1. BOOSTER FOR EXPLOSIVES
E. E. Cloete
AECI Explosives Limited
Modderfontein, Gauteng
South Africa
R.I. McCrindle
Department of Chemistry and Physics
Technikon Pretoria
Pretoria, Gauteng
South Africa
ABSTRACT
Permitted explosives were previously nitroglycerine based and cap sensitive. Due to safety, health and
environmental requirements, water-containing explosives, such as watergels and emulsions, were used
instead. However, in order for these explosives to perform at their designed level during blasting, a more
powerful stimulus than is delivered by detonators on their own is required.
AJAX was a gelatinous nitroglycerine based explosive, manufactured by AECI Explosives Limited, for
all-round use in underground coal mining. After the development of the non-cap-sensitive Permitted
Pumpable Emulsion Explosive R100C by AECI Explosives Limited, AJAX (29 mm x 200 g) cartridges
were used as primers for the initiation of the R100C. With the demise of nitroglycerine based explosives,
the requirement for a permitted initiator that was not nitroglycerine based came about.
The AECI Explosives Limited test gallery for permitted explosives was used to determine the incendivity
of various booster formulations so as to establish their suitability for use as permitted explosives. The gas
energy, heats of combustion, detonation pressure and initiation efficiency of the different booster
formulations were also measured. Small scale field trials were carried out with selected booster
formulations to evaluate their performance and to enable selections of the optimum formulation.
Potassium hydrogen tartrate was found to be more effective at limiting the heat of explosion, mass for
mass, than sodium chloride. Problems were experienced in the scaling up of the “Permitted Pentolite”
production from laboratory scale to pilot plant scale. Sedimentation of PETN and potassium hydrogen
tartrate in the TNT resulted in ignitions in the test gallery during routine batch testing. When oxygen
donors like sodium- and potassium perchlorate were used instead of inert salts/thermal ballast (e.g.
potassium hydrogen tartrate) in the formulation of the “Permitted Pentolite”, much lower percentages
were required to achieve the same level of ‘permittedness’. In spite of the lower percentages required,
uneven distribution of the oxygen donors in the pentolite due to sedimentation still posed a problem.
Segregation or settling out of the flame retardant salts in “Permitted Pentolite” formulations could be
prevented by forming a water-in-explosive emulsion. As a result of the good distribution of the flame
retardant salt in the pentolite, even lower percentages of salt were required to attain the same level of
‘permittedness’ achieved with flame retardant salts added in the solid form. This pentolite booster
formulation has therefore been selected as it meets the criteria for initiation of water-based explosives
more consistently than other initiators previously used.
INTRODUCTION
As a rule, permitted explosives were previously nitro-glycerine (NG) based and cap sensitive (Urbanski,
1967: 403-408). However, due to safety, health and environmental requirements, water-containing

2. explosives, such as watergels and emulsions are now used instead. It has been found that these types of
explosives are less sensitive to initiation than the NG based explosives. This property made watergel and
emulsion explosives safer to use because they were less susceptible to accidental detonation. However,
in order for these explosives to perform at their designed level during blasting, a more powerful stimulus
than is delivered by detonators on their own was required (Lindner, 1993: 50-53), (Van der Walt et al,
1993: 4).
AJAX was a gelatinous NG-based permitted explosive manufactured by AECI Explosives Limited (AEL)
for all-round use in underground coal mining. After the development of the non cap-sensitive Permitted
Pumpable Emulsion Explosive R100C by AEL, AJAX (29mmx200g) cartridges were used for the
initiation of the R100C. With the demise of NG-based explosives, the requirement for a permitted
initiator that was not NG based, came about.
Initial experimental work (Cloete, 1992) entailed limiting the heat (energy) of explosion by the addition of
inert salts to the Pentolite composition. Potassium hydrogen tartrate (KHC4H4O6or KHT) was found to
be more effective at limiting the heat of explosion, mass for mass, than sodium chloride.
Both salts absorb part of the heat produced during explosion through volatilization or molecular
dissociation, thus cooling the gaseous products produced during the explosion. It was decided to
investigate the use of KHT [∆Hf
o
(c) = -1545 kJ/mol] as the flame retardant. This was because KHT not
only acts as a heat absorber but increases the permissible level of the energy of the explosives because of
the catalytic activity of the flame-extinguishing salt.
METHODS
To determine the minimum quantity of inert salt required for reducing the heat of explosion of Pentolite
to a level that would render it "permitted", different percentages (mass/mass) of KHT were mixed into
the molten Pentolite before casting. The incendiary characteristics of these boosters were tested in the
test gallery in accordance with the gallery test specified by SABS 1484-1989 in conjunction with SABS
Method 1141, modified as described below.
Initially the Pentolite formulations were cast into standard plastic booster shells. When a high number of
ignitions occurred irrespective of the percentage of inert salt in the formulation, it was decided to remove
the plastic shell and test the 'bare' Pentolite in the Gallery.
Initial incendivity testing of the Pentolite/KHT formulations in the Modderfontein Test Gallery,
highlighted the need for a non-flammable container (booster shell). To prevent the initiation of the
methane-air mixture in the Test Gallery, the booster shell was injection moulded from low density
polyethylene (LDPE) that had been compounded with a flame retarding mixture (Performance
Masterbatch PL 0056) containing bromine- and antimony- compounds (Cloete, 1992: 7). LDPE booster
bodies containing 5 and 10% of the Performance Masterbatch PL 0056 respectively, were filled with
Permitted Pentolite and tested in the Gallery.
With respect to the previous work it was decided that the booster configuration would be as follows:
a. The Pentolite would contain 25% KHT (m/m) to assure its non-incendivity in a methane/air
atmosphere
b. The Permitted Pentolite formulation would be cast into an injection moulded plastic shell (LDPE
WRM 19 code 190 800 compounded with 10% (m/m) PL 0056 Performance Masterbatch). See

3. Figure 1 for dimensions. The mould used to produce the non-flammable booster shell was an existing
mould for a standard Pentolite booster.
PENTOLITE EMULSION
During the manufacture and casting of Pentolite separation can occur, due to the sedimentation of the
PETN (δ[s] = 1,778 g/cm3
) in the molten TNT (δ[l] = 1,545 - 1,016x10-3
T [°
C]g/cm). Constant stirring is
consequently required to keep the PETN in suspension as only about 20% of the PETN dissolves in the
TNT at 90°
C (the TNT-PETN eutectic occurs at 76,7°
C for a 87/13 TNT/PETN mixture). If the molten
Pentolite is not constantly stirred, the solid PETN will accumulate in the lower areas of the booster,
resulting in a "PETN rich" and "PETN poor" regions in the booster.
To investigate the manufacture of Pentolite emulsions that have higher viscosities than molten Pentolite,
thereby reducing or preventing the segregation and/or settling out of PETN and flame suppressing salts,
various Pentolite emulsions were prepared (Grigor, 1992: 1 - 2) by melting together milled Pentolite and
Crill 41 (sorbitan tristearate based emulsifing agent) in the mixing vessel of the experimental mini-rig
situated in a research laboratory in Technical Department, Modderfontein. The solution phase consisting
of the flame suppressant dissolved in water was then blended into the molten oil phase (Pentolite and
emulsifier). The different emulsions thus produced were tested in the Modderfontein Gallery.
EVALUATION - GALLERY TEST
The final Permitted Pentolite Booster formulations (i.e. Pentolite/KHT and Pentolite/NaClO4 emulsion)
were tested in accordance with the Gallery Tests specified by SABS 1484-1989 in conjunction with
SABS Methods 1141-1989, modified as required.
a. Direct primed with a No. 4 STATSAFE Copper CARRICK electric detonator and stemmed with
a standard fire clay disc (Test Series II; permitted pentolite 15 g + 785 g R100C - no. of ignitions
allowed 0/5 shots).
b. Inverse primed with a No. 4 STATSAFE Copper CARRICK electric detonator and fired
unstemmed directly into a methane/air mixture. The primed booster was located at the front
(collar) of the cannon (Modified Test Series I - no. of ignitions allowed 0/10). The number of
ignitions allowed with packaged permitted products is 13/26 shots.
c. Series I test, booster explosive charge made up to 140 g with the Permitted Pumpable Emulsion
Explosive R100C (permitted pentolite 15 g + 125 g R100C - no. of ignitions allowed 0/10 shots).
This test was essentially the same as the incendivity test for detonators - 2 ignitions per 50
detonators are allowed (no. of ignitions allowed 2/50).
As was previously mentioned the modified Series I test is the most stringent of the above mentioned tests.
In this test the initiators were in direct contact with the methane/air mixture, while the initiators were
immersed in a permitted explosive in the other tests and providing the explosive was truly permitted, the
initiators will not ignite the methane/air mixture as there was no contact between them.
UNDERWATER EXPLOSION TEST
A hydrophone and a Tektronix Oscilloscope Model 221 was used at the Underwater Test Facility at
Modderfontein to determine the bubble energies of standard and Permitted Pentolite (25 + 30% KHT +
Pentolite), for comparison with that of Permitted AJAX and Permitted POWERGEL (Louw, 1991: 1 -
2).
HEAT OF COMBUSTION

4. The heat of combustion of Pentolite and Pentolite + 25% KHT [m/m] in an inert atmosphere (N2) was
determined using a bomb calorimeter (Digital Data Systems CP500). The purpose of this experiment was
to compare the heat of combustion of Pentolite + 25% KHT [m/m] with that of standard Pentolite.
DETONATION PRESSURE
The detonation pressure of the Permitted Pentolite Emulsion (Pentolite/NaClO4) and standard Pentolite
was determined by high speed photography (Imacon Model 790) in the test facility at Pretoria Metal
Pressings, Pretoria West (Prinsloo, 1994). The tests were based on the technique discussed in the
publication by Held (1987).
INITIAL TESTS
As the Permitted Pumpable Emulsion Explosive R100C is not cap sensitive, the non permitted cap
sensitive explosive emulsion R100Q was used to determine the run-up VOD of nine different initiators
including two types of permitted detonators (Zeeman, 1995: 2 - 3). The MREL VODSYS-4 VOD
system was used to determine the VOD of the R100Q emulsion explosive when initiated with different
initiators (15 g x 28 mm Pentolite booster and 15 g x 28 mm Permitted Pentolite booster).
FIELD TRIALS – KRIEL COLLIERY
An initial field trial with the KHT based Permitted Pentolite Booster (flame retardant - potassium
hydrogen tartrate) and R100C was carried out in a specially prepared development end in the open-cast
section of Kriel Colliery (Louw, 1992). The VODEX-100 system was used to determine the VODs in
the run-up region of the blasthole. VOD results obtained when using NG based primer cartridges
(COALEX and AJAX) to initiate the R100C are given for comparison. Another objective of the trial was
to determine whether the Permitted Pumpable Emulsion/Permitted Pentolite Booster system would
enable blasting off the solid (BOTS).
The VODEX-100 system consists of an intelligent eight channel high speed timer, that records the time
intervals between each of the eight channels and calculates the velocity of detonation for each time
interval. Ribbon cable pairs, cut to the required length, are used to trigger the timers. This enables the
monitoring of the VOD in a specific region of the explosive column. The timers are triggered by the
highly charged plasma that is generated in the detonation front of an explosive. For the purpose of this
trial the VOD in the first 350 mm of the explosive column, divided into seven 50 mm increments was
determined. The VODEX-100 system consists of an intelligent eight channel high speed timer, that
records the time intervals between each of the eight channels and calculates the velocity of detonation for
each time interval. Ribbon cable pairs, cut to the required length, are used to trigger the timers. This
enables the monitoring of the VOD in a specific region of the explosive column. The timers are triggered
by the highly charged plasma that is generated in the detonation front of an explosive. For the purpose of
this trial the VOD in the first 350 mm of the explosive column, divided into seven 50 mm increments was
determined. The Permitted Pentolite Booster was used for both direct and inverse initiation of the
R100C in the blastholes.
BANK COLLIERY
A limited field trail with the Perchlorate based Permitted Pentolite Booster (flame retardant - sodium
perchlorate) and R100C was carried out at Bank Colliery (Brown Shaft). AEL's Bulk Stemming product
was also evaluated during this trial. The performance of the above mentioned devices was compared
with that of two COALEX cartridges (29 g x 200 mm) used as primer cartridges to initiate the R100C
emulsion.

5. The Permitted Pentolite Boosters were reverse primed (i.e. base charge of detonator facing towards the
collar of the borehole) with CARRICK detonators with different delay periods as determined by the blast
pattern. In-hole VODs were measured using ribbon cable attached to the VODEX-100 system (Louw,
1993). The sensor points on the ribbon cable were 8 cm apart. The start of the VOD probe was placed
approximately 3 cm from the end of the Permitted Booster. The first three sensor points of the VOD
probe were placed along the sides of the two COALEX cartridges. Air blast and ground vibration was
measured using an INSTANTEL DS-200 monitor.
RESULTS
The results obtained during the initial Gallery testing of 'bare' Pentolite charges containing between 0 and
30 percent (m/m) of KHT are given in Table 1.
A second lot of Permitted boosters containing between 1 and 5% (m/m) of KHT was produced so that
the lowest mass percentage of KHT required to pass the gallery test could be determined and was found
to be 3%. The gallery test showed that the minimum mass percentage of KHT required to render the
Pentolite safe for use in fiery mines lies between 3 and 4% (mass/mass). This however is true only for
boosters that are direct initiated and stemmed.
To determine what would happen if a Permitted Pentolite booster was accidentally initiated outside a
borehole, a booster containing 4% KHT (m/m) was inversely initiated without stemming in the test
gallery and an ignition resulted.
The above result confirmed that ignition of the gas mixture is more likely to occur if an unstemmed
explosive charge is inversely initiated than with the direct initiation of a stemmed charge. An additional
set of tests was carried out to determine the minimum mass of KHT required to render the Pentolite non-
incendive when inversely initiated in a fiery atmosphere. This was found to be 25%.
The results of the investigation using LDPE booster shells are given in Table 2.
KHT is insoluble in TNT. As the density of the KHT is 1,984 g/cm3
the molten pentolite/KHT mixture
has to be constantly agitated to prevent the KHT from settling out and causing the uneven distribution of
the KHT in the pentolite, leading to areas deficient in KHT.
Problems were experienced in the scaling up of the Permitted Pentolite production from laboratory scale
to pilot plant scale. Sedimentation of PETN and KHT in the TNT resulted in methane ignitions at the
test gallery during routine batch testing. The layer of PETN and KHT rich TNT remaining in the bottom
of the pouring vessels at the end of the day's production, even with continuous stirring, highlighted the
sedimentation problem.
When oxygen donors like sodium- (NaClO4.H2O - ρ[s] = 2,02 g/cm3
) and potassium perchlorate were used
(KClO4 - ρ[s] = 2,52 g/cm3
) instead of inert salts/thermal ballast (KHT) in the formulation of the Permitted
Pentolite (Cloete et al, 1994), much lower percentages were required to achieve the same level of
permittedness. In spite of the lower percentages required, uneven distribution of the oxygen donors in
the Pentolite, due to sedimentation, still posed a problem.
Segregation or settling out of the flame retardant salts in Permitted Pentolite formulations could be
prevented by forming a water-in-explosive emulsion (Cloete et al, 1994: 3). Emulsions are dispersed

6. multiple phase systems, consisting of at least two fluids (i.e. molten pentolite and flame retardant
solution) that are almost completely insoluble in each other. The dispersed or inner phase (flame
retardant solution) is made up of droplets within the continuous or outer phase (molten pentolite). The
average droplet size was 14,1µm, resulting in excellent dispersion of the flame retardant salt throughout
the pentolite. As a result of the good distribution of the flame retardant salt in the pentolite, even lower
percentages of salt were required to attain the same level of 'permittedness' achieved with flame retardant
salts (oxygen donors) added in the solid form (2,5 - 7% vs 16 - 18%). Because of the lower flame
retardant salt content the explosive performance of the boosters was also improved. The processing of
these explosive-water-emulsions are well suited to continuous and batch processing.
The Gallery test results of the different emulsion formulations manufactured, are given in Table 3.
The Pentolite - sodium perchlorate (NaClO4) emulsion proved to be the most promising formulation with
respect to explosive performance and emulsion stability. While the Pentolite - KHT emulsion passed the
Gallery test, the addition of the inert KHT significantly reduced the explosive performance of the
Pentolite.
The average bubble energies and the standard deviations of Pentolite and Pentolite containing 25% KHT
are given in Table 4. From this table it may be seen that the bubble energy of Pentolite containing 25%
KHT was very similar to that of Permitted AJAX. The bubble energy of an explosive is not a reliable
measure for determining how efficient a given explosive will be as a booster/primer. What the bubble
energy does reveal is how much heave energy a particular explosive has available.
The heat of combustion for Pentolite was 10,916 MJ/kg compared to the 9,455 MJ/kg of the Pentolite +
25% KHT mixture.
The measured (VOD, initial density and shock velocity in the perspex aquarium) and calculated values
(detonation pressure) of Pentolite and Pentolite containing 5% NaClO4 are given in Table 5.
The results obtained during the INITIAL TESTS clearly indicated that the R100Q emulsion explosive
was readily initiated by low energy initiators, e.g., No. 10 NONEL detonator - 780 mg PETN base
charge. Fresh product therefore could be classified as cap sensitive. Because the initiation sensitivity of
this product was so high, the task of ranking the different initiators tested according to their initiation
efficiency was extremely difficult. Nevertheless, Figure 2 clearly shows that the initial VOD in the
R100Q was significantly higher when initiated with cast boosters. The average VOD as depicted in
Figure 2 over the first 20-30 cm, was that of the initiator. The shock wave from the initiator at first
proceeded as a non-reactive shock. After a delay, which increased with decreasing shock pressure and
was dependent on the explosive characteristics of the emulsion explosive, a detonation wave originated
within the shock compressed explosive. The depth at which the detonation wave originates within the
emulsion explosive can be related to the detonation pressure of the initiator and to the effect an increase
in the density of the emulsion explosive has on its initiation sensitivity.
Blasting off the solid appeared to work well. Results obtained compared favourably with the results
achieved with 'cut' faces. This was based on the subjective viewing of the face profile, the muck pile
position and profile as well as the fragmentation of the coal.
From the limited results obtained, the Permitted Pentolite Booster (Pentolite + 5% NaClO4) could be
considered a suitable replacement for primer cartridges. The best results obtained with the Permitted

7. Pentolite Booster (Pentolite + 5% NaClO4) occurred when the boreholes were indirectly primed with the
booster. Tables 6 and 7 give blast hole detail found for Kriel Colliery, while the results for Bank Colliery
are found in Tables 8 and 9.
The highest average velocity of detonation was measured in faces initiated with the Permitted Pentolite
Booster (Pentolite + 5% NaClO4) and stemmed with the AEL Bulk Stemming product (Table 8). The
lowest readings were measured in faces where two COALEX primer cartridges were used to initiate the
R100C and the individual boreholes were stemmed with BENTAMP cartridges (Table 8).
In blasts initiated with the Permitted Booster (Pentolite + 5% NaClO4) the highest individual VOD
readings were recorded at the first measuring point of the ribbon cable, i.e., near the 'toe' of the individual
boreholes. This would indicate the prompt and efficient initiation of the R100C by these initiators leading
to better utilisation of the energy stored in the main explosive charge.
Figure 3 gives a graphical representation of the average VOD calculated from the VOD data given for
each of the initiating devices in Tables 8 and 9. The curve in Figure 3 clearly shows that the Permitted
Booster (Pentolite + 5% NaClO4) initially overdrives the R100C emulsion explosive which then runs
down to its stable velocity of detonation in that diameter. The COALEX primer cartridges however
show an initial run-up to the R100C emulsion explosives stable VOD, thus the energy of the explosive
was not fully utilised.
CONCLUSIONS
PERMITTED PENTOLITE – KHT
The permitted pentolite - potassium hydrogen tartrate (KHT) formulation performed well and passed all
the required incendivity tests (Table 3). Problems, however, were experienced during scaling up of the
process from laboratory scale to pilot plant scale. Because KHT is insoluble in TNT and has a density
that is much higher than that of TNT, separation of the KHT and TNT occurred during pilot plant
production, which resulted in ignitions at the test gallery when this product was tested. This method is
therefore not recommended for the large scale production of Permitted Pentolite.
PERMITTED PENTOLITE – SODIUM PERCHLORATE
By producing a water-in-explosive emulsion that consists of a flame retardant solution (sodium
perchlorate) dispersed within the continuous or outer phase (molten pentolite) segregation, or settling out
of the flame retardant salt, was eliminated. Because of the lower salt content, the explosive performance
of these boosters was comparable with that of the standard pentolite formulation. The average
detonation pressure of the Permitted Pentolite (explosive-water-emulsion) and the standard pentolite
formulation was 21,1 GPa and 21,8 GPa respectively, thus there is only a 3,29% difference in detonation
pressure between the two formulations.
The processing of these explosive-water-emulsions are well suited to continuous and batch processing.
REFERENCES
CLOETE, E.E. 1992. Booster/Primer Explosive. Republic of South Africa - Patent Application, date of
filing 12 August 1992, No.: RSA 92/6069. Adams & Adams: Pretoria, South Africa.
CLOETE, E.E. 1994. Detonation Pressure of AN/GEL Formulation. AECI Explosives Limited,
Technical Department, Test Note No.: D/023/94. Modderfontein, Johannesburg, South Africa.

8. CLOETE, E.E. and GRIGOR, W.G. 1994. Booster/Primer Explosive. Republic of South Africa -
Patent Application, date of filing 20 May 1994, No.: RSA 94/3516. Adams & Adams: Pretoria, South
Africa.
GRIGOR, C.W. 1992. Progress Report - Development of Permitted Pentolite Boosters. AECI
Explosives Limited. Technical department, File ACC 403.3, Modderfontein, Johannesburg, South Africa.
HELD, M. 1987. Determination of the Chapman-Jouget Pressure of a High Explosive From One Single
Test. Defence Science Journal. 37(1): 1 -9.
LINDNER, V. 1993. Explosives and Propellants. In: Kirk-Othmer Encyclopedia of Chemical
Technology. Fourth Edition. Vol 10: New York: Wiley Interscience Publication, John Wiley & Sons: 1 -
68.
LOUW, M.J. 1991. Memorandum - Underwater Explosion Tests. Ref. No.: MJL/MLM/TS 009/3
dated 9 April 1991. AECI Explosives Limited, Technical Department, Modderfontein, South Africa.
LOUW, M.J. 1992. In-hole VODs. AECI Explosives Limited, Technical Department, Test Note No.:
E/086/92. Modderfontein, Johannesburg, South Africa.
LOUW, M.J. 1993. In-hole VODs. AECI Explosives Limited, Technical Department, Test Note No.:
E/018/93. Modderfontein, Johannesburg, South Africa.
PRINSLOO, J.I. 1994. Detonation Pressure Results of AN/GEL Explosive. Pretoria Metal Pressings.
AV 0012/04/94, Pretoria West, South Africa.
URBANSKI, T. 1967. Chemistry and Technology of Explosives. Volume 3. New York: Pergamon
Press Inc.
VAN DER WALT, L.T.P., MOSTERT, J.M., STEYN, J.P. and GOOSEN, A.J. 1993. Detonator
Booster. Republic of South Africa - Patent Application, date of filing 25 June 1993, No.: RSA 93/4574.
D.M. Kisch Inc.: Johannesburg, South Africa.
ZEEMAN, J.D. 1995. Initiating Capabilities of Various Initiators on R100Q. AECI Explosives
Limited, Technical Department, Test Note No. D/001/95. Modderfontein, Johannesburg, South Africa.
TABLE 1
Gallery Test: Pentolite Containing Different Percentages of KHT
BOOSTER
ORIENTATION
KHT CONTENT
[%]
METHANE
[%]
DEW POINT
[°C]
RESULTS
Direct initiation 30 8,8 3 No ignition
Direct initiation 25 8,8 3 No ignition
Direct initiation 20 8,9 1 No ignition
Direct initiation 15 9,0 5 No ignition
Direct initiation 10 8,9 4 No ignition
Direct initiation 0 8,9 5 Ignition

9. TABLE 2
Gallery Test: LDPE Booster Bodies
BOOSTER
CONFIGURATION
KHT CONTENT
[%]
METHANE
[%]
DEW POINT
[°C]
RESULT
'Bare' Pentolite 24 8,8 -2,0 No ignition
LDPE & 5% PL 0056 24 9,0 -3,2 No ignition
LDPE & 5% PL 0056 24 9,2 -0,8 No ignition
LDPE & 5% PL 0056 24 8,8 1,2 No ignition
LDPE & 5% PL 0056 24 8,7 -2,2 Ignition
LDPE & 5% PL 0056 24 8,9 -2,2 Ignition
LDPE & 10% PL 0056 25 9,0 -0,25 No ignition
LDPE & 10% PL 0056 25 9,0 0,25 No ignition
LDPE & 10% PL 0056 25 9,0 0,6 No ignition
LDPE & 10% PL 0056 25 8,9 3,5 No ignition
LDPE & 10% PL 0056 25 8,9 -1,8 No ignition
LDPE & 10% PL 0056 25 8,9 2,5 No ignition
LDPE & 10% PL 0056 25 9,0 1,9 No ignition

10. TABLE 3
Gallery Test Results - Pentolite Emulsions (Mini - rig)
FORMULATION MASS OBSERVATIONS
[g]
Pentolite
Sodium nitrate
Water
Crill 41
25,00
4,25
3,40
0,60
Formulation passed Gallery test. Forms a
'good' emulsion but NaNO3 leaches out if
moisture is present. Booster performance is
low in comparison to that of standard
Pentolite.
Pentolite
Potassium nitrate
Water
Crill 41
25,00
5,00
3,00
0,60
Formulation passed Gallery test. Does not
form a 'good' emulsion. Booster performance
is low in comparison to that of standard
Pentolite.
Pentolite
Ammonium nitrate
Water
Crill 41
25,00
5,00
0,80
0,60
This formulation did not pass the Gallery test.
Forms a very unstable emulsion. Booster
performance almost equals that of standard
Pentolite. % AN required to pass Gallery test
impractical.
Pentolite
Ammonium nitrate
Crill 41
25,00
5,00
0,60
Does not pass Gallery test. Forms a very
viscous emulsion. Booster performance very
good. % AN required impractical.
Pentolite
Sodium perchlorate
Water
Crill 41
25,00
3,00
0,50
0,60
Formulation passes Gallery test. Forms an
extremely stable emulsion. Slight leaching of
salt occurs in the presence of moisture.
Explosive performance almost equals that of
standard Pentolite.
Pentolite
KHT
Crill 41
25,00
7,00
0,60
Formulation passes Gallery test. KHT
appears to settle out. Explosive performance
inferior. KHT only slightly soluble in water.
TABLE 4
Average Bubble Energies
EXPLOSIVE AVERAGE BUBBLE
ENERGY
[MJ/kg]
STANDARD
DEVIATION
Pentolite 2,167 ± 0,023
Pentolite + 25% KHT 1,793 ± 0,005
Permitted AJAX 1,747 ± 0,009
TABLE 5
Detonation Pressure Test Results
FORMULATION VOD DENSITY SHOCK DETONATION

11. VELOCITY PRESSURE
(m/s) (g/cm3) Us
(mm/µs)
PCJ
(GPa)
Pentolite + 5% NaClO4 7 430 1,71 5,5339 21,1
Standard Pentolite 7 620 1,68 5,6149 21,8
TABLE 6
Blast Hole Information and VOD data
(Coalex and Ajax 29 mm x 200 g Primer Cartridges)
BOOSTER/PRIMER Coalex
(29mm x 200g)
Coalex
(29mm x 200g)
Ajax
(29mm x 200g)
Ajax
(29mm x 200g)
BLAST HOLE DIA.
[mm]
36 36 36 36
BLAST HOLE DEPTH
[m]
2,4 2,4 2,4 2,4
CONFINEMENT Coal Coal coal coal
FACE PREPARATION Cut face cut face cut face solid face
STEMMING Bentamp Bentamp Bentamp Bentamp
VOD/50 mm INTERVAL
[m/s]
4 340
3 828
-
-
-
-
-
3 660
3 462
2 853
-
-
-
-
-
2 593
3 858
3 591
3 546
3 481
-
-
4 065
-
4 310
2 127
2 890
2 155
AVERAGE VOD
[m/s]
4 084 3 325 3 414 3 109
TABLE 7
Blast Hole Information and VOD data
(Permitted Pentolite [Pentolite/NaClO4] Booster vs Ajax 29 mm x 200 g)
BOOSTER/PRIMER Pentolite/NaClO4
Inverse Initiation
(28mm x 15g)
Pentolite/NaClO4
Direct Initiation
(28mm x 15g)
Ajax
(29mm x 200g)
Pentolite/NaClO4
Direct Initiation
(28mm x 15g)

12. BLAST HOLE DIA.
[mm]
36 36 36 36
BLAST HOLE DEPTH
[m]
2,4 2,4 2,4 2,4
CONFINEMENT Coal Coal coal coal
FACE PREPARATION cut face cut face solid face solid face
STEMMING Pumpable Pumpable Pumpable Bentamp
VOD/50 mm INTERVAL
[m/s]
-
3 703
3 125
3 424
3 311
3 311
3 184
4 464
3 623
-
-
-
-
3 875
-
-
2 617
-
3 787
3 496
3 521
3 164
3 184
2 958
3 731
2 840
3 378
3 225
AVERAGE VOD
[m/s]
3 343 3 987 3 355 3 211
[*Note that the average VOD's quoted should be viewed with some caution in cases where only two or three readings were obtained.]
TABLE 8
Blast Results - COALEX Primer Cartridges
FACE 1
VOD
[m/s]
FACE 2
VOD
[m/s]
AVERAGE
VOD
[m/s]
2 610 - 2 610
4 220 3 100 3 660
3 330 2 620 2 975
- 4 880 4 880
3 640 4 070 3 855
2 680 4 240 3 460
- - -
BENTAMP BENTAMP STEMMING
Blast results as for a standard
COALEX blast.
Poor blast due to incorrect timing
between boreholes. R100C did not gas
properly - density to high.
OBSERVATIONS
TABLE 9
Blast Results - Permitted Pentolite Booster
FACE 3
VOD
[m/s]
FACE 4
VOD
[m/s]
FACE 5
VOD
[m/s]
FACE 6
VOD
[m/s]
AVERAGE
VOD
[m/s]
3 890 4 910 5 000 5 440 4 810
- - - 4 260 4 260
3 940 4 710 4 260 4 120 4 258
3 330 3 650 4 620 4 170 3 943

13. - 3 430 - 4 040 3 735
- 3 430 3 050 3 920 3 467
3 670 3 070 - 3 920 3 553
AEL BULK BENTAMP AEL BULK AEL BULK STEMMING
Coal finely
fragmented.
Cleaned out well.
Face frozen. Good blast. Good blast. Good
advance.
OBSERVATIONS
FIGURE 1
Dimensions of the 15 g x 28 mm Gram Permitted Pentolite Booster Shell
(All dimensions are given in mm)

15. Figure 2
Average VOD's per length of probe consumed by detonation front
3000
3500
4000
4500
5000
5500
6000
6500
10 20 30 40 50 60 70 80 90
Length of probe consumed
VelocityofDetonation(m/s)
15*28 Pentolite 15*28 Pentolite + NaClO4
Figure 3
Average VOD's Achieved with the different initiating systems
0
1000
2000
3000
4000
5000
6000
0 8 16 24 32 40 48 56
Distance along ribbon cable(cm)
VelocityofDetonation(m/s)(Thousands)
Average VOD COALEX (m/s) AverageVOD Pentolite + NaClO4 Booster (m/s)