An apparatus and method for lining a blast hole

Abstract

The present invention relates to apparatus and methods for lining a blast hole. The apparatus includes a body comprising an upper face and a lower face and a centrally located opening within the body extending between the upper face and the lower face. A length of a flexible tubular liner in a gathered state is located below the lower face of the body and comprises a longitudinal passage extending between an open upper end connected to the opening and a closed lower end. The apparatus also includes a liner retainer for retaining the liner in the gathered state below the lower face of the body, wherein the body is adapted to be retained at or near the open end of a blast hole and the liner retainer is operable for releasing the flexible tubular liner down into the blast hole to be filled with bulk explosive material provided through the opening within the body.

Description

AN APPARATUS AND METHOD FOR LINING A BLAST HOLETECHNICAL FIELD

[0001] The present invention relates to the field of blasting, particularly in the fields of mining, quarrying, and excavations. In particular, the invention relates to an apparatus and method for deploying a liner into a blast hole to line the blast hole before loading with explosives.BACKGROUND OF THE INVENTION

[0002] In the mining industry, desired minerals such as iron ore and coal can be recovered in a variety of methods including above-ground open-cut mining methods. Such methods can involve the use of blasting with bulk explosives to dislodge or break up bulk quantities of ore for excavation and recovery through subsequent handling via excavators and the like. This process can often involve drilling an array of blast holes up to 20 metres or more in depth and up to 300 millimetres or more in diameter, followed by depositing bulk explosive material into the blast hole. The explosive material in the blast hole is contacted with an explosive initiator, such as a detonator and a booster, and covered or “stemmed” with material such as aggregate. The initiator is activated electrically, non-electrically, or by some other means to initiate or cause the bulk explosive material to detonate.

[0003] Of the many explosive materials utilized, a mixture of porous prilled ammonium nitrate and fuel oil, also referred to as ANFO, bulk emulsion, or packaged explosives are typically used. ANFO is the least expensive option and therefore the most popular out of the three. However, since ammonium nitrate is water soluble and highly hygroscopic, water or moisture ingress in blast holes can significantly affect its explosive performance. Uncontrolled moisture or water ingress into blast holes may cause failed, incomplete, or unsatisfactory blasts. Accordingly, ANFO has limited use in wet mining conditions, such as when blast holes are drilled below the water table and tend to fill with water.

[0004] Furthermore, some blast holes are drilled into challenging geologies such as uneven terrain or geologies comprising sub-surface voids or cavities in the bedrock. When filling blast holes that have been drilled into geology comprising subsurfacevoids with bulk explosive material, the explosive material will fill the geological voids. As a result, some of the explosive material spreads out from the blast hole column and into these voids and is not contained in a column of predetermined diameter and height according to the blast design. Such uncontained explosive material due to uncontrolled spreading of explosive from the column is not desirable.

[0005] The amount of bulk explosive material required and the dimensions of the explosive charge (i.e. diameter and height) are carefully calculated for each blast hole during the blast design process. Uncontrolled spreading of uncontained explosive into geological voids can result in uncontrolled blast wave propagation and undesired outcomes of the blasting operation.

[0006] One solution that ameliorates the problem of uncontained explosive material in blast holes drilled into geology comprising sub-surface voids and / or protects nonwaterproof explosive material from water / moisture in the blast hole is to use a liner material. The liner material is an elongated tube that is typically fed from a roll, cut to length and sealed at one end before the sealed end is fed down into the blast hole. The liner is primed and filled with the bulk explosive material and then pulled to the side of the hole and then the hole is stemmed. However, the use of a liner involves an additional sequence of steps to the blasting process and requires that additional material and equipment be deployed to the blasting site. Furthermore, the deployment of a liner into a blast hole in challenging or uneven terrain can be time-consuming and dangerous.

[0007] Accordingly, there exists a need for an efficient and convenient means for ameliorating the problem of uncontained bulk explosives in blast holes drilled in geology comprising sub-surface voids.

[0008] Similarly, there exists a need for an efficient and convenient means for protecting non-waterproof explosive material from water or moisture in the blast hole.

[0009] Furthermore, there exists a need for a readily deployable self-contained blast hole liner that enables fast and efficient lining of a blast hole for receiving explosives without the need for additional steps, equipment, and materials.

[0010] Any discussion of background art throughout the specification should in no way be considered as an admission that any of the documents or other material referred to was published, known or forms part of the common general knowledge.SUMMARY OF THE INVENTION

[0011] In one aspect, the invention provides an apparatus for lining a blast hole, the apparatus including a body comprising an upper face and a lower face and a centrally located opening within the body extending between the upper face and the lower face, a length of a flexible tubular liner in a gathered state below the lower face of the body and comprising a longitudinal passage extending between an open upper end connected to the opening and a closed lower end, and a liner retainer for retaining the liner in the gathered state below the lower face of the body, wherein the body is adapted to be retained at or near the open end of a blast hole and the liner retainer is operable for releasing the flexible tubular liner down into the blast hole to be filled with bulk explosive material provided through the opening within the body.

[0012] In embodiments, in the gathered state, the longitudinal passage of the liner is empty.

[0013] In embodiments, the liner retainer is responsive to a predetermined force intentionally applied to the gathered liner or the liner retainer to release the flexible tubular liner.

[0014] In embodiments, the liner retainer extends over an external surface of a side and the closed end of the gathered liner for retaining the gathered liner below the lower face of the body.

[0015] In embodiments, the liner retainer includes a strap and / or a container, wherein the container covers the entire external surface of a side and the closed end of the gathered liner.

[0016] In embodiments, the apparatus further includes a liner release that is intentionally operable for causing the liner retainer to release the flexible tubular liner down into the blast hole.

[0017] In embodiments, the liner release is accessible from above the upper face of the body.

[0018] In embodiments, the liner retainer is connected to the body and the liner release is operable to, at least partially, disconnect the liner retainer from the body and thereby release the flexible tubular liner down into the blast hole.

[0019] In embodiments, the liner retainer comprises a strap that retains the gathered liner and wherein one end of the strap is connected to the upper face of the body and the liner release includes a portion of the strap that is manually operable for at least partially disconnecting the strap from the upper face of the body.

[0020] In embodiments, the body is self-retaining at or near the level of a surface surrounding the open end of the blast hole.

[0021] In embodiments, the lower face of the body engages the open end of the blast hole for retaining the apparatus at or near the level of the surrounding surface.

[0022] In embodiments, the body comprises an upper part and a lower part, wherein the opening through the body comprises an upper portion of the opening through the upper part and a lower portion of the opening through the lower part, wherein the upper portion of the opening has a smaller diameter and / or circumference than the lower portion of the opening.

[0023] In embodiments, the liner is connected to the body between the upper part and the lower part of the body.

[0024] In embodiments, an upper end of the liner is sandwiched between the upper part and the lower part of the body.

[0025] In embodiments, the liner has a diameter, in an open state, that is larger than the diameter of the upper portion of the opening.

[0026] In embodiments, in the gathered state the liner comprises an empty longitudinal passage extending between the upper end connected to the body and a lower closed end.

[0027] In embodiments, in the gathered state, the exterior of the liner is substantially free of any surrounding along at least a portion of, or substantially the entire longitudinal length of the liner.

[0028] In embodiments, the body includes an upwardly open channel extending transversely from the opening for receiving and retaining a lead line, wherein a portion of the channel adjacent to the opening is open downwardly for the lead line to pass downwardly therethrough.

[0029] In embodiments, wherein the body includes an aperture adjacent to a peripheral edge for securing the lead line and for use as a hand hold.

[0030] In another aspect, the invention provides a method for loading bulk explosives into a blast hole, the method including locating an apparatus in the open end of a blast hole including a body comprising an upper face and a lower face and a centrally located opening within the body extending between the upper face and the lower face, a length of a flexible tubular liner in a gathered state below the lower face of the body and comprising a longitudinal passage extending between an open upper end connected to the opening and a closed lower end, and a liner retainer for retaining the liner in the gathered state below the lower face of the body, releasing the liner retainer whereby the liner extends down into the blast hole, and providing bulk explosive material through the opening of the body to thereby fill the tubular liner with explosive material within the blast hole.

[0031] In embodiments, locating the apparatus in the open end of a blast hole includes placing the body with the lower face engaging the open end of the blast hole for retaining the apparatus at or near the level of the surrounding surface

[0032] In embodiments, the method further includes connecting an open end of a length of a flexible tubular liner to the body and sealing close the other end of the liner.

[0033] In embodiments, the method includes gathering the flexible tubular liner below the lower face of the body and securing the liner in the gathered state to the lower face of the body with the liner retainer.

[0034] In embodiments, the method further includes placing an initiator in the flexible tubular liner and depositing an amount of stemming material into the blast hole.

[0035] In embodiments, intentionally releasing the liner retainer includes applying a predetermined downward force to the gathered liner or the liner retainer.

[0036] In embodiments, a hose for providing bulk explosive material is inserted through the opening of the body towards a sealed end of the gathered liner to apply the predetermined downward force to the gathered liner.BRIEF DESCRIPTION OF THE FIGURES

[0037] The present invention will now be described in more details with reference to preferred embodiments illustrated in the accompanying figures, wherein:

[0038] Figures 1(a) to 1(d) illustrate: (a) a cross section view; (b) a top view; (c) a bottom view; and (d) a side view of an apparatus for lining a blast hole including a body comprising an upper face and a lower face and a centrally located opening within the body extending between the upper face and the lower face, a length of a flexible tubular liner connected to the opening, wherein the flexible tubular liner is gathered below the lower face of the body, and a liner retainer for retaining the gathered liner below lower face of the body;

[0039] Figure 2 illustrates a cross section view of a blast hole including an open end, a surrounding surface of the blast hole, and a sub-surface void or cavity;

[0040] Figure 3 illustrates a cross section view of the apparatus of Figure 1 located in the open end of the blast hole of Figure 2;

[0041] Figure 4 illustrates a cross section view of the apparatus of Figure 1 located in the open end of the blast hole of Figure 2 wherein the flexible tubular liner is released down into the blast hole;

[0042] Figure 5 illustrates a cross section view of the apparatus of Figure 1 located in the open end of the blast hole of Figure 2, wherein the flexible tubular liner, which is released down into the blast hole, which is sealed at the bottom and is being filled with bulk explosive material;

[0043] Figure 6 illustrates a cross section view of the apparatus of Figure 1 located in the open end of the blast hole of Figure 2, wherein the flexible tubular liner is filled with bulk explosive material to a desired level within the blast hole;

[0044] Figure 7 illustrates a cross sectional view of the apparatus of Figure 1 located in the open end blast hole of Figure 2, wherein a stemming material is deposited to fill the portion of the blast hole left empty above the explosive material to the level of the open end of the blast hole;

[0045] Figure 8 illustrates an embodiment of the apparatus of Figure 1 , wherein the body comprises an upper part and a lower part, wherein the opening through the body comprises an upper portion through the upper part and a lower portion through the lower part,

[0046] Figures 9(a) and 9(b) illustrate: (a) a side view; and (b) a top view of an embodiment of the apparatus of Figure 8, wherein the body further comprises an upwardly open channel extending transversely from the opening for receiving and retaining a lead line;

[0047] Figures 10(a) and 10(b) illustrate: (a) a side view; and (b) a top view of an embodiment of the apparatus of Figure 9, wherein the body further includes anaperture adjacent to an edge of the body for securing the lead line and for use as a handhold;

[0048] Figure 11 illustrates a cross section view of an embodiment of the apparatus of Figure 1 located in the open end of the blast hole of Figure 2, wherein the body comprises an upwardly open channel and an aperture for receiving and retaining a lead line and wherein a length of a lead line with an initiator is pre-installed therein;

[0049] Figure 12 illustrates a cross section view of an embodiment of the apparatus of Figure 1 located in the open end of the blast hole of Figure 2, wherein the flexible tubular liner is released down into the blast hole and wherein the body comprises a upwardly open channel and an aperture for receiving and retaining a lead line to which is attached an initiator that is dropped down into the sealed end the liner; and

[0050] Figure 13 illustrates a cross section view of an embodiment of the apparatus of Figure 8, wherein the upper portion of the opening has a smaller diameter than the lower portion of the opening, and wherein the liner has a diameter, in an open state, that is larger than the diameter of the upper portion of the opening, and wherein an upper end of the liner is sandwiched between the upper part and the lower part of the body.DETAILED DESCRIPTION

[0051] Referring to Figures 1(a) to 1(d), there is shown an apparatus 1 for lining a blast hole in accordance with an embodiment of the invention. The apparatus 1 includes a body 10 comprising an opening 11 and an upper face 12 and a lower face 13 and a centrally located opening 11 within the body 10 extending between the upper face 12 and the lower face 13.

[0052] A length of a flexible tubular liner 20 is connected to the opening 11. The flexible tubular liner 20 is in a gathered state below the lower face 13 of the body 10, and the apparatus 1 includes a liner retainer 30 for retaining the liner 20 in the gathered state below the lower face 13 of the body 10. In use, the body 10 is adapted to be retained at or near the open end 41 of a blast hole 40 and the liner retainer 30 is intentionally operable for releasing the flexible tubular liner 20 down into the blast hole40 to be filled with bulk explosive material 60 provided through the opening 11 within the body 10.

[0053] In embodiments, as illustrated in Figures 3-7 and 11 and 12, the body 10 engages the open end 41 of the blast hole 40 for retaining the apparatus 1 at or near the level of the surrounding surface 42 of the blast hole 40. Referring to Figures 1 and 3 to 13, the body 10 has an opening 11 . Preferably, the opening 11 is circular in shape and has a diameter that is the same or smaller than the diameter of the blast hole.

[0054] The body 10 is rigid and can be formed out of wood or engineered wood material, rigid paper material, cardboard material, or plastic. In exemplary embodiments, as illustrated in Figure 1 and 3-13, the body 10 is planar and square in shape. In another embodiment (not shown), the body 10 is cone or funnel shaped. A part of the body 10 has an external length, width, and / or diameter greater than the diameter of the open end11 of the blast hole 40, such that in use, the body 10 engages the open end 41 of the blast hole 40 for retaining the apparatus 1 at or near the level of the surrounding surface 42 of the blast hole 40. In embodiments where the body 10 is planar, the lower face 13 engages the ground surface surrounding the open end 41 of the blast hole 40. In embodiments where the body 10 is cone shaped, the lower face 13 engages and is wedged within the open end 41 of the blast hole 40.

[0055] In embodiments illustrated in Figures 8 to 10, the body 10 comprises an upper part 15 and a lower part 16, wherein the opening 11 through the body 10 comprises an upper portion through the upper part 15 and a lower portion through the lower part 16. In embodiments, wherein the body 10 comprises an upper part 15 and a lower part 16 as illustrated in Figures 9 to 13, the opening 11 through the body 10 comprises an upper portion, the upper portion of the opening has a smaller diameter than the lower portion of the opening, as shown in Figure 13

[0056] In embodiments of the apparatus 201 , 301 illustrated in Figure 9 and Figure 10, the body 10 includes an upwardly open channel 14 extending transversely from the opening 11 for receiving and retaining a lead line 50. In use, the lead line 50 can be inserted within the upwardly open channel 14 to retain the lead line 50 securely at the open end 41 of the blast hole 40.

[0057] The upwardly open channel 14 extends transversely from the opening and includes a portion of the channel 14 adjacent to the opening 11 that is open downwardly (not shown) for the lead line 50 to pass downwardly therethrough. The upwardly open channel 14 is advantageous as it enables secure retention of the lead line 50, which will typically include an attached initiator 51 , to the body 10 during subsequent loading of the blast hole 40 with explosive material 60 and stemming material 61. The upwardly open channel 14 is advantageous as it provides a recess into which the lead line 50 is received which provides a degree of protection from abrasion due to the provision of stemming material into the blast hole. The portion of the channel 14 adjacent to the opening 11 that allows the lead line 50 to pass downwardly therethrough further provides a degree of protection for the lead line 50 against abrasion during loading with explosive, such as from an explosive loading hose or upon loading with stemming.

[0058] Referring to the embodiment illustrated in Figure 10, the body 10 includes an aperture 18 adjacent to a peripheral edge of the body 10 for securing the lead line 50 and for use as a hand hold. In use, the lead line 50 can be wrapped one or more times around the aperture 18 and / or tied to the aperture 18 to retain the lead line 50 securely to the open end 41 of the blast hole 40.

[0059] The length of flexible tubular liner 20 comprises, in an open condition as illustrated in Figure 4, a cylindrical side wall 23 surrounding a longitudinal passage 24. Referring to Figures 1 and 3-13, an open upper end 21 of the flexible liner 20 is connected to the body 10, wherein the open end 21 of the flexible tubular liner 20 aligns axially with the opening 11 of the body 10. In embodiments as illustrated in Figure 13, the flexible tubular liner 20 includes an outwardly extending part 21 for connecting the open end 21 of the flexible tubular liner 20 to the body 10.

[0060] The flexible tubular liner 20 is connected to the body 10 by fasteners or an adhesive or by being clamped or fused thereto. In exemplary embodiments, the liner 20 is connected to the upper face 12 and / or lower face 13 of the body 10. Additionally, wherein the body 10 comprises an upper part 15 and a lower part 16, the upper end of the liner 20 is sandwiched between the upper part 15 and the lower part 16 of the body10 thereby connecting the flexible tubular liner 20 to the body 10, as illustrated in Figure 13.

[0061] An opposite lower end 22 of the liner 20 is sealed closed by being tied off with tie wire or by plastic welding (e.g. using heat or ultrasonic welding) or by other suitable means.

[0062] The flexible tubular liner 20 is comprised of a lay-flat tubular polymeric material. Suitable materials for the tubular liner 20 include low density polyethylene, polypropylene, or other suitable material with the desired characteristics such as abrasive-resistant, flexible, and / or waterproof materials. In another embodiment, the tubular liner 20 is formed out of an organic material such as a cellulose or another plant-based material.

[0063] The flexible tubular liner 20 has a length of 10m, or 15m, or 20m, or 25m, or 30m, or 35m, or 40m, or 45m or 50m, or any increment therebetween. The length of the flexible liner 20 is of a length at least equal to the total depth of the blast hole 40.

[0064] Referring to Figure 1 , 3, and 8, the liner 20 is gathered below the lower face 13 of the body 10. In exemplary embodiments, gathering the flexible tubular liner 20 below the lower face 13 of the body 10 is by means of bunching, concertinaing, or rolling the flexible tubular liner 20 below the lower face 13 of the body 10.

[0065] Preferably, the liner 20 is gathered below the lower face 13 of the body in such a way that, as illustrated in Figure 1(a), a longitudinal passage 17 is formed between the opening 11 within the body 10 and the sealed end 22 of the liner 20. In an embodiment, the liner 20 is gathered by inserting a length of tubing or pipe into the open end 21 towards the closed lower end 22. The wall 23 of the liner 20 is fed onto the tube or pipe so that the open end 21 and the closed end 22 of the liner 20 are brought towards each other over the outside of the tubing or pipe. The wall 23 of the liner 20 is fed onto the pipe until the entire length of the wall 23 is gathered on the pipe. The tubing or pipe operates to maintain the open longitudinal passage or lumen 17 within the tubular liner 20. The form is removed to leave behind the longitudinalpassage 17 within the gathered liner 20. The liner 20 can be gathered in the manner described above before or after connection with the body 10.

[0066] Referring to the embodiments of Figures 1 (a)-1 (d) and 8 to 10(b), the gathered liner 20 is retained below the lower face 13 of the body 10 by means of a liner retainer 30. The liner retainer 30 is adapted for retaining the gathered liner 20 below the lower face 13 of the body and for releasing the flexible tubular liner 20 down into the blast hole to be filled with bulk explosive material provided through the opening 11 within the body 10.

[0067] The liner retainer 30 is connected to the body 10 to gather and retain the liner 20 below the body 10 by fasteners or an adhesive or by being clamped or fused to the body 10.

[0068] In embodiments, the liner retainer 30 is adapted to release the liner 20 when a predetermined force is intentionally applied to the gathered liner 20 or to the liner retainer 30. The predetermined force applied to the gathered liner 20 or to the liner retainer 30, at least in part, disconnects the liner retainer 30 from the body 10 thereby releasing the gathered liner 20. In embodiments, the predetermined force is 10 newtons, 20 newtons, 30 newtons, 40 newtons, 50 newtons, 60 newtons, 70 newtons, 80 newtons, 90 newtons or 100 newtons or any increment therebetween. In other embodiments, the predetermined force is 110 newtons, 120 newtons, 130 newtons, 140 newtons, 150 newtons, 160 newtons, 170 newtons, 180 newtons, 190 newtons or 200 newtons or any increment therebetween. In other embodiments, the predetermined force is 210 newtons, 220 newtons, 230 newtons, 240 newtons, 250 newtons, 260 newtons, 270 newtons, 280 newtons, 290 newtons or 300 newtons or any increment therebetween.

[0069] In use, the predetermined force is applied to the closed lower end 22 of the liner 20 by manually inserting an object, such as a rod, into the opening 11 of the body 10 and imparting a sufficient force through the rod to the closed lower end 22 of the liner 20 to break the liner retainer 30, or to overcome the means by which the liner retainer 30 is connected to the body 10. In another embodiment, a bulk explosive material loading hose 70, such as that which is illustrated in Figure 5, is inserted intothe opening 11 of the body 10 and used to impart sufficient force through the rod to the closed lower end 22 of the liner 20.

[0070] In embodiments, the apparatus further includes a liner release 31 operable for releasing the liner retainer 30, preferably manually, to thereby release the liner 20 down into the blast hole. Preferably, the liner release 31 is located on the upper face 12 of the body 10. The liner release 31 located on the upper face 12 of the body 10 is advantageous as it enables accessible and fast deployment of the liner 20 when the apparatus 1 is located in an open end of the blast hole.

[0071] In preferred embodiments as illustrated in Figures 1 and 3 to 12, the liner retainer 30 includes a strap 32. The strap 32 wraps around the gathered liner 20 to retain the liner 20 below the lower face 13 of the body 10. In exemplary embodiments, the strap 32 is connected to the upper face 12 of the body 10 and the liner release 31 is accessible from above the upper face 12 of the body 10.

[0072] Connection of the strap 32 to the body 10 can be by fasteners, an adhesive or by being clamped or fused thereto. In embodiments in which the liner retainer 30 is a strap 32, the liner release 31 can be a tab formed at an end of the strap 32 fastened to the upper face 12 of the body 10. The liner release 31 is operable by pulling the tab to disconnect said end of the strap 32 from the body 10, thereby releasing the liner 20. The liner release 31 can also be the fastener that connects one end of the strap to the body 10, and activating said liner release 31 is by means of removing or undoing the fastener, thereby disconnecting the liner retainer 30 and releasing the liner 20.

[0073] The strap 32 is comprised of a plastic material such as polypropylene, polyester, and / or nylon, metals such as steel, organic materials, or other suitable strapping materials. The strap has a thickness of 0.1 mm, 1 mm, 5 mm or any increment therebetween. The strap has a width of about 10mm, 15mm, 20mm or any increment therebetween.

[0074] In further embodiments, the liner retainer 30 includes a container, preferably comprised of a rigid can, a flexible plastic cup-shaped member or a heat shrinkable polymeric cover material that covers the entire external surface of a side and,preferably, the closed end 22 of the gathered liner 20, for retaining the gathered liner below the lower face 13 of the body 10. The can or cup shaped member has a diameter at least equivalent to the external diameter of the gathered liner 20.

[0075] Referring to Figures 2 to 7, there is shown a method for loading bulk explosives into a blast hole, the method including locating an apparatus 1 in the open end 41 of a blast hole 40 including a body 10 comprising an upper face and a lower face and a centrally located opening within the body extending between the upper face and the lower face, a length of a flexible tubular liner connected to the opening, wherein the flexible tubular liner is gathered below the lower face of the body, and a liner retainer for retaining the gathered liner below lower face of the body, releasing the liner retainer, and providing bulk explosive material through the opening of the body to thereby fill the tubular liner with explosive material within the blast hole.

[0076] Referring to Figure 2, the blast hole 40 is comprised of a hollow column that is generally cylindrical in shape according to the diameter of the drill bit used to drill the blast hole 40. The blast hole 40 penetrates a sub-surface void or cavity 43 in the bedrock into which explosive material would spread in an uncontrolled manner upon loading the blast hole 40 with explosive material 60.

[0077] Referring to Figure 3, the method includes locating the apparatus 1 described above and illustrated in Figure 1 in the open end 41 of a blast hole 40. The body 10 engages the open end 41 of the blast hole 40 and / or the surface 42 surrounding the blast hole 40 to maintain the apparatus 1 at the open end 41 of the blast hole 40.

[0078] Referring to Figure 4, the method includes releasing the flexible tubular liner 20 gathered below the lower face 13 of the body 10. The flexible tubular liner 20 is retained below the lower face 13 of the body 10 by means of a liner retainer 30 with a liner release 31. Activating the liner release 31 of the liner retainer 30, releases the liner 20 from the liner retainer 30. Without being retained below the lower face 13 of the body 10, the liner 20 hangs from the body 10, wherein the open end 41 of the liner 20 is connected to the body 10, and the opposite end or the sealed end 22 of the liner 20 falls below the bottom end of the blast hole 40. Upon release from the liner retainer 30, the flexible tubular liner 20 may not fully extend below the bottom end of the blasthole 40, as illustrated in Figure 4 or may fully extend below the bottom end of the blast hole (not shown).

[0079] Figure 9 to 10 illustrate an embodiment in which the body 10 includes a upwardly open channel for receiving and retaining the lead line 50. In use, the lead line 50 can be inserted within the upwardly open channel 14 to retain the lead line 50 securely at the open end 41 of the blast hole 40. The body 10 can also include an aperture 18, as illustrated in Figure 10, adjacent to a peripheral edge of the body 10 for securing the lead line 50 and for use as a hand hold. In use, the lead line 50 can be wrapped one or more times around the aperture 18 and / or tied to the aperture 18 to retain the lead line 50 securely to the open end 41 of the blast hole 40.

[0080] Prior to charging with bulk explosive material 60, the operator provides an initiator 51 into the opening 11 of the body 10 as illustrated in Figure 12. The initiator 51 , which is preferably comprised of a detonator and a booster, are attached to the end of a lead line 50 which is dropped down through the opening 11 of the body 10. A length of the lead line 50 is fed into the blast hole 40 until the initiator 51 reaches an appropriate depth within the blast hole 40. In another embodiment as illustrated in Figure 11 , the apparatus can be pre-installed with the initiator 51 attached to the end of the lead line 50. In use, the initiator drops down within the blast hole as the gathered liner 20 is released from the liner retainer 30.

[0081] Referring to Figure 5, a bulk explosive material loading hose 70 is inserted into the opening 11 of the body 10 and explosive material 60 is gradually fed into the apparatus 1. The bulk explosive material 60, such as ANFO or an emulsion explosive, passes down through the opening 11 of the body 10 and through the open end 41 of the flexible tubular liner 20 to thereby fill the tubular liner 20 with explosive material 60 within the blast hole.

[0082] In embodiments illustrated in Figure 5 and 6, the explosive material 60 collects at the sealed end of the liner 20. If the liner is not already fully extended, the weight of the explosive material 60 allows the liner 20 to fully extend and the sealed end 15 of the liner 20 to reach the bottom of the blast hole. The liner 20 continues to fill with the explosive material 60 until the liner 20 is filled up to a desired level. Usually, the liner20 is filled to a level below the open end of the blast hole by a predetermined distance of 1 , 2, or more metres.

[0083] In another embodiment, the explosive loading hose 70 is inserted into the opening 11 of the body 10. If the liner is not already fully extended, the hose 70 can be used to fully extend the liner 20 towards the bottom of the blast hole. The hose is inserted towards the bottom of the blast hole until the liner 20 is fully extended and / or the sealed end of the liner 20 reach the bottom of the blast hole. The explosive material 60 is then pumped out through the explosive loading hose 70 into the liner 20. As the liner 20 is filled with the bulk explosive material 60, the explosive loading hose 70 is drawn upwards and out of the blast hole until the liner 20 is filled up to a desired level within the blast hole.

[0084] Subsequently, the operator would stem the blast hole by depositing an amount of stemming material 61 such as crushed rock, aggregates or other chosen stemming material into the blast hole. The stemming material 61 may be deposited into the open end 41 of the liner 20. The stemming material 61 will usually fill the portion of the blast hole left empty above the explosive material to the level of the open end of the blast hole. Finally, the initiator 51 from a series of the blast holes are tied and fired.

[0085] Embodiments of the invention provide a self-contained apparatus 1 that is readily deployable into a blast hole that includes a length of flexible liner for containing a full load of bulk explosive material within the blast hole. Embodiments of the invention are advantageous as they enable loading of blast holes with a predetermined amount of bulk explosive material and without uncontrolled spreading out of the bulk explosive material from the column of the blast hole.

[0086] Accordingly, embodiments of the apparatus illustrated in the Figures are advantageous in that they may provide an efficient and convenient method for the delivery of bulk explosives such as ANFO and explosive emulsion mixtures of varying compositions into blast holes. Embodiments of the invention are also advantageous by enabling the efficient loading of blast holes drilled into challenging geologies such as uneven terrain and / or geologies comprising sub-surface voids or cavities in the bedrock. Embodiments of the invention are also advantageous by enabling loading ofblast holes with a predetermined amount of explosive material and effectively containing the explosive material in the blast hole column and preventing the explosive material from spreading out from the blast hole column to fill geological voids penetrated by the blast hole.

[0087] Furthermore, embodiments of the invention are advantageous in that they provide an apparatus that provides an effective blast hole liner that can be quickly deployed into a blast hole. Such embodiments obviate the need for labour intensive and time-consuming drawing, cutting and insertion of long lengths of flexible blast hole liner material into a blast hole.

[0088] Furthermore, embodiments of the invention are advantageous in that they provide an apparatus that provides an effective blast hole liner into a blast hole that protects the liner from damage or tearing during the insertion process and / or the explosive loading process.

[0089] Although the disclosure has been described with reference to specific examples, it will be appreciated by those skilled in the art that the disclosure may be embodied in many other forms, in keeping with the broad principles and the spirit of the disclosure described herein.

Claims

CLAIMS1. An apparatus for lining a blast hole, the apparatus including: a body comprising an upper face and a lower face and a centrally located opening within the body extending between the upper face and the lower face; a length of a flexible tubular liner in a gathered state below the lower face of the body and comprising a longitudinal passage extending between an open upper end connected to the opening and a closed lower end; and a liner retainer for retaining the liner in the gathered state below the lower face of the body; wherein the body is adapted to be retained at or near the open end of a blast hole and the liner retainer is operable for releasing the flexible tubular liner down into the blast hole to be filled with bulk explosive material provided through the opening within the body.

2. The apparatus of claim 1 , wherein in the gathered state the longitudinal passage of the liner is empty.

3. The apparatus of claim 1 or claim 2, wherein the liner retainer is responsive to a predetermined force intentionally applied to the gathered liner or the liner retainer to release the flexible tubular liner.

4. The apparatus of any one of the preceding claims, wherein the liner retainer extends over an external surface of a side and the closed end of the gathered liner for retaining the gathered liner below the lower face of the body.

5. The apparatus of any one of the preceding claims, wherein the liner retainer includes a strap and / or a container, wherein the container covers the entire external surface of a side and the closed end of the gathered liner.

6. The apparatus of any one of the preceding claims, further including a liner release that is intentionally operable for causing the liner retainer to release the flexible tubular liner down into the blast hole.

7. The apparatus of claim 6, wherein the liner release is accessible from above the upper face of the body.

8. The apparatus of claim 6 or claim 7, wherein the liner retainer is connected to the body and the liner release is operable to, at least partially, disconnect the liner retainer from the body and thereby release the flexible tubular liner down into the blast hole.

9. The apparatus of any one of claims 6 to 8, wherein the liner retainer comprises a strap that retains the gathered liner and wherein one end of the strap is connected to the upper face of the body and the liner release includes a portion of the strap that is manually operable for at least partially disconnecting the strap from the upper face of the body.

10. The apparatus of any one of the preceding claims, wherein the body is selfretaining at or near the level of a surface surrounding the open end of the blast hole.11 . The apparatus of claim 10, wherein the lower face of the body engages the open end of the blast hole for retaining the apparatus at or near the level of the surrounding surface.

12. The apparatus of any one of the preceding claims, wherein the body comprises an upper part and a lower part, wherein the opening through the body comprises an upper portion of the opening through the upper part and a lower portion of the opening through the lower part, wherein the upper portion of the opening has a smaller diameter and / or circumference than the lower portion of the opening.

13. The apparatus of claim 12, wherein the liner is connected to the body between the upper part and the lower part of the body.

14. The apparatus of claim 12, wherein an upper end of the liner is sandwiched between the upper part and the lower part of the body.

15. The apparatus of claim 12, wherein the liner has a diameter, in an open state, that is larger than the diameter of the upper portion of the opening.

16. The apparatus of any one of the preceding claims, wherein in the gathered state the liner comprises an empty longitudinal passage extending between the upper end connected to the body and a lower closed end.

17. The apparatus of any one of the preceding claims, wherein in the gathered state, the exterior of the liner is substantially free of any surrounding along at least a portion of, or substantially the entire longitudinal length of the liner.

18. The apparatus of claim 1 , wherein the body includes an upwardly open channel extending transversely from the opening for receiving and retaining a lead line, wherein a portion of the channel adjacent to the opening is open downwardly for the lead line to pass downwardly therethrough.

19. The apparatus of claim 1 , wherein the body includes an aperture adjacent to a peripheral edge for securing the lead line and for use as a hand hold.

20. A method for loading bulk explosives into a blast hole, the method including: locating an apparatus in the open end of a blast hole including a body comprising an upper face and a lower face and a centrally located opening within the body extending between the upper face and the lower face, a length of a flexible tubular liner in a gathered state below the lower face of the body and comprising a longitudinal passage extending between an open upper end connected to the opening and a closed lower end, and a liner retainer for retaining the liner in the gathered state below the lower face of the body; releasing the liner retainer whereby the liner extends down into the blast hole; providing bulk explosive material through the opening of the body to thereby fill the tubular liner with explosive material within the blast hole.

21. The method of claim 20, wherein locating the apparatus in the open end of a blast hole includes placing the body with the lower face engaging the open end of the blast hole for retaining the apparatus at or near the level of the surrounding surface.

22. The method of claim 20 or claim 21 , including connecting an open end of a length of a flexible tubular liner to the body and sealing closed the other end of the liner.

23. The method of any one of claims 20 to 22, including gathering the flexible tubular liner below the lower face of the body and securing the liner in the gathered state to the lower face of the body with the liner retainer.

24. The method of any one of claims 20 to 23, further including placing an initiator in the flexible tubular liner and depositing an amount of stemming material into the blast hole.

25. The method of any one of claims 20 to 24, wherein intentionally releasing the liner retainer includes applying a predetermined downward force to the gathered liner or the liner retainer.

26. The method of claim 25, wherein a hose for providing bulk explosive material is inserted through the opening of the body towards a sealed end of the gathered liner to apply the predetermined downward force to the gathered liner.

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