CA2842822A1 - Improved explosive composition comprising hydrogen peroxide and a sensitizer - Google Patents

Abstract

An explosive composition comprising hydrogen peroxide and a sensitiser, wherein the sensitiser comprises a compressible material having one or more gas-filled voids and/or bubbles of gas. The sensitiser is included in a detonation-sensitive concentration, and the explosive composition is preferably adapted to retain the sensitiser in a substantially homogenous dispersion throughout. The invention also relates to a method of preparing an explosive composition comprising combining hydrogen peroxide and a sensitiser, wherein the sensitiser comprises a compressible material and/or bubbles of gas, and use of said explosive composition.

Description

2 PCT/AU2012/000890 IMPROVED EX PLOSI V E COMPOSITION
RELATED APPLICATIONS
The present application claims the benefit of Australian provisional patent application number 2011903076 filed on 27 July 2011, the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to an improved explosive composition. More particularly, the invention relates to a peroxide-bassd explosive composition which provides several advantages over the prior art, such as a reduction in the production of toxic nitrogen oxides (N0x) in the after-blast fumes. The invention has been developed primarily for use as a hydrogen peroxide-based explosive composition for use in mining applications and will be described hereinafter with reference to this application.
HOWSVer, it Will be appreciated that the invention is not limited to this particular field of use.
BACKGROUND OF THE INVENTION
The following dimussion of the prior at is provided to place the invention in an appropriate technical context and enable the advantages of it to be more fully understood. It should be appreciated, however, that any discussion of the prior art throughout the specification should not be considered as an express or implied admission that such prior at is widely known or forms part of common general knowledge in the field.
Nearly all commercial and mining explosives used in the world today are based on ammonium nitrate (AN) or combinations of AN with other alkaline and/or alkaline earth nitrate salts, eg. sodium or calcium nitrate. Most explosives of this type rely on the energetic reaction of 'nitrogen compounds incorporated within the explosive to provide , the necessary explosive power. AN, which is a strong oxidiser, has been used as the base of commercial explosives for at least the last 50-60 years.
Initially, mining companies used AN as an ekplosive on its own. However, they soon realised that the addition of diesel increased the energy output without a large increase on costs (ammonium nitrate¨fuel oil, now commonly referred to as ANFO').
However, the water residence of ANFO is quite poor, which limited its um in wet blast holes. To ameliorate this issue, slurries and watergels were developed.
Slurries typically comprise AN dissolved/diqperesd in water, other salts (calcium nitrate, sodium nitrate, etc) to depress the crystallisation point of the AN solution, and other additives such as guar gum (as thickener) and fuel (diesel). They can also be blended with ANFO
depending on the charaoteristics of the ground being blasted. Slurries also typically include solid ssnsitisars (aluminium and high explosives such as TNT, RDX, etc) to enable the slurry to donate and to minimise misfires Watergels have similar compositions to slurries however, crosslinkers can be added to enhance the water resistance of the product. Watergels can be mated or gassed with bubbles chemically generated in situ or mixed with glass/plastic microspheres to lower the density, improve sensitivity and change the levels of energy delivered to the ground being blasted.
One of the dravvbaoks of watergels and slurries is that there is a limit of AN
which can be incorporated Into the solution. This drawbaok was overcome by the development of water-in-oil emulsions Thew emulsions can contain AN in high concentration (see US Patent No. 3,447,978). Water in oil emulsions are made of a hot aqueous phase (composed of AN, other nitrate salts, perchlorate salts, etc) digoersad into an organic fuel. The aqueous¨ organic mixture is stabilised by the use of an emulsifier.
Emulsions can also be blended with ANFO in different ratios Watergels can be asrated, gassed with bubbles chemically generated in situ or mixed with glass/plastic microvheres to lower the density, improve sensitivity velocity of detonation (VOD) aid change the levels of energy delivered to the ground being blasted.
Despite the development of AN emulsions AN slurries and watergels, however, there is still a need to develop improved explosives which are preferably more cost effective corrpared to existing explosive compositions and are capable of 'being produced in large quantities to meet the high demand from industry. Preferably any explosive composition which can be substituted for an AN-based explosive is insensitive to misfires and is not desansitissd by wet blast holes Furthermore, preferably any AN
substitute is a sustainable ram material which has a relatively low carbon footprint, and which can be manufactured relatively easily and preferably near the wtual mine site to minimise transport issues In addition, preferably any AN substitute cal be produced on an as-needs basis to minimise the need for stockpiling aid to increase safety.
Further still, preferably any AN substitute can be used in slurry or in emulsion form so that existing equipment can be used, and when in slurry form or is emulsified such that the viscosity enables pumping without difficulty. It would also be ideal if there are no onerous regulatory requirements for such a substitute, thereby reducing administrative costs It would also be preferable for the explosive composition to be cross linkable in-tu to increase viscosity down the blast hole.

- 3 -Despite of the advances on the types of composition that can be manufactured from ammonium nitrate, one of the disadvantmes is that during the detonation.
NOx fumes can be generated, due to the presence of nitrogen compounds in the explosive composition (from nitrates). These NO fumes are toxic and can affect the health of mine site personnel. Therefore the emission of NO fume after blasting is a safety issue and in countries like Austral ia there are now strict regulatory controls in pla:e to manage such emissions See for example "Queensland Guidance Note: Manmement of oxides of nitrogen in open cut blasting" issued by the regulator in Queensland, Australia, 2011.
Likewise, explosive manufacturers in Australia have also issued a code of prmtice to manage the NO fumes after blasting (AEISG Code of Practice, Prevention and Management of Blast Generated NO Gases in Surface Blasting, 2011). Therefore there is a need to find explosive compositions that substantially eliminate NO
emissions or preferably reduces the production of NON.
One material that is also an oxidiser and that has the potential to meet at least some of these needs is hydrogen peroxide (HP). Use of HP as a liquid explosive has been patented by Shanley (US Patent No. 2,462,074) in which HP was mixed with glycerol and water, and initiated with a detonator. US '074 tembm that to whieve detonation the explosive compositions can only contain up to 52 wt% water. In 1962 a.
patent was granted to Baler (US Patent No. 3,047,441) in which HP was mixed with a range of different combustibles (wood products, hulls, metals, etc). Mixtures of HP and gelforming materials (corn starch) were also disclosed. The mixtures were sensitive to detonation with No. 6 blasting caps, but no velocities of detonation (VOD) were disclosed.
More recently, in 1990 mixtures of HP and water soluble resins were patented by Bouil let as a pmkaged explosive (US Patent No. 4,942,800). Examples provided in the patent show that some of the mixtures detonated at velocities above 6,000 m/s (in 33 mm diameter, unconfined blasts). Also, work published by Shell Co. (Concetrated Hydrogen peroxide suranary of research data on safety limitations 1961) presents the detonation limits of the system HP-acetic acid-water in a ternary diwiram. In 2004 an investigation into the detonation properties of HP at alcohols was published ("Investigation of eiplosive hazard of trixtures containing hydrogen perodde and different alcohols", Journal of Hazardous Matelals A108 pp. 1-7,2004).
Despite these prior art examples of HP-based explosives, there is still a need to develop improved explosive compositions In particular, there is a need to develop HP-

- 4 fuel¨water explosive compositions in which the sensitivity, density, velocity of detonation (VOD) and the delivery of the energy can be controlled.
It is an object of the present invention to overcome or ameliorate one or more of the disadvantmes of the prior art, or at least to provide a useful alternative SUMMARY OF THE INVENTION
The present invention relates to an explosive which substantially avoids the release of unwanted NO), fumes upon detonation into the atmosphere surrounding the blasting site. A preferred objective of the present invention is to reduce and preferably eliminate nitrogen containing ingredients from the explosive composition. It will be appre:iated that with little or no nitrogen present in the explosive virtually no NO is released into the atmosphere, or a albstaitially reduced amount. The present invention relates to explosives for use in commercial, construction, mriculture, mining, and similar fields However, it will be appreciated that the invention could be utilised in other related fields.
According to a first aspect the present invention provides an explosive composition comprising hydrogen peroxide and a sensitiser, wherein the ssnsitisar comprises a compressible material and/or bubbles of gas Preferably the compressible material includes one or more gas-filled voids.
, Preferably the composition further includes other additives, such as fuel, water, stabilisers (either thickeners or emulsifiers), as dis:ussed further below. In one preferred embodiment the composition comprises no components which lead to the production of NO in the after-blast fumes However, in other embodiments components are added which result in minimal NO in the after-blast fumes.
Whild the preferred explosive oxidiser of the invention is hydrogen peroxide, it will be appreciated that other oxidisar salts or peroxide derivatives can be used with the invention, either as complete or partial replacements of HP. Non-limiting examples include nitrates salts, perchlorates ssdts, sodium/potassium peroxide, etc The preferred concentration of HP in the composition of the invention is bdween about 25% to 85% by weight. By way of example only, a concentrated HP solution can be sourced (70% w/w) and diluted down to 25% w/w for use in the composition.
Other possibilities will be apparent to the skilled person. Preferably the HP
concentration in the composition is around 25, 30, 35, 40, 45,50, 55, 60, 65, 70, 75, 80, or 85% (w/w).
Preferably the HP concentration in the composition is around between about 25 to 30, 30 to 35, 35 to 40, 40 to 45, 45 to 50, 50 to 55, 55 to 60, 60 to 65, 65 to 70, 70 to 75, 75 to =
=

-5-80, or 80 to 85 % (w/w).
The present invention relies on sensitisation of a hydrogen peroxide based composition to result in an explosive composition, aid to control key factors such as , explosive sensitivity, density, velocity of detonation (VOD) and the delivery of the energy. Sensitisation of AN-based explosive compositions is known in the art.
In particular, it is known to sensitise by the addition of solid materials, high explosives, and the addition of micro balloons and gas bubbles. However, sensitisation of peroxide-based compositions is not commonly practiced in the art. Without wishing to be-bound by theory, it is believed that because HP in high concentration may detonate as it is relatively unstable to impact or friction, explosive engineers have steered away from its use. However, it has been found that lower concentrations of HP (safer to impwt or friction) can be formulated which can be made explosive by sensitisation. It has been surprisingly found that sensitisation of HP by use of compressible or low density materials containing gas-filled voids, or bubbles of gas providesexplosive compositions which are superior to those taught in the prior an.
= Preferably the explosive composition of the invention is adected to retain the sensitiser in a substantially homogenous dispersion. It will be appreciated that a variety of techniques can be utilised to echi eve this property, as discussed further below.
Preferably a minimum concentration of sensitiser is included into the composition to cause it to be explosive. Preferably the sensitiser is included in a detonation-sensitive concentration or amount. The sensitiser is also preferably maintained in a detonation-sensitive dispersion/distribution throughout the composition.
Preferably the final density of the composition is controlled into a preferred pre-determined explosive range. Preterably the final density is controlled with sensitiser to around 1.25 to 1.3 g/ml. Preferably the density of the composition is formulated to be around 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, or 1.4 g/ml. Preferably the final density of the composition is formulated to be between around 0.1 to 0.2, 0.2 to 0.3, 0.3 to 0.4, 0.4 to 0.5, 0.5 to 0.6, 0.6 to 0.7, 0.7 to 0.8, 0.8 to 0.9, 0.9 to 1.0, 1.0 to 1.1, 1.1 to 1.2, 1.2 to 1.3, or 1.3 to 1.4 g/ml. However it will be appreciated that for some applications other high density additives can specifically be included to increase the density, up to 1.6, 1.7, 1,8, 1.9 or 2.0 g/ml.
The *Hied person will eppreoiate that a mathematical conversion will be required to convert the weight of glass/plastic micro balloons to yield a certain density, to volume (for gas bubbles). However, irrespective of thetype of sensitisation, it will be

- 6 -apprEciated that the final density is controlled to a predetermined value to yield an explosive composition and to thereby control the parameters disoussed above.
Many advant ag=es result from the inventive explosive compositions taught herein.
For example, certain formulations of the compositions of the invention are more cost effective compared to scisting explosive compositions, and are capable of being produced in large quantities to meet the demand from the mining industry. The explosive compositions of the invention uti I iw HP, which is a sustainably-produced raw =
material that has a relatively low carbon footprint compared to other types oxidisars used in the art. The explosive compositions of the invention can also be formulated into slurry or emulsion form. It will also be appreciated that the inventive compositions of the invention produce reduced amounts of NO, and in preferred forms of the invention no NC)x at all.
Sendtiars The explosive compositions of the present invention comprise a disoontinuous gaseous component to sansiti se the composition. Once the explosive is sensitised, it can be easily initiated by a primer, which as the *Hied person will be aware is an egplosive which generates a high detonation pressure which then initiates detonation of the sensitised explosive. The gassous component is incorporated into the compositions of the present invention as fine gas bubbles dispersed throughout the composition.
Alternatively, hollow gas-filled compressible particles such as micro balloons, or porous particles, or mixtures thereof are included. The disoontinuous phase of fine gas bubbles may be incorporated into the compositions of the present invention by mechanical agitation, injection by bubbling the gas through the composition, or by in dtu generation of the gas by chemical means Suitable chemicals for the in situ generation of gas bubbles include HP itself which can be decomposed with Mn salts, yeast, iodide salts, etc ; nitrogen-based compounds such as, for example, sodium nitrite, nitrosoarnines such as, for example, N,Ntlinitrosopentamethylenetetramine; boron-based compounds such as, for example, sodium borohydride; carbonates such as, for example, sodium carbonate.
Examples of suitable hollow particles include small hollow microspheres of glass and resinous materials such as phenol-formaldehyde, poly(vinylidene chloride)/poly(acrylonitrt le) copolymers and ureaforrnaldehyde. Examples of suitable hollow particles include 0-Cal, Cenospheres, Expancel õ 3M, Extendospheres, etc. Examples of porous materials include expanded minerals such as perlite, fly ash or hollow particles that are a by-product of

- 7 -coal fired power stations Typically, sufficient bubbles and/or hollow particles and/or porous particles are used in the compositions of the present invention to give an explosive composition having a density in the range of from 0.1 to 1.4 g/cm3.
Using conventional mixing techniques to provide bubbles in emulsion explosive compositions often produce bubbles with a range of bubble sizes. For example, the bubbles often have diameters up to 2000 microns and average bubble diameters of less than 50 microns we also common. By choice of suitable surfactants bubbles of smaller or larger diameters can be produced. Thus by choice of an appropriate surfmtant at a desired concentration the mean gas bubble diameter in the discontinuous gas phase may = be controlled, and bubbles of 50 to 200 microns are possible. It will be appreciated that the bubble size influences the overall density, and if low densities are required large gas bubbles are preferred. For emulsified explosives the density range is preferably around 0.60 ¨ 1.20 g/ml, and for watergels the density range is preferably between 0.2 ¨ 1.2 g/ml. In an emulsified system the gas bubbles are preferably 10 ¨100 times larger than the disperw phase droplets. The oily phase is likely to be in contaot the gas bubble, whereas the oxidiser (or di soonti nuous phase) does not.
As disoussed above, the introduction of gas bubbles can be provided by a variety of techniques, which are all applicable to the present invention. In one embodiment the bubbles may be 'trapped' during the preparation of the explosive composition or by their formation through a chemical reaotion. In US Patent No. 3,400,026 a formulation which uses protein in solution (albumin, collagen, soy protein, Etc.) in order to favour the formation of bubbles and their stabilization is deecribed. US Patent No.
3,582,411 describes a watergel explosive formulation which contains a foaming a:gent of the guar gum type modified by hydroxy groups In US Patent No. 3,678,140 a process for the incorporation of air by means of the use of protein solution is desaibed, by passing the composition through a series of openings at pressures from 40 to 200 psi and simultaneously introducing air through eductors. Incorporation of gas bubbles by means of their generation as a result of a chemical reaction is also described in the following prior art (we for example US Patent No's 3,706,607; 3,711,345; 3,713,919;
3,770,522;
3,790,415 and 3,886,010).
Various gases in bubble form have been used to sensitise blasting agents, for example nitrogen (me US Patent No.'s 4,875,951; 4,305,766; and 3,390,030), carbon dioxide (a-:e US Patent No.'s 3,288,658 at 3,390,032), oxygen (we US Patent No.'s

-8-3,706,607; 5,397,399; 4,081,299 and 3,617,401), and hydrogen (we US Patent No.

3,711,345). It is alsc known to directly inject air or gas into the explosive mixture (see for example US Patent No.'s 6,537,399; 3,582,411 and 3,642,547).
As discussed above, in other embodiments the compressible material is hollow microspheres such as glass or plastic micro balloons, which are suTended in the composition. Preferably the microspheres/micro balloons contain gas such as pentane, etc. In alternative embodiments, the compressible material is a cellular material, such as expanded polystyrene (EPS), polyurethane foam, cotton mats, expanded pop corn, husks, etc In related embodiments the compressible material is any low density material which has a specific gravity < 1.0 g/cm3 In brief summary, examples of glass balloons can be men in US Patent No.'s 4,326,900 and 3,447,978, and plastic micro .
balloons in US Patent No.'s 4,820,361 aid 4,547,234. These balloons are typically 0.05 mm in diameter and have a bulk density of 100 g/L. Use of expanded polystyrene can be wen for example in US Patent No.'s 5,470,407 and 5,271,779. Other types of sensitising materials can be used in the compositions of the invention, ag.
TNT, HMX, RDX and aluminium or silicon powder.
Watergel-tezhnology for H P-based explosive compositions Fuels for vvatergels HP-based watergels can be prepared with either water-miscible or water immiscible fuels Water-soluble fuels which can be used with the present invention can be selected from the group consisting of: glycerol, sugar, amine nitrates, hexamine and urea Water-inscluble fuels which can be used with the present invention can be selected from the group consisting of: include aliphatic, alicyclic and aromatic compounds and mixtures thereof which are in the liquid state at the formulation temperature. Suitable organic fuels may be chosen from fuel oil, diesel oil, distillate, kerosene, naphtha, waxes, (ag. microcrystalline wax, paraffin wax and slack wax) paraffin oils, benzene, toluene, xylenes, asphaltic materials, polymeric oils such as the low molecular weight polymers of olefins, vegetable oils, animal oils, fish oils, and other mineral, hydrocarbon or fatty oils, and mixtures thereof. Preferred organic fuels are liquid hydrocarbons generally referred to as petroleum distillates such as gasoline, kerosene, fuel oils, paraffin oils and vegetacle oils or mixture thereof.
Typically, the water miscible or water-immiscible fuel of the watergel composition of the present invention comprises from 5 to 30% by weight and preferably 10 to 25% by weight of the total composition. Preferably the fuel is included in a

- 9 -concentration of about 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% (w/w).
Preferably the fuel is included in a concentration of betwesn about 5 to 10, 10 to 15, 15 to 20, 20 to 25, 25 to 30, 30 to 35, 35 to 40, 40 to 45, or 45 to 50% (w/w).
Thickeners and crosslinkers Because bubbles of gas and materials enclosing gas have a relatively low density, they will tend to migrate towards the surface of the column of explosive if the viscosity of the HP-based explosive composition is not cable of maintaining the sensitising material homogeneously dispersed throughout. Migration of the sensitising material towards the surfaoe is undesirable as it may render the explosive too insensitive to initiation, and therefore the explosive composition may not deliver the energy and gases needed to bredc and move the rock as required or even worst, the explosive may undergo a misfire. One way to ameliorate this issue is to formulate the explosive composition into a watergel. These types of compositions can be formulated with different levels of viscosity by using a thickener. Viscosities can be selected to generally retain the sensitising material in a homogeneously dispersed state throughout the composition.
If desired the aqueous solution of the compositions of the present invention may comprise thickening agents which optionally may be cross! nked. The thickening agents, when used in the compositions of the present invention, are suitably polymeric materials, especially gum materials typified by the galactomannan gums such as locud bean gum or xalham gum or guar gum or derivatives thereof such as hydroxypropyl guar gum.
Other useful, but less preferred, gums are the so-called biopolymeric gums such as the heteropolysaccharides prepared by the microbial transformation of carbohydrate material, for example the treatment of glucose with a plant pathogen of the genus Xanthomonas typified by Xanthomanas canpestris Other useful thickening agents include synthetic polymeric materials and in particular synthetic polymeric materials which are derived, at least in part, from the monomer aorylamide.
Typically, the thickening agent component of the compositions of the present invention comprises from 0 to 5% by weight of the total composition.
As indicated above, when used in the compositions of the present invention, the thickening ment may be crosslinked. It is convenient for this purpose to use conventional crosslinking agents such as zinc chromate or a cichromate either as a separate entity or as a component of a redox system such as, for example, a mixture of potassium dichromate and potassium antimony tartrate. Salts of Ca, Ti, Sb can also be used as crosslinkers.

- 10 -Typically, the crosslinking agent component of the compositions of the present invention comprises from 0 to 0.5% and preferably from 0 to 0.1% by weight of the total composition.
=
Emulsion-technology for HP-based explosive compositions Fudsfor emulsions HP-based emulsions can be prepared with water-immiscible fuels The water-immiscible organic phase component of the composition of the present invention comprises the continuous "oil" phase of the water-in-oil emulsion and is the fuel.
Suitable organic fuels include aliphatic, alicyclic and aromatic compounds and mixtures thereof which are in the liquid date at the formulation temperature Suitable organic fuels may be chosen from fuel oil, diesel oil, distillate, kerosene, naphtha, waxes, (ag.
microcrystalline wax, paraffin wax and slack wax) paraffin oils, benzene, toluene, xylenes, asphaltic materials, polymeric oils such as the low molecular weight polymers of olefins, vegetable oils, animal oils, fish oils, and other mineral, hydrocarbon or fatty oils, and mixtures thereof. Preferred organic fuels are liquid hydrocarbons generally referred to as petroleum distillates such as gasoline, kerosane, fuel oils paraffin oils and vegetable oils or mixture thereof..
Typically, the organic fuel or continuous phase of the HP-based emulsion composition of the present inventioncomprises from 2 to 20% by weight and preferably 3 to % 20% by weight of the total composition. Preferably the organic fuel is included in a concentration of about 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20% (w/w).
Preferably the organic fuel is included in a concentration of between about 2 to 4, 4 to 6, 6 to 8, 8 to 10, 10to 12, 12to 14, 14to 16, 16to 18,or 18to20%(w/w).
Emuldfier/Stabilis3r HP-based emulsion compositions are made of a discontinuous phase of oxidising material that is dispersed in a continuous phew of an organic fuel in the presence of one or more emulsifying ments. The emulsifying agent is adapted or chosen to maintain phase separation.
The emulsifying agent component of the composition of the present invention may be chosen from the wide range of emulsifying agents known in the art for the preparation of water-in-oil emulsion explosive compositions. Examples of such emulsifying ments include polyisobutylene succinic anhydride (PIBSA) reacted with amines; other emulsifiers examples are alcohol alkoxylates, phenol alkoxylates, poly(oxydkylene) glycols, poly(oxyalkylene) fatty wid esters, amine alkoxylates, fatty

- 11 -wid esters of sorbitol and glycerol, fatty acid salts sorbital esters poly(oxyalkylene) sorbitan esters, fatty amine alkoxylates, poly(oxyalkylene) glycol esters fatty wid amides, fatty acid amide alkoxylates, fatty amines, quaternary amines, alkyloxazolines, alkenyloxazol i nes, i midazol i nes, al kyl -sulfonates, alkylarylsulfonates, alkylsulfosuccinates alkylphosphates, alkenylphosphates, phosphate esters, lecithin, copolymers -of poly(oxyalkylene) glycols and poly(12-hydroxystearic acid), and mixtures thereof. Among the preferred emulsifying ments are the 2-alkyl- and 2-alkeny1-4,4'-bis (hydroxymethyl) oxazoline, the fatty acid esters of sorbitol, lecithin, copolymers of poly(oxyalkylene) glycols and poly(12-hydroxystearic wid), and mixtures thereof, and particularly sorbitan mono-oleale, sorbitan sesquioleate, 2-oley1-4,4'-bis (hydroxymethyl) oxazoline, mixture of sorbitan sesquioleate, lecithin and a copolymer of poly(oxyalkylene glycol and ply (12-hydroxystearic acid), and mixtures thereof.
Typically, the emulsifying agent component of the composition of the present invention comprises up to 5% by weight of the total composition. Higher proportions of the emulsifying sgent may be used and may serve as a supplemental fuel for the composition but in general it is not necessary to add more than 5% by weight of emulsifying ment to achieve the desired effect. One of the sclvantsges of the compositions of the present invention is that stable emulsions can be formed using relatively low levels of emulsifying agent and for reasons of economy it is preferable to keep to amount of emulsifying ment used to the minimum required to have the desired effect. The preferred level of emulsifying agent= used is in the range from 0.1 to 2.0% by weight of the total composition.
Secondary fuels for watergels and emulsions If desired, other optional fuel materials, hereinafter referred to as secondary fuels, may be incorporated into the compositions of the present invention in addition to the water-immiscible organic fuel phase Examples of such secondary fuels include finely divided solids, and water-miscible organic liquids Examples of solid secondary fuels include finely divided materials such as: sulfur; aluminium; and carbonaceous materials such as gilsonite, comminuted coke or charcoal, carbon black, resin wids such as abietic acid, vegetable products such as starch, nut meal, grain meal and wood pulp.
Typically, the optional secondary fuel component of the compositions of the present invention comprise from 0 to 20% by weight of the total composition.

,

- 12 -Other oxidisersfor watergel and emulsion HP-based Explosive compositions It lies within the invention that there may also be incorporated into the HP-based watergel/emulsion compositions herei nbef ore described other substances or mixtures of substances which are themselves suitable as explosive materials. As a typical example of such a modified compositions reference is maJe to compositions wherein there is added to and mixed with an watergel/ernulsion composition as hereinbefore described up to 90% w/w of an oxidizing salt such as ammonium nitrate or an explosive composition comprising a mixture of an oxidizing salt such as ammonium nitrate and fuel oil and commonly referred to by those skilled in the art as "ANFO". The compositions of "ANFO" are well known and have been described at length in the literature relating to explosives It also lies within the invention to have as a further explosive component of the composition well known explosive materials comprising one or more of for example trinitrotoluene, nitroglycerine or pentaerythritol tetranitrate.
It will also be appreciated that these other oxidisers can be used to partially replace HP in the HP compositions. Examples of such oxidisers are nitrate salts, perchlorate salts, sodium! potassium peroxide, etc.
pH
The pH of the emulsion explosive compositions of the present invention is not narrowly critical. However, in general the pH is between 0 and 8 and preferably the pH
is between 1 and 6, and may be controlled by suitable addition of conventional additives, for example inorganic or organic acids and salts =
Preparation d composition The HP-based compositions of the present invention may be prepared by a number of methods.
In one preferred method of manufwture the HP-based watergel type compositions may be prepared by combining hydrogen peroxide with water miscible fuels and thickeners until the thickener starts increasing the viscosity of said composition. Once the watergel is formed, solid ingredients (fuels, energy diluting ments, etc) are optionally mixed into said watergel. Finally, sensitising merits are mixed into said watergel capable in an amount capable to sensitise said watergel.
In one preferred Method of manufacture the HP-baSed emulsion type compositions may be prepared by: combining hydrogen peroxide with said water-immiscible organic phase, a water-in-oil emulsifying ment, with rapid mixing to form a water-in-oil emulsion; then mixing until the emulsion is uniform. Once the emulsion is

- 13 -formed, solid ingredients (fuels, energy diluting agents, etc) are optionally mixed into said watergel. Finally, sensitising ments are mixed into said watergel in an amount capable of sensitising said watergel.
Viszosity of the HP-based compositions =
The viscosity of the HP-based compositions (wane( or emulsion type) will be discussed in terms of apparent viscosity. Where umd herein the term "apparent viscosity" refers to viscosity measure using a Brookfield RVT viscometer, #7 spindle at 50 r.p.m. It is preferred in the process of the present invention that the explosive composition of the wafer-in-oil emulsion explosive particles have an apparent viscosity greater than 10Pa's (Pal* second) prior to the entrainment of gas bubbles.
Apparent viscosity is more preferably in the range 10 to 50 Pa* s A more preferred viscosity range for the entrainment of gm bubbles by mechanical mixing is from 10 to 35Pes.
The range 10 to 25Pes provides the most efficient entrainment of gas bubbles by mechanical mixing.
Energy diluents (optional) In the context of this invention, energy diluting ments are inert materials that have minimal contribution to the detonation process and can be used to replace pal of the energetic material in the composition aid therefore reduce the energy output of the hydrogen peroxide-based explosive In some cases these energy diluting ments are able to reduce the density of the HP-bassd composition without increasing the sensitivity.
Examples of these diluents materials .are granulated/shredded rubber (from tyres), cotton seeds, saw dust, husk, expanded pop corn, plastic beads wool meal, saw dust, bsgasse, peanut aid oat husks, peanut shells etc. US Patent No. 5,409,556 describes some example of these energy reducing ments. These materials could also be used in combination with sensitising ments to offer more flexibility as fa as the performance properties of the hydrogen peroxide-based explosive is concerned. Therefore another advantme of the HP-based explosive is that the performance properties of the explosive can be altered to suit the characteristics of the blasting site Possible variations of this general procedure will be evident to those skilled in the art of the preparation of emulsion explosive compositions In one preferred embodiment the HP-based explosive compositions of the invention comprise the, following components: HP:fuel:water in the range between 25%:5%:70% to 73%:11%:16%.

- 14 -= Table 1 lists the components of explosive systems disoussed herein and provides typical ranges for each.
Watergel Emulsion HP (% by weight) From 25 to 64 From 27 to 80 Other oxidiser (% by weight) From 0 to 60 From 0 to 60 Sensitise (% by volume) From 1 to 800* From 1 to 800*
Fuds ("/0 by wdght) From 8 to 12 From 7 to 12 Secondary fuds (% by weight) From 0.1 toll From 0.1 toll Water (% by weight) From 21 to 67 From 8 to 71 Thickeners (% by weight) From 0.5 to 5 N/A
Emulsifiers (% by weight) N/A From 0.5 to 5 Additive (`'/0 by weight) 0.1 to 5 0.1 to 5 Energy diluting agents (% by From 1 to 300** From 1 to 300**
volume) Oxygen Balance From 3 to -10 From 3 to -10 Final densities (qm1) 0.1 to 1.40 0.1 to 1.40 Table 1: components for explosive systems dismssed herein with typical ranges for eh. NOTE: it will be appreciated that the volume can be increased by 8x (*), and 3x(**), respectively.
According to a sacond aspect the present invention provides a method of preparing an explosive composition comprising combining hydrogen peroxide and a sansitiser, wherein the sansitissr comprises a compressible material and/or bubbles of gas It will also be appreciated that the invention relates to a method of preparing an explosive composition oomprising combining hydrogen peroxide and one or more compounds which produce a sansitisar.
According to a third aspmt the present invention provides use of an explosive = composition comprising hydrogen peroxide and a sansitisar, wherein the wnsitiser comprisas a compreesible material and/or bubbles of gas. It will be qoprecialed that the composition of the invention can be used for many purposas, but in particular to bred( and move ground in mining operations.
According to a fourth aspect the presant invention provides a sensitissd explosive composition comprising hydrogen peroxide and compressible material and/or bubbles of gas

-15-In some embodiments the present invention consists essentially of hydrogen peroxide and a sansitiser, wherein the sansitis3r comprises a compressible material and/or bubbles of gas. In other embodiments the present invention consists essentially =
of hydrogen peroxide, a sensitisar, a thickener and/or crosslinker, wherein the sansitimr comprises a compressible material and/or bubbles of gas. In other. embodiments the preserrt invention consists essentially of hydrogen peroxide, a ssnsitiser, fuel, a thickener and/or crosslinker, wherein the sensitiser comprises a compressible material and/or bubbles of gas. In other embodiments the present invention consists essentially of hydrogen peroxide, a sensitiser, fuel, surfactant/emulsifier, a thickener and/or crosslinker, wherein the sansitiser comprises a compressible material and/or bubbles of gas.
The skilled addressse will understand that the invention comprises the embodiments and features disclosed herein as well as all combinations and/or permutations of the di wl ossd embodiments and features.
=
=

- 16 BRI EF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Figure 1 is a schematic outlining the preparation of a HP-based watergel explosive composition according to the invention; and Figure 2 is a schematic outlining the preparation of a HP-based water-in-oil emulsion explosive composition aocording to the invention.
DEFI NI TI ONS
= In describing and claiming the present invention, the following terminology will be used in a000rdance with the definitions set out below. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting. Unlem defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the invention pertains Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sm.% of 'including, but not limited to'.
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term 'about'. The examples are not intended to limit the scope of the invention. In what follows, or where otherwise indicated, ' /0' will mean 'weight /01, 'ratio' will mean 'weight ratio' and 'parts' will mean 'weight parts'.
The terms ' preferred' and 'preferably' refer to embodiments of the invention that may afford certain benefits, under certain circumstances However, other embodiments may also be preferred, under the same or other circumstances Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the mope of the invention.
The terms 'a', 'an' and 'the' mean 'one or more, unless expressly Tecified otherwise. The terms 'an embodiment', 'embodiment', 'embodiments', 'the embodiment', 'the embodiments', 'an embodiment', 'some embodiments', 'an example embodiment', 'at I east one embodiment', 'one or more embodiments' and 'one

- 17 -embodiment' mean 'one or more (but not necessarily all) embodiments of the present invention(s)' unless expressly specified otherwise.
As used herein the term "mnsitissr" is meant to define voids that can increase the sensitivity to detonation of energetic materials. Examples are air bubbles, entrapping air, aid material like micro balloons/spheres.
= The prior al referred to in this specification is incorporated herein by reference.
PREFERRED EMBODIMENT OF THE INVENTION
Numerous embodiments are described in this patent application, and are presented for illustrative purposes only. The described embodiments are not intended to be limiting in any sense. The invention is widely applicable to numerous embodiments, as is readily apparent from 'the dimlosure herein.
The present invention relates to a peroxide-based explosive composition that is preferably prepared as watergel or water-in-oil emulsion, and is sensitised.
Typical components for eEr,h type of explosive technology we listed in Table 2.
Explosive technology Element Watergel Water-In-oil emulsion Oxiciser agent hydrogen peroxide hydrogen peroxide optionally nitrate salts and /or optionally nitrate salts and /or, perchlorate salts and/or sodium perchlorate salts and/or sodium /
/ potassium peroxide potassium peroxide Sensitiser gas bubbles (chemically gas bubbles (chemically generated generated or injected bubbles) or injected bubbles)and/or ardor compressible materials compressible materials Fuel water soluble fuels or water- water soluble fuels or water-nsol ubl e f uels i nsoluble fuels Stabilisers thickeners emulsifiers Additives cross linking agants, catalysts cross linking agents, catalysts for for gassing, pH alusters gassing, pH alusters Energy dluents Granulated / shredded rubber, Granulated / shredded rubber, (optional) expanded popcorn, expanded expanded popcorn, expanded rice =
rice plastic beads plastic beads Table 2: Typical components of the present invention for eat type of explosive technology.

- 18 -µ=
Preparation of watergel HP-based explosive composition Watergel explosive compositions made according to the present invention preferably include HP in concentrations between 25¨ 64% by weight. =
It will also be appreciated that other oxidisers can be combined with HP, as discussed above. For example nitrate salts, perchlorate salts, amine nitrates;

sodium/potassium peroxide, etc., can be also incorporated in combination with HP.
The ci I led person will appreciate that there are many options that are available for use as a fuel. For example the fuel may be a product of vegetable origin, such as sugars or molasses, alcohols, organic acids, ethers, esters, urea, hexamines,etc.
Alternatively, it may be a product derived from crude oil such a diesel, paraffinic oils or mineral oil, etc. Other fuels may be sil icone oils, eta Secondary fuels may be a solid hydrocarbon, such as coal and recycled plastic waste. It may also be a metallic fuel, such as aluminium / silicon, etc, or gilsonite, comminuted coke or charcoal, carbon black, resin acids such as abietic acid, vegetable products such as starch, nut meal, grain meal and wood pulp; or nitrogen compounds such as amides, arni nes, etc.
Preferably the amount of these fuels materials in the formulation can be adjusted so the HP-based composition has an oxygen balance between 3 and -10 and the HP-based composition can be easily pumped. The preferred fuels are glycerol, sugar, syrup, alcohol, carbon, ground coal, waxes, oils such as corn, cottonseed, olive, peanut, or fatty acid oils.
= It will be Appreciated that for an HP-based composition in accordance with the invention to be functional, it is important that gas bubbles are homogeneously distributed throughout the composition. It is also important that once distributed throughout, the gas bubbles should be maintained in a homogenous distribution throughout the composition, i.e little or no segregation or sattling. In accordance with the present invention this may be achieved by formulating the explosive as a stable watergel. Formation of such forms of compositions is conventional in the art and one ski I led in the art will be familiar with the various f orms that may be produced. Typically this will involve the use of a thickener that acts on the liquid oxidant component of the composition. Herein the term "thickener" is also intended to include gelling ments, crosslinking agents, and the like.
As diszussscl above, any conventional thickening Agent may be used with the present invention. The thickener may be selected from natural gums, such guar gum,

- 19 -xanthan gum, sodium alginate, carboxymethylcellullo, methylcellulose and the like.
Synthetic thickeners, such polyaorylamide, may also be used. Inorganic thickeners, such as fumed silica, clays and carbosi I, may also be used, or a combination thereof.
Crosslinkers can also used with the present invention. Thickening ments in combination with crow,' inkers can improve the water resistance and mechanical strength of the HP-based explosive. Examples of crosslinkers are those from antimony, calcium, titanium, chromium, borate salts aid dichromate salts, etc.
Various additional ingredients, familiar to those skilled in the art, may be employed in the formulation of the invention.
Preparation of water-in-oil HP-based explosive composition Water-in-oil explosive compositions made according to the present invention include hydrogen peroxide in concentration betwesn 25 - 85% by weight. It will also be appreciated that other oxidisers can be combined with HP, as discussed above. For example nitrate salts, perchlorate salts, amine nitrates, sodium /
potassium peroxide, etc., can be also incorporated in combination with HP.
The fuel can be any fuel such as diesel fuel. Alternatively it can be paraffinic, . mineral, olefinic, naphtenic, animal, vegetable, fish and silicone oils Other types of fuels are benzene, toluene, xylenes, asphaltic materials and the likes Secondary fuels may be a solid hydrocarbon, such as coal and recycled plastic waste,. It may also be a metallic fuel, such as aluminium / silicon, etc, or gilsonite, comminuted coke or charcoal, carbon blaok, resin wids such as abietic acid, vegetable products such as starch, nut meal, grain meal and wood pulp; or nitrogen compounds such as amides, amines, etc.
Preferably the amount of these fuels materials in the formulation can be adjusted so the HP-based composition has an oxygen balance between 3 and -10 and the HP-based composition can be easily pumped..
In relation to sensitisation, similar considerations apply to water-in-oil explosive compositions as the watergei explosive compositions discussed above, namely preferably the gas bubbles are homogeneously distributed throughout the composition.
In aocordance with the present invention this is achieved by formulating the explosive as a stable water-in-oil emulsion. Formation of emulsified explosives is conventional in the art aid one (illed in the al will be familiar with the various forms may be produced. Typically this will involve the use of an emulsifier, which is adapted to keep the oxidiser dispersed throughout the continuous organic phase (fuel).

- 20 -Emulsifiers commonly U 93:i in emulsion explosive compositions include sorbitan mono oleate, sorbitan sesguioleate, poly isobutylene succinic anhydrides (PIBSA) and amino derivatives of PIBSA, PIB-lactone and its amino derivatives, fatty acid salts, lecithin, etc.
Sensitisation of watergel or water-in-oil emulsions HP-based compositions The present invention relates to the use of HP-based composition and a specific class of sensitisers. As discussed above, sensitising agents include gas bubbles generated in situ or injected air or air/gas entrapped material. A further example of sensitisation for hydrogen peroxide-based explosives is the decomposition in situ of a portion of the hydrogen peroxide with permanganates (or other ions) to form oxygen gas bubbles.
Another example to produce gas bubbles is the decomposition of carbonates with wid in situ to form carbon dioxide bubbles. Examples of air entrapped material for sensitisation for hydrogen peroxide-based explosives are glass or plastic microballoons, expanded polystyrene beads, polyurethane foam, etq as discussed above. Another example of sensitisation is the combination of both gas bubbles (chemically generated aid or injected) and air entrepped material.
Watergel or water-in-oil HP-based explosive compositions male according to the present invention include sensitisers in concentration between 1 ¨ 800% by volume. (i.e.
the volume can be increased by 8x).
Energy-di luting agents In the context of this invention, diluting agents could be used to replaoe part of the mass of the HP-based composition and thus reduce the energy output. These energy-diluting agents may increase, decrease or not alter the density of the HP-based composition. Examples of these energy-diluting energy agents are granulated shredded rubber (from tyres), plastic beads, cotton seeds, saw dust, husk, expanded pop corn, plastic beads, wool meal, saw dust, bagasse, peanut and oat husks, peanut shells etc.
These diluents material could also be used in combination with sensitising agents to offer more flexibility as far as the performance properties of the HP-basal explosive is concerned. Therefore another edvantage of the HP-based explosive is that the performance properties of the explosive can be altered to suit the characteristics of the blasting site.
Watergel or water-in-oil HP-based explosive compositions made according to the present invention include energy-diluting agents in concentration IxAween 0 ¨
800% by volume. As a result, the use of the edditives (sensitising ment aid energy-diluting

-21 -agents), provides a better control of the density, VOD and energy delivery in the ground being blasted. Therefore an additional advantme of the HP-based explosive is that it could be used in a range of density between 0.1 g/ml to 1.40 g/ml.
The present invention can be used for a variety of forms of explosives provided of coLirm that the principles of the invention as described herein are observed. The invention is further illustrated with reference to the following examples Examples In example 1 to 3 suTensions of various gelling agents in glycerol were formed by gently stirring the ingredients, and then a solution of hydrogen peroxide 50% by weight was added. Gentle Stirring was applied until the mixture became a gel within 60 monds.
In example 4 to 6, blends of gelling ments and sugar were prepared, followed by the addition of a solution of hydrogen peroxide 50% by weight with gentle stirring. The mixture became a gel within 5 minutes.
In Examples 7 to 8, fuels were heated up to 402C and emulsifier aided. The mixture was stirred for 1 minute to dissolve the emulsifier, and then the mixture was plaoe in a container and mixed at 400 rpm. A solution of hydrogen peroxide 50%
by weight was slowly added during mixing over apart 8 minutes. The resulting product has a paste-like consistency. Compositions from 1 to 8 were dable over time.

_ 22 _ Composft ions (weight percent) watergel water-In-di emulsion hydrogen peroxide 82.6 82.6 81.0 82.0 82.0 81.0 - 91.6 93.0 50 /0 w/w glycerol 14.4 14.4 16.0 sugar 15.0 15.0 16.0 gua;gum 3.0 3.0 =
xantham gum 3.0 3.0 sod um algi nate 3.0 3.0 vegetable oil (peanut) 6.4 diesel 5.0 P3000 2.0 2.0 oxygen balance -1.45 -1.34 -0.36 -0.88 -0.77 -1.14 -3.31 -1.42 density (g/m1) 1.19 1.19 1.19 1.21 1.21 1.21 1.13 1.14 . Table 3: Explosive compositions prepared apoording to the invention.
P3000 is an emulsif ier manufmtured by Croda chemicals Detonation teeting 'Selected compositions were tested to determine detonation. PVC pipes 50 mm in diameter by 600 mm in length, aled on one end were usscf. VOD was measured using the D' Autriche method.
=
=
=

Composition Sensitiser air + EPSP1 GMB(2) 02(33 cop) _____ GM B(5) Density 0.55 0.93 0.80 1.05 0.81 (011) Prima Booster 50 g Booster 50 g . Booster 50 g Booster 50 g Booster 50 g VOD (m/s) 2100 4200 2800 3600 2400 Table 4: Sensitised explosive compositions primed with a 50g booster and resulting VOD measurements.
Note (1) - Composition 2 had a density after entrapping air of 0.89 g/ml. A
0.1% by weight (or 25% by volume) of expanded polystyrene, density 4 g/L, was mixed into the oomposition, producing a final density of 0.55 g/ml.
Note (2) - Composition 3 was mixed with 2.5% (or 25% by volume) of glass micro balloons (GM B), from 3M, density 100 g/L.
Note (3) - Composition 3 was gad using 5% of a KMnO4 solution (0.3% w/w).
Composition gasssd quickly. Bubbles were lost when pouring into the testi ng pipe.
Note (4) - Composition 6 was mnsitissd with a combination of 1.8% of a citric wid 'solution (10 /0 w/w) and 2% of a solution NaHCO3 (4% w/w). The product was detonated 90 minutes after adding the gassing agents.
Note (5) - Composition 3 was mixed with 3.75% of glass micro balloons (GMB) (or 37.5% by volume) from 3M, density 100 g/L.
In order to tests whether or not samples were sensitive to detonation without the presence of sensitisar, sample 6 was initiated with a detonator aid with a 50 g booster =
(sse Table 5). =
Formula number Sensiti ser none none Density (g/m1) 1.21 1.21 Primer Detonator No. 8 Booster 50 g VOD (m/s) f I ed f ai I ed .20 Table 5: Sample 6 with no sensitissr present aid resulting VOD data The examples above show that a HP-basad explosive composition will not detonate unless sensitiser is incorporated into the composition. Accordingly, it is clear to the skilled person that the above examples fall within the scope of the claims.
Although the invention has been described with reference to specific examples, it will be qppreciated by thow *Hied in the art that the invention may be embodied in many other forms. In particular features of any one of, the various described examples may be provided in any combination in any of the other described examples.
=

Claims (59)

CLAIMS:

1. An explosive composition comprising hydrogen peroxide and a sensitiser included in a detonation-sensitive concentration, wherein the sensitiser comprises bubbles of gas incorporated by mechanical agitation, injection by bubbling said gas through said composition or by in situ generation of said gas by chemical means, wherein the concentration of hydrogen peroxide in the composition is between about 25% to 80%
w/w.

2. A composition according to claim 1 further comprising nitrate salts and/or perchlorate salts and/or sodium/potassium peroxide.

3. A composition according to claim 1 or claim 2 wherein a sufficient amount of said sensitiser is included such that the density of said composition is between around 0.1 to 1.4 g/ml.

4. A composition according to any one of the preceding claims wherein in situ generation of gas bubbles is provided by the decomposition of chemicals compounds that can produce O2, CO2, N2, H2, NO or combinations thereof.

5. A composition according to any one of the preceding claims further comprising a gas-filled compressible material selected from small hollow microspheres of glass or resinous materials or porous materials, and combinations thereof.

6. A composition according to claim 5 wherein said microspheres are sized between about 20 to 2000 micron and have a bulk density of less than 1000 g/L.

7. A composition according to claim 5 or claim 6 wherein said gas-filled compressible material is perlite or fly ash.

8. A composition according to any one of claims 5 to 7 wherein said compressible material further comprises a cellular material selected from expanded polystyrene, polyurethane foam, and combinations thereof.

9. A composition according to any one of the preceding claims wherein an additional energetic material is included and is selected from TNT, HMX, RDX and aluminium powder and combinations thereof.

10. A composition according to any one of the preceding claims wherein said composition is formulated as a watergel or an emulsion.

11. A composition according to claim 10 further comprising a water-miscible fuel selected from the group consisting of glycerol, sugar, mono methyl ammonium nitrate, hexamine and urea.

12. A composition according to claim 11 wherein said water-miscible fuel is included at to 25% by weight of the total composition.

13. A composition according to any one of claims 10 to 12 wherein said watergel composition is adapted to retain the sensitiser in a substantially homogenous dispersion.

14. A composition according to any one of the preceding claims further comprising a thickener and/or a crosslinker for retaining said sensitiser in a substantially homogenous dispersion.

15. A composition according to claim 14 wherein said thickener is selected from locust bean gum, guar gum, hydroxypropyl guar gum, sodium alginate, and heteropolysaccharides, and combinations thereof.

16. A composition according to any one of claims 14 to 15 wherein said thickener is included at from 0 to 5% by weight of the total composition.

17. A composition according to claim 14 wherein said crosslinker is selected from salts containing zinc, calcium, titanium, antimony, chrome, and combinations thereof.

18. A composition according to claim 17 wherein said crosslinker is included at from 0.1 to 0.5% by weight of the total composition.

19. A composition according to claim 10 further comprising a water-immiscible fuel selected from the group consisting of fuel oil, diesel oil, distillate, kerosene, naphtha, waxes, paraffin oils, benzene, toluene, xylenes, asphaltic materials, low molecular weight polymers of olefins, animal oils, fish oils, and other mineral, hydrocarbon or fatty oils, and mixtures thereof.

20. A composition according to claim 19 wherein said water-immiscible fuel is included at 7 to 12% by weight of the total composition.

21. A composition according to any one of claims 19 to 20 wherein the emulsion composition is adapted to retain the sensitiser in a substantially homogenous dispersion by an emulsifier.

22. A composition according to claim 21 wherein said emulsifier is selected from polyisobutylene succinic acid (PIBSA) reacted with amines, PIB-lactone and its amino derivatives, alcohol alkoxylates, phenol alkoxylates, poly(oxyalkylene) glycols, poly(oxyalkylene) fatty acid esters, amine alkoxylates, fatty acid esters of sorbitol and glycerol, fatty acid salts, sorbitan esters, poly(oxyalkylene) sorbitan esters, fatty amine alkoxylates, poly(oxyalkylene) glycol esters, fatty acid amides, fatty acid amide alkoxylates, fatty amines, quaternary amines, alkyloxazolines, alkenyloxazolines, imidazolines, alkyl-sulfonates, alkylarylsulfonates, alkylsulfosuccinates, alkylphosphates, alkenylphosphates, phosphate esters, lecithin, copolymers of poly(oxyalkylene) glycols and poly(12-hydroxystearic acid), and mixtures thereof.

23. A composition according to any one of claims 21 to 22 wherein said emulsifier is included at up to 5% by weight of the total composition.

24. A composition according to any one of the preceding claims further comprising a secondary fuel selected from sulphur, aluminium, gilsonite, comminuted coke or charcoal, carbon black, abietic acid, glucose or dextrose, starch, nut meal, grain meal, wood pulp, methanol, ethylene glycol, formamide and methylamine, and combinations thereof.

25. A composition according to claim 24 wherein said secondary fuel is included at 0.1 to 12% by weight of the total composition.

26. A composition according to any one of the preceding claims further comprising a secondary oxidiser selected from nitrate salts, perchlorate salts, sodium/potassium peroxide and combinations thereof.

27. A composition according to any one of claims 11 to 26 wherein the viscosity of the emulsion or watergel explosive composition is in the range 10 to 50 Pa*s.

28. A composition according to any one of the preceding claims further comprising an energy diluting agent selected from granulated/shredded tyres rubber, expanded rice, expanded pop corn, expanded wheat, and combinations thereof.

29. A composition according to any one of claims 14 to 28 wherein the explosive composition comprises hydrogen peroxide:fuel:water in the range between 24%:4%:72% to 73%:8.75%:18.25% (wt%).

30. A method of preparing an explosive composition comprising combining hydrogen peroxide and a sensitiser, said sensitiser being included in a detonation-sensitive concentration and wherein said sensitiser comprises bubbles of gas incorporated by mechanical agitation, injection by bubbling said gas through said composition or by in situ generation of said gas by chemical means, wherein the concentration of hydrogen peroxide in the composition is between about 25% to 80% w/w.

31. A method according to claim 30 wherein said concentration of said hydrogen peroxide is partially substituted with nitrate salts and/or perchlorate salts and/or sodium/potassium peroxide.

32. A method according to claim 30 or claim 31 further comprising the step of adding a sufficient amount of said sensitiser such that the density of said composition is between around 0.1 to 1.4 g/ml.

33. A method according to any one of claims 30 to 32 wherein said in situ generation of gas bubbles is provided by the decomposition of chemicals compounds that can produce O2, CO2, N2, H2, NO and combinations thereof. .

34. A method according to any one of claims 30 to 33 wherein said composition further comprises gas-filled compressible material selected from small hollow microspheres of glass or resinous materials or porous materials, and combinations thereof.

35. A method according to claim 34 wherein said microspheres are sized between about 20 to 2000 micron and have a bulk density of less than 1000 g/L.

36. A method according to claim 34 or claim 35 wherein said gas-filled compressible material is perlite or fly ash.

37. A method according to any one of claims 34 to 36 wherein said compressible material further comprises a cellular material selected from expanded polystyrene, and polyurethane foam, and combinations thereof.

38. A method according to any one of claims 30 to 37 further comprising the step of adding an additional energetic material selected from TNT, BMX, RDX and aluminium powder and combinations thereof

39. A method according to any one of claims 30 to 38 comprising the step of formulating said composition as a watergel or an emulsion.

40. A method according to claim 39 further comprising adding a water-miscible fuel selected from the group consisting of glycerol, sugar, mono methyl ammonium nitrate, hexamine and urea.

41. A method according to claim 40 wherein said water-miscible fuel is included at 5 to 25% by weight of the total composition.

42. A method according to any one of claims 40 to 41 wherein the watergel composition is adapted to retain the sensitiser in a substantially homogenous dispersion.

43. A method according to claim 42 wherein said sensitiser is retained in a substantially homogenous dispersion by use of a thickener and/or a crosslinker.

44. A method according to claim 43 wherein said thickener is selected from locust bean gum, guar gum, hydroxypropyl guar gum, sodium alginate and heteropolysaccharides, and combinations thereof.

45. A method according to any one of claims 43 to 44 wherein said thickener is included at from 0.1 to 2% by weight of the total composition.

46. A method according to claim 43 wherein said crosslinker is selected from salts containing zinc, calcium, titanium, antimony, chrome and combinations thereof.

47. A method according to claim 46 wherein said crosslinker is included at from 0.1 to 0.5% by weight of the total composition.

48. A method according to claim 39 further comprising the step of adding a water-immiscible fuel selected from the group consisting of: fuel oil, diesel oil, distillate, kerosene, naphtha, waxes, paraffin oils, benzene, toluene, xylenes, asphaltic materials, low molecular weight polymers of olefins, animal oils, fish oils, and other mineral, hydrocarbon or fatty oils, and mixtures thereof.

49. A method according to claim 48 wherein said water-immiscible fuel is included at 7 to 12% by weight of the total composition.

50. A method according to claim 48 or claim 49 wherein said emulsion is adapted to retain said sensitiser in a substantially homogenous dispersion by use of an emulsifier.

51. A method according to claim 50 wherein said emulsifier is selected from polyisobutylene succinic acid (PIBSA) reacted with amines, PIB-lactone and its amino derivatives, alcohol alkoxylates, phenol alkoxylates, poly(oxyalkylene) glycols, poly(oxyalkylene) fatty acid esters, amine alkoxylates, fatty acid esters of sorbitol and glycerol, fatty acid salts, sorbitan esters, poly(oxyalkylene) sorbitan esters, fatty amine alkoxylates, poly(oxyalkylene) glycol esters, fatty acid amides, fatty acid amide alkoxylates, fatty amines, quaternary amines, alkyloxazolines, alkenyloxazolines, imidazolines, alkyl-sulfonates, alkylarylsulfonates, alkylsulfosuccinates, alkylphosphates, alkenylphosphates, phosphate esters, lecithin, copolymers of poly(oxyalkylene) glycols and poly(12-hydroxystearic acid), and mixtures thereof

52. A method according to any one of claims 50 to 51 wherein said emulsifier is included at up to 5% by weight of the total composition.

53. A method according to any one of claims 30 to 52 further comprising the step of adding a secondary fuel selected from sulphur, aluminium, gilsonite, comminuted coke or charcoal, carbon black, abietic acid, glucose or dextrose, starch, nut meal, grain meal, wood pulp, methanol, ethylene glycol, formamide and methylamine, and combinations thereof.

54. A method according to claim 53 wherein said secondary fuel is included at 0.1 to 12% by weight of the total composition.

55. A method according to any one of claims 30 to 54 further comprising the step of adding a secondary oxidiser selected from nitrate salts, perchlorate salts, sodium/potassium peroxide and combinations thereof.

56. A method according to any one of claims 39 to 55 wherein the viscosity of the emulsion or watergel explosive composition is in the range 10 to 50 Pa*s.

57. A method according to any one of the preceding claims 30 to 56 further comprising the step of adding an energy diluting agent selected from granulated/shredded tyres rubber, expanded rice, expanded pop corn, expanded wheat, and combinations thereof.

58. A method according to any one of claims 30 to 57 wherein the explosive composition comprises hydrogen peroxide:fuel:water in the range between 24%:4%:72% to 73%:8.75%:18.25% (wt%).

59. Use of an explosive composition comprising hydrogen peroxide and a sensitiser included in a detonation-sensitive concentration, wherein the sensitiser comprises bubbles of gas incorporated by mechanical agitation, injection by bubbling said gas through said composition or by in situ generation of said gas by chemical means, wherein the concentration of peroxide in the composition is between about 25%
to 80% w/w.