CA1331514C

CA1331514C - Emulsion explosive-containing composition having a high viscosity

Info

Publication number: CA1331514C
Application number: CA000592625A
Authority: CA
Inventors: Vladimir Sujansky; David Curtin; Mathew Ballard
Original assignee: ICI Australia Operations Pty Ltd
Current assignee: Orica Explosives Technology Pty Ltd
Priority date: 1988-03-02
Filing date: 1989-03-02
Publication date: 1994-08-23
Anticipated expiration: 2011-08-23
Also published as: EP0331430A1; CN1049417C; NO890869D0; ZW3089A1; PH26253A; ZA891501B; GB8904585D0; NO890869L; ZM1289A1; GB2216513A; MW1089A1; CN1035817A; NZ228181A

Abstract

ABSTRACT
EMULSION EXPLOSIVE-CONTAINING COMPOSITION HAVING A HIGH VELOCITY
An explosive composition comprising a blend of 45 to 95% by weight of the composition of water-in-oil emulsion comprising a discontinuous aqueous phase comprising at least one oxygen-releasing salt, a continuous water immiscible organic phase and a water-in-oil emulsifying agent; and 5 to 55% by weight of the composition of solid particulate ammonium nitrate and wherein the Brookfield Viscosity of the water-in-oil emulsion is in the range of from 25,000 to 60,000 cps. The composition has the advantage of being collar loadable into water-containing bore-holes.

Description

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EMULSION EXPLOSIVE-CONTAINING COMPOSITION HAVING A HIGH VELOCITY

The present lnvent10n relates to an exploslve composltlon ~nd ln p~rt1cul2r to such ~ compos1tlon compr1sln9 ~ blend of ~n emulslon explostve and sol1d ~mmontum nltrote p3rt1cles.

Emulslon exploslve compos1tlon~ have been widely ~cceptet ln the explos~es 1ndustr~ because of thelr ~xcellent ~xpl~slv- propertles and ease of handl1ns.
~he omul~1Dn exptos1ve compos~t~ons now 1n common use 1n th~ 1ndustry were 1rst d~sclo5e~ by Bluhm ln Un1ted States ~tent No. 3 447 978 ond comprlse ~s components~ a discontlnuous aqueous phase ~ ~
compr1s1ng dtscr~te droplets of ~n ~ueous solut10n ~: :
of lnorg~nlc oxygcn-rele~s1nD s~lts; (b) a contlnuous w~ter-1mm~sc1ble org~n1c phase throu~hout ~ 15 wh1ch the droplet~ ~re dlsperse~; (C) ~n emutslfler I wh1ch forms ~n omuls10n of th~ dropl~ts of ox1d1zer s~lt solutlon throu~hout the cont~n~ous organ1c -~
pho3~; ~nd (d) ~ d1scontlnuous oasaous ph~se.
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1331~14 ::

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More recently explosive compositions which comprise a blend of a water-in-oil emulsion and a solid particulate ammonium nitrate (AN) such as ammonium nitrate prills or ammonium nitrate prills coated with fuel oil (referred to as ANFO) have become popular because of the reductions in cost due to the inclusion of a significant propoxtion, for example, 5 to 50% of AN.

Compositions comprising blends of a water-in-oil emulsion and AN (or ANFO) are described, for example, in Australian Patent Application No. 29408/71 (Butterworth) published November 30, 1973 and US Patents 3 161 551 (Egly et al) published December 15, 1964, and 4 357 184 (Binet et al) published November 2, 1982. A serious problem of prior art blends is evident when loading the compositions into wet bore holes.

Although the tendency of the solid AN prill to break up or `
dissolve in water is reduced somewhat by the presence of the emulsion component, collar loading of prior art emulsion/prill blends into water-containing bore holes results in a significant reduction in blast performance.

As a result it has hitherto been necessary when loading emulsion/AN blends into water-containing bore-holes to pump the product to the bottom of the holes using a long delivery hose and to fill the hole by displacing water above the rising explosive column.

This pumping technique however does not allow the rapid loading rates that can be achieved when loading the blends from the top of bore-holes using techniques such as augering. Consequently as well as having to accept a slower loading rate in wet bore-holes, frequent users of such explosives have been forced to maintain two sets of equipment for loading bore-holes according to the prevailing weather conditions.

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We have now found that by selecting a water-in-oil emulsion having a viscosity in the range of from 25,000 to 60,000 cps the water resistance of a blend of water-in-oil emulsion and solid particulate ammonium nitrate is significantly increased while the blend retains a consistency suitable for collar-loading.

Accordingly, we provide an explosive composition comprising a blend o~ 45 to 95% by weight of the composition of a water-in-oil emulsion comprising a discontinuous aqueous phase comprising at least one oxygen-releasing salt, a continuous water-immiscible organic phase and a water-in-oil emulsifying agent; and 5 to 55% by weight of the composition of solid particulate ammonium nitrate and wherein the Brookfield Viscosity of the water-in-oil emulsion is in the range of from 25,000 to 60jO00 cps.

Where used herein the term Brookfield Viscosity refers to the viscosity measured at 60C using a Brookfield*RVT
Viscometer No. 7 spindle at 50 rpm. It preferred that the Brookfield Viscosity of the water-in-oil emulsion be in the range of 28,000 to 40,000 cps.

A variety of factors influence the viscosity of the emulsion component. For example, the nature of the oil and the water-in-oil emulsifier as well as their interaction. These features may be balanced without undue experimentation to provide a Brookfield Viscosity within the characterising range of from 25,000 to 60,000 cps. ~
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Th~ emulslon exp~os1vQ component of the compos1tion ~2y conta1n ~diuvants, ~or exa~ple, vo1d a~ents Such as ~s bubbles, porous p~rt1cles or balloons to rQ~uce the dens1ty o~ent wh1ch st~b111ze vo1d agents ~nd sol1d p~rtlcul~te ~aterl~1 such as c~rbon or ~lum1n1u~.

Such mater1~1s 1nfluence the vlscos1ty o~ the compos1t10n ~s does the ~ol1d part~culate ammon1u~, n1trAte ~nd the Brookf1eld Vlscoslty of the ~-lo water 1n-oil omuls10n ls therefore deter~lned on the w~ter-ln-o11 e~ lon devold of ~dJuvants.

The water-l~m1sc1ble or~nlc phase component of the w~ter-1n-oll e~uls10n of the composit10n of the 1nvent10n comprlses the continuous "o~l" phase of t~.e w~ter~ln-o11 emuls10n ~nd 1s the fuel. Exa~ples of oro~n1c fu~ls lnclude allphat~c, ~11cycllc ant ~rom~t1~ compounds ~nd ml~tunes thereof whlch ~re in the 11qu1d state ~t the ~ormul~tlon te~perature.
Su1t~ble oro-n1c ~uels m~y be chosen from fuel o11, dlesel o~l, distillate, kerosene, n~phtha, ~%ss ~eg. m1crocryst~111ne wax, paroff1n w~x ~nd sl~ck w~x), p~roff1n o11s, benzene, toluene, x~l~nes, ~sDh~ltlc mater1~1s, polymerlc o11s such ~s the low molecul-r we1aht poly~ers of olef1ns, an1m~
o11s, flsh olls, ~nd other mlneral, hydroc~rbon or ~atty olls, ~nd mlx~uros thereof, Preferred or~2nic ~ -~
fuets ~re 11qu1d hydroc~r~ons g~ner~lly referred to ~s petroleum d1st111~tes Such as gasoline, kerosene, ~uel 0115, furn~co o11s, ~nd p~raff1n oils.

Typ~c~lly, tho orp~n1c fuel of th~ cont1nuous ph~o ~:
of the w~tor-ln-o11 emuls10n component comprises trom 2 to 154 by weloht ~nd preferobly 3 to 10% by ;~ wel~ht of th~ w~ter-1n-oll emuls10n component sf the ~ ;
~ exploslv- composltlon of the lnvent10n.
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.-` 5 typ1cally we h~ found th~ o11s h-v1ng ~ vl~coslty lr the r~nge o~ from 4 ~o lO00 ~nd prof~r~bly 6 to , 200 c~ntl-~tok~s ar~ p~rtlcul~rly ~u1tod ~o ~rov1dlng ~ water-1n-ol 1 emuls1On h~vlng the 5 c~,~racterl~t1c Y1sco~lty ran~ ot from 25,000 to 6C,0~0 cps l~ ls p~rt1cularly ~r~fe~red th~t the or~an~c ~uel 0' th2 e~ul~lon component o~ the eomposlt10ns of the 1~vent10n co~prls~ ~t l~ast one p~afftn1c o11.

Gen~r~ 1t has bcen the pr~ctlce 1n thQ ~r~ to ~se d~-sel otl or No 2 fu-l o11 1n the emulslon ph~se cf e~ulslon/AN blonds However we h~Ye foun~ th~t tte use ot par~ff~n1c o11s ~s part~cul~rly sulted to prod~c1ng blends havtno h1gh re~1st~nc~ to w~ter aLsorptlon emulslfy1nc agent of the w~er-1n-oil ~ulslon m~y be selQcted trom thc wlde rang- of e~ulslfy1ng ' ~-a;ents known 1n the ~rt; Ex~plcs of ~uls1fyln~
a ents 1~1cude ~lcohol ~lkoxyl~t~s, phenol 20 ~lkoxyl~tns, poly(oxy~lkylen~ ~lytols, pcly~oxy~lkylen~ tatty ~c~d est~rs, ~mlnc ~lkoxy1~tns, fatty acld esters of sor~ltol ~nd glyçorol, fatty ~cld s~ltS, sorblt~n nsters, poly~
~exyl1kyl~ne) sor~1tan ~st~rs, f~tty ~m1ne 25 ~t~oxyl~t~s, poly~oxy~ yl~nQ~ glycol ~sters, fatt~
~c1d ~mld~s, f~tty ~cld ~mlde alkoxylat-s, f~tty ~e1nes, quatern~ry amtnes, ~lkylox~201~n~s, ~7~onylox~zot1nes, lmld~zol1nes, elkyl~sutfon~tes, ~l~yl~rylsulfon~tes, ~lkylsulfos~ccln~t~s, 30 sl~ylphosph~es, ~lkenylphosph~tes, phosph~te es:-rs, te~1thln, copolymers of poly~oxy~lkylene1 olYcol~ ~n~ polyt12-hydroxy-tc~rlc c1d3, ~n~
m1xturrs ther~of A~on~ th~ pref~rr~d ~muls1~y1ng ~g~nts ~r~ the 2-~kyl- ~nd 2--lk~nyl-e,~'-b1s .

1331~1A
(hydroxymethyl)oxazoline, the fatty acid esters of sorbitol, lecithin, copolymers of poly(oxyalkylene) glycols and poly~12-hydroxystearic acid), and mixtures thereof, and particularly sorbitan mono-oleate, sorbitan sesquioleate, 2-oleyl- 4,4'-bis(hydroxymethyl) oxazoline, mixture of sorbitan sesquioleate, lecithin and a copolymer of poly(oxyalkylene) glycol and poly (12-hydroxystearic acid), poly[alk(en)yl]succinic acid and derivatives thereof, and mixtures thereof.

Although a range of emulsifying agents may be used in preparing compositions of the invention we have found that a particularly high water resistance is provided where the water-in-oil emulsion component has a viscosity in the range of 25,000 to 60,000 cps and the emulsifying agent component comprises a condensa'ion product of an amine and a poly[alk(en)yl]succinic acid and/or anhydride.

Typical examples of condensation products of an amine and poly[alk(en)yl]succinic acid and/or anhydride may include esters, imides, amides, and mixtures thereof. Preferably, ;
said emulsifier has an average molecular weight in the ~
range 400 to 5000. ~ ;

In said poly[alk(en)yl]succinic acid-based emulsifier it is preferred that the hydrocarbon chain is derived from polymerization of a mono-olefin and generally the polymer ~ -chain will contain from 40 to 500 carbon atoms.

Preferably the poly[alk(en)yl] moiety is derived from olefins containing from 2 to 6 carbon atoms and in particular from ethylene, propylene, 1-butene and isobutene. The emulsifier may be derived from poly~alk(en)yl]succinic anhydride. Such emulsifiers ;

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derivatives are disclosed in Australian Patent, Patent Application No. 40006/85 published September 26, 1985.

Such derivatives are commercially-available materials which are made by an addition reaction between a polyolefin containing a terminal unsaturated group and maleic anhydride, optionally in the presence of a halogen containing catalyst. The succinic acid or anhydride residue in the above compounds may be reacted to introduce a polar group. Generally the said polar group is ;
monomeric oligomeric groupings containing not more than about 10 repeat units may be employed. Examples of ~ -suitable polar groups may include "olar groups derived from polyols such as glycerol, pentaerythritol, and sorbitol or an internal anhydride thereof (e.g. sorbitan);
from amines such as ethylene diamine, tetraethylene triamine and dimethylaminopropylamine; and from heterocyclics such as oxazoline or imidazoline. Suitable oligomeric groupings include short-chain poly(oxyethylene) groups (i.e. those containing up to 10 ethylene oxide ; ~-units)~
Formation of emulsifiers for use in accordance with the invention may be effected by conventional procedures depending upon their chemical nature.

In order to prepare a derivative of poly(alk(en)yl)succinic acid comprising a polar group derived from an alcohol or amine, the acid group or anhydride thereof can be caused to react with the hydroxyl or amino group by heating the two components together in a suitable solvent, in the presence of a catalyst if desired. -~

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The emulsifiers may be of a non-ionic character, but they may alternatively be anionic or cationic in nature, as, for example, where the hydrophilic moiety incorporates the residue of a polyamine or a heterocyclic compound.

Preferred emulsifiers are poly(isobutylene)succinic anhydride derivatives and most preferably condensates thereof with amines such as ethanolamine. `

Typically, the emulsifying agent component of the composition of the present invention comprises up to 5~ by weight of the emulsion component of the composition.
Higher proportions of the emulsifying agent 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 agent to achieve the desired effect.

In particular we have found that the use of a poly(isobutylene)succinic anhydride/amine condensation product in combination with a paraffinic oil in the composition of the invention provides particularly good water resistance and is well suited for collar loading into significant volumes of water.

It is preferred that the composition of the invention further comprises voiding agents which may, for example, be in the form of fine gas bubbles dispersed through the composition, hollow particles (often referred to as ~ i microballoons), porous particles or mixtures thereof.

Techniques for preparing gassed emulsion explosives are well known in the art and include mechanical agitation, injection or bubbling the gas through the composition, ~ :' ~. , 1331~1~

or chemical generation of the gas in situ.

The preferred process for introducing a gaseous phase is by in situ chemical gassing. Suitable chemicals for the in situ generation of gas bubbles include peroxides, such as hydrogen peroxide, peroxide nitrates, such as sodium nitrite, nitrosamines, such as N, N1-dinitrosopenta-methylene tetramine, alkali metal borohydrides and alkali metal carbonates, such as sodium carbonate. Catalytic agents such as thiocyanate or thiourea may be used to accelerate the decomposition of a nitrite gassing agent.
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Where used the voiding agent may be added before or after the emulsion is blended with the ammonium nitrate particles however it is generally preferred that the voiding agent is added to a blend of the emulsion and parti~,les. ~;~

Typically the voiding agent comprises 0.05 to 50% by volume of the emulsion explosive component at ambient temperature and pressure. More preferably, where used, the voiding agent is present in the range 10 to 30% by volume of the emulsion explosive component and preferably the preferred bubble size of occluded gas is below 200 -microns. More preferably, at least 50% of the gas component will be in the form of bubbles or microspheres of 20 to 200 microns internal diameter. -We have found that the presence of a dispersed gaseous phase significantly improved the water resistance of the composition of the invention when a gas bubble stabilising agent is also present. Such agents are described in our ~ .

1331~1~

copending Australian Patent Application No. 40968/85 published October 24, 1985.

Accordingly we further provide an explosive composition comprising from 45 to 95 percent by weight of the total composition of a water-in-oil emulsion comprising a -~
discontinuous aqueous phase comprising at least one oxygen-releasing salt, a continuous water immiscible organic phase, a water-in-oil emulsifying agent and at least one agent capable of facilitating the production of lo gas bubbles in the presence of said water immiscible organic phase; and 5 to 55% by weight of the total composition of solid particulate ammonium nitrate; and wherein said water-in-oil emulsifying agent is selected from the group consisting of condensation products of an 15 amine and a polyl[alk(en)yl]succinic acid and/or anhydride and mixtures thereof.

The ability of various agents to facilitate the production of small gas bubbles in compositions of the invention may be determined by a foam stabilization test.

20 Accordingly in another aspect of the invention there is provided an explosive composition as hereinbefore described wherein the agent referred to therein is characterized further in that it has properties which provide a suitable stabilizing effect and which are 25 established by means of a foam stabilization test as hereinafter described.

In the said foam stabilization test 0.2 part by weight of active ingredient of the candidate agent or mixture of agents to be tested is added to and mixed with 100 parts 30 by weight of diesel fuel. 5 ml of the mixture is placed in a graduated cylindrical vessel of 15 mm internal ~' -11- ',~ '' 1 3 3 1 ~ 1 4 diameter. The mixture is shaken for 15 seconds. A foam forms on the surface of the mixture. The volume (V5) of the foam is measured 5 minutes after the mixture has ceased to be shaken using the graduations on the vessel. ;~
The foam volume (V60) is measured again 60 minutes after -~
the mixture has ceased to be shaken, the vessel and the mixture being kept at a temperature of 18 to 22C during -~
this period of time. A foam stability parameter 06 / S iS
calculated from the foam volumes by means of the formula ::
~6 / S = V6 o It has been found that those agents or mixtures of agents in which the V5 value was equal to or greater than 1 cubic centimetre and had a 06 / S equal to or greater than 0.3 impart the desired gas bubble stablization effect of this embodiment of the invention. Hence the foam stabilizing agents preferred for use in the compositions of the invention are those having a Vs value equal to or greater than 1 cubic centimetre and a 06 I S value equal to or ~ ~
greater than 0.3 as determined by the foam stabilization ~-test hereinbefore described.

The most preferred gas bubble stabilising agents are non-ionic fluoroalkyl esters such as are available under the trade name "FLUORAD"*.

Typically when used the gas bubble stabilising agent will be present in the range of 0.0001 to 5.0% by weight of the emulsion component of the composition and preferably in the range 0.001 to 1%.

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su1e~bl~ oxyoen-rele~s1ng ~lts for use ln t~e ~quoous ph~st component o- the composltlon o~ th~
pr~sent 1nventton ~ncluCe ehe ~lk~ nd ~lk~tlno ~rth met~l n1tr~t~s, ch~orates ~nd perchlor~tes, ;~
5 ~monlum nltr~te, ammonlum ~hlor~t-, ~m~on1um perchlor~te ~nd m~xt~res therQ~. ~he pr~ferred oxy~en-rele~s1ng s~lts ~nclude ~mmon1um n~tret~, sodlum nltrate ~nd c~lclum n~trate. More prefera~ly t~e oxysen-role~stng salt compr1slng ~m00nium nltr~te or ~ ~1xturo o~ ~mmon~um n1tr~te and soctlum or c~lc1um n1tr~tes.

Typ1c~11y, th~ oxy~en-r~le~slno s~lt of tho ~muls~on componont of thc com~os1t10ns of the present 1nventton compr1ses from 45 to 95S ~nd preferably lS fro~ 60 to 90% ~y we~9ht of the tot~l e~ulslon component of the compos~tton. In oomposlttons ~hereln the oxyQen-r~leas1ng s~lt comprises 1xture of ~mon1um n~tr~te ~nd sod1u~ n1tr-te the :
pr-~crred composttlon r~nge ~or such a ~l~n~ ~s from ~
20 S to 80 p~rts of sod1um nttr~te for e~er~ ~00 p~rts ::
o~ ~mmon1um n1tr~t-. T~erefore, ln the ~referrod co~pos1t10ns of the present 1nventlon the ~:
o~yo~n-rele~1n~ s~lt compon~nt co~pr1ses from 45 to ~04 by weloht ~o~ the c~ulslon component) ~monlum 2s n~tr~t~ o~ ~1xturts o~ from 0 to 40~ by ~ei~ht (of t~.o omuls10n component) ~mmonlum n1tr~t~

T~p1c~11y, the ~mount of w~ter cmployed 1n the co~po~1t10n ôf the present lnvent10n ~s 1n the r-n~e of from I to ~04 by w~ht of the emuls10n component. Pre~er~bly the ~mount employ~d 1s ~rom ~; tc 254, ~nd ~ore prefer~bly from 6 to ~4 by we1cht o~ th~ ~mul~ion component.

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ProfQr~bly th~ r~tlo o- whter-ln-o11 ~mul~10nsso~id ~-p~rt1culat~ ammonlum nltr~t~ ls ln the r~no~ 45~55 1 to ~0 30 ~nd more p~e~er~ly 45 S5 to ~0 40 She ~erm a~monlum nltrate p~rtlcles 1s used hereln to ~ncompass co~posltlons of pr1110d ~mmon1um n1~r~te wh1e~ m~y o~tlon~lly ~e co~t~d wlth ~ fuel ~ -co~ponent ~uch ~s 1n th~ c~se of the w~17 known AN~0 1 composlt10ns, !

~yp~c~llr the solla p~rt1cul2te am~on1Ym nltrate lo ~111 comprlse up to lG~ ~w sf fuel o11 w1th about 6~ b-lng pr~err~d, At ~out 6~ the ~11d parttcul~t~ ~mmon1um n1tr~te t~ essentt~l1y ,-oxy~n-b~lanced ~ urther embod1~e~t of the lnvent~on t~ere 1s 15 pr~vlded a process for prepartng the compos~t10n herelnbe~oro dQscrtbe~, the process co~prlses blondln~ from 45 to 95 ~rts by we10ht of ~
~er-1n-o11 muls~on ~n~ from 5 to 55 p~rts by w-1~ht of ~ solld ~rttcul~te ~mmonlum n1trate 20 ~ watcr-1n-o11 emuls10n m~y b~ prep~red ln pr~ lnary procedur~ compr1slng s :
dlssolv1no the oxyg~n-rolt~sln~ solt 1n w~ter ~t a temper~ture ~ove th~ ~udge polnt of the salt solutlon, prefer~bly ~t ~ temperatur- in th~ ~an~t from 25 to }10, to ~1ve ~n ~qUeOU5 s~lt solutlon;

combln1n~ th- aqueo~s s-lt solu~10n, the w~ter~1mm1sclble oro-nle ph~s~ ~nd ~h~
wator-ln-oll emulstfylng ~gent ~1th r~p1d ~1xlno to for~ ~ w~ter-ln-o11 orul~10n; ~nd ,~

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~1~1ng unt11 th~ omulston ls ~n1~orm.

ln a pr~forrct ,~mbod1ment of th1s p~ocess th~ :
proces~ further compr1scs mlx~ng wlth th~ emulston ~:
compon,~nt or one or mor~ constltuents theraof a ~as ~-5 ~ubbl,e st~b1~1~1ng ~gent ,~nd an a~ent ca~able of ~- -ln ~ltu g~neratlon o~ 9~s b~b~l-S.
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As her~lnbefore d1scussed She presen$ lnv~n~10n ~ro~1des slgn1~c~nt ,~dvantagQs ln load1ng of wat~r conta1nlng bor,~-holes.

10 ~ccord~ng~y we further prov~d,~ a ~ethod of loading a , :
~ter-cont-1n1nc bore-hole comprlsSng pour1ng an exploslve heri~lnbcfor~ descr1~ed tnto the :
~ater-contalnlnt borehole fro~ a poslt10n adJacent the collar of the ~ter-tonteln1ng bore-hole.

By the term "pour1ng" lt ls mesnt that the explos1ve compos1tlon ls rcle~sed fro~ 1ts co~ta1nment or i~
tr~nsport means. It 1s pre~erred th~t the exploslve compos~t10n ls ouctred to the coltar of the ~cra-holc ~nd rele~sed from ,~ poslt10n a~ove the 20 c O ~

~'e llso prov1de ~ ~sthod of bl~stlng 1n ~, ~oter-cont~lnlng bor~ole tomprls1ng the steps of ls~d1ng ~ water-cont~tnlng bore-hole as here1nbefore C-scr1bed ~nd detonat1n~ the explos1v~.

lt ls ~ p~rttcYl~r adv~nt~ge of our composttlons tk~t th~y detonate well evon wh~n poure,~ from ~d~,lcent th- coll,~r of the borehol- 1nto slgnif1cant ~epths of water.

ptc~lly composlttons of o~r ~nventlon ~ay be ~etonat~ su~c~s~fully ~ven whon the exploslv~wa~en ~i - -15- ~331~4 ~1ght r~t10 15 l~S5 thdn lO ~n~ pl~fer-bly ln th~
r~nge o~ from 1~1 tQ 6/l. ~;

~e ~lso provld~ a method Of ~ldstlng comprlsln9 deton~t1n~ an ~xplosivo co~posltlon ~S h~relnd~o~e .
5 tescrlbed ln w~er wher1n thQ exp10sl~eJwater w~1~ht r~t~o 1s less ~hdn lO, preferably ln the ran9e of ~rom ~/1 to 6~1.
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The invention is now demonstrated by but in no way limited to the following examples in which the term Brookfield : .
Viscosity is used to refer to measurements carried out at 20C using a Brookfield Viscometer No. 7 spindle at 50 rpm.

Example 1 and Comparative Example A

The Explosives of Example 1 and Comparative Example A
having the compositions as shown in ~'able 1 were prepared according to the following procedure. :~

Example 1 CE A
Parts w/w Parts w/w : Emulsion component Ammonium nitrate22.77 22.77 Calcium nitrate20.32 20.32 Water 6.85 6.85 Acetic acid 0.48 0.48 Distillate (oil) - 4.20 Sorbitan mono-oleate - 0.84 Paraffin (oil) 4.2 * PIBSA emulsifier 0.84 Ammonium nitrate particles Gas bubkle stabiliser "FLUORAD", 5% solution . ' in distillate 0.3 0.3 Gasser agent 0.1 0.1 (solution of 15%
sodium nitrite and 30~ sodium thiocyanate in ;~ water) ~ .
~ ~ .

1 3 3 ~ 4 * The PIBSA emulsifier used was a 1:1 molar condensate of polyisobutylene succinic anhydride and ethanolamine. -~

An aqueous solution was prepared by mixing the ammonium nitrate, CN (calcium nitrate), water and acetic acid. The composition was heated to about 80C and was added to a rapidly stirred blend of the oil and emulsifier. When addition was complete stirring was continued until the emulsion was uniform (about 60 seconds).

The ANFO (which comprised particulate ammonium nitrate on which had been absorbed 6% by weight of fuel oil) was blended with the emulsion and the gas stabilizing agent -was then added with mixing, followed by the addition of the gasser solution.
, The water-in-oil emulsion of the explosive composition of Example 1 prepared according to this process had a Brookfield Viscosity of 30,000 cps.

The water-in-oil emulsion of the explosive composition of Comparative Example A had a Brookfield Viscosity of 10,000 cps.

The compositions prepared according to the above process were tested as follows~
The explosive (15 kg) is poured down a 4 m high (150 mm diameter) artificial borehole with a 200 mm diameter package at the bottom containing water (15 kg). The package was removed and excess water poured from the top.
The explosive was then primed with 400 g of "ANZOMEX" (trade mark) primer.

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The co~po~ltlon o~ Ex-~pl- ~ ~ucc~ ully ~oton-Sod on c~rry1n~ out th~ ~bov~ test but th~ co~poslt~on of comp~r-tlvc Ex~mple A ~a11~a to deton~te.

ExamDles 2 and 3 ~h~ Exploslv~s of Ex~mplY 2 ~ng 3 htv1ng the compos1t10ns ~s ~hown ln T~ble 2 wor~ prep~r~d ~ccord1n~ to the ~ol10wlng proc~dur~

~ABLE 2 , :
E~a~pt~ 2 Ex~mple 3 lo Parts w~w P~rts ~rw ~mU 15 l on ~-QmDonent Ammonlum n1tr~te tchem1cally pure)40.66 40.66 ~later 1~.16 10.1~
P~r~fr1n Sotl) 2.~5 2.55 ~ PIBSA cmulslfl~1.53 l.S3 Lmmonlum nltr.ate ~rticl~
ANFO 45.0 45.0 VOI~lNG ~A~RIAL
"MICR08ALLOO~S"
4.0 :.
~ The PlBSA tmuls1fl~r w~s th- cond~ns~t10n product of~MOBlLAD C207" ~MOBILAD 15 a tr~d- ~rk~ ~nd oth~nolamlne 1n 1:1 mol~r r~tlo. MO~ILA~ C207 ls 25 poly1sobutylenc succ1nlc anhydrld~ ln a p~r~ffln d11uent.

~ An ~qu~ous so1ut~on w~s pnepared by ~1x1no th~
: ~.mon1um nltr~t~ tind w~ter. Thc tompo~lt10n w~s ho~te~ to about 80C ~nd w~s 4td~ to rapl~ly 30 Stlrrod bl~nd of the oll ~nd ~mul61f1~r. ~h~n . ., .... ~, ~. , . ~ , .. ... .

- . . - . . ~ . .-. - ~ .. , . ~ ~ , , -19- ~33~
~ddlt~on ~s compl~tc ~elrr1no ~dS continu~t until tho ~mulslon w~s unlform ~out 60 5~conds).

T~le AN~O (w~lch compr1sc~1 part1cul~t~ ~rnmontum r,1Sr~o on wh1ch h~ D~en ~bsorbr~ 6% by welght Df fuel o11 ) w~s bl~nCcd ~lth th~ ~ul5ton And th~ :
MICRo~ALbOONS ~er~ then ~ddtt ~1t~l ~1xlng. . ~ ~;

t~ w~Ser-tn-oll e~ulslon of th~ ~xplostv~ ~
compos1tlon o~ Ex~mpl~s 2 ~n~ 3 11~ d Brookf1eld -costty ~ 34,S60 - 38560 cps.

The compo~1tlons of ~xamplo~ 2 ~nd 3 show~d 11ttl~
loss of AN from tho ~NFO ~h~n l~m~r~ 1n ~ t~r.

~h~ compostt10n of ~x-~nple 2 ocve ~8% of ~hock when : ::
detonated in water-containing bore-holes.

Ex~mDlc 4 The composition of example 2 was prepared and che~tc~lly 9~sscd to ~ d~nsltY of 1.10 9Cm~3. ~ ;~

~h~ composltlon of ex4mple ~ ~vr 83~ of full energy shock ~nd bubbl-) whtn ~ton~ d 1 n ~:
I~t~r-cont~ln1n~ bore-hol~s.

2 0 E x~

The composition of example 2 was prepared except that . t~c p~r~ff1n o1i w~ repl~c~d ~1t~ ~urn~co o11.

T~o co~,pos1t10n of ex~mple 5 o~v~ 85-96~ of ful 1 en~roy ~-h~ck ~n~ bubbl~) when ~e~on~t~ld ln 25 h~t~r-cont~1n~no bor~-hol~s~200 ~ me~-r).

.. ,~ .
c = a ~ =

.,.;~. ~ ~ . ... ..... ; .. .

E~mDle 6 1331~

The composition of example 5 was prepared except that ~`
tho P~BSA ~muls1f10r ~5 roptdced W~th sorbltan m~ no-o l e~te .

5 ~he osmpos1t1On o~ ex~mple 6 g~v~ 81-86k of ~ul l en~r~y ~shock n~ bubbl~) wh-n d~ton~toJ ln w~ter-c'ont~1n1ng bore-holes~200mm dl~meter). ~ :-,. ~,~.
,~,, ~ . .
, t

Claims

1. An explosive composition comprising a blend of 45 to 95% by weight of the composition of a water-in-oil emulsion comprising a discontinuous aqueous phase comprising at least one oxygen-releasing salt, a continuous water immiscible organic phase and a water-in-oil emulsifying agent; and 5 to 55% by weight of the composition of solid particulate ammonium nitrate and wherein the Brookfield Viscosity of the water-in-oil emulsion, devoid of adjuvant, is in the range of from 25,000 to 60,000 cps.

2. An explosive composition according to claim 1 wherein the Brookfield Viscosity of the water-in-oil emulsion is in the range of 28,000 to 40,000 cps.

3. An explosive composition according to claim 1 wherein the water-in-oil emulsion comprises a continuous phase having a viscosity in the range of from 4 to 1000 centi-stokes.

4. An explosive composition according to claim 3 wherein the water-in-oil emulsion comprises a continuous phase having a viscosity in the range of from 6 to 200 centi-stokes.

5. An explosive composition according to claim 1 wherein the continuous phase comprises a paraffinic oil.

6. An explosive composition according to claim 1 wherein the emulsifying agent comprises a condensation product of an amine and a poly[alk(en)yl]succinic acid and/or anhydride.

7. An explosive composition according to any one of claims 1 to 6 wherein the emulsifying agent comprises a condensation product of ethanolamine and polyisobutylene succinic anhydride.

8. An explosive composition according to claim 1 wherein the emulsifying agent comprises a condensation product of ethanolamine and polyisobutylene succinic anhydride and wherein the continuous phase comprises a paraffinic oil.

9. An explosive composition according to claim 1 wherein the explosive composition further comprises voiding agents selected from the group consisting of gas bubbles dispersed through the composition, hollow particles, porous particles or mixtures thereof.

10. An explosive composition according to claim 1 wherein the explosive composition comprises: from 45 to 95% by weight of a water-in-oil emulsion comprising a discontinuous aqueous phase comprising at least one oxygen-releasing salt, a continuous water-immiscible organic phase, a water-in-oil emulsifying agent and at least one agent capable of facilitating the production of gas bubbles in the presence of said water immiscible organic phase; and from 5 to 55% by weight of the total composition of solid particulate ammonium nitrate; and wherein said water-in-oil emulsifying agent is selected from the group consisting of the condensation products of an amine and a poly[alk(en)yl]succinic acid and/or anhydride and mixtures thereof.

11. An explosive composition according to claim 1 wherein the explosive composition comprises a water-in-oil emulsion and a solid particulate ammonium nitrate in the ratio, water-in-oil emulsion:solid particulate ammonium nitrate, in the range 45:55 to 70:30.

12. An explosive composition according to claim 11 wherein the explosive composition comprises a water-in-oil emulsion and a solid particulate ammonium nitrate in the ratio, water-in-oil emulsion: solid particulate ammonium nitrate, in the range 45:55 to 60:40.

13. An explosive composition according to claim 1 wherein the solid particulate ammonium nitrate comprises fuel oil constituting up to 10% by weight of the solid particulate ammonium nitrate.

14. An explosive composition according to claim 13 wherein the solid particulate ammonium nitrate comprises fuel oil constituting 6% by weight of the solid particulate ammonium nitrate.

15. A process for preparing a composition according to claim 1, which process comprises blending from 45 to 95 parts by weight of a water-in-oil emulsion with from 5 to 55 parts by weight of a solid particulate ammonium nitrate.

16. A process according to claim 15 wherein the water-in-oil emulsion is prepared in a preliminary procedure comprising:

dissolving the oxygen-releasing salt in water at a temperature above the fudge point of the salt solution to give an aqueous salt solution;

combining the aqueous salt solution, the water-immiscible organic phase and the water-in-oil emulsifying agent with rapid mixing to form a water-in-oil emulsion; and mixing until the emulsion is uniform.

17. A process according to claim 15 wherein said process-further comprises mixing with the emulsion component, or one or more constituents thereof, a gas bubble stabilizing agent and an agent capable of in situ generation of gas bubbles.

18. A method of loading an explosive composition according to claim 1 into a water-containing bore-hole comprising pouring said explosive composition into the water-containing borehole from a position adjacent the collar of the water-containing bore-hole.

19. A method of blasting in a water-containing borehole comprising the steps of loading an explosive composition according to claim 1 into a water-containing bore-hole and detonating the explosive.

20. A method of blasting in a water-containing borehole according to claim 19 wherein the explosive composition to water weight ratio is less than 10.

21. A method of blasting in a water-containing borehole according to claim 20 wherein the explosive composition to water weight ratio is in the range of from 1:1 to 6:1.