AU2016206394A1 - A shell for use in blasting - Google Patents

Abstract

H: \xb\lInterwoven\NRPortbl\DCC\TXB\105342051.docx-22/07/2016 A shell for use in blasting, the shell comprising an elongated body arranged for insertion and explosion in a hole, the elongated body having a distal end arranged for 5 housing an explosive material, a proximal end arranged to permit introduction of at least one detonator into an interior of the shell, and an intermediate portion for holding the at least one detonator in a location in which operation of the detonator results in explosion of the explosive material, wherein an aperture is provided in a sidewall of the shell to allow an activation wire connected to the detonator to pass through the aperture to an exterior of 10 the shell. Figure 1

Description

A SHELL FOR USE IN BLASTING

This application is a divisional application derived from Australian Patent Application No. 2012205130, the entire contents of which, as originally filed, are incorporated herein by reference.

Field of the Invention

The invention relates to a shell for use in blasting.

Background of the Invention

Blasting is a common technique in mining for fracturing a substrate, such as rock, to facilitate excavation and removal. Blasting involves controlled explosions, typically using shells that contain an explosive charge that is initiated by a detonator. A detonator is a device for initiating an explosive, and may be in the form of an explosive device that has transmission wires attached to initiate the explosive from a remote position on the surface. The explosive charge is primed with the detonator sitting in the explosive or explosive cavity region, with the transmission wires protruding outside the shell and any attached anchoring devices up to the surface of the blasthole. It is critical for successful explosives initiation that the integrity of the transmission wires be preserved, as compromised wires can result in an abandoned charge and potentially dangerous condition.

The applicant has determined that the detonator transmission wires can be damaged or broken under blasthole loading conditions and that wire exposure to the medium surrounding the blasthole contributes significantly to wire damage.

Examples of the present invention seek to provide a shell which overcomes or at least alleviates one or more disadvantages associated with existing shells.

Summary of the Invention

In accordance with one aspect of the present invention, there is provided a shell for use in blasting, the shell comprising an elongated body arranged for insertion and explosion in a hole, the elongated body having a distal end arranged for housing an explosive material, a proximal end arranged to permit introduction of at least one detonator into an interior of the shell, and an intermediate portion for holding the at least one detonator in a location in which operation of the detonator results in explosion of the explosive material, wherein an aperture is provided in a sidewall of the shell to allow an activation wire connected to the detonator to pass through the aperture to an exterior of the shell.

Preferably, the proximal end is arranged to permit introduction of two detonators, and the intermediate portion is adapted to hold both detonators in a location in which operation of either or both detonator results in explosion of the explosive material.

Preferably, a ridge is provided on an exterior surface of the side wall to protect the wire from abrasion during insertion of the shell in the hole. More preferably, the ridge is formed at a leading edge of the aperture. Even more preferably, the ridge extends longitudinally along the sidewall on either side of the aperture to define a protective region for running the wire from the aperture to a proximal end of the sidewall.

In one form, the ridge extends to the proximal end of the sidewall on either side of the aperture.

Preferably, the distal end portion is threaded. More preferably, the proximal end portion is threaded. Even more preferably, the distal end portion has an external thread and the proximal end portion has an internal thread.

In a preferred form, the external and internal threads are configured such that like shells can be coupled together by threading the distal end of one shell into the proximal end of the other shell.

Preferably, the internal thread is also configured such that the proximal end of the shell can be coupled to an external thread of an anchoring device.

Preferably, the intermediate portion is arranged to contain ignition material in proximity to the at least one detonator.

Preferably, the aperture is sized to allow a detonator to pass therethrough.

In a preferred form, the sidewall has a second aperture, a bridge portion for supporting the wire between the first aperture and the second aperture, and a recessed tunnel along an interior surface of the sidewall leading longitudinally from the second aperture toward the proximal edge of the sidewall.

More preferably, the ridge defines an external passage from the first aperture to the proximal edge of the sidewall, and the tunnel defines an internal passage from the second aperture to the proximal edge of the sidewall, allowing passage of the wire in two alternative configurations.

In one form, the ridge and the tunnel each have a depth equal to or greater than a thickness of the wire.

Preferably, the ridge defines a leading bulb shape at a leading edge of the protective region.

Preferably, at least one of the first and second apertures are sized to allow a detonator to pass therethrough.

Brief Description of the Drawings

The invention is described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figure lisa perspective side view of a shell for use in blasting in accordance with an example of the present invention, showing a detonator wire in a looped configuration;

Figure 2 is an opposite side perspective view of the shell;

Figure 3 is a side view of the shell;

Figure 4 is an end perspective view of the shell;

Figure 5 is a distal end perspective view of the shell; and

Figure 6 is a distal end perspective view of the shell, showing the detonator wire in a straight configuration.

Detailed Description

With reference to Figures 1 to 6, there is shown a shell 10 for use in blasting, the shell comprising an elongated body 12 arranged for insertion and explosion in a hole, for example, for use in seismic exploration operations. The shell 10 is adapted to provide improved protection of a wire of a detonator which initiates explosive material contained within the shell 10. More specifically, the elongated body 12 has a distal end 14 arranged for housing an explosive material 16, a proximal end 18 arranged to permit introduction of at least one detonator 20 into an interior of the shell 10, and an intermediate portion 22 for holding the at least one detonator 20 in a location in which operation of the detonator 20 results in explosion of the explosive material. The explosive material 16 may typically be in a liquid or granular form that is pumped, injected or poured into the distal end 14 of the shell 10. An aperture 24 is provided in a side wall 26 of the shell 10 to allow an activation wire 28 connected to the detonator 20 to pass through the aperture 24 to an exterior of the shell 10. Advantageously, by virtue of the aperture 24, additional protection for the activation wire 28 is provided. In particular, the aperture 24 facilitates longitudinal support of the wire 28 and/or shielding of the wire 28 from the structure of the hole in which the shell 10 is inserted, as described in further detail below. Alternatively or additionally, the aperture 24 facilitates shielding the wire 28 from a like shell and / or another device (such as an anchoring device) that may be inserted in the proximal end 18 of the shell 10.

Figure 1 shows a side perspective view of the shell 10 which displays the manner in which the activation wire 28 runs along a tunnel 30 which is formed on an interior surface of the side wall 26. Figure 2 shows an opposite side perspective view of the shell 10 which displays a looped configuration of the activation wire 28, wherein the activation wire 28 exits the shell 10 through the first aperture 24, crosses a bridge 32, enters the shell 10 through a second aperture 34, and runs along the tunnel 30. Figure 3 shows a side view of the shell 10 which displays both the distal end 14 and the proximal end 18 having a generally circular cross section, with the intermediate portion 22 having a narrowed cross section.

With reference to Figure 4, the proximal end 18 is arranged to permit introduction of two detonators 20, although only one detonator 20 is shown. The intermediate portion 22 has a pair of receptacles 23 that are each for receiving a detonator. In these receptacles 23, the intermediate portion is able to hold both detonators in a location in which operation of either or both detonator results in explosion of the explosive material 16.

As shown clearly in the perspective view of Figure 5, a ridge 36 is provided on an exterior surface of the side wall 26 to protect the wire 28 from abrasion during insertion of the shell 10 in the hole. The ridge 36 is formed at a leading edge 38 of the first aperture 24. The ridge 36 extends longitudinally along the side wall 26 on either side of the first aperture 24 to define a protective region 40 for running the wire(s) 28 from the aperture 24 to a proximal end 42 of the side wall 26. The ridge 36 may extend to the proximal end 42 of the side wall 26 on either side of the first aperture 24. Although this is achieved in the example shown by way of the ridge curving back around the second aperture 34 to an opposite side of the bridge 32 so as to form an elongated conduit along an external surface of the side wall 26, in an alternative example, the ridge may curve simply around the first aperture 24 in a generally 180 degree turn, and the second aperture 34 and tunnel 30 may be omitted.

The distal end 14 is threaded with an external thread 44, and the proximal end 18 has an internal thread 46. The external and internal threads 44, 46 may be configured such that like shells can be coupled together by threading the distal end of one shell into the proximal end of the other shell. The internal and external threads can also be used to connect the shell 10 to various anchoring and / or loading devices.

The intermediate portion 22 may be arranged to contain ignition and /or explosive material in proximity to the at least one detonator 20.

Advantageously, the shell 10 shown in the drawings allows passage of the activation wire 28 in two alternative configurations: the "looped" configuration shown in Figures 1 to 5, in which the wire 28 extends internally of the side wall 26, and within the recessed tunnel 30; or the "straight" configuration shown in Figure 6, in which the wire 28 extends externally of the side wall 26, and within the protective region 40. The looped configuration is achieved by virtue of the side wall 26 having the second aperture 34, the bridge portion 32 for supporting the wire 28 between the first aperture 24, the second aperture 34, and the recessed tunnel 30 along the interior surface of the side wall 26. The tunnel 30 leads longitudinally from the second aperture 34 toward the proximal edge 42 of the side wall 26. Similarly, the ridge 36 defines an external passage (which is the protective region 40) from the first aperture 24 to the proximal edge 42 of the side wall 26, and the tunnel 30 defines an internal passage from the second aperture 34 to the proximal edge 42 of the side wall 26. Where two detonators are used, either or both of the internal and external passages may be utilised.

The ridge 36 and tunnel 30 may each have a depth equal to or greater than a thickness of the wire 28 such that the wire is able to fit snugly within the internal or external passage where it is able to be housed away from abrasion/damage. Advantageously, by protecting the wire 28 from abrasion and breakage, reliability of the explosive is improved such that fewer undetonated explosives will pose a danger. The ridge 36 may define a leading bulb shape 48 at a leading edge 38 of the protective region 40 to assist in preventing ground material from the hole in which the shell 10 is inserted from interfering with the wire 28.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope -7 - of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

In one variation, the detonator may be in the form of a two-part wired laser initiator. The explosive part of the initiator may be contained within the shell, whereas the part that is attached to the shell in field-use may be non-explosive. The part containing the wires may benefit from the improved design/configuration of examples of the present invention.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (18)

1. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

   1. A shell for use in blasting, the shell comprising an elongated body arranged for insertion and explosion in a hole, the elongated body having a distal end arranged for housing an explosive material, a proximal end arranged to permit introduction of at least one detonator into an interior of the shell, and an intermediate portion for holding the at least one detonator in a location in which operation of the detonator results in explosion of the explosive material, wherein an aperture is provided in a sidewall of the shell to allow an activation wire connected to the detonator to pass through the aperture to an exterior of the shell.
2. 2. A shell as claimed in claim 1, wherein the proximal end is arranged to permit introduction of two detonators, and the intermediate portion is adapted to hold both detonators in a location in which operation of either detonator results in explosion of the explosive material.
3. 3. A shell as claimed in claim 1 or claim 2, wherein a ridge is provided on an exterior surface of the side wall to protect the wire from abrasion during insertion of the shell in the hole.
4. 4. A shell as claimed in claim 3, wherein the ridge is formed at a leading edge of the aperture.
5. 5. A shell as claimed in claim 3, wherein the ridge extends longitudinally along the sidewall on either side of the aperture to define a protective region for running the wire from the aperture to a proximal end of the sidewall.
6. 6. A shell as claimed in claim 5, wherein the ridge extends to the proximal end of the sidewall on either side of the aperture.
7. 7. A shell as claimed in any one of claims 1 to 6, wherein the distal end is threaded.
8. 8. A shell as claimed in claim 7, wherein the proximal end is threaded.
9. 9. A shell as claimed in claim 8, wherein the distal end has an external thread and the proximal end has an internal thread.
10. 10. A shell as claimed in claim 9, wherein the external and internal threads are configured such that like shells can be coupled together by threading the distal end of one shell into the proximal end of the other shell.
11. 11. A shell as claimed in any one of claims 1 to 10, wherein the intermediate portion is arranged to contain ignition and/ or explosive material in proximity to the at least one detonator.
12. 12. A shell as claimed in any one of claims 1 to 11, wherein the sidewall has a second aperture, a bridge portion for supporting the wire between the first aperture and the second aperture, and a recessed tunnel along an interior surface of the sidewall leading longitudinally from the second aperture toward the proximal edge of the sidewall.
13. 13. A shell as claimed in claim 12, wherein said ridge defines an external passage from the first aperture to the proximal edge of the sidewall, and the tunnel defines an internal passage from the second aperture to the proximal edge of the sidewall, allowing passage of the wire in two alternative configurations.
14. 14. A shell as claimed in claim 13, wherein the ridge and the tunnel each have a depth equal to or greater than a thickness of the wire.
15. 15. A shell as claimed in any one of claims 1 to 14, wherein the ridge defines a leading bulb shape at a leading edge of the protective region.
16. 16. A shell as claimed in any one of claims 1 to 11, wherein the aperture is sized to allow a detonator to pass therethrough.
17. 17. A shell as claimed in any one of claims 12 to 14, wherein at least one of the first and second apertures are sized to allow a detonator to pass therethrough.
18. 18. A shell for use in blasting substantially as hereinbefore described with reference to the accompanying drawings.