Patent Application
20230280142
The present invention relates to the on demand treatment of bulk oxidiser (for making bulk explosives) or bulk explosives for use in reactive ground to prevent premature detonation of the explosives.
In surface mining operations blasting is generally carried out by drilling a pattern of blast holes into a geological formation. The holes are filled with an uninhibited explosive, typically in lose pored solid, liquid or gel form, which is detonated to break up rock of the formation.
After inserting explosives into the holes, the uninhibited explosives can interact with the surrounding lithology when the composition comprises certain reactive substances such as pyrite. The reaction may cause premature detonation of the explosives prior to the intended detonation time.
The explosives to be inserted into the holes can be treated with an inhibitor to prevent an interaction between the explosives and reactive ground which results in premature detonation, misfiring, or other undesired outcomes.
The process for inhibiting explosives currently requires knowledge of the site specific geology prior to dispatching or mixing explosives on site. In other words, the inhibited explosives become inhibited for the conditions of the specific site and cannot be used on other reactive ground sites, unless the other site has the same reactivity.
Typically, bulk uninhibited explosives are treated to become bulk inhibited explosive within a vessel in which the inhibitor is added to/combined with the uninhibited explosives. Once this occurs the whole of the bulk explosives in the vessel is treated separately from uninhibited explosives or their raw materials thereof and additional storage of the inhibited explosives is required. The inhibited explosives cannot be mixed with standard bulk explosives raw materials. Also equipment holding or handling the inhibited explosives needs to be cleaned (eg. washed down) before different explosives or material can be held or handled in that equipment.
If areas in the vicinity of blasting activities are found to be reactive, the entire area is treated as having reactive geology due to the difficulties in the logistics of carrying alternative bulk explosives or having 2 different mobile processing units (MPU)/mobile manufacturing units (MMU). This can result in inhibited bulk explosive being used for non-reactive ground, which is less efficient and/or wasteful of the inhibitor.
US Application 2019/0257,632 discloses a process of making inhibited bulk explosives from uninhibited emulsion matrix 31 (comprising a mixture of fuel oil and aqueous oxidizer solution) and by injecting inhibitor 51 storing in reservoir 50 into the emulsion matrix stored in reservoir 30 using injector 52 to produce only a continuous inhibited bulk explosives in stream 47 which is provided to mixer 60. The teaching of this document exemplifies the problem as it does not obviate the need to 2 MPU/MMUs.
U.S. Pat. No. 6,125,761 depicts a system in which inhibitor is added to an uninhibited emulsion explosive in order to form an inhibited emulsion explosive mixture, which is either mixed off-site and then transported to site or mixed on site and stored on site before insertion into a blast hole. This requires pre-mixed inhibited emulsion explosive to be transported to site or storage containers on site for mixing on site. Adding an inhibitor is an irreversible process such that after an inhibitor is added to an uninhibited emulsion explosive and converted to an inhibited emulsion explosive then it is the only emulsion explosive available for use. Therefore there is no option to selectively decide which explosives (inhibited or uninhibited) are to be inserted into a blast hole once the storage of uninhibited bulk explosive is converted to an inhibited bulk explosive, regardless of whether or not subsequent blast holes have been found to have reactive ground. Further the addition of the inhibitor increases the cost per unit of volume of the explosives and requires 2 MPU/MMU's if loading inhibited or uninhibited bulk explosives from the same bulk explosives plant.
Accordingly, the current situation presents limitations.
Any document, reference, patent application or patent that might be cited in this text is expressly incorporated herein in their entirety by reference, which means that it should be read and considered by the reader as part of this text. That the document, reference, patent application, or patent cited in this text is not repeated herein is merely for reasons of conciseness.
In this specification, where a literary work, act or item of knowledge (or combinations thereof), is discussed, such reference is not an acknowledgment or admission that any of the information referred to formed part of the common general knowledge as at the priority date of the application. Such information is included only for the purposes of providing context for facilitating an understanding of the inventive concept/principles and the various forms or embodiments in which those inventive.
According to a first aspect of the invention, there is provided an apparatus for selectively outputting either one at a time of two alternative outputs, the alternative outputs consisting of: an uninhibited bulk explosive and an inhibited bulk explosive, the apparatus comprising:
In an embodiment the outlet is for streaming the output of bulk explosive into a blast hole. In an alternative the outlet is for streaming the output of bulk explosive into plant or equipment.
According to a second aspect of the invention, there is provided an apparatus for selectively outputting either one at a time of two alternative outputs, the alternative outputs consisting of: an uninhibited bulk explosive oxidiser and an inhibited bulk explosive oxidiser, the apparatus comprising:
Typically, the oxidiser is dry or substantially dry, preferably dry ammonium nitrate (dry AN). The dry AN may be in prill or other form.
According to a third aspect of the invention, there is provided a vehicle for producing an inhibiting oxidiser for mixing with at least one other ingredient (such as for example fuel oil) to form an inhibited bulk explosive at the site of use of the inhibited bulk explosive, the vehicle comprising:
a storage for carrying inhibited bulk explosive oxidizer and a storage for the least one other ingredient to the site of a blast hole and a dispersion means for adding the least one other ingredient into to a stream of inhibited bulk explosive oxidiser from the storage so as to convert the stream of uninhibited bulk explosive oxidiser into a stream of inhibited bulk explosive for insertion into a blast hole.
In an embodiment the dispersion means is configured for inhibited bulk explosive oxidizer that is in a dry or substantially dry form.
According to a fourth aspect of the invention, there is provided a device for selectively outputting either one at a time of two alternative outputs, the alternative outputs consisting of: an uninhibited bulk explosive and an inhibited bulk explosive, the device comprising:
In the preferred embodiment of the invention, the bulk explosive is Ammonium Nitrate Fuel Oil (ANFO), Heavy ANFO (HANFO), Emulsion blends, Water-gels or bulk oxidiser.
In the preferred embodiment of the invention, the inhibitor comprises zinc oxide or urea or a mixture of zinc oxide and urea.
In an embodiment of the invention, the dispersion means is configured to disperse the inhibitor on demand into the stream of uninhibited bulk explosive.
In an embodiment of the invention, the dispersion means is configured to inject the inhibitor on demand into the stream of uninhibited bulk explosive.
In an embodiment of the invention, the dispersion means comprises a nozzle.
In the preferred embodiment of the invention, the dispersion means is adjacent to the outlet. The dispersion means may also be at an opening of the outlet.
In an embodiment of the invention, the dispersion means is upstream of the opening.
In an embodiment of the invention, the dispersion means is downstream of the opening.
In the preferred embodiment of the invention, the apparatus further comprises a feed to the dispersion means.
In the preferred embodiment of the invention, the dispersion means comprises a control means for feeding the inhibitor to the dispersion means on demand.
In the preferred embodiment of the invention, the control means comprises a valve.
In an embodiment of the invention, the outlet comprises an auger, chute, hopper or suitable conduit.
According to a fifth aspect of the invention, there is provided a method for selectively outputting either one at a time of two alternative outputs, the alternative outputs consisting of: an uninhibited bulk explosive and an inhibited bulk explosive for insertion into a blast hole, the method comprising:
According to a sixth aspect of the invention, there is provided a method for outputting inhibited bulk explosive into a blast hole, the method comprising:
Throughout the specification and claims, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
In order to provide a better understanding of the present invention embodiments will now be described may be described, by way of example only, with reference to the drawings, in which:
Referring to
Referring to
The on demand ability in this embodiment is apparent when the crusher 32 is turned on or off or when inhibitor 30 is inserted into the feed 31 or left empty. In the instance where the rotary or conical crusher 32 is turned on and the feed 19 has inhibitor 30 loaded and available for dispersion, the inhibitor 30 will be dispersed by the dispersion means into the stream of uninhibited bulk explosives at the transfer junction 34 to convert the stream of uninhibited bulk oxidiser 28 to a stream of inhibited bulk explosive 36 for insertion into the blast hole. In the instance that the rotary, jaw, pin, conical or crusher of any sort 32 is turned off or there is no inhibitor 30 inserted into the feed 31, a negligible amount or no inhibitor 30 will be added by the dispersion means throughout the stream of uninhibited bulk explosive 28 at the transfer junction 34. Negligible in this context means substantially low such that it is unable to convert the stream of uninhibited bulk oxidiser 28 into a stream of inhibited bulk explosive 36. Accordingly, a stream of uninhibited bulk oxidiser 28 or a stream of inhibited bulk explosive 36 can be produced without needing to dose the uninhibited bulk oxidiser 28 prior to arriving at site or on site converting the entire supply of uninhibited bulk oxidiser 28 to an inhibited bulk explosive 36. Using inhibitor 30 to convert the uninhibited bulk oxidiser 28 stream to an inhibited bulk explosive stream could be selectively done only on blast holes which contain reactive ground. Otherwise the stored uninhibited bulk oxidiser 28 will be used for blast holes that do not contain reactive ground.
It should be appreciated by the skilled address that there are various other methods for producing the on demand feature. For example, a valve could separate the feed 31 with the inhibitor 30 from each of a dispersion means such that the valve can be opened or close. The valve in the open position would allow dispersion of the inhibitor 30 into the stream of uninhibited bulk oxidiser 28 converting it into a stream of inhibited bulk oxidiser 36. The valve in the closed position would not provide inhibitor 30 through the dispersion means preventing the uninhibited bulk oxidiser 28 from converting to an inhibited bulk oxidiser 36 as it is streamed through the transfer junction 34, which is in operative association with the apparatus 46, and then fuel oil can be added to form bulk explosive for insertion into the blast hole.
Referring to
Referring to
A first dispersion point disperses the inhibitor 30 from a transfer hose 44 with the assistance of gravity, pneumatically or by some other means 42 to a dispersion means located at the rear transfer 20. A second dispersion point disperses inhibitor 30 from the transfer hose 44 to a dispersion means located at the transfer junction 34. A third dispersion point disperses inhibitor 30 from the transfer hose 44 to a dispersion means at a point between the transfer junction 34 and the swivel 24. A fourth dispersion point disperses the inhibitor 30 from the transfer hose 44 to a dispersion means at the output 18.
The skilled addressee will appreciate that other suitable points for adding or locating dispersing means for adding inhibitor 30 to the stream of uninhibited bulk oxidiser 28 or a stream of uninhibited bulk oxidiser 28 in the process of being converted to a stream of inhibited bulk explosive 36 are envisaged in this invention. Furthermore, the skilled addressee will also appreciate that the invention anticipates any number of dispersion means being added to the system for selectively adding inhibitor 30 to the stream of uninhibited bulk oxidiser 28 or a stream of uninhibited bulk oxidiser 28 in the process of being converted to a stream of inhibited bulk explosive 36.
The skilled person will also appreciate that the inhibitor may be in granular, power, emulsion or dissolved liquid form. Preferably it will be in granular form.
Modifications may be made to the present invention within the context of that described and shown in the drawings. Such modifications are intended to form part of the invention described in this specification.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020902091 | Jun 2020 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2021/050654 | 6/23/2021 | WO |
