Vegetable oil modified explosive

A method of increasing the viscosity, and the resistance to high shear induced crystallization, of a pumpable, shear thickened emulsion explosive, is provided wherein the explosive has been prepared by emulsifying an oxidizer salt phase into a fuel phase, and at least a portion of said fuel phase has been replaced with a vegetable oil. The explosives are particularly suitable for use in up-hole blasting operations because of their high viscosity and resistance to shear induced crystallization of the oxidizer salt.

FIELD OF THE INVENTION 
This invention is related to emulsion explosives and, in particular, to 
pumpable emulsion explosives with increased resistance to shear induced 
crystallization of the oxidizer salt. 
DESCRIPTION OF THE RELATED ART 
Water-in-fuel emulsion explosives are widely used in the explosives 
industry due to their low cost, ease of manufacture, and their excellent 
blasting results. Bluhm, for example, in U.S. Pat. No. 3,447,978, 
disclosed an emulsion explosive composition comprising an aqueous 
discontinuous phase containing a dissolved oxidizer salt, a carbonaceous 
fuel continuous phase, an occluded gas for density reduction, and an 
emulsifier. Since Bluhm, many further disclosures have been made in this 
field which have described improvements and variations in water-in-fuel 
emulsion explosives. 
One application where emulsion explosives have been used is in mining 
operations where, on occasion, it is desirable to fill upwardly inclining 
boreholes, termed as up-holes, with the emulsion explosive and 
subsequently detonating the explosive. In this use, the emulsion explosive 
must be of relatively high viscosity in order to avoid drainage, or 
leakage, of the explosive from the borehole. However, the explosive 
composition must also be of a viscosity such that it is pumpable upwardly 
into the borehole. One method for providing suitable pumping and borehole 
viscosities, is to subject the emulsion explosive to high shear in order 
to increase its viscosity. This high shear can be created, for example, by 
pumping the emulsion explosive formulation through a check valve typically 
set at up to about 200 psi. 
When subjected to these shear forces when being pumped, or when passing 
through the check valve, typical emulsion explosive tend to become 
unstable in that the oxidizer salt present in the aqueous phase will 
crystallize. This crystallization adversely affects the blasting 
capabilities of the explosive. 
Various approaches have been taken in the past in order to overcome the 
crystallization problem, including increasing the surfactant level by up 
to 50%. However, it is still desirable to provide a more advantageous and 
economical method to provide a pumpable emulsion explosive which is 
responsive to shear induced thickening, while being resistant to shear 
induced crystallization. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention provides a method of increasing the 
shear induced viscosity, and the resistance to high shear induced 
crystallization, of a pumpable, shear thickenable emulsion explosive, 
which explosive has been prepared by emulsifying an oxidizer salt phase 
into a fuel phase, and which method comprises replacing at least a portion 
of said fuel phase with a vegetable oil. 
Preferably, the vegetable oil comprises at least one glyceride, and more 
preferably, the glyceride is derived from straight chain carboxylic acids 
having from 3 to 24 carbon atoms. The vegetable oil may comprise a number 
of different glycerides, and may be saturated or unsaturated. The 
vegetable oil used may also be a mixture of various vegetable oils. 
Preferred vegetable oils include: corn oil, canola oil, soya oil, sunflower 
oil, linseed oil, peanut oil, and safflower oil, or mixtures thereof. 
The compositions of various oils, typical of oils of use in the present 
invention are shown in Table 1, although other oils may also be used. 
The vegetable oil may be used to replace all or part of the fuel used in 
the emulsion explosive depending on the degree of resistance to shear 
induced crystallization which is desired. Preferably, vegetable oil 
comprises at least 30% of the fuel phase of the emulsion explosive. More 
preferably, the fuel phase comprises between 30 and 704, by weight of the 
fuel phase, of a vegetable oil. 
The emulsion explosives of the present invention may be heated in order to 
improve the liquidity of the composition in order to improve pumpability. 
However, the emulsion explosives of the present invention are pumpable at 
a temperature of less than 40.degree. C., and more preferably, at a 
temperature less than 25.degree. C. 
TABLE 1 
__________________________________________________________________________ 
Vegetable Oil Composition 
Fatty Acid 
Canola 
Peanut 
Sunflower 
Corn Soybean 
Safflower 
Olive 
__________________________________________________________________________ 
Palmitic 
4.0% 
8.3% 
6.4% 8-12% 6.4% 9.4% 
Stearic 1.5 3.1 1.3 2.5-4.5 3.1 2.0 
Oleic 58.0 
56.0 
21.3 19-49 26% 13.4 83.5 
Linoleic 
22.0 
26.0 
66.2 34-62 49 76.6-79 
4.0 
Linolenic 
10.0 &lt;0.1 11 0.04-0.13 
Arachidic 
0.8 2.4 4.0 0.2 0.9 
Eicosenoic 
2.0 
Behenic 0.3 3.1 0.8 
Erucic 1.0 
Lignoceric 1.1 
Myristic 0.1-1.7 
Hexadecenoic 0.2-1.6 
Saturated Acids 14 
__________________________________________________________________________ 
While the use of vegetable oils in emulsion explosives has been described 
in the prior art as merely being one of a variety of suitable oils which 
may be used as a fuel in emulsion explosives in general, the beneficial 
effects of increased viscosity and resistance to shear induced 
crystallization, observed in the pumpable, shear thickened formulations of 
the present invention, have not been described. 
Prior to pumping, the emulsion explosives of the present invention have 
similar properties as emulsions of the prior art. When subjected to high 
shear forces such as, for example, passing through a 100 to 200 psi. check 
valve, the viscosity of the composition rapidly increases to levels where 
the explosive is sufficiently thick to remain stationary in the borehole, 
without leakage. The explosive also has increased resistance to shear 
induced crystallization of the oxidizer salt, under these conditions. 
Accordingly, the present invention also provides a method of manufacturing 
a pumpable, shear thickened emulsion explosive as described hereinabove, 
comprising: 
emulsifying a liquefied oxidizer salt into a fuel phase to form an emulsion 
explosive premix; and 
subjecting said emulsion explosive premix to high shear to produce a high 
viscosity emulsion explosive, characterized in that said fuel phase 
comprises a vegetable oil. 
The oxidizer salt for use in the discontinuous phase of the emulsion is 
preferably selected from the group consisting of alkali and alkaline earth 
metal nitrates, chlorates and perchlorates, ammonium nitrate, ammonium 
chlorates, ammonium perchlorate and mixtures thereof. It is particularly 
preferred that the oxidizer salt is ammonium nitrate, or a mixture of 
ammonium and sodium nitrate. 
A preferred oxidizer salt mixture comprises a solution of about 69% 
ammonium nitrate, 15% sodium nitrate and 16% water. 
The oxidizer salt is typically a concentrated aqueous solution of the salt 
or mixture of salts. However, the oxidizer salt may also be a liquefied, 
melted solution of the oxidizer salt where a lower water content is 
desired. 
The oxidizer salt-containing discontinuous phase of the emulsion explosive 
may also be a eutectic composition. By eutectic composition it is meant 
that the melting point of the composition is either at the eutectic or in 
the region of the eutectic or the components of the composition. 
The oxidizer salt for use in the discontinuous phase of the emulsion may 
further comprise a melting point depressant. Suitable melting point 
depressants for use with ammonium nitrate in the discontinuous phase 
include inorganic salts such as lithium nitrate, silver nitrate, lead 
nitrate, sodium nitrate, potassium nitrate; alcohols such as methyl 
alcohol, ethylene glycol, glycerol, mannitol, sorbitol, pentaerythritol; 
carbohydrates such as sugars, starches and dextrins; aliphatic carboxylic 
acids and their salts such as formic acid, acetic acid, ammonium formate, 
sodium formate, sodium acetate, and ammonium acetate; glycine; chloracetic 
acid; glycolic acid; succinic acid; tartaric acid; adipic acid; lower 
aliphatic amides such as formamide, acetamide and urea; urea nitrate; 
nitrogenous substances such as nitroguanidine, guanidine nitrate, 
methylamine, methylamine nitrate, and ethylene diamine dinitrate; and 
mixtures thereof. 
Typically, the discontinuous phase of the emulsion comprises 60 to 97% by 
weight of the emulsion explosive, and preferably 85 to 954 by weight of 
the emulsion explosive. 
The continuous water-inniscible organic fuel phase of the emulsion 
explosive of the present invention comprises a vegetable oil as described 
hereinabove. However, the vegetable oil may be mixed with a variety of 
other organic fuels which are typically used in the manufacture of 
emulsion explosives. Suitable organic fuels for use in the continuous 
phase 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, furnace oil, kerosene, naphtha, waxes, (eg. 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, 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 distillate, 
such as gasoline, kerosene, fuel oils and paraffin oils. More preferably 
the organic fuel is paraffin oil. 
Typically, the continuous water-immiscible organic fuel phase of the 
emulsion explosive comprises 3 to 30% by weight of the emulsion explosive, 
and preferably 5 to 15% by weight of the emulsion explosive. 
The emulsion explosive comprises an emulsifier component to aid in the 
formation to the emulsion, and to improve the stability of the emulsion. 
The emulsifier component may be chosen from the wide range of emulsifying 
agents known in the art to be suitable for the preparation of emulsion 
explosive compositions. Examples of such emulsifying agents include 
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 amine, quaternary amines, alkyloxazolines, 
alkenyloxazolines, imidazolines, alkyl-sulfonates, alkylarylsulfonates, 
alkylsulfosuccinates, alkylphosphates, alkenylphosphates, phosphate 
esters, lecithin, copolymers of poly(oxyalkylene) glycols and 
poly(12-hydroxystearic acid), condensation products of compounds 
comprising at least one primary amine and poly[alk(en)yl)succinic acid or 
anhydride, and mixtures thereof. 
Among the preferred emulsifying agents are the 2-alkyl and 
2-alkenyl-4,4'-bis(hydroxymethyl)oxazolines, the fatty acid esters of 
sorbitol, lecithin, copolymers of poly(oxyalkylene)glycols and 
poly(12-hydroxystearic acid), condensation products of compounds 
comprising at least one primary amine and poly[alk(en)yl]succinic acid or 
anhydride, and mixtures thereof. 
More preferably the emulsifier component comprises a condensation product 
of a compound comprising at least one primary amine and a 
poly[alk(en)yl]succinic acid or anhydride. A preferred emulsifier is a 
polyisobutylene succinic anhydride (PIBSA) based surfactant, which 
surfactants are described in Canadian Patent No. 1,244,463 (Baker). 
Australian Patent Application No. 40006/85 (Cooper and Baker) discloses 
emulsion explosive compositions in which the emulsifier is a condensation 
product of a poly[alk(en)yl] succinic anhydride and an amine such as 
ethylene diamine, diethylene triamine and ethanolamine. Further examples 
of preferred condensation products may be found in Australian Patent 
Applications Nos. 29933/89 and 29932/89. 
Typically, the emulsifier component of the emulsion explosive comprises up 
to 5% by weight of the emulsion explosive composition. Higher proportions 
of the emulsifier component 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 emulsifier component to achieve the desired effect. 
Stable emulsions can be formed using relatively low levels of emulsifier 
component and for reasons of economy, it is preferable to keep to the 
minimum amounts of emulsifier necessary to achieve the desired effect. The 
preferred level of emulsifier component used is in the range of from 0.4 
to 3.0% by weight of the emulsion explosive. 
The surfactant levels used in the manufacture of the emulsion explosive of 
the present invention can be reduced over the formulations of the shear 
induced crystallization-resistant formulations typical of the prior art, 
and may be more typical of the values used for other standard emulsion 
explosives as described hereinabove. 
If desired other, optional fuel materials, hereinafter referred to as 
secondary fuels, may be incorporated into the emulsion explosives. 
Examples of such secondary fuels include finely divided solids. Examples 
of solid secondary fuels include finely divided materials such as: sulfur; 
aluminum; carbonaceous materials such as gilsonite, comminuted coke or 
charcoal, carbon black, resin acids such as abietic acid, sugars such as 
glucose or dextrose and other vegetable products such as starch, nut meal, 
grain meal and wood-pulp; and mixtures thereof. 
The explosive composition is preferably oxygen balanced. This may be 
achieved by providing a blend of components which are themselves oxygen 
balanced or by providing a blend which, while having a net oxygen balance, 
comprises components which are not themselves oxygen balanced. This 
provides a more efficient explosive composition which, when detonated, 
leaves fewer unreacted components. Additional components may be added to 
the explosive composition to control the oxygen balance of the explosive 
composition. 
The explosive composition may additionally comprise a discontinuous gaseous 
component which gaseous component can be utilized to vary the density 
and/or the sensitivity of the explosive composition. 
The methods of incorporating a gaseous component and the enhanced 
sensitivity of explosive compositions comprising gaseous components are 
well known to those skilled in the art. The gaseous components may, for 
example, be incorporated into the explosive composition as fine gas 
bubbles dispersed through the composition, as hollow particles which are 
often referred to as microballons or as microspheres, as porous particles, 
or mixtures thereof. 
A discontinuous phase of fine gas bubbles may be incorporated into the 
explosive composition by mechanical agitation, injection or bubbling the 
gas-through the composition, or by chemical generation of the gas in situ. 
Suitable chemicals for the in situ generation of gas bubbles include 
peroxides, such as hydrogen peroxide, nitrates, such as sodium nitrate, 
nitrosoamines, such as N,N'-dinitrosopentamethylenetetramine, alkali metal 
borohydrides, such as sodium borohydride, and carbonates, such as sodium 
carbonate. Preferred chemicals for the in situ generation of gas bubbles 
are nitrous acid and its salts which react under conditions of acid pH to 
produce gas bubbles. Preferred nitrous acid salts include alkali metal 
nitrites, such as sodium nitrite. Catalytic agents such as thiocyanate or 
thiourea may be used to accelerate the reaction of a nitrite gassing 
agent. Suitable small hollow particles include small hollow microspheres 
of glass or resinous materials, such as phenol-formaldehyde, 
urea-formaldehyde and copolymers of vinylidene chloride and acrylonitrile. 
Suitable porous materials include expanded minerals such as perlite, and 
expanded polymers such as polystyrene. 
In a further aspect, the present invention also provides a pumpable, shear 
thickenable emulsion explosive comprising a discontinuous phase of an 
oxidizer salt, and a continuous fuel phase, wherein said fuel phase 
comprises a vegetable oil. Preferably, the fuel phase comprises at least 
30%, and more preferably between 30 and 704, vegetable oil. 
In a still further aspect, the present invention also provides a method of 
blasting comprising placing an explosive initiator such as, for example, a 
booster, a primer, or a detonator, as appropriate, in operative attachment 
to an emulsion explosive as described hereinabove, and igniting said 
initiator.

EXAMPLES 
The invention will now be described, by way of example only, by reference 
to the following examples. 
EXAMPLE 1 
Emulsion explosive compositions were prepared, for this example and all 
subsequent examples unless indicated otherwise, by the following 
technique. A first premix of an oxidizer salt or a mixture of oxidizer 
salts, in water was heated to above 75.degree. C. until a liquefied 
solution of the oxidizer salts was obtained. A second premix of organic 
fuels and emulsifying agent(s) was heated in the bowl of a Hobart mixer to 
a temperature of 90.degree. C. While mixing the second premix at a 
moderate speed (Speed 2) in the Hobart mixer, the first premix of the 
oxidizer salt solution was slowly added and an emulsion explosive formed. 
The formulations used to manufacture the emulsion formulations of Example 1 
are set out in Table 2. 
In order to measure the increase in viscosity caused by shear induced 
thickening, the various emulsion formulations of Example 1 were mixed at 
an increased speed (Speed 3) in the Hobart mixer, for various additional 
mix times, and the viscosity of each emulsion, after the additional mix 
time, was measured using a Brookfield viscometer (Spindle 6, Speed 10). 
The results are of the experiments are also set out in Table 2. 
TABLE 2 
______________________________________ 
Effect of Shear on Emulsion Explosives 
______________________________________ 
Formulation No. 
1 2 3 4 
______________________________________ 
AN/SN Liquor.sup.1 
93.2 93.2 93.2 92.6 
Diesel Oil 3.7 2.7 2.7 -- 
Slack Wax 1.7 -- -- -- 
Canola Oil -- 2.7 -- -- 
Corn Oil -- -- 2.7 6.0 
Sorbitan Monooleate 
1.4 1.4 1.4 1.4 
Additional 
Mix time (sec.) 
Viscosity (cps) 
______________________________________ 
0 19,000 29,000 20,000 40,000 
30 29,000 42,000 29,000 a 
60 35,000 49,500 45,000 a 
90 40,000 57,000 55,000 a 
150 45,000 63,000 65,000 a 
270 56,000 82,000 75,000 a 
______________________________________ 
.sup.1 69% Ammonium nitrate, 15% Sodium nitrate, and 16% water. 
a Viscosity was too high to measure, ie. very thick 
As can be seen from Table 2, all emulsions, including those such as 
Formulation 1 which are not in accordance with the present invention, tend 
to thicken under shear. However, those emulsions which are in accordance 
with the present invention (Formulations 2, 3 and 4) have a more rapid 
development of high viscosity, and achieve a higher viscosity. Formulation 
4 demonstrates the very high viscosity which can be rapidly achieved using 
the present invention. 
EXAMPLE 2 
A series of experiments were conducted on a variety of formulations to 
determine the effect of various check valve pressures on the rheology of 
the emulsion. Typically, crystallization of the oxidizer salt phase is 
more likely to occur as the pumping temperature is decreased. Further, as 
the oxidizer salt phase crystallizes, the temperature of the emulsion 
increases. While some increase in temperature can be attributed to the 
mechanical forces of pumping, the relative increases in temperature 
between two emulsions is indicative of the degree of crystallization of 
the emulsion. The formulations of the emulsions used in this example are 
set out in Table 3. 
The emulsions produced from formulations 5 to 11 were pumped at various 
temperatures and pressures, and passed through check valves set at the 
different pressures shown in Table 4. The viscosity and temperature of the 
emulsion after check valve thickening was measured. Further, the blasting 
characteristics of the emulsions after thickening was measured in order to 
determine if there was any detrimental effect on the blasting properties 
of the emulsions. 
TABLE 3 
______________________________________ 
Formulations for Example 2 
Formula- 
tion No. 
5 6 7 8 9 10 11 
______________________________________ 
AN/SN Liquor.sup.1 
91.5 91.5 91.0 91.0 91.5 91.4 91.3 
HT-22.sup.2 4.0 2.75 -- -- -- -- -- 
Isopar.sup.3 
-- -- -- -- 4.0 3.1 2.1 
Corn Oil -- -- 4.5 3.25 -- 1.0 2.1 
PIBSA based 2.0 3.0 2.0 3.0 2.0 2.0 2.0 
surfactant 
Sorbitan Mono- 
0.5 0.75 0.5 0.75 0.5 0.5 0.5 
oleate 
______________________________________ 
.sup.1 69% Ammonium nitrate, 15% Sodium nitrate, and 16% water. 
.sup.2 High viscosity mineral oil 
.sup.3 Low viscosity paraffin oil 
TABLE 4 
__________________________________________________________________________ 
PUMPING PRESSURE TESTS.sup.a 
PUMPING PUMPING 
TEMPERATURE 
PRESSURE.sup.c 
VISCOSITY.sup.d 
.DELTA. T 
.phi..sup.e /Primer.sup.f 
/Velocity.sup.g 
FORMULATION.sup.b 
(.degree.C.) 
(psi) (cps) (.degree.C.) 
(kms.sup.-1) 
__________________________________________________________________________ 
5 20 0 60,000 0 2"/20 g/5.0 
100 X 15 3"/PX/F 
200 X 15 3"/PX/F 
6 20 0 160,000 0 2"/20 g/5.0 
100 X 15 3"/PX/F 
200 X 15 3"/PX/F 
40 0 120,000 0 2"/20 g/5.0 
100 200,000 Not measured 
2"/PX/B 
100 200,000 Not measured 
3"/PX/4.7 
200 140,000 Not measured 
3"/PX/F 
7 30 0 160,000 0 2"/60 g/5.0 
100 &gt;400,000 
4 2"/60 g/5.0 
200 &gt;400,000 
7 2"/60 g/5.1 
8 30 0 200,000 0 2"/20 g/4.7 
100 360,000 0 3"/60 g/4.8 
200 &gt;400,000 
8 3"/60 g/4.9 
9 15 0 49,000 0 2"/20 g/5.0 
100 190,000 4 2"/20 g/5.0 
200 280,000 10 2"/20 g/5.0 
60 0 36,000 0 2"/20 g/5.0 
100 132,000 0 2"/20 g/5.0 
200 212,000 0 2"/20 g/5.0 
10 14 0 53,000 0 2"/20 g/5.0 
100 240,000 2 2"/20 g/5.0 
200 &gt;400,000 
4 2"/20 g/5.0 
60 0 40,000 0 2"/20 g/5.0 
100 150,000 0 2"/20 g/5.0 
200 288,000 0 2"/20 g/5.0 
11 7 0 98,000 0 2"/20 g/5.0 
100 350,000 0 2"/20 g/5.0 
200 &gt;400,000 
8 2"/40 g/4.5 
40 0 90,000 0 2"/20 g/5.0 
100 360,000 0 2"/20 g/4.3 
200 &gt;400,000 
0 2"/20 g/3.8 
75 0 57,000 0 2"/20 g/5.0 
100 340,000 0 2"/20 g/5.0 
200 &gt;400,000 
0 2"/20 g/5.0 
__________________________________________________________________________ 
.sup.a Experiments were performed on emulsion batches manufactured on a 
Gelmaster bowl; mechanical equipment employed consisted of a 4 inch 
diameter "Powergel" pump, using 3 inches of a 2 or 3 inch diameter hose 
(zero line pressure) and an adjustable check/relief valve arrangement 
(spring loaded with an adjustable screw tension) 
.sup.b Formulations as shown in Table 3 
.sup.c Check valve setting 
.sup.d Brookfield viscometer: spindle 7, speed 10 "X" = massive 
crystallisation 
.sup.e Diameter of hose 
.sup.f Grams of primer used for initiation; PX = Pentomex primer 
.sup.g Velocity of detonation in km/sec 
F = failed to detonate 
B = burned 
Formulations 5, 6 and 9 were not prepared in accordance with the present 
invention, while formulations 7, 8, 10 and 11 were prepared in accordance 
with the present invention. 
It can be seen from Table 4 that, under similar conditions, the viscosity 
of the emulsions of the present invention were greater after check valve 
thickening than the viscosities of the formulations not in accordance with 
the present invention. Further, the viscosity of formulations 7, 8, 10 and 
11 were, under certain conditions, greater than 400,000 cps. which value 
was not obtained for the emulsions not in accordance with the present 
invention. 
The temperature increase, which can be considered to be an indication of 
the degree of crystallization of the shear thickened emulsion, is greater 
for the emulsions not in accordance with the present invention, and ranged 
anywhere from 4.degree. to 15.degree. C., while the emulsions in 
accordance with the present invention increased in temperature by a 
maximum of 8.degree. C. and only then under conditions of low or ambient 
temperature and high shear (200 psi), conditions under which maximum 
crystallization would normally be expected. This reduced tendency to 
crystallize, in combination with significantly increased viscosity, 
provides an improved emulsion explosive through the use of corn and/or 
other vegetable oils in accordance with the present invention. Thus, it is 
believed that less crystallization of the emulsions in accordance with the 
present invention has occurred. Further, massive crystallization of the 
emulsion was observed with formulations 5 and 6 after shear thickening was 
conducted. 
Blasting results obtained on 2 and 3 inch diameter cartridges of the shear 
thickened emulsions made under the conditions shown in Table 4 are also 
shown. All formulations made in accordance with the present invention 
detonated and provided velocity of detonation (VOD) values of greater than 
3.8 km/sec, and typically greater than 4.7 km/sec. The emulsions prepared 
from formulations not in accordance with the present invention frequently 
failed to detonate, or merely burned rather than detonate. 
Accordingly, it can be seen that increased viscosity and increase 
resistance to shear induced crystallization of the oxidizer salt can be 
achieved by the method of the present invention. 
Having described specific embodiments of the present invention, it will be 
understood that modification thereof may be suggested to those skilled in 
the art, and it is intended to cover all such modifications as fall within 
the scope of the appended claims.