CN114651109A

CN114651109A - Method and apparatus for drilling and positioning an orifice support sleeve into a blast hole

Info

Publication number: CN114651109A
Application number: CN202080077671.1A
Authority: CN
Inventors: G·帕钦
Original assignee: Aquarian Technologies
Current assignee: Aquarian Technologies
Priority date: 2019-10-30
Filing date: 2020-10-29
Publication date: 2022-06-21
Also published as: EP4051860A4; BR112022008153A2; ZA202204990B; MX2022004998A; AU2020373299A1; WO2021081592A1; CA3158178A1; CL2022000977A1; CO2022006420A2; EP4051860A1; US20240102363A1

Abstract

The present invention provides an apparatus and method for preventing surrounding loose rock fragments from falling or collapsing into a borehole during drilling and immediately upon removal of a drill string from the borehole. The apparatus comprises a borehole casing for a drilling tool, the casing comprising a tubular member adapted to be coupled to a mast of a movable drilling tool and positioned in an aperture region of a borehole, the tubular member comprising a longitudinal internal passage for receiving a drill string therethrough, and an outer surface for facing outwardly against a wall of the borehole.

Description

Method and apparatus for drilling and positioning an orifice support sleeve into a blast hole

Technical Field

The present invention relates to the field of drilling and boring, particularly but not exclusively blasting operations for mining and quarrying.

Background

At the surface, methods of surface mining minerals may involve explosive blasting to remove large quantities of ore for excavation and recovery. Step blasting is a process that involves drilling a hole into rock to a depth of 50 meters or more and filling the hole with explosive material to form a cylindrical charge that fractures the rock in a controlled manner. The diameter of the blast hole may be as large as 270 to 311 or even as high as 350 mm.

Typically blast holes are drilled using percussive drilling techniques. Impact energy is generated by a reciprocating piston, where each piston strike causes carbide buttons in the bit to penetrate the rock. The drill string is rotated after each impact to turn the drill bit to a new position so that the buttons strike a new rock surface. Top hammer impact drilling is the case where impact energy is applied to the upper end of the drill string by a piston. Down-the-hole percussive (DTH) drilling is a condition where impact energy is applied by a piston to the lower portion of the drill string, just above the drill bit. Top hammer drilling is typically used to drill relatively small diameter holes whereas DTH drilling is typically used to drill larger diameter holes.

Rotary drilling is another technique for drilling blast holes. Rotary drilling does not use percussion. Instead, rotary drilling applies a feed force and a rotational torque. The torque causes the drill bit to rotate while the feed force keeps the drill bit firmly against the rock surface. The combination of the rotational torque and the feed force enables the drill bit to penetrate rock by cutting into the rock surface.

Most of the broken rock after the blasting operation is removed by the excavator for further treatment. However, a large amount of loose rock fragments, or "pre-conditioned" material, from the sub-drilled area after reaching the lowered height (RL) may remain on the step at the location where the blast hole is drilled for subsequent blasting operations. Pretreatment layers up to a depth of 4 meters or more can increase the efficiency of the comminution process by maximizing the amount of fine fragmentation that can occur from subsequent blasting operations.

Loose rock fragments from the pretreatment layer around the blast hole, commonly referred to as the "collaar" region of the blast hole, can collapse into the blast hole after drilling. Applicant's patent application WO2019014716 discloses an orifice support apparatus for preventing loose rock fragments from falling or collapsing into a blast hole. The apparatus includes a generally planar flexible sheet formed into a curved form to define a longitudinal channel and then inserted into the open end of the blast hole. The bent sheet material faces closely to the inner surface of the blast hole and forms a barrier that prevents surrounding loose rock fragments from falling or collapsing into the open end of the blast hole.

However, even during or after drilling, and before the aperture support apparatus is positioned in place, surrounding loose rock fragments may collapse into the borehole. Therefore, there is a need for a drilling system to minimize any possibility of loose rock fragments from the pretreatment layer collapsing into the borehole.

Also, the process of manually manipulating the preformed orifice support device and inserting the orifice support device into the borehole can be time consuming and labor intensive. Accordingly, there is a need for a drilling system whereby the orifice support device can be positioned in the borehole and which is time and labor efficient.

Any discussion of the background art throughout the specification should in no way be considered as an admission that any document or material referred to was published, known or part of the common general knowledge.

Disclosure of Invention

Accordingly, in one aspect, the present invention provides a borehole casing apparatus for a borehole drilling tool, the casing apparatus comprising a tubular member adapted to be coupled to a mast of a movable borehole drilling tool and positioned within an aperture region of a borehole, the tubular member comprising a longitudinal inner passage for receiving a drill string therethrough, and an outer surface for facing outwardly against a borehole wall.

Preferably, the pipe member and the mast comprise couplings for fixing the pipe member to the mast.

Preferably, the coupling is adapted for releasably securing the pipe member to the mast.

Preferably, the coupling is adapted to allow movement of the pipe member relative to the mast between a position in which the pipe member is aligned with the axis of the drill string and another position in which the pipe member is offset from the axis of the drill string, while the pipe member and mast remain coupled together.

Preferably, the coupling comprises a slot mount coupling.

Preferably, the coupling comprises an adapter secured to the mast, the adapter comprising a slot for receiving a flange at an end of the tubular member.

Preferably, the slot is defined between a pair of opposed plates, the direction of which, in use, is oriented substantially parallel to the step surface.

Preferably, the flange is adapted to enter and exit the slot with horizontal movement of the adapter relative to the tubular member.

Preferably, the flange is adapted to move in the slot between a position in which the tubular member is aligned with the axis of the drill string and another position in which the tubular member is offset from the axis of the drill string.

Preferably, the flange is a substantially planar member secured to one end of the tubular member. Preferably, the flange has a polygonal shape. Preferably, the flange has opposed tapered edges providing a narrower width at one end of the flange for guiding the flange into the slot.

Preferably, each of the plates of the pair includes an opening, preferably centrally located, for receiving a drill string therethrough and for aligning with the longitudinal interior passage of the tubular member.

Preferably, the opening through the lower one of the plates is open to one side of the plate for receiving the tube member therein.

Preferably one or more projections extend from the flange for engaging the step surface and maintaining a gap between the flange and the step surface. Preferably, the projections extending from the flange are adapted to engage the step surface and support a mast thereon. Preferably, the projection is adapted to keep the flange proud of the step surface to allow one of the plates of the adapter to be placed between the flange and the step surface.

Preferably, the tubular member is adapted to be self-supporting in the bore of the bore so as to receive the bore support apparatus within the longitudinal internal passage.

Preferably, the tubular member includes a rigid, cylindrical body portion having openings at opposite ends and a longitudinal internal passage extending therebetween.

In a preferred embodiment, the tube member is self-supporting and one end of the longitudinal internal passage is located at the level of the step surface.

In another aspect, the present invention provides a drilling apparatus comprising:

the movable platform can move along the direction of the platform,

a mast, placed on the platform, comprising a support for the drill string;

a drill string rotary drive mechanism for driving the drill string to drill a hole in the rock;

a borehole casing apparatus comprising a tubular member coupled to a mast for positioning in an aperture region of a borehole, the tubular member comprising a longitudinal internal passage for receiving a drill string therethrough, and an outer surface for facing outwardly against a wall of the borehole.

In an embodiment, the pipe member is movable between a position in which the pipe member is aligned with an axis of the drill string and another position in which the pipe member is offset from the axis of the drill string while remaining coupled to the mast. These embodiments are particularly, but not exclusively, suitable for use with smaller surface drilling platforms typically used for drilling boreholes having diameters between about 89 and 165 millimeters, commonly referred to as "track-type rigs".

In an embodiment, the tubular member is axially movable while remaining coupled to the mast to lower the tubular member into the borehole and to raise the tubular member out of the borehole. Preferably, the borehole casing apparatus includes a hydraulic drive to translate, e.g., raise or lower, the tubular member axially relative to the borehole. These embodiments are particularly, but not exclusively, suitable for use with larger surface drilling platforms, commonly referred to as "platform rigs", typically used for drilling boreholes having diameters between about 165 and 351 millimeters.

In an embodiment, the drilling apparatus further comprises a sheet deployment apparatus for deploying the flexible sheet in the open end of the tubular member located in the borehole.

In an embodiment, the sheet deployment apparatus comprises a sheet forming apparatus adapted to form a planar flexible sheet into a curved form and to feed the curved sheet to an open end of a tube member located in the bore hole.

Preferably, the forming apparatus comprises a wide mouth inlet and tapering to a narrower circular outlet to define a path for the flexible sheet material, and a feed mechanism for feeding the flexible sheet material through the inlet and the circular outlet into the tube member.

Preferably, the drilling apparatus comprises a store of a plurality of flexible sheets and a picker adapted to pick up one sheet at a time. The flexible sheet may be planar and arranged in a stack, or the flexible sheet may be a pre-rolled sheet and include ties to hold each pre-rolled sheet in a roll. In an embodiment, the deployment device is adapted to pick up one of the pre-rolled sheets and feed the pre-rolled sheet through the tube member into the bore hole.

Preferably, the drilling apparatus further comprises a shroud adapted to securely seal against the longitudinal internal passage of the tubular member for guiding cuttings (cuttings) and/or bails (bailings) emerging from the borehole during drilling.

Preferably, the shroud includes an axial passage for receiving the drill string therethrough and a discharge port positioned transverse to the axial passage.

Preferably, the discharge opening is adapted to be coupled to a flexible conduit of a vacuum device.

Preferably, the shroud is mounted to the mast and the drive is adapted to translate the shroud up and down within a range of linear motion.

Preferably, the drilling apparatus further comprises an outlet located proximate to or below the movable platform for directing cuttings and/or bails emerging from the borehole during drilling to a pile adjacent to or below the movable platform.

Embodiments of the drilling apparatus include various types of movable drilling apparatus including a movable tracked platform including a drill tool mast supporting a drill string and an accompanying percussive rotary air blast drilling apparatus. In some embodiments, such mobile drilling equipment includes smaller surface drilling platforms typically used for drilling boreholes between about 89 and 165 millimeters in diameter, commonly referred to as "track-type rigs," and are produced by manufacturers such as Sandvik, Epiroc, Komatsu, and Caterpillar. In other embodiments, such mobile drilling equipment includes large surface drilling platforms typically used for drilling boreholes between about 165 and 351 millimeters in diameter, commonly referred to as "platform rigs," and are produced by manufacturers such as Sandvik, Epiroc, Komatsu, and Caterpillar.

When implemented in such larger movable drilling platforms, such as those typically used for drilling large diameter boreholes of 165 to 351 millimeters, embodiments of the drilling apparatus that include a shroud for guiding cuttings and/or bails that occur from the borehole during drilling are advantageous. Such existing drilling platforms may include cuttings and/or bailing management systems, including simply surrounding the borehole with a flexible curtain attached to and hanging from beneath the platform. Embodiments of the present invention may replace or supplement such existing systems.

In an embodiment, the drilling apparatus comprises a system for injecting a composition between the outer surface of the tubular member and the surrounding wall of the borehole.

Preferably, the system for injecting the composition comprises a reservoir of the composition, coupled to a network of conduits and openings formed in the tubular member. Thus, when the tubular member is placed in the borehole, the composition escapes through the openings and into the space between the tubular member and the borehole or penetrates surrounding loose rock fragments or both.

In another aspect, the present invention provides a method of drilling, comprising:

coupling a tubular member to a mast of a mobile drilling rig, the tubular member including a longitudinal internal passage for receiving a drill string therethrough;

drilling a hole in the stepped surface and lowering a tubular member to an orifice region of the hole, the tubular member including an outer surface facing outwardly against a wall of the hole.

In another aspect, the present invention provides a method of providing an orifice-support device into a borehole, the method comprising:

drilling a hole in the stepped surface and lowering a tubular member into the orifice region of the hole, the tubular member including an outer surface facing outwardly against the wall of the hole;

providing support in the borehole for stabilizing the orifice region of the borehole; and

the tubular member is removed from the borehole.

Preferably, providing support within the bore comprises inserting an orifice support device comprising a sheet of flexible material into the longitudinal internal passage of the tubular member, and wherein removing the tubular member from the bore leaves the orifice support device within the bore.

Preferably, moving the mast relative to the pipe member comprises moving the mast between a position in which the pipe member is aligned with the axis of the drill string and another position in which the pipe member is offset from the axis of the drill string while the pipe member and the mast remain coupled together.

Preferably, removing the tubular member from the borehole includes manipulating the mast to raise the tubular member out of the borehole.

Preferably, coupling the pipe member to the mast comprises horizontally translating the mast relative to the pipe member. In an embodiment, decoupling the tube member and the mast also includes horizontally translating the mast relative to the tube member.

Preferably, the adapter secured to the mast includes a slot and the one end of the tube member includes a flange, whereby horizontal movement of the mast relative to the tube member causes the flange to move into or out of the slot.

In an embodiment, providing support in the borehole for stabilizing the orifice region of the borehole comprises injecting a composition between the outer surface of the tubular member and the surrounding wall of the borehole.

In embodiments, the injected composition cures or otherwise hardens or solidifies to become self-supporting or to bind loose rock fragments to form a composite orifice support.

In a further aspect, the present invention provides a sheet forming apparatus adapted to form a flat flexible sheet into a curved form and to feed the curved sheet to a tube member located within an aperture region of a bore, the apparatus comprising:

a forming device adapted to form a flat flexible sheet into a curved form; and

a feed mechanism for feeding the bent sheet material to the tube member located in the aperture area of the bore hole.

Preferably, the forming apparatus comprises a wide mouth inlet and tapers to a narrower circular outlet to define a path for the flexible sheet, wherein the feed mechanism feeds the flexible sheet to the tube member through the inlet and outlet of the forming apparatus.

Preferably, the plurality of flexible sleeves are arranged in a stack, the feed mechanism being configured to pick up one sheet at a time from the stack.

Preferably, the sheet forming apparatus is configured to be attached to a mast of the borehole drilling apparatus.

Drawings

The invention will now be described in more detail with reference to preferred embodiments shown in the accompanying drawings, in which:

FIG. 1 illustrates a perspective view of a tubular member of a borehole casing apparatus according to an embodiment of the present invention;

FIG. 2 is a side view in longitudinal section of the pipe member of FIG. 1;

FIG. 3 shows a perspective view of an adapter of an embodiment of the borehole casing apparatus;

FIG. 4 is a top view of the cross-section of the adapter of FIG. 3;

FIG. 5 is an oblique perspective view of a drilling apparatus including a mobile drill rig having a hydraulic arm and a drilling mast attached thereto, and the adapter of FIGS. 3 and 4 connected to the mast, and the tubular member of FIGS. 1 and 2 coupled to the adapter;

FIG. 6 illustrates a front perspective view of the drilling apparatus of FIG. 5;

fig. 7-14 are a set of elevation views of a portion of the drilling mast and borehole casing apparatus of the embodiments of fig. 1-6 described above, illustrating a series of steps in a method of drilling a borehole according to an embodiment of the invention and in a method of providing an orifice support apparatus into a borehole according to an embodiment of the invention.

Fig. 15 is an elevation view of the orifice support apparatus of fig. 7-14 in a planar configuration;

fig. 16 is a front view of the orifice support apparatus of fig. 7-14 in a curved configuration;

FIG. 17 is an oblique perspective view of a drilling apparatus including a movable drill rig similar to the embodiment of FIG. 5 having a hydraulic arm and a drilling mast attached thereto, and further including a sheet forming apparatus adapted to form a planar flexible sheet into a curved form and feed the curved sheet to an open end of a tubular member located in a borehole;

FIGS. 18 and 19 are a set of front views of a portion of the drilling apparatus of FIG. 17, including a portion of the drilling mast, the sheet forming apparatus and the aperture-supporting apparatus including the bent flexible sheet, and illustrating a series of steps of forming the flat flexible sheet into a bent form and feeding the bent sheet to the open end of the borehole casing apparatus located in the borehole and withdrawing the casing apparatus from the borehole to leave the aperture-supporting apparatus;

FIG. 20 illustrates an embodiment of the drilling apparatus of FIG. 5 further comprising a shroud adapted to securely seal against the longitudinal interior passage of the tubular member for guiding cuttings and/or bailing occurring from the borehole during drilling;

FIG. 21 illustrates an embodiment of the drilling apparatus of FIG. 5, and further comprising a shroud adapted to securely seal against the longitudinal interior passage of the tubular member, wherein the shroud is coupled to the flexible conduit of the vacuum apparatus for guiding cuttings and/or bailing occurring from the borehole during drilling;

figures 22 to 25 show one embodiment of a method of drilling by reference to another embodiment of the drilling apparatus of the present invention comprising a surface drilling platform of the type typically used for drilling large diameter boreholes having a diameter of between about 165 and 351 millimetres, wherein the casing apparatus comprises a hydraulic drive to raise and lower the tubular member axially relative to the borehole, and wherein the hydraulic drive is adapted to raise and lower a shroud relative to the tubular member to direct cuttings and/or bailing occurring from the borehole during drilling;

FIG. 26 illustrates another embodiment of the drilling method and apparatus adapted to pick up one pre-rolled and tied flexible sheet at a time and place the pre-rolled sheet in a tube member within a borehole;

FIG. 27 is a bottom view of the surface drilling platform embodiment of FIGS. 22-26 illustrating the placement of a curtain attached to and depending from beneath the platform to contain cuttings and/or bails guided by the shroud beneath the platform; and

figures 28 to 29 show a further embodiment of a method of stabilising an aperture of a borehole, comprising injecting a stabilising agent into the wall of the borehole or loose rock fragments surrounding the borehole in the region of the aperture.

The invention will now be described in more detail with reference to an embodiment shown in the drawings.

Detailed Description

Blast hole drilling is a technique used to extract mineral and rock products from strip mines and quarries. The drill rig produces a borehole according to a predetermined shape and depth. The hole is then filled with explosives, and the minerals and rocks are blasted and broken up for subsequent removal by an excavator for further processing. A large amount of loose rock fragments, or "pre-conditioned" material, from the ultra-deep drilling zone after reaching the lowered height (RL) may remain on the step. The pretreatment layer having a depth of 4 m or more can improve the efficiency of the pulverizing process by maximizing the volume of fine pulverization generated by the subsequent blasting operation.

Referring to fig. 5 and 6, the present invention is directed to a casing apparatus 100 adapted for use with a drilling rig 10 for drilling a borehole. Referring to fig. 1 to 6 and 9 to 13, the casing device 100 comprises a tubular member 110, the tubular member 110 being adapted to be placed in use within a borehole in a manner to be described in more detail below. The tubular member 110 includes a longitudinal internal passage 120 for receiving a drill string of a drilling rig therethrough. The tubular member 110 also includes an outer surface 125 for facing outwardly against the borehole wall.

The casing apparatus 100, and in particular the tubular member 110, is adapted to support the bore hole 2 during and immediately after drilling and before the bore hole support apparatus can be placed in position within the bore hole of the bore hole 2. In some embodiments, the cannula device 100, and in particular the tube member 110, is adapted to receive an orifice support device therein. The tube member 110 can thus assist in the steps of forming the generally planar orifice supporting device into a curved form and inserting the orifice supporting device into the borehole.

Drilling machine

Fig. 5 and 6 illustrate an exemplary mobile drilling rig 10 for drilling a borehole 2. The illustrated drill 10 is a percussive top hammer type drill. However, it should be understood that the present invention is more broadly applicable to other types of drills, such as down-the-hole (DTH) drills and rotary drills. The embodiment of the mobile drill rig 10 shown in the drawings is a type of surface drilling platform commonly used for drilling boreholes having a diameter of between about 89 and 165 millimeters, commonly referred to as a "track-type drill rig". However, it should be understood that embodiments of aspects of the present invention are also applicable to larger surface drilling platforms of the type typically used for drilling boreholes between about 165 and 351 millimeters in diameter, commonly referred to as "platform rigs". The smaller and larger classes of platforms are well known to originate from many manufacturers, such as Sandvik, Epiroc, Komatsu and Caterpillar, to name a few.

The drilling rig 10 includes a self-propelled vehicle 12 having a hydraulic arm 14 that supports a mast 20. The mast 20 itself is adapted to support a drill string 30 comprising a plurality of drill rods 35 and a drill bit 37 at the end of the drill string 30. The drill rods 35 are coupled together by a threaded connection therebetween.

In one aspect, the present invention relates to a borehole casing apparatus 100 adapted to be coupled to a mast 20 in a manner to be described in greater detail below. In another aspect, the present invention relates to a combination of a mobile drill rig 10 and a borehole casing apparatus 100.

The mast 20 carries a drilling head 25, the drilling head 25 including a reciprocating piston or hammer assembly and a rotation assembly that are collectively adapted to apply an impact force and a rotational torque to the drill string 30. The drill head 25 can be raised and lowered by a hydraulically driven up-and-down feed system 29 to enable pipes or rods to be removed from, or added to, the drill string.

The mast 20 includes a storage portion 27 of a plurality of drill rods 35. During drilling operations, when the top of the uppermost drill rod 35 reaches the bottom of the mast 20, subsequent drill rods 35 are swung into position by the rod feed system 29 and axially aligned with the uppermost mast drill rod 35 of the drill string 37. The drilling head 25 engages and rotates the subsequent drill rod 35 to threadably couple with the top of the drill rod 35 below. Thereafter, the drilling head 20 continues drilling by applying impact forces and rotational torque to the drill string 30.

Borehole casing equipment

As shown in fig. 9 to 13, the casing apparatus 100 comprises a tubular member 110, which tubular member 110 is adapted in use to be placed within a borehole 2 in a process that has been drilled or is being drilled by a drilling rig 10. Preferably, the tubular member 110 is formed of a rigid and durable material such as metal (e.g., low carbon steel). The tube member 110 is configured to be releasably coupled to the bottom of the mast 20. When coupled to the mast 20, the longitudinal inner passage 120 of the tubular member 110 is adapted to be aligned with an axis of the drill string 30 to receive the drill string 30 therethrough.

The outer surface 125 of the tubular member 110 is adapted to face outwardly against the wall of the borehole 2. The diameter of the outer surface 125 of the tubular member 110 is desirably slightly larger, or slightly smaller or approximately equal to the diameter of the drill bit 37. The diameter of the outer surface 125 of the tubular member 110 is desirably slightly larger, or slightly smaller or approximately equal to the diameter of the borehole 2 to be formed thereby. Accordingly, different diameter tubular members 110 may be provided for use with different diameter drill bits 37 and/or different diameter boreholes 2.

In some drilling operations, pretreatment layers up to 4 meters or more in depth may be employed. The portion of the borehole 2 in the pretreatment layer is sometimes referred to as an "aperture". The pretreatment layer comprises crushed rock, is comprised of a wide range of grain sizes including fine, medium, and coarse, and ranges from 1mm to 100mm or more. The borehole casing apparatus 100 is adapted to provide temporary support to the wall of the borehole 2 in the region of the aperture, both during drilling operations and after the borehole has been drilled to a desired depth.

Coupling piece

In another aspect, the present invention relates to a coupling between the mast 20 and the tubular member 110 of the drilling rig 10 for securing the tubular member 110 to the mast 20. As is apparent from the above description, in the embodiments disclosed herein, the coupling is adapted to allow movement of the pipe member 110 relative to the mast 20 between a position in which the pipe member 110 is aligned with the axis of the drill string 30 and another position in which the pipe member 110 is offset from the axis of the drill string 30 while the pipe member 110 remains coupled with the mast 20.

Referring to fig. 1 and 2, the tube member 110 has

openings

112, 114 at opposite ends 111, 113 thereof. A longitudinal channel 120 extends between the

openings

112, 114. At one of the ends, 111, the tube member 110 includes a flange 115 extending radially outward from the edge surrounding the opening 112. The flange 115 comprises a plate that may be welded or otherwise secured or formed as one piece with the end 111 of the tube member 110. The flange 115 is shown as a generally planar member that is secured to the end 111 of the tubular member 110, such as by welding. The flange 115 has a polygonal shape with

opposite sides

117, 118. The opposite side edges comprise parallel edge segments 117a, 118a and tapered

segments

117b, 118 b. The

tapered edge segments

117b, 118b provide a narrower width dimension at one end 119 of the flange 115. In other embodiments, the flange 115 may be circular or partially circular or oval. A boss 116 extends from the lower surface of the flange 115, adapted to engage the surface of the step in use. The raised portion 116 functions to keep the flange 115 spaced above, or raised from, the surface of the step.

Referring to fig. 3 and 4, an adapter 150 is provided, as shown in fig. 5, 6 and 8-14, configured to be secured to the mast 20. Adapter 150 includes a foot pad 155 that in some cases is adapted to engage a step surface to at least partially support and maintain stability of mast 35 during drilling operations. A riser 157 extends upwardly from the foot pad 155 and is adapted to be coupled to an end of the mast 20. The riser 157 may be configured to replace and match the position of the riser for a proprietary foot pad assembly of the mast 20 of the rig 10, such as the proprietary foot pad assembly of fig. 7. In other words, the adapter 150, including the foot pad 155 and the riser 157, is configured to be directly interchangeable with a proprietary foot pad assembly 9 such as that shown in fig. 7. In other embodiments, the adapter 150 is configured without the foot pad 155 or can be configured without the foot pad 155 and the risers 157, but rather is coupled to the risers and foot pads of the proprietary foot pad assembly 9.

The adapter 150 also includes a horizontal slot 160 defined between horizontal upper and

lower plates

164, 174. The slot 160 is closed at laterally

opposite sides

161, 163 and open to an end 162. In an embodiment not shown, the lower plate 174 is everted, however, both the upper plate 164 and the lower plate 174 may or may not be everted at the open ends 162 of the slots 160. The upper and

lower plates

164, 174 are positioned horizontally adjacent to the foot pad 155.

The riser 157 is formed with a vertical upright section 156 and a pair of opposed corner plate sections 158, 159 extending between the upright section and upper and

lower plates

164, 174. The corner plate sections 158, 159 provide structural support and rigidity to the connection between the vertical upright section 156 and the upper and

lower plates

164, 174.

The upper plate 164 and the lower plate 174 each include a

central opening

165, 175, and when coupled to the mast 20, both

central openings

165, 175 are axially aligned with the drill string 30. The corner plate sections 158, 159 are disposed opposite each other and are spaced apart by a distance at least equal to or greater than the diameter of the central opening 165 in the upper plate 164. The central opening 175 of the lower plate 174 is open to the side portion 162 such that the flange 115 can be received in the slot 160 through the opening on the side portion 162 and positioned between the upper and

lower plates

164, 174, and the tube member 110 extends downwardly through the central opening 175 in the lower plate 174, as shown in fig. 4 and 5. The horizontal slot 160 and the flange 115 together provide a slot mount coupling between the tubular member 110 and the adapter 150. It will be appreciated that in some instances, the tube member 110 and the adapter 150, and thus the mast 20, can be releasably coupled by horizontally translating the adapter 150 relative to the tube member 110.

As the adapter 150 moves horizontally relative to the tubular member 110, the lower plate 174 of the adapter 150 is received in the space between the flange 115 and the surface of the step that is retained by the boss 116. Thus, the raised portion 116 raises the flange 115 above the surface of the step to allow the flange 115 to be positioned below and engage the bottom surface of the flange 115.

The tubular member 110 and the adapter 150 are configured such that the tubular member 110 is movable between a position in which the tubular member 110 is aligned with the axis of the drill string 30 and another position in which the tubular member 110 is offset from the axis of the drill string 30. This can be achieved in different ways. However, in the embodiment shown in the figures, this is achieved by relative movement of the flange 115 with respect to the horizontal slot 160. During movement of the tube member 110 and the adapter, the flange 115 is located within the slot 160 between the upper plate 164 and the lower plate 174 of the adapter 150.

The height of the lobes 116 extending from the flange 115 of the tube member 110 is greater than the combined height of the lower plate 174 and the footpad 155 and any lobes associated with the footpad. The raised portion 116 raises the flange 115 above the surface of the step by a height sufficient to allow the lower plate 174 and any raised portions (if any) associated with the foot pad 155 to be positioned below the flange 115 and still clear the surface of the step. Accordingly, the boss 116 of the tube member 110 has a height sufficient to enable the adapter 150 to disengage from the stepped surface when resting on the stepped surface, and to be horizontally movable relative to the tube member 110 when the flange 115 is located within the slot 160.

In use, the drill string 130 passes through the central openings 165, 167 of the upper and

lower plates

164, 174 and further through the longitudinal internal passage 120 in the pipe member 110, as shown in fig. 8-10.

In another embodiment, the adapter 150 may be configured to mate with a proprietary foot pad assembly. In such embodiments, the adapter 150 may not include the foot pads 155 or risers 157, but may instead primarily include only the horizontal upper and

lower plates

164, 174.

Drilling method

In fig. 9 to 14, a front cross-section of the open end of the top of a single bore 2 is shown. It will be appreciated, however, that a plurality of such boreholes 2 will be drilled on the step for a single blasting operation. The bore 2 can be drilled to a diameter of 270 to 311 mm or to a size of 350 mm or more and a depth of 50 m or more. After drilling, the borehole 2 is filled with an explosive substance suitable for the surface conditions, such as a mixture of Ammonium Nitrate and Fuel Oil (ANFO) or an emulsion or a mixture thereof, and is ready for detonation.

The operator of the drilling rig 10 causes the hydraulic arm 14 to maneuver the mast 20 to which the adapter 150 is secured. The tube member 110 is preferably supported upright, such as on a vehicle or some other support structure, with the flange 115 on top. The mast 20 is manipulated such that the slot 160 is oriented to align with the flange 115. The mast 20 is then manipulated relative to the tube member 110 such that the flange 115 is received into the slot 160, whereby the tube member 110 and the adapter 150 are coupled together with the mast 20 connected thereto.

The slot 160 between the closed laterally

opposite sides

161, 163 has a width dimension that is greater than the width dimension between the parallel-sided segments 117a, 118a of the flange 115. The

tapered edge segments

117b, 118b provide a narrower width dimension at one end 119 of the flange 115 to assist in guiding the flange 115 into the slot 160.

The drilling machine 10 is moved to a position adjacent to the position where the drill hole 2 is to be drilled. As shown in fig. 8, the drill string 30 is then lowered through the tubular member 110 and into engagement with the surface of the step. The drilling head 25 is activated and the drill bit 37 penetrates quite easily, since the top layer material is pretreated. The operator lowers the hydraulic boom 14, which in turn lowers the pipe member 110, until the projections 116 extending from the lower surface of the flange 115 engage the surface of the step, as shown in fig. 9. At this point, the tubular member 110 is almost entirely below the surface of the step and the outer surface 125 of the tubular member 110 faces outwardly against the wall of the bore 2, and the flange 115 is spaced above, or proud of, the surface of the step.

Drilling continues until the desired hole depth is reached. The drill string 30 is then withdrawn from the borehole 2 as shown in figure 10. As shown in fig. 11, the mast 20 is manipulated horizontally to cause the flange 115 to move relative to the slot 160.

In an embodiment not shown in the figures, the mast 20 is manipulated horizontally such that the flange 115 moves out of the slot 160, whereby the tube member 110, the adapter 150, and the mast 20 connected thereto are separated. In the embodiment shown in the figures, the mast 20 is manipulated horizontally such that the flange 115 moves relative to the slot 160 but remains within the slot 160 between the upper and

lower plates

164, 174 of the adapter 150. Embodiments in which the flange 115 is left within the slot 160 are advantageous because they do not require an operator to reposition the lower plate 174 of the adapter 150 in the relatively small space between the flange 115 and the surface of the step.

Orifice support device

The borehole casing apparatus 100 is adapted for use with an aperture support apparatus 200 for preventing loose rock fragments in the pretreated layer from falling or collapsing into the borehole, such as the apparatus 200 shown in fig. 15 and 16.

The orifice support apparatus 200 includes a flexible sheet 210, the flexible sheet 210 including a pair of opposing

surfaces

211, 212, and a pair of spaced apart longitudinally extending side edges 214, 216, and a pair of spaced apart laterally extending

end edges

215, 217. The generally planar sheet 210 is adapted to form a curved, substantially cylindrical shape in use to define a longitudinal channel 218 extending between openings at longitudinally opposite ends 211, 219.

The flexible sheet 210 preferably comprises a resilient material, such as a resiliently flexible polymeric material reinforced by nylon or some other flexibility enhancing agent. Sheet 210 is preferably rectangular in shape such that side edges 214, 216 are parallel and end

edges

215, 217 are also parallel. The side edges 214, 216 taper at one end. The sheet 20 includes a series of apertures 213, the apertures 213 being arranged in laterally spaced and longitudinally aligned pairs for holding and suspending the aperture support apparatus 200 when not in use.

As shown in fig. 12, orifice support apparatus 200 may be inserted into longitudinal internal passage 120 within tubular member 110 when tubular member 110 is placed within borehole 2. As shown in fig. 12 to 14, the tubular member 110 may then be removed from the borehole 2 by performing the reverse of the above-described process. That is, the flange 115 is moved within the slot 160 by manipulating the mast 20 horizontally until the flange 115 is substantially completely within the slot 160. The mast 20 is then raised to bring the tubular member 110 up out of the borehole 2, leaving the orifice support apparatus 200 in the orifice region of the borehole 2. The elastic properties of the material forming the sheet 210 allow the sheet 210 to expand and assume a substantially cylindrical form within the borehole 2, as shown in figure 14.

One of the

surfaces

211, 212 of the sheet 210 faces outwardly against the inwardly facing surface of the borehole 2 and forms a barrier preventing surrounding loose rock fragments from falling or collapsing into the borehole 2. Since the material forming the sheet 210 is elastic, the sheet 210 tends to assume its planar form, and this characteristic causes the outwardly facing

surfaces

211, 212 of the sheet 210 to exert pressure against the inwardly facing surfaces of the bore 2. At least a portion of the orifice support apparatus 200 can also be raised above the step surface to provide additional protection against surrounding loose rock fragments on the step surface falling or collapsing into the borehole 2.

The longitudinal dimension of the sheet 210 between the longitudinally opposing end edges 215, 217 can be a length of 1 meter, 1.5 meters, 2 meters, 2.5 meters, 3 meters, 3.5 meters, 4 meters, or more, or any length therebetween. When positioned within the blast hole 2, the sheet 210 provides support for the inner surface of the borehole 2 through most of the wall of the borehole 2 within the area of the hole.

The width of the sheet 210 between the pair of parallel side edges 214, 216 is preferably, but not necessarily, slightly larger than the circumference of the borehole 2. When the sheet 210 assumes a substantially cylindrical form within the borehole 2, the side edges 214, 216 of the sheet 210 slightly overlap. However, in another embodiment, the side edges 214, 216 of the sheet do not overlap but are slightly spaced apart.

The drilling machine 10 is moved to a position adjacent to the position where the next drill hole 2 is to be drilled and the above process is repeated. The orifice-supporting device 200 is left in place within the blast hole 30 during the subsequent step of setting down explosives and other consumables into the borehole 2. After the borehole is filled and ready, the orifice support apparatus 200 may be removed from the borehole 2 or partially withdrawn and formed into a funnel shape prior to setting down the stemming material into the borehole 2.

Fig. 17 to 19 show another embodiment of a mobile drilling machine 310 for drilling a borehole 2. The illustrated drill 310 is similar to the drill 10 of fig. 5 and 6, and like reference numerals will be used to identify like features. The primary difference is that the drilling rig 310 further includes a deployment apparatus 350 mounted to the mast 20 for forming the planar flexible sheet 210 into a bent form and inserting the bent sheet 210 into the borehole casing apparatus 100 located within the orifice region of the borehole 2 to form the orifice support apparatus 200.

The deployment apparatus 350 includes a plurality of sheets 210 arranged in a stack 315. A stack 315 of sheets 210 is supported on the frame 209. The apparatus 350 includes a sheet pickup feeder 355 operable to pick up individual sheets 210 from the stack 315 and feed the sheets 210 into the vertical forming apparatus 330. In the embodiment illustrated in fig. 9, the pick feeder 355 includes a driven roller arrangement and a belt arrangement operable to pick sheets 210 from the stack 315 one at a time. However, any mechanical arrangement adapted to pick one sheet 20 from the stack 315 and feed the sheet 20 to the vertical forming apparatus 330 may constitute another embodiment of the invention.

The forming apparatus 330 is operable to form the sheet 210 into a curved, substantially cylindrical shape, defining a longitudinal channel 218 extending between openings at longitudinally opposite ends 211, 219. The forming device 330 includes a wide mouth 331 and tapers to a narrower circular outlet 333 to define a path 335 for the flexible sheet. The feeding mechanism feeds the flexible sheet 210 into the pipe member 110 through the inlet 331 and the circular outlet 333.

The illustrated embodiment of the forming device 330 includes a funnel-shaped portion 332, the funnel-shaped portion 332 defining a wide mouth 331 and transitioning to a cylindrical portion 336 defining a narrower circular outlet 333. The funnel-shaped portion 332 and the cylindrical portion 336 are defined by a sidewall 338 preferably formed of sheet metal or similar material. Instead of the funnel-shaped portion 332, the forming apparatus comprises an elongated and substantially planar opening, which resembles the shape of the planar sheet 210 and gradually transitions to the circular shape of the cylindrical portion 336. However, other mechanical arrangements adapted to be mounted to the mast 20 of the rig 10 for picking up individual sheets 210 from the stack 315 and forming the sheets 210 into a curved form and inserting the sheets into the tubular member 110 are within the scope of the disclosure contained herein.

Referring to fig. 18 and 19, after the borehole 2 is drilled to the desired hole depth, the drill string 30 is withdrawn from the borehole 2 and the mast 20 is manipulated horizontally so that the pipe member 110 flange 115 moves relative to the slot 160 and the drill string 30 is deflected from the opening of the pipe member 110. The circular outlet 333 is thus located above and aligned with the open end of the tubular member 110, as shown in fig. 18 and 19. The deployment device 350 is activated so as to pick up a single sheet 210 from the stack 315 and form it into a curved form and insert it into the tubular member 110 located within the borehole 2, as shown in figure 19. The deployment apparatus 350 includes another feed mechanism 339, the feed mechanism 339 including one or more driven rollers or belt drives at the outlet 333 for inserting the bent sheet 210 into the tube member 110 and the open end of the bore 2 to a desired depth.

The tubular member 110 may then be withdrawn from the borehole 2 in the same manner as described above with reference to the process illustrated in the embodiment shown in figures 12 to 14. That is, by manipulating the mast 20 horizontally, the flange 115 is moved within the slot 160 until the flange 115 is substantially completely within the slot 160. The mast 20 is then raised to bring the tube member 110 up out of the borehole 2, leaving the orifice support apparatus 200 including the bent sheet 210 within the orifice region of the borehole 2.

The deployment apparatus 350 may be mounted to the mast 20 of the drilling rig 310, or in another embodiment may be mounted to a separate vehicle (not shown) or a trailer (not shown) coupled to the vehicle or any other movable apparatus suitable for maneuvering around the terrain. The vehicle or other movable equipment may be a truck, manually operable by a driver or, in one embodiment, configured to be fully or semi-automatically operable. The vehicle or other movable device may include a control module that includes a GPS positioning device and is adapted to control the drive and steering of the vehicle. The control module is adapted to receive or be programmed with the location coordinates of one or more of the plurality of blast holes and automatically operate the deployment device 350.

The embodiment shown in fig. 20 and 21 comprises a movable shroud 400 for guiding cuttings and/or bailing occurring from the borehole 2 during drilling operations. The shroud 400 includes a body 410, the body 410 including a hollow interior cavity having openings at the bottom and top. The top of the body 410 is adapted to mount to a movable shroud adapter 420 coupled to the mast 20 of the drilling rig 10. The movable shroud adapter 420 is adapted to translate up and down within a linear range of motion of about 50 cm. The shield 400 is made of a durable material such as an alloy and has a tapered upper portion 405 and a flexible and durable plastic or rubber lower cover 407. The lower cover 407 seals around an opening at the bottom of the body 410. The shroud 400 is positioned in alignment with the axis of the drill string 30, and openings at the top and bottom of the shroud 400 allow the drill string 30 to pass therethrough.

In use, movable shroud adapter 420 is adapted to lower shroud 400 downward toward adapter 150 such that lower shroud 407 is in contact with upper plate 164. The lower cover 407 of the adapter thereby seals around the central opening 165 of the upper plate 164 of the adapter 150. The shroud 400 is aligned with the longitudinal passage 120 of the tubular member 110 such that the drill string 30 may pass therethrough to allow drilling to commence. Shroud 400, including lower shroud 407, is sized and configured to be positionable between

gusset portions

159, 159 of adapter 150.

During drilling, as shown in fig. 9 and 10, cuttings and/or bailing emerging from the borehole 2 travel up through the longitudinal passage 120 of the tubular member 110 and emerge from the opening 112. Cuttings and/or bailing that overflow from the opening 112 of the tubular member 110 are directed upward into the body 410 of the shroud 400. The shroud 400 includes a drain 415 for cuttings and/or bails to exit from the body 410 of the shroud. The discharge port 415 is oriented transverse to the axis of the drill string 30.

In the embodiment shown in fig. 20, the discharge port 415 is uncovered so that cuttings and/or bails can freely emerge from the discharge port 415 and be distributed to the step surface adjacent the borehole 2 being drilled. This embodiment is suitable for wet drilling operations where mud containing cuttings and/or bails mixed with water emerges from the borehole 2.

In the embodiment shown in fig. 21, the exhaust port 415 is coupled to a flexible hose 425, which flexible hose 425 is in turn coupled to a vacuum pump system. Cuttings and/or bailing emerging from the drain 415 are extracted through the flexible hose 425 and deposited onto the step surface at a sufficient distance from the borehole 2 being drilled. This embodiment is suitable for dry drilling operations where cuttings and/or bails emerging from the borehole 2 are dry and comprise a substantial proportion of dry particles.

The opening at the top of the body 410 of the shroud 400 includes a seal between the opening and the drill rod 35 comprising the drill string 30. A seal between the opening at the top of the body 410 of the shroud 400 and the drillpipe 35 prevents cuttings and/or bailing entering the shroud 400 from emerging from the opening at the top of the body 410 of the shroud 400. The seal may comprise a ring made of metal or a durable polymer or rubber material. The seal is sized to within a fairly small tolerance around the outer circumference of the drill rod 35.

Drilling platform

Fig. 22-27 illustrate another embodiment of a mobile platform drill 510 for drilling a borehole 2. The drilling platform 510 shown may be used for rotary drilling or hammer drilling specifically designed for mining, but it should be understood that embodiments of the present invention may have broader application. The mobile drill 510 shown in the figures is a type of surface drilling rig typically used for drilling large diameter boreholes having a diameter between about 165 and 351 millimeters and is commonly referred to as a "platform drill". These larger-scale platforms are believed to originate from many manufacturers, such as Sandvik, Epiroc, Komatsu, and Caterpillar.

The drilling rig 510 includes a self-propelled tracked platform 512, the platform 512 including hydraulic arms that support a mast 520. The mast 520 itself is adapted to support a drill string 530, the drill string 530 including one or more drill pipes 535 and a drill bit 537 at the end of the drill string 530. The drill rods 535 are coupled together by a threaded connection therebetween.

The mast 520 carries a drilling head that includes a reciprocating piston or hammer assembly and a rotation assembly, collectively adapted to apply an impact force and/or a rotational torque to a drill string 530. The drill head 525 can be raised or lowered by a hydraulically driven up-and-down feed system to enable a pipe or rod to be removed from or added to the drill string.

The borehole casing apparatus 600 is adapted to be coupled to the mast 520 in a manner to be described in greater detail below. The sleeving apparatus 600 is similar to the sleeving apparatus embodiment 100 described above and therefore like reference numerals have been used to identify like features.

As shown in fig. 22 to 26, the casing apparatus 600 comprises a tubular member 110, which tubular member 110 is adapted, in use, to be placed within a borehole 2 that has been drilled or is being drilled by a drilling machine 510. Similar to the other embodiments, in the embodiment of fig. 22-27, the adapter 550 is fixed to the platform 512 relative to the mast 520. The adapter 550 is similar in construction to the adapter 150 described above, and therefore like reference numerals are used to identify like features.

As shown in fig. 22, the adapter 550 supports and holds the casing apparatus 600 relative to the platform 512 such that the drill string 530 can pass axially therethrough. The drill bit 537 engages the step surface to start drilling of the borehole 2. The platform 512 includes a linear drive, such as a hydraulic drive, to axially translate and thereby raise or lower the adapter 550 and the casing apparatus 600 coupled thereto in the axial direction of the drill string 530 and borehole 2.

As shown in fig. 23, the sleeve apparatus 600 is lowered down into the bore 2 until the projection 116 extending from the lower surface of the flange 115 engages the surface of the step. At this point, the tubular member 110 is almost entirely below the surface of the step and the outer surface 125 of the tubular member 110 faces outwardly against the wall of the bore 2, and the flange 115 is spaced above, or proud of, the surface of the step.

The shroud adapter 420 and the movable shroud 400 are coupled to the platform 512 to enable the shroud to move up and down within a range of linear motion. The shroud adapter 420 includes a linear drive, such as a hydraulic drive, coupled to the shroud 400 to axially translate and thereby raise and lower the shroud 400. As shown in fig. 23, the shroud 400 is lowered to the sleeve device 600 and provides a seal around the central opening 165 of the upper plate 164 of the adapter 550.

During drilling, as shown in fig. 24 and 27, cuttings and/or bailing emerging from the borehole 2 travel up through the longitudinal passage 120 of the tubular member 110 and emerge from the opening 112. Cuttings and/or bailing emerging from the opening 112 of the tubular member 110 are directed upwardly into the body 410 of the shroud 400. The exhaust 415 of the shroud 400 directs the swarf beneath the platform 512. In fig. 22-27, the drain 415 is coupled to a flexible hose 425, however, it should be understood that there may be no hose and that cuttings and/or bails are flushed directly from the drain.

As shown in FIGS. 24 and 27, the curtains 511 are positioned beneath the platform 415. The curtain 511 extends along the length of the platform 415 adjacent the track 502 supporting the platform 415 to block cuttings and/or sand from entering the track 502. The strip curtain 515 extends laterally across the rear of the platform 415 between the rails 502. Optionally, another curtain 516 is also provided beneath the portion of the platform 512 that supports the mast 520 to contain any cuttings and/or bails that escape the shroud 400 or otherwise move forward beneath the platform 512.

When the desired borehole 2 depth is reached, the drill string 530 is withdrawn and the shroud 400 is lifted. The deployment device 350 is mounted to the platform 512 and is adapted to pick up the sheet 20 from the stack 315 and form the sheet 20 into a roll and feed it through the tube member 110 to the borehole 2. The deployment apparatus 350 includes an angled chute 352 to direct the rolled sheet material 20 into the tube member 110 and out of the lifted shield 400.

In another embodiment, as shown in fig. 26, the storage of the pre-rolled sheet 20 is supported on a platform 512. Each pre-rolled sheet 20 comprises a tie 21 for holding each pre-rolled sheet 20 in a rolled form. The deployment device 350 is mounted to the platform 512 and is adapted to pick up one of the pre-rolled sheets 20 and feed the pre-rolled sheet 20 through the tube member 110 into the borehole 2. The tie 21 may be connected to a cable which when pulled releases the tie and thereby allows the sheet 20 to open and come into face-to-face contact against the wall of the bore 2.

The platform 512 may then be moved to the location of the next borehole 2 to be drilled and the process repeated.

Composite stable support

Fig. 28 and 29 show another embodiment of a method of stabilizing the orifice of the borehole 2. The tubular member 110 of the borehole casing apparatus 100 provides temporary support to the wall of the borehole 2 in the region of the aperture and acts as a form, and in some embodiments is capable of penetrating the surrounding wall of the borehole 2, when the composition is injected. The composition is injected and cures or otherwise hardens or sets, becoming self-supporting or binding loose rock fragments to form composite orifice support 613.

The composition may be a fluid that is injected into a line 610 coupled to a network of conduits and openings 612 formed in the tubular member 110. Thus, when the tubular member 110 is placed in the borehole 2, the injected fluid exits the opening 612, enters the space between the tubular member 110 and the borehole 2, or penetrates surrounding loose rock fragments, or both. The tubular member 110 is left in the borehole 2 for a period of time sufficient for the composition to harden, cure, set to be self-supporting or otherwise bond with the surrounding fine and coarse aggregate to form the composite orifice support 613.

The composition will have cured within the time it takes to complete the drilling operation, and the borehole casing apparatus 100 can then be withdrawn from the borehole 2. A small rotational motion may be applied to borehole casing apparatus 100 to break adhesion with the surrounding composite orifice support 613.

The composition may be comprised of a material such as a polymer or resin that is injected as a liquid and then hardens to form a structural self-supporting sleeve between the tubular member 110 and the borehole 2. Alternatively, the composition may also be comprised of a material such as a polymer or resin that is injected as a liquid and penetrates into the surrounding fine and coarse aggregates (e.g., pre-treatment material) to form composite orifice support 613.

The composition may include a polyurethane resin, a cross-linked polymer or resin, an epoxy resin, a polyester or a phenolic resin, or may also include a mineral blocking agent such as portland cement.

Although the present disclosure has been described with reference to specific examples, it will be appreciated by those skilled in the art that the present disclosure may be embodied in many other forms without departing from the broad principles and spirit of the disclosure.

Claims

1. A borehole casing apparatus for a borehole drilling tool, the casing apparatus comprising:

a tubular member adapted to be coupled to a mast of a movable drilling tool and positioned within an aperture area of a borehole, the tubular member including a longitudinal inner passage for receiving a drill string therethrough, and an outer surface for facing outwardly against a wall of the borehole.

2. The casing apparatus of claim 1, wherein the tube member and the mast comprise a coupling for securing the tube member to the mast.

3. The sleeve member according to claim 2, wherein the coupling is adapted to releasably secure the tube member to the mast.

4. A casing apparatus according to claim 2 or 3, wherein the coupling is adapted to allow movement of the pipe member relative to the mast between a position in which the pipe member is aligned with an axis of the drill string and another position in which the pipe member is offset from the axis of the drill string, while the pipe member and the mast remain coupled together.

5. A casing device according to any one of claims 2 to 4 wherein the coupling comprises a slot mount coupling.

6. A casing apparatus according to any one of claims 2 to 5 wherein the coupling comprises an adapter member secured to the mast and including a slot for receiving a flange at an end of the pipe member.

7. A casing device according to claim 6, wherein the slot is defined by a pair of opposed plates which, in use, are oriented substantially parallel to the step surface.

8. A casing apparatus according to claim 6 or 7, wherein the flange is adapted to move within the slot between a position in which the tubular member is aligned with an axis of the drill string and another position in which the tubular member is offset from the axis of the drill string.

9. A casing apparatus according to claim 7 or 8 wherein each of the pair of plates includes an opening for receiving the drill string therethrough and for alignment with the longitudinal internal passage of the tubular member.

10. The cannula device according to claim 9, wherein the opening through the lower one of the plates is open to one side of the plate to receive the tube member.

11. A casing device according to any one of claims 6 to 10, wherein one or more projections extend from the flange for engaging a stepped surface and for maintaining a gap between the flange and the stepped surface.

12. A casing device according to any preceding claim wherein the tubular member is self-supporting in the bore of the bore and is adapted to receive an aperture support device within the longitudinal internal passage.

13. A casing device according to any one of the preceding claims, wherein the tube member comprises a rigid cylindrical body portion having openings at opposite ends of the body portion, and the longitudinal internal passage extends between the openings.

14. A drilling apparatus comprising:

a movable platform;

a mast placed on the platform and including a support for a drill string;

a drill string rotary drive mechanism for driving the drill string to drill a hole in rock;

a borehole casing apparatus comprising a tubular member coupled to the mast for positioning into the aperture region of a borehole, the tubular member comprising a longitudinal internal passage for receiving the drill string therethrough, and an outer surface to face outwardly against a wall of the borehole.

15. The drilling apparatus as recited in claim 14, wherein said pipe member is movable while remaining coupled to said mast between a position in which said pipe member is aligned with an axis of said drill string and another position in which said pipe member is offset from said axis of said drill string.

16. The drilling apparatus as claimed in claim 14 or 15, wherein the tubular member is axially movable while remaining coupled to the mast to lower the tubular member into the borehole and to raise the tubular member out of the borehole.

17. The drilling apparatus as claimed in claims 14 to 16, comprising a sheet deployment apparatus for deploying a flexible sheet into an open end of the tubular member located within the borehole.

18. The drilling apparatus as claimed in claim 17, wherein the sheet deployment apparatus comprises a sheet forming apparatus adapted to form a planar flexible sheet into a curved form and to feed the curved sheet to the open end of the tubular member located within the bore hole.

19. The drilling apparatus as claimed in claim 18, wherein the forming apparatus comprises a wide mouth inlet and tapers to a narrower circular outlet to define a path for the flexible sheet material, and a feed mechanism for feeding the flexible sheet material into the tubular member through the inlet and the circular outlet.

20. The drilling apparatus according to any one of claims 16 to 19 comprising a store of a plurality of said flexible sheets and a picker adapted to pick up one said sheet at a time.

21. The drilling apparatus according to any one of claims 14 to 20, further comprising a shroud adapted to substantially seal against the longitudinal internal passage of the tubular member to guide cuttings and/or bailing occurring from a borehole during drilling.

22. The drilling apparatus as claimed in claim 21, wherein said shroud comprises an axial passage for receiving said drill string therethrough and a discharge port positioned transverse to said axial passage.

23. The drilling apparatus of claim 22, wherein the discharge port is adapted to be coupled to a flexible conduit of a vacuum apparatus.

24. The drilling apparatus according to any one of claims 21 to 23, wherein the shroud is mounted to the mast and a drive is adapted to move the shroud up and down within a range of linear motion.

25. The drilling apparatus according to any one of claims 21 to 24, further comprising an outlet proximate to or below the movable platform for directing cuttings and/or bails occurring from the borehole during drilling to a pile adjacent to or below the movable platform.

26. The drilling apparatus as claimed in any one of claims 14 to 25, comprising a system for injecting a composition between the outer surface of the tubular member and the surrounding wall of the borehole.

27. A method for drilling a borehole, comprising:

drilling into a stepped surface and lowering the tubular member into an orifice region of the bore, the tubular member including an outer surface facing outwardly against a wall of the bore.

28. A method for disposing an orifice support apparatus in a borehole, the method comprising:

drilling into a stepped surface and lowering the tubular member into the orifice region of the bore, the tubular member including an outer surface facing outwardly against a wall of the bore;

providing support in a borehole for stabilizing the orifice region of the borehole; and

removing the tubular member from the bore.

29. The method of claim 28, wherein providing support in the borehole comprises inserting an orifice support device comprising a sheet of flexible material into the longitudinal internal passage of the tubular member, and wherein removing the tubular member from the borehole leaves the orifice support device within the borehole.

30. The method of claim 29, including moving the mast relative to the pipe member to access the longitudinal interior passage of the pipe member.

31. The method of claim 30, wherein moving the mast relative to the pipe member comprises moving the mast between a position in which the pipe member is aligned with an axis of the drill string and another position in which the pipe member is offset from the axis of the drill string while the pipe member and the mast remain coupled together.

32. The method of any one of claims 28 to 31, wherein removing the tubular member from the borehole comprises manipulating the mast to raise the tubular member out of the borehole.

33. The method of any of claims 28-32, wherein coupling the pipe member to the mast comprises translating the mast horizontally relative to the pipe member.

34. The method of claim 28, wherein providing support in a borehole for stabilizing the orifice region of the borehole comprises injecting a composition between the outer surface of the tubular member and the surrounding wall of the borehole.

35. The method of claim 34, wherein the injected composition cures or hardens or sets to be self-supporting or to bind loose rock fragments to form a composite pore support.

36. A sheet forming apparatus adapted to form a planar flexible sheet into a curved form and to feed the curved sheet into a tube member located within the aperture region of a bore, the apparatus comprising:

a forming apparatus adapted to form a planar flexible sheet into a curved form; and

a feed mechanism for feeding a bent sheet material into the open end of the tube member within the aperture area of the bore.

37. The apparatus of claim 36, wherein the forming apparatus comprises a wide mouth inlet and tapers to a narrower circular outlet to define a path for the flexible sheet, wherein the feed mechanism feeds the flexible sheet through the inlet and the outlet of the forming apparatus and to the tube member.

38. Apparatus according to claim 36 or 37, comprising a plurality of said flexible sheets arranged in a stack, said feed mechanism being configured to pick up one said sheet at a time from said stack.

39. The apparatus of any one of claims 36 to 38, wherein the apparatus is configured as a mast for attachment to a borehole drilling device.