is raised and rotated to enlarge the pilot hole  20 , as shown in FIG. 1, the spreader assembly  16  is also raised. The reamer  17  rotates and thereby producing debris  34  and the bore hole  22 . Once a section of the bore hole  22  is produced, the drill string  12  is lowered and the spreader assembly  16  rotated to direct the liner material against the side of the produced bore hole  22  for producing a lined bore hole  25 .  
         [0029]    As shown in more detail in FIG. 3, the drill string  12  of the apparatus  10  is composed of a series of connected drill rods  36 , with a female coupling  37  and a male coupling  38  at opposite ends. The couplings  37 ,  38  have complementary threads  39  for connecting adjacent drill rods  36  to form the drill string  12  (see FIG. 1). It is recognised that the drill rods  36  could also have at either end two male couplings  38  or two female couplings  37  with suitable inserts, if desired. The drill rod  36  has an outer casing  41  within which a liner  40  is located. The liner  40  can be made of a rigid plastic material, such as but not limited to polyethylene, and defines a series of ducts for supplying the material used in the process from the raise drill  18  to the spreader assembly  16 . The liner includes three concentric tubes,  42 ,  44 ,  46  that extend between a sleeve  43  at the male coupling  38  and a locating ring  47  adjacent the threaded portion  39  of the female end  37 . The sleeve  43  has a radial flange  49  to locate it axially on the casing  37  and is sealed by O-rings  45  to the casing. The flange  49  is situated on top of the coupling  37  to sit on a leading edge of the threaded portion of the drill rod  36  to help prevent the liner  40  of the drill rod  36  iron being pushed through when threading the drill rods  36  together as shown in FIG. 4.  
         [0030]    Referring to FIG. 4, the alignment of adjacent drill rods  36 , is shown to permit the rods  36  to be connected by mating the respective threads  39  of the female coupling  37  of rod  36  with the male coupling of the rod  36 . The Tube  42  has a sleeve  49  secured to it at one end with an O-ring  48   a  located within the sleeve  49 . The inner diameter of sleeve  49  is dimensioned to receive the tapered upper end of the tube  42  and provide a continuous passageway across the coupling.  
         [0031]    The tube  42  is located radially within the tube  44  by spiders  50  at opposite ends that do not impede flow along the tube  44 . Tubes  44  are interconnected by a female—female fitting  51  that; is secured to one end of the tube  44 . The opposite end of the tube  44  has all annular groove  53  to receive an O-ring  48   b  that forms a seal between adjacent ends of tubes  44 .  
         [0032]    The tube  44  is in turn supported within the tube  46  on spaced supports  54  that permit flow across the coupling in the annulus between the tubes  44 ,  46 . The O-ring seals  48   a,b  provide for continuity of flow in the tubes passageways  42 , 44 ,  46  between adjacent drill rods  36   a,b , thereby facilitating the transfer of the material and fluid from the raise drill  18  to the reamer assembly  16 . It is recognised that other forms of seals  48   a,b  other than O-rings could be used for the passageways  42 ,  44 , if desired.  
         [0033]    A particular form oil rod  36  used in the body of the string  12  is shown in FIG. 4. It is conventional to use a ribbed stabilized rod, as shown in FIG. 5 periodically in the drill string  12  and the liner  40  may be incorporated within such a rod. As shown in FIG. 5, the stabilizer rod  36   a  has an internal cavity  23  to receive the liner  40  but the casing  37  has ribs providing a greater bending strength and guidance of the string  12  within the pilot bore  20 .  
         [0034]    The tubes  42 ,  44 ,  46  are connected to respective material supplies within the drill unit  18  as shown more fully in FIGS. 6 and 7. The drill unit  18  includes a drive head generally indicated  60  to which the drill string  12  is connected, The drive head  60  is supported on the drill unit  18  for movement along the axis of the rod  12  in a conventional manner to allow the coupling and uncoupling of the rod  36  to the drill string  12  as required. The drive head  60  includes a support casing  62  secured to the frame of the drill unit  18 . A motor  64  is located on the casing  62  and drives a gear train  66 . The gear train is connected to a drive shaft  68  that extends through the casing  62  and is supported by a pair of bearings  70 . An adapter  72  is bolted to the lower end of the drive shaft  68  and has a configuration corresponding to the male end  38  of a drill rod  36 .  
         [0035]    The opposite end of the drive shaft  68  is connected to a hub  74  of a rotary seal assembly  76  with a carrier stationary  78  of the seal assembly  76  secured to the casing  62 . A central bore  80  extends through the drive shaft  68  and carries a tube  82 . The tube  82  is connected to the hub  74  in alignment with a feed cavity  84  that is in communication with a gravity fed hopper (not shown). The tube  82  defines an outer annulus  86  between the tube  82  and bore  80  that is in communication with an internal passage  88  extending through the hub. The passage  88  is aligned with a supply passage  90  in the carrier  78 . A pair of slip seals  92  are axially spaced on opposite sides of the passage  88  to permit rotation between the hub and carrier.  
         [0036]    An inner conduit  94  extends through the tube  82  and is connected to a supply line  96  within the hub  74 . The line  96  is axially aligned with a supply passage  98  in the carrier with seals  100  axially spaced on opposite sides of the passage  98  to permit relative rotation between the carrier  78  and hub  74 .  
         [0037]    The arrangement of the shaft  68  and carrier  78  permits three fluid supplies to be introduced independently through the stationary carrier  78  through passages  84 ,  90 , and  98  for connection with the tubes  42 ,  44 ,  46 , in the drill rods  36 . The connection to the drill rod  36  is provided by the adaptor  72 .  
         [0038]    The adaptor  72  has a base  102  and a nose  104  projecting from the base. The outer diameter of the nose  104  is dimensioned to be a close fit within the sleeve  37  of the liner  40  and to be sealed by the O-ring  48   b . The nose  104  has an inner cone  106  that is similarly dimensioned to fit within the female-female sleeve  53  and internal passageways  108  on a land  110  are aligned with the annulus formed between the tube  44  and tube  46 .  
         [0039]    The inner conduit  94  extends through the nose  104  and has a sleeve  112  at its lower end to receive the upper end of tube  42 . There is thus a fluid connection through the carder  78  to the passageways in the liner  40 .  
         [0040]    The drill rod  36  is secured to the shaft  68  by means of the coupler  51 . The coupler  51  has a female threaded portion  112  to receive the male threaded end of the rod  36  and an outer spline  114  that is received in an internal socket  116  on the shaft  68 . The coupling  51  is secured by a retainer ring  117  and permits limited axial float relative to the drive shaft for secure connection of the adaptor  72  to the rod  36 . It will be apparent that as the drive shaft  68  is rotated by the motor  64 , the torque is transmitted to the rod  36  through the coupling  51 . The tubes within the shaft  68  rotate with it and switch the slip coupling between the carrier  78  and hub  74  allowing the transfer of fluids between the stationary and rotating portions.  
         [0041]    A tool  13  is connected at the opposite end of the drill string  12  and may either be a conventional drill bit for drilling the pilot hole or a reamer assembly  14  as shown in FIGS. 8 and 9.  
         [0042]    Referring firstly to FIG. 8, the reamer assembly  14  has a main body  120  equipped with cutting teeth  122  with a drive shaft  124  extending from the body  120 . The drive shift  124  is configured to be connected to the lower end of a drive rod  36 , typically the stabilizer drive rod  36   a  and includes an internal liner  40  corresponding functionally to the liner  40  found in the drill rods  36 . A spreader assembly  16  is secured to the underside of the body  120 .  
         [0043]    The spreader assembly  16  includes an outer housing  126  depending from the underside of the body  120  with a mounting plate  128  spaced from the underside of the body  120 . The fluid motor  30  is supported on the plate  128  with a drive shaft  132  connected to the motor  30  and, supported in a bearing  134 . The shaft  132  extends through the bearing  134  aid is connected to a spinner plate  136 . The spinner plate  136  has a frusto conical shield  138  extending inwardly and upwardly toward the body  120  with fins  140  spaced circumferentially around the periphery of the plate  136 . The motor  130  is as operable to rotate the plate  128  relative to the body  120  and impart a radial force on material deposited on the plate. The fins may be linear or, preferably curved rearwardly, to assist in the radial flow of material.  
         [0044]    A terminal block  142  is located within the housing  142  to separate the fluid flows delivered through the liner  40 . The terminal block  142  has a radial passage  144  that extends into a central cavity  146 . The tube  46  terminates within the cavity  146  with the tube  44  extending across the cavity to be sealed within the block  142 . Accordingly, fluid in the annulus between the tubes  44  and  46  flows through the radial passage  144  and is conveyed by flexible pipe  148  to the motor  30 . A primary reservoir  150  is formed within an end cap  152  of the terminal block  142  and the tube  44  opens into the reservoir  150 . The tube  42  extends through the reservoir  150  into a secondary reservoir  154  so that fluid supplied through the tube  44  is received in the reservoir  150  and fluid supplied through the tube  42  is received in the reservoir  154 .  
         [0045]    A set of transfer pipes  156  are connected to the primary reservoir  150  and extend downwardly past the motor  30  to terminal adjacent the shield  138 . Typically, four transfer pipes  156  are provided although, it will of course be appreciated that more or less transfer pipes may be used according to particular design constraints. A second set of transfer pipes  158  are connected to the secondary reservoir  154  and terminate adjacent the termination of the transfer pipes  156 . The supply of fluid to the tubes  42 ,  44 ,  46  through the hub  74  is determined according to the mode of operation of the apparatus  12 .  
         [0046]    In operation of the apparatus  10 , during drilling of the pilot hole  20 , drilling fluid is supplied to the cavity  84  and bore  80  in the hub  74  and is directed through the tube  82  and into the tube  44 . The drilling fluid is thus delivered to the drill bit for flushing and returned to the drill unit  18  around the casing  37  in the normal manner. Once the pilot hole  20  has been made, pilot drill bit (not shown) and roller stabilizers (if used) are removed and the reamer  17  is affixed to the lower end of the drill string  12  while in the pilot hole  20 . The reamer  17  is then placed at the bottom of the pilot hole  20  adjacent to the rock face. The spreader wheel assembly  16  is now connected to the underside of the reamer head  17 , and reaming begins as the raise drill I  8  rotates the drive shalt  58  and simultaneously the coupled drill string  12  and reamer bead  14 . Teeth.  122  on the reamer head  17  cut into the rock face and expands the pilot hole  20  to the larger diameter of bore hole  22 . After a certain distance, reaming is halted, the reaming assembly  14  is lowered. A supply of shotcrete is connected to the tube  82  and shotcrete is pumped through the tube  44  into the reservoir  150 . Simultaneously, the passage  88  is connected to a supply of additive, such as an accelerator, for supply through the tube  42  to the secondary reservoir  154 . A source of compressed air is connected to passage  98  which is supplied through the tube  46  to the motor  30 . The supply of compressed air or other drive fluid, causes the plate  136  to rotate. Shotcrete and accelerator is delivered by respective transfer pipes  156 ,  158  to the spinning plate  136  which sprays shotcrete onto the recently created bore hole  22  wall to produce the lined bore hole  25 . As the plate  136  rotates, the coupled reamer assembly is raised at a predetermined rate to apply a specified thickness of shotcrete to the wall of the bore hole  22 . The proximity of the delivery of accelerator to the shotcrete facilitates rapid solidification of the lining.  
         [0047]    When the reamer assembly  14  is again flush with the rock face of the top of the borehole  22 , pumping of shoterete is halted, and water is then pumped through the tube  44  in the rod  36 . The spreader assembly  16  and the passageway  42  are thus flushed clean with water, It should be noted the shoterete on the bore hole wall  26  should be sufficiently set before flushing the spreader assembly. The reamer head  14  is then raised to contact the rock face, and reaming is continued. The sequential process of reaming and lining is repeated until the lined bore hole  25  is completed. As the reamer head  14  is raised by each drill rod  36  length, the drill string  12  is wrenched in order to remove the topmost drill rod  36  and then the reaming process is continued.  
         [0048]    It is noted that prior to set up of the reamer head  14  and drill string  12  to the raised drill  18 , the drill rods  36  and reamer core are lined with the liner  40 . The liner  40  can also fit reasonably tight inside the passage  23  of the drill rod  36  to help prevent the liner  40  falling out during transport. Further, the combined liner  40  and drilling apparatus  10  helps to reduce the amount of equipment required and thereby facilitates a reduction in time in the creation of a borehole  22 . This system  10  enables reinforcement to be provided to the wall of the borehole  22  immediately behind the reamer head  14 .  
         [0049]    It will also be appreciated that during the lining process the reamer may rotate or be stationary. The motor  30  provides independent rotation of the plate  136  at a higher rate than usually associated with the reamer, thereby facilitating depositing of the shotcrete on the borehole  22  to form the liner.  
         [0050]    Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the claims appended hereto,