WO2019053528A1

WO2019053528A1 - Explosives blasting

Info

Publication number: WO2019053528A1
Application number: PCT/IB2018/055838
Authority: WO
Inventors: Laurence Justin Pienaar Wilson; André Pienaar; Gabriel Hendrik SMIT
Original assignee: Ael Mining Services Limited
Priority date: 2017-09-12
Filing date: 2018-08-03
Publication date: 2019-03-21
Also published as: ZA201906906B; WO2019053527A1; ZA201906905B

Abstract

A method of explosives blasting includes the steps of pressure-tightly sealing gassed emulsion explosive inside an explosives blasting container and locating the sealed explosives blasting container at a blasting location.

Description

EXPLOSIVES BLASTING

FIELD OF THE INVENTION THIS INVENTION relates to explosives blasting. The invention provides a method of explosives blasting.

SUMMARY OF THE INVENTION

IN ACCORDANCE WITH ONE ASPECT OF THE INVENTION IS PROVIDED a method of explosives blasting, which method includes the steps of

pressure-tightly sealing gassed emulsion explosive inside an explosives blasting container; and

locating the sealed explosives blasting container at a blasting location. By "pressure-tightly sealing" is meant that the explosives blasting container is closed such that the pressure inside of the explosives blasting container after sealing, to which the gassed emulsion explosive is subjected, remains substantially unaffected by changes in ambient pressure outside of the explosives blasting container. It would be appreciated that "pressure-tightly" includes "air-tightly".

Thus, for example, pressure tightly sealing the explosives blasting container would be such that an increase in ambient pressure e.g. due to submergence of the explosives blasting container in water, does not result in a concomitant increase in pressure inside of the explosives blasting container, with the pressure inside of the explosives blasting container remaining substantially constant. Further, "explosives blasting container" means a container in which detonation of the emulsion explosive is ultimately initiated, i.e. from which it is not transferred for the purpose of detonation.

The method of explosives mining may form part of a method of mining.

The explosives blasting container may comprise a plurality of compartments containing gassed/sensitized emulsion explosive. In this specification generally, "gassed" or "gassing" refers to the well-known practice of sensitization of emulsion explosives through gassing thereof, typically by using some or other gassing agent such as a gassing solution.

The method may include a later step of intentionally causing, e.g. by initiating, detonation of the gassed emulsion explosive contained in the explosives blasting vessel at the blasting location.

The method may include an earlier step of gassing emulsion explosive to obtain the gassed/sensitized emulsion explosive.

The step of gassing (sensitizing) of emulsion explosive to obtain the gassed/sensitized emulsion explosive may be effected outside of and/or inside of the explosives blasting container. Preferably the step of gassing of emulsion explosive to obtain the gassed emulsion explosive is at least partly effected inside of the explosives blasting container. It will be appreciated that the step of gassing of emulsion explosive would be effected prior to the step of pressure-tightly sealing the explosives blasting container. Preferably, the step of gassing of emulsion explosive is fully effected, i.e. such that the gassed emulsion explosive is fully gassed, before effecting the step of pressure-tightly sealing the pressure explosives blasting container.

The method may also include an earlier step of loading the explosives blasting container with emulsion explosive. It will be appreciated that, in accordance with the invention, emulsion explosive loaded into the explosives blasting container may be un- gassed, partially gassed, or fully gassed.

Typically, locating the sealed explosives blasting container at the blasting location would include vertically lowering the sealed explosives blasting container.

In one embodiment of the invention, vertically lowering the sealed explosives blasting container may be effected in water. Thus, in such an embodiment, the blasting location may be underwater, with the method thus effectively being a method of underwater blasting.

A vertical distance that the sealed explosives blasting container may be lowered may be from surface to any depth. In a preferred embodiment of the invention, the explosives blasting container comprises an elongate hollow pipe. The invention thus extends, as a separate aspect thereof, to such an explosives blasting container. Typically, the pipe may have a length of from 1 m to 6m.

The pipe may have a diameter of from 25mm to 300mm.

The step of pressure-tightly sealing the pipe may include closing open ends of the pipe.

Closing open ends of the pipe would typically be effected by means of removable closures. It will be appreciated that one end of the pipe would typically need to be closed before effecting the step of loading the pipe with emulsion explosive.

The method may also include locating means for initiating detonation of the gassed/sensitized emulsion explosive in initiating vicinity to the gassed emulsion explosive. Typically, the explosives blasting container may provide the means for initiating detonation of the gassed emulsion explosive, e.g. with such means being mounted to the explosives blasting container.

Such means for initiating detonation of the gassed emulsion explosive may typically be selected from an electronic detonator and a pyrotechnic detonator. BRIEF DESCRIPTION OF THE DRAWINGS

THE INVENTION WILL NOW BE DESCRIBED IN MORE DETAIL with reference to the following diagrammatic drawings which show a cap and two closures for pressure- tightly sealing a pipe part of an explosives blasting container in accordance with the invention for use in accordance with the method of the invention.

More specifically,

FIGURE 1 shows, in one perspective view, a cap for a pipe part of an explosives blasting container for use in accordance with the method of invention;

FIGURE 2 shows, in another perspective view, the cap of Figure 1 ;

FIGURE 3 shows, in one perspective view, one closure for a pipe part of an explosives blasting container for use in accordance with the invention;

FIGURE 4 shows, in another perspective view, the closure of Figure 3;

FIGURE 5 shows in one perspective view, another closure for a pipe part of an explosives blasting container for use in accordance with the invention;

FIGURE 6 shows, in another perspective view, the closure of Figure 5; and FIGURE 7 shows, in perspective view, a pressure-tightly sealed explosives blasting container for use in accordance with the method of the invention. DETAILED DESCRIPTION OF THE INVENTION

REFERRING TO THE DRAWINGS, reference numerals 10, 20 and 30 respectively generally indicate a cap, one closure and another closure for a pipe part of an explosives blasting container for use in accordance with the invention. In use, the closures 20, 30 would serve to close, pressure-tightly, the pipe part, and the cap 10 would serve to assist with handling of the explosives blasting container in locating it at a blasting location, and to accommodate an initiating device for initiating detonation of gassed/sensitized emulsion explosive contained inside the pipe part in use. These functions are elaborated on below, with reference to physical characteristics of the cap 10 and closures 20, 30.

The pipe part may be an off-the-shelf pipe. The pipe would, in the present embodiment, be screw-thread at its ends, typically with a male, i.e. outer, thread at one end and a female, i.e. inner, thread at the other end.

To close the pipe at the male screw-thread end of the pipe, the closure 20 has a female screw thread 22 at one of its ends.

To close the pipe at the female screw-thread end of the pipe, the closure 30 has a male screw-thread 32 at one of its ends.

The other end of each of the closures 20, 30 is screw-thread with a male screw-thread 24, 34, to be received by a female screw-thread at one end 12 of the cap 10, for respective caps to be mounted to each of the closures 20, 30.

The other end 14 of the cap 10 is conical with a rounded apex 16. In use, the rounded apex 16 would facilitate handling in that it would prevent the explosives blasting container from being caught by interfering structures, e.g. rock outcrops, while being displaced to a blasting location, typically at least by vertical lowering of the explosives blasting container in accordance with the invention.

The apex 16 has apertures 18 defined in it (only one being visible in each of Figures 1 and 2). In use, a handling aid such as a rope can be threaded through the apertures 18, to assist with handling of the explosives blasting container, e.g. its displacement to a blasting location.

Each of the closures 20, 30 defines, by means of elongate cylindrical formations 25, 35, an elongate cylindrical cavity 26, 36. These cavities 26, 36 in use axially align with a cavity 19 in the cap 10. The cavity 19 in the cap 10 serves for mounting of an initiating device, which is typically of elongate cylindrical construction. By mounting of caps 10 to the closures 20, 30, the initiating device would be received in the cavities 24, 34 of the closures 20, 30 respectively.

It is noted that mounting of caps 10 to the closures 20, 30 does not result in a pressure- tight seal between the caps 10 and the closures 20, 30.

It is also noted that screwing engagement between the male screw thread end of the pipe and the female screw thread 22 of the closure 20, and between the female screw thread end of the pipe and the male screw thread 32 of the closure 30, the pipe is sealed pressure tightly.

In use, in accordance with the method of the invention, gassed emulsion explosive would be sealed inside the pipe by means of the closures 20, 30. Caps 10 would then be fitted to each of the closures 20, 30, and rope would be thread through the apertures 18 for displacement of the explosives blasting container to a blasting location.

The above "in use" configuration is illustrated in Figure 7, in which reference numeral 100 generally indicates a pressure-tightly sealed explosives blasting container for use in accordance with the method of the invention.

The container 100 includes a pipe 102 which has an internal thread at its one end 104 and an external thread at its other end 106 (neither thread being visible). The external thread is threadingly engaged with the internal thread of the closure 20, and the internal thread is threadingly engaged with one of the external threads of the closure 30. Each closure 20, 30 has a cap 10 mounted to it, in each case through threading engagement between the internal thread of the cap 10 and the external thread of the closure 20 and the other external thread of the closure 30.

Claims

1 . A method of explosives blasting, which method includes the steps of pressure-tightly sealing gassed emulsion explosive inside an explosives blasting container; and

locating the sealed explosives blasting container at a blasting location.

2. The method according to claim 1 , which includes an earlier step of gassing emulsion explosive to obtain the gassed emulsion explosive.

3. The method of claim 2, wherein the step of gassing of emulsion explosive to obtain the gassed emulsion explosive is effected outside of and/or inside of the explosives blasting container.

4. The method of claim 2 or claim 3, wherein the step of gassing of emulsion explosive is fully effected, such that the gassed emulsion explosive is fully gassed, before effecting the step of pressure-tightly sealing the pressure explosives blasting container.

5. The method according to any of claims 1 to 4, wherein locating the sealed explosives blasting container at the blasting location includes vertically lowering the sealed explosives blasting container.

6. The method according to any of claims 1 to 5, wherein locating the sealed explosives blasting container at the blasting location includes vertically lowering the sealed explosives blasting container in water, with the blasting location thus being underwater.

7. The method according to any of claims 1 to 6, wherein the explosives blasting container comprises an elongate hollow pipe.

8. The method according to claim 7, wherein the pipe may has a length of from 1 m to 6m.

9. The method according to claim 7 or claim 8, wherein the pipe has a diameter of from 25mm to 300mm.

10. The method according to any of claims 7 to 9, wherein the step of pressure-tightly sealing the explosives blasting container includes closing open ends of the pipe.

1 1. The method according to claim 10, wherein closing open ends of the pipe is effected by means of removable closures.

12. The method according to any of the preceding claims, which includes locating means for initiating detonation of the gassed emulsion explosive in initiating vicinity to the gassed emulsion explosive.

13. The method according to any of the preceding claims which includes a later step of intentionally causing detonation of the gassed emulsion explosive contained in the explosives blasting vessel at the blasting location.