Abstract:
An earth boring apparatus for sinking shafts and removing shaft material from the shaft, the apparatus having at least two decks; hydraulic means for allowing movement of the decks relative to one another; releasable anchoring means associated with the decks for engaging walls of the shaft to secure the apparatus in a stationary position; whereby the releasable anchoring means of one of the decks engages the wall while the releasable anchoring means of the other deck is released from the wall to allow motion of the other deck along the shaft, in cooperation with the hydraulic means. The apparatus also includes guide means for forcing a bucket for hoisting shaft material from the shaft along a predetermined path and an in-stage cut-boom drill.

Description:
[0001]     This application claims priority from U.S. application Ser. No. 60/523,319 filed on Nov. 20, 2003. 
     
    
     BACKGROUND OF THE INVEITON  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to earth boring systems.  
         [0004]     2. Description of the Prior Art  
         [0005]     Earth boring systems are used for sinking shafts, and such systems typically use large unitary stages suspended by cables and moved by one or more winches. A stage is generally a multi-decked apparatus with platforms to hold equipment, supplies or workers.  
         [0006]     The process of sinking shafts involves the steps of drilling a hole from the stage, placing an explosive charge in the hole and then detonating the charge. The resultant broken rock is removed with a bucket system, and thereafter the process is repeated. The shaft wall is often reinforced with a lining to minimize the chances of the shaft caving in, this step is performed from the stage.  
         [0007]     The stage is moved to various positions along the shaft by a winch and cables. This process is labour intensive and dangerous work and the winch, sheaves and cable require careful and continuous monitoring and maintenance.  
         [0008]     Other drawbacks are that the stage is subject to bounce from cable stretch, which leads to costly and time consuming process of doubling down cable procedure, difficulty and expense of periodic rope inspection and the depth restriction of cables for stages due to cable safety factors.  
       SUMMARY OF THE INVENTION  
       [0009]     In one of its aspects the present invention provides an earth boring apparatus, the apparatus includes: 
        at least two decks;     extensible drive members for allowing movement of one of the decks relative to the other;     releasable anchors associated with respective ones of the decks for engaging walls of the shaft to secure the apparatus in a stationary position;     whereby the releasable anchors means of one of the decks engages the wall while the releasable anchors of the other of the decks is released from the wall to allow motion of the other deck along the shaft, under control of said drive members.        
 
         [0014]     In another of its aspects the present invention provides a stage having openings and guides for a bucket used for hoisting shaft material, the bucket is coupled to a bucket crosshead having permanent guide means which force the buckets along a predetermined path through the decks. The bucket crosshead is also equipped with temporary guide means on a frame at right angles to the regular permanent guide means, such that the crosshead can be transferred between the permanent guides and the temporary guides. Advantageously, by using the temporary guides, the crosshead can descend through the stage at increased speeds, such as 360 feet per minute, rather than the creep speed of 120 feet per minute, until the crosshead is finally chaired at a bottom deck of the lower stage.  
         [0015]     Advantageously, once the stage has been introduced into shaft, generally by cables and winches, subsequent movement up and down the shaft is achieved using hydraulic means and anchoring means, such that the stage is self-driven. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     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:  
         [0017]      FIG. 1  is a view of an earth boring apparatus in use within a shaft;  
         [0018]      FIG. 2  is aside view of the earth boring apparatus;  
         [0019]      FIG. 3  is a font view of the earth boring apparatus;  
         [0020]      FIG. 4   a  is an exploded view of an equipping deck;  
         [0021]      FIG. 4   b  is an exploded isometric view of the equipping deck;  
         [0022]      FIG. 4   c  is a top view of the equipping deck;  
         [0023]      FIG. 4   d  is a plan view of a top deck;  
         [0024]      FIG. 4   e  is a plan view of a stage deck;  
         [0025]      FIG. 5  is an exploded view of a stage in the shaft;  
         [0026]      FIG. 6  is a view of the bottom deck;  
         [0027]      FIG. 7  is an exploded view of a chaired crosshead;  
         [0028]      FIG. 8  is a view of the bottom section of the stage with a drill jumbo;  
         [0029]      FIG. 9  is view of a chairing leg;  
         [0030]      FIG. 10  is a view of a bucket well;  
         [0031]      FIG. 11  is a side elevation view of a cut-boom;  
         [0032]      FIG. 12   a  is a view of the apparatus in operation;  
         [0033]      FIG. 12   b  is another view of the apparatus in operation;  
         [0034]      FIG. 12   c  is another view of the apparatus in operation;  
         [0035]      FIG. 12   d  is another view of the apparatus in operation;  
         [0036]      FIG. 13   a  is another view of the apparatus in operation;  
         [0037]      FIG. 13   b  is another view of the apparatus in operation;  
         [0038]      FIG. 14   a  is another view of the apparatus in operation;  
         [0039]      FIG. 14   b  is another view of the apparatus in operation;  
         [0040]      FIG. 15  is another view of the apparatus in operation;  
         [0041]      FIG. 16  is a section of the earth boring apparatus shown in  FIG. 1 ;  
         [0042]      FIG. 17  is a view similar to  FIG. 16  in an alternative configuration; and  
         [0043]      FIG. 18  is an enlarged view of a component used in the apparatus of  FIG. 16 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0044]     Referring to FIGS.  1  to  10 , there is shown an earth boring apparatus  10 , in a preferred embodiment. The earth boring apparatus  10  is used for excavating from the surface of an opening in the earth. Generally, the earth boring apparatus  10  operates within a shaft  12  which has reinforced walls  14  to minimize the possibility of the shaft  12  from caving in. The walls  14  are reinforced with friction rock stabilizers which include bolts that tighten and exert pressure against the rock wall  14  should lateral rock displacement occur and are lined with concrete to enhance stability. The earth boring apparatus  10  includes a stage  15  having a plurality of decks, such as  16 ,  18 ,  20 ,  22 ,  24  and  26 . The stage  15  includes an upper portion  15   a  with an equipping deck  16 , and a lower portion  15   b  having a top deck  18  and other decks  20 ,  22 ,  24  and  26 . The decks  16 - 26  are constructed from structural steel components, or other materials exhibiting suitable strength and durability and support service equipment such as power supplies, as well as excavating equipment. After the location of the proposed shaft  12  has been chosen and the shaft collar has been developed, the stage  15  is then lowered into the shaft  12  with sheaves, winches and cables which allow the stage  15  to be suspended from the surface prior to chairing within the shaft  12 . The stage  15  is chaired within the shaft  12  by retractable chairing means  28  or anchoring means which engage recessed pockets  30  spaced along the depth of the shaft  12  at predetermined distances as describe more fully with reference to  FIG. 18  below.  
         [0045]     The upper stage portion  15  has a structural ring  17  that supports the equipping deck  16 . The equipping deck  16  provides a platform to hold supplies such as concrete, steel for lining the shaft  12 , or shaft sinking personnel. The lower stage portion  15   b  is formed as a cylindrical framework with the decks  18 - 26  spaced apart from each other by fixed distances. A set of hydraulic cylinders, typically 3, are circumferentially spaced and extend between the upper stage portion  15   a  and lower stage portion  15   b.  The cylinders are telescopic and control movement between the equipping deck  16  and the top deck  18 . Anchoring means  28  are provided at spaced intervals on the equipping deck  16  and the top deck  18  as shown in  FIG. 18 . Each of the anchoring means  28  includes a leg  100  pivotally secured by a pin  102  to the respective deck  16 ,  18 . A link  104  from the leg  100  to a leg operating cylinder  106  that can extend and retract to cause pivotal movement of the leg  100 . In its extended position, the leg  100  radially beyond the deck  16 ,  18  to engage a pocket  110  formed in the wall  14  of the shaft  12 .  
         [0046]     At any given moment the stage  15  is anchored by chairing legs  100  equipping deck or the top deck. The stroke of the cylinders  34  permit the lower stage  15   b  to be moveable from zero to sixty feet from the equipping deck  16  using hydraulic lifting devices  34 . By sequenced operation, the stage  15  “walks” up and down the shaft  12  to permit progressive excavation  
         [0047]     In a rest position with both sets of chairing means  28  and the top extended and engaging the respective chairing pocket in the shaft wall  14  so as to securely locate the stage  15 . To lower the lower portion  15   b,  the top deck chairing legs  100  are then released to a retracted position away from the chairing pocket  30  and clear of the shaft wall  14 . Using the telescoping hydraulic cylinders  34 , the lower stage  15   b  is caused to move relative to the stationary equipping deck  16 . Similarly, the equipping deck  16  can be moved relative to the lower stage  15   b  by maintaining the lower stage  15   b  in a stationary position via the engagement of the top deck chairing legs  100  with the chairing pocket  30 , while the equipping deck chairing legs  100  are released. Advantageously, the stage  15  can “walk” up and down using the chairing legs  100  and the telescoping hydraulic cylinder  34 .  
         [0048]     The lack of cables also provides for less clutter and less congestion on the decks  16 - 26  and thus provides greater flexibility of movement for the shaft personnel. Another advantage of the separable decks  16 - 26  is that there is no requirement to move the whole stage  15  away from the blast site, as only the lower stage  15   b  needs to have sufficient clearance of the blast site, while the remaining equipping deck  16  is stationary. Therefore, it is more efficient to move a portion of stage  15 , relative to the equipping deck  16  as the drilling/blasting and mucking continues.  
         [0049]     As maybe seen in  FIGS. 4   c,    7  and  10 , the stage  15  is configured to accommodate a variety of excavation equipment. The decks  16 - 26  are configured to allow the equipment to pass through the stage  15  as required and each deck may be configured to support a particular piece of equipment or function. Accordingly, each of the decks has a pair of bucket wells  37  that permit movement of buckets through the stage  15 . As shown, this includes bucket crossheads  38  for providing guide means for forcing a bucket  32  carrying shaft materials along a predetermined and predicted path up and down the shaft  12 . The crossheads  38  include permanent guide shoes  40  adjacent to permanent guides  42 . The permanent guides  42  are typically constructed of wood or structural steel shapes such as hollow structural sections, and fastened to a structural steel backer  43 . Substantially perpendicular to the permanent guides shoes  40  are temporary guide roller shoes  44  which engage temporary guides  46 . The crossheads  38  can thus be transferred between the permanent guides  42  and the temporary guides  46 . Advantageously, by using the temporary guides  46 , the crossheads  38  can descend through the stage  15  at increased speeds, such as 360 feet per minute, rather than the creep speed of 120 feet per minute, until the crossheads  38  are finally chaired at a bottom deck  26 .  
         [0050]     The temporary guides  46  are constructed from threaded heavy wall tubing that are anchored on the deck  16  and hang freely down and inside the bucket wells  45  of the main stage  15 . The temporary guides  46  are threaded through sleeves in the well  45  at the bottom deck  26 . When the stage  15  is raised the temporary guides  46  extend into the blast damage zone. However, the temporary guides  46  are positioned above the concrete forms to substantially diminish chances of damage by fly rock. Advantageously, if a temporary guide  46  is damaged during blasting another tube can easily be threaded in its place.  
         [0051]     As stated above, the process of sinking shafts involves the step of drilling holes for placement of explosive charges. For this step, the drill jumbos  35  are lowered to drill into the bottom of the shaft  12  by making a cut comprising a hole or group of holes drilled in the centre of the shaft excavation which serve to weaken the formation. The charges are then placed in the cut such that the outside circumference of the shaft  12  implodes rather than explodes and thus he cut prevents expansion of the shaft diameter beyond a predetermined diameter. Genially, the number, pattern and size of these holes is determine by qualified personnel based on a plurality of factors, such as composition of the rock depth, shaft diameter, and so forth.  
         [0052]     Looking at  FIG. 11 , the drilling jumbo  35  includes a cut-boom drill  48  having mounting beams  50  affixed to the lower stage  15   b,  on the underside centre line of the two lower decks  24 ,  26 . A feed rail assembly  52  moves firm side to side hydraulically on a slide arrangements affixed to the beams  50  and feed rail  52 . The cut boom drill  48  can be removed between a positron with the lower stage  15   b  to another position beyond the deck  26  via the feed rail assembly. Thus, the feed rail  52  moves up and down on a slide arrangement using a roller chain, sprockets and a hydraulic motor  56 . The feed rail  52  is stroked down until a stinger  54  contacts the shaft face securely. A drill bit  58  and length of rod  60  is threaded into the drive output and the “cut” is drilled off.  
         [0053]     To facilitate removal of blast rock, a pair of mucking machines  36  are located on the lower stage  15   b.  The mucking machine  36  is slidably supported on the top deck  18  and can be lowered beyond the end of the bottom deck stage for loading spoil.  
         [0054]     The operation of the earth boring apparatus  10  will now be described by looking at FIGS.  6  to  15 . In  FIG. 12   a  the equipping deck  16  and the lower stage  15   b  are both chaired at a maximum extension of the cylinders  34 , with the bottom deck  26  positioned at a sufficient distance from the bottom of the shaft  12  to allow personnel to work, drill and lay charges.  FIG. 12   b  shows the mucking machine  36  lowered to transfer the muck from the bottom of the shaft  12  into the bucket  32  which can then be removed through the stage  15  and along the shaft, With the spoil removed, the upper portion  15   a  and equipping deck  16  is lowered ( FIG. 12   c ) by retracing the legs  100  of upper deck  16 . The cylinders are lowered to advance the deck  16  towards the chaired top deck  18 . The equipping deck  16  comes to rest and is anchored at a predetermined distance from the top deck  18  while the lower stage  15   b  is chaired. In this position, it will be noted that the temporary guides  46  project below the bottom deck  26 .  
         [0055]     In  FIG. 12   d , the top deck chairing legs  100  are removed from the chairing pockets  30  and the lower stage  15   b  is lowered while the equipping deck  16  is chaired. After final positioning, the top deck  18  is chaired so that the bottom stage  15   b  is secured in the shaft in a configuration similar to  FIG. 12   a  but lower. With the stage lowered, the wall  14  may be worked upon from the bottom deck  26 . In  FIG. 13   a  the equipping deck  16  and the lower stage  15   b  are both chaired while the curb forms are lowered including the A/ring and main forms, concrete, steel and other supplies. In this position the personnel can pour concrete or spray concrete onto the shaft walls  14  in order to reinforce the shaft walls  14  and define the chair pockets.  
         [0056]     As shown in  FIG. 14   a,  the drill jumbos  35  are lowered to drill into the bottom of the shaft  12  and lay charges in the drilled holes. With the equipping deck  16  chaired, the lower stage  15   b  is subsequently raised and chaired at a clearance distance from the blast area, in  FIG. 14   b,  to allow for blasting by ignition to explode and loosen the rock material in  FIG. 15 . Once again the lower stage  15   b  is lowered and mucking and removal of muck begins, as described above. This process may be repeated several times depending on the desired results of the shaft mining or productivity requirements.  
         [0057]     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.