Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
DETERMINATION OF BLASTING PARAMETERS IN UNDERGROUND MINING OPERATIONS
Onur METİN
Department of Mining Operation, Dokuz Eylül University, The Graduate School of Natural and Applied
Sciences
E-mail: metin.onur@ogr.deu.edu.tr
January 10, 2022
Abstract
The limited underground resources and the rarity of economically operable metal mines in our country
necessitate efficient production. This situation necessitates optimum production and planning of
excavation-production works with good engineering. Drilling and blasting processes are important that
directly affect every step of production and reflect this effect on costs seriously. For the drilling and
blasting operations to be carried out optimally, the rock properties should be well known, and these
parameters should be considered at every stage while planning the production method.
In this study, necessary parameters will be mentioned for efficient drilling-blasting operations in
underground mining enterprises, drilling and blasting machine-equipment types, explosive types, and
applications in an example underground metal mine will be included, underground blasting and charge
calculations will be made, and a sample face design will be created. The study will be a resource created by
compiling literature research for drilling-blasting processes in metal mines where the cut-fill production
method is applied and by following the drilling-blasting applications in an example underground metal
mine.
1. Introduction
The limited resources of the mines and
Turkey, with its geopolitical position, is
among the countries with economic resources in
the rarity of economically operable metal mines
in our country necessitate optimum production.
many fields such as mining, agriculture, animal
For the production to be carried out in an
husbandry,
Mining
optimum way, it is inevitable to plan the
activities in Anatolia also date back to ancient
excavation and production works with good
times. 2.5% of the world's industrial raw material
engineering. Drilling and blasting processes are
reserves; 1% of coal reserves; 0.8% of geothermal
important that directly affect every step of
potential and 0.4% of metallic mineral reserves
production and reflect this effect on costs
are in Turkey. The richest mine in terms of its
seriously. For drilling and blasting operations to
place in the world: Boron minerals, where 72% of
be carried out optimally, rock properties should
the world's reserves are found.
be well known and considered. It is necessary to
maritime,
and tourism.
create a work organization that will last with the
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
right
production
the
questions of what methods the excavation can be
parameters related to drilling and blasting should
carried out. Excavation works are the basic works
be calculated on a unique basis based on the
that cover a significant part of the operating costs
enterprise. Some factors should be considered
of mines and quarries. Excavation operations can
after blasting as well as factors that affect before
be done with manpower, hydraulic excavation
blasting. Propagation of detonation waves after
technologies, cutter and cutter-loaders, solution
blasting,
size
and gasification chemistry, mechanical excavation
distribution are important issues to be followed
machines, drilling-blasting methods. However,
to
gas
improve
method,
pressure,
the
and
and
particle
process.
Proper
each of these methods cannot be suitable for all
and
blasting
conditions at an acceptable level in terms of
operations in the light of this information means
technical, physical, and cost. For example,
that costs are reduced, every stage of production
although cutting machines are suitable for soft
is relaxed and at the same time, a safe working
and brittle ores or rocks, machine parts costs are
environment is provided.
high in hard rocks, and they are insufficient for
implementation
blasting
then
of
drilling
In this study, the points to be considered
the targeted production amounts at a certain
in the selection of production method and in
time. In production with manpower, problems
addition to these, the parameters to be known in
are encountered in terms of labor costs,
drilling and blasting works will be mentioned.
production efficiency, capacity, and safety. While
calculations will be made, and a sample face
the initial setup and repair costs of the systems to
design will be created. The study will be a
be established for mechanized excavation may be
resource created by compiling the literature
high, the shape of the ore layer and the
research for drilling-blasting operations in metal
production
mines where the cut-fill production method is
mechanized works. Drilling-Blasting, on the other
applied and by following the drilling-blasting
hand, has a wide range of advantages in terms of
applications in İzmir, Menderes, Efemçukuru Gold
production capacity, time, and compatibility with
mine in detail.
the diversity of rock structures. It is easier and
2. Importance of Drilling-Blasting Operations
faster to apply
Fields of activity such as underground and
open-pit mines, tunnels, roads, infrastructure,
and superstructure constructions are areas that
continue their work with rock and ground
excavation. The geological structure and rock
mechanics characteristics of the formation to be
excavated enable us to find answers to the
method
must
be
suitable
compared to
for
mechanized
methods, and it is also cost-effective.
Although the Drilling-Blasting application
is low cost compared to other applications, it
corresponds to almost half of the production
cost. At this point, the engineer and his team
responsible
for
blasting
should
frequently
conduct field studies of scientific approaches, act
according to varying formations, and experiment
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
with alternative explosives to improve blasting
evaluation of operating economies. (Kahriman A.,
and reduce costs.
2003)
With the research and studies carried out,
3. Factors Affecting Drilling-Blasting Operations
excessive use of explosives and excessive
excavation are prevented. Accurately drilled
holes,
appropriate
type,
and
amount
of
explosives also prevent heel formation, thus
minimizing time loss.
Drilling-Blasting is a part of the work
organization in preparation and production works
and cannot be considered independent from
other works. The failure of blasting to bring the
ore layer to the appropriate grain size increases
the transportation cost and the plant cost. If the
effect of blasting is too severe, it causes an
increase in the use of explosives if the particle
size is reduced. In addition, excessive excavation
causes the mixing of the country-rock with the
ore, an increase in the fortification material, and
a heeled structure in the face. It may be
necessary to blast the heels at the bottom of the
face or on the gallery sides. This causes too much
work,
a
waste
of
time,
and
explosive
consumption. Since increasing the amount of
explosive
material
will
not
affect
the
transportation cost after a while, the total cost
will increase gradually, while the quality of the
work will not increase to the same degree.
As a result, we can say that knowing that
When we divide the drilling-blasting
operations into two as drilling the holes, charging
the appropriate amount of explosive into the
holes, and creating the ignition circuit, we
encounter many factors that affect the drilling of
the holes in the desired shape and time and the
desired grain size, geometry and amount of
product with the charged explosive. These factors
range from the physical properties of the rock,
the work skill of the operator, the suitability of
the hole geometry to the type and amount of
explosive. The task of the blasting engineer is to
consider all the factors affecting the blasting
performance and to conclude the calculations
according to these factors, to ensure that the
operations are carried out in optimum conditions,
and at the same time, by using different brands
of equipment and materials with equivalent
properties in line with the calculations, by trying
different approaches in the design, the particle
size distribution after blasting, the production
amount. and to make improvements by revealing
the expenditures for this production.
3.1 Content and Mass Properties of Rock Pieces
•
Density
•
Compressive, tensile, and impact
the performance of blasting is the most
important
costs,
•
Seismic wave propagation
capacities, efficiency, and safety of post-blasting
•
Self-structural impedance
operations, looking at drilling and blasting from
•
The state of discontinuity and degree of
this
factor
perspective
determining
will
provide
the
strengths
a
healthier
solidity in mass
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
•
water condition
4. Methods Used in This Study to Create an
•
Elasticity (young) module
Underground Drilling-Blasting Design
•
Poisson's ratio
•
State of variability (homogeneity,
blasting can be demonstrated as a result of the
anisotropy, and isotropic)
calculations
and
selections
Hardness
considering
the
relationships
•
A suitable approach for drilling and
(Kahriman, 1999)
3.2 Explosive Type, Properties and Distribution
to
be
made,
between
the
elements divided into three main headings
above. Many scientists and researchers have
•
Density
•
Detonation speed
drawn attention to the issues of specific charges
•
Strength
and appropriate slice thickness. With the
•
Sensitivity
appropriate determination of two parameters,
•
Water resistance
•
Freezing resistance
and a drilling-blasting design can be created.
•
Gas properties
(Gustafsson, 1973; Langefors and Kihlstrom,
•
Explosion heat and specific gas volume
1978; Leighton, 1982; Tamrock, 1984; Olofsson,
•
Storage features
1988; Bilgin and Ark, 1986; Ashby, 1990; Arıoğlu,
•
Weight force
1990; Konya and Walter, 1990; Zeigler, 1991;
•
Volume force
Rustan, 1993; Singh, 1993; Özkahraman, 1994;
•
Resistance to desensitization
Özer, Anıl 1996).
•
Packaging and ease of use
4.1 Information About the Face Where the
3.3 Blasting Geometry
•
Hole location, inclination, diameter, and
other parameters can be calculated in this way
Drilling-Blasting Will Take Place
Contour holes (ceiling holes, wall holes,
length
and floor holes) should be drilled outside the
•
Hole quantity, layout
contour, "facing out," so the tunnel will save its
•
Distance between holes and slice
designed space. A hole length of 10cm + 3cm/m
thickness
can be taken as a guide value. Usually, 20 cm is
•
Face state, shape, height, and tilt
calculated.
•
Tightening margin
•
Hole base allowance
increase in the dimensions of the desired gallery
•
Specific charge, charge form, and
section. (Olofsson, Stig O, 1988)
distribution
However, this value should not lead to an
The holes drilled in different parts of the
•
Feeding-firing method and order
face for Drilling-Blasting are given different
•
Delay types and duration
names in the literature. This is because different
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
calculations are effective in drilling-blasting
design of holes in different areas. An outside view
of the face section is shown in Figure 1.
Figure 4 Center cutting positions on the gallery
section (Olofsson, Stig O, 1988)
Figure 1 An external view of th
If the cut is placed close to a wall, it
enables more efficient use of the hole pattern
with a small number of holes. Also, the cut can be
placed alternately on the right or left side, thus
ensuring that the cut is placed within a crack-free
e face
rock mass. For good forward movement of the
section (Olofsson, Stig O, 1988)
blasted rock mass, it can be placed in the middle
The zones in the underground gallery blast were
of the cross section and lowered considerably.
shown by Dingxiang as in Figure 2.
This
location
will
allow
less
explosive
consumption. The high position of the cut
provides extended and easily loaded strength but
requires high explosive consumption and greater
drilling due to more explosives. The normal
position of the cut is in the first auxiliary row
Figure 2 Zones in the underground gallery
above the ground. (Olofsson, Stig O, 1988).
blasting (Dingxiang Z., 2017)
Center cut positions on the face are shown in
Rune Gustafsson, on the other hand, classified
Figure 4.
the gallery regions as in Figure 3.
4.2 Specific Charge
The specific charge briefly indicates the
amount of explosive required per cubic meter. In
underground blasting, the fact that only one
surface of the face is mostly empty requires a
higher specific charge than in open pit blasting to
Figure 3 Zones in the underground gallery blast
break up the rock sufficiently. The amount of
(Gustafsson, Rune, 1973)
charge is higher in the middle pulling part where
blasting occurs first, and the amount of charge
decreases towards the contour points. From this
4.1.1 Position of Center Cut
point of view, as the cross-sectional area of the
gallery increases, the amount of specific charge
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
decreases, and as the cross-sectional area of the
4.3 Hole Parameters
gallery decreases, the amount of specific charge
There are many factors that determine
increases. The specific charge amount depending
the length, width, diameter of the holes. Usually,
on the cross-sectional area and rock type is
the gallery progression is 2/3 the width of the
shown in Figure 5 and Figure 6.
gallery. In addition, limitations on the amount of
explosives due to the distance of the support and
environmental factors affect the hole length and
thus the progress.
After the gallery section, the amount of
advance and the specific charge are determined,
the explosive is properly distributed in this area.
Figure 5 Specific charge depending on cross-
For this, holes must be drilled in a certain order.
sectional area and rock type. (ICI Australia
Appropriate hole diameter and number of holes
Operations Pty Ltd, 1980)
can be determined with various approaches.
The undesirable event is drilling- blasting
for a given amount of feed, but not breaking the
rock during the feed. This will cause loss of
efficiency as well as create difficulties in the next
drilling-blasting
Figure 6 Specific charge depending on crosssectional area and rock type. (Erkoç, 1996)
operation
as
it
excessively
disturbs the remaining rock. Errors in the
selection of the method, errors in the application
of the chosen method, errors in the direction and
The approaches that have been reached
as a result of the research bring us similar
graphics about the specific charge. Although the
same values are valid for similar rock structures,
the results are different because the composition
of each formation is different. The optimum value
of the specific charge can be determined
according to the data to be reached by the
blasting experiments to be created with these
data.
geometry of the hole drilling, errors in the delay
intervals may be responsible for obtaining the
targeted feed length. (Uyar, Güzin Gülsev, 2017)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
4.3.1 Hole Diameter
Figure 9 Relationship between gallery crosssectional area, specific hole length and hole
Figure 7 Gallery cross section and hole diameter
according to specific charge (Olofsson, Stig O,
1988)
We can find Gallery cross section and hole
diameter (Olofsson, Stig O,1988)
We can see relationship between gallery crosssectional area, specific hole length and hole
diameter from Figure 9.
diameter according to specific charge from Figure
7.
Figure 10 Relationship between gallery crossFigure 8 Gallery cross section and hole diameter
relative to specific charge (Gustafsson, Rune,
1973)
4.3.2 Specific Hole Length
section area, specific hole length and hole
diameter (Jimeno CL, 1995)
We can see relationship between gallery crosssection area, specific hole length and hole
diameter from Figure 10.
The specific hole length gives the hole
length that needs to be drilled per cubic meter. If
4.3.3 Number of Holes
we divide the total cubic meters of a shot by the
As can be seen from Figures 11 and 12,
specific hole length, we can approximate the total
the number of holes decreases as the hole
number of holes required.
diameter increases. The reason for this is that the
increase in the diameter of the hole will increase
the amount of explosives in the hole, and the
load distance will increase. Increasing the load
distance will reduce the number of holes.
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
formation
of
an
excessively
cracked
and
encrusted face both affects the blasting efficiency
and prevents a safe working environment.
Another thing to consider is whether the medium
drawing, that is, the cutting holes, is inclined. In
general, middle draw holes are drilled in two
ways. The first is the middle drawing, which is
drilled in a conical shape, inclined towards each
Figure 11 The relationship between the gallery
cross-section area and the hole diameter and the
other, and the second is the middle drawing,
which is drilled in parallel.
number of holes (Erkoç, 1996)
We can see the relationship between the gallery
cross-section area and the hole diameter and the
number of holes from Figure 11.
Figure 13 Advancement (pulse) length according
to gallery cross section (Arı H., 1996)
According to the graph in Figure 13, the
length of progression in a face with a width of 5
meters and a height of 5 meters should be
approximately 3.8 meters. When we take the 2/3
Figure 12 Galeri kesit alanı ve delik çapı ile delik
ratio as a basis, this value becomes 3.33 meters.
sayısı arasındaki ilişki (Gustafsson, Rune, 1973)
The optimum advance length can be determined
4.4 Advance (Pulse) Length
Although the gallery progression length is
2/3 of the gallery width in the literature, it is
important to list the reasons that affect this
length in practice. First of all, the strength of the
rock is taken into account as the rock property. If
by evaluating the rock factor, medium shrinkage
shape, amount of explosive material and
restrictions, required production amount, and
post-blast vibration and particle size analysis.
Korkmaz tabulated the stroke length in
medium-hard rocks with a formula.
the rock is without support as long as the face to
In diagonal blasting a= √0,5xF
be blasted cannot maintain its stability, a dent
In parallel blasting a= √0,75xF
occurs in the face. Due to the rock structure, the
F: Cross-sectional area (m2)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
With the parallel cutting method, the
amount of feed in the chuck is higher than the
Table 1 Progression length according to gallery
cross section (Korkmaz, 1996)
other methods. However, the hole lengths are
not dependent on the available working area.
Having parallel holes is advantageous in terms of
ease of work. The resulting pile is high, providing
a good basis for scaling and fortification. The
parallel cutting method has a higher drilling and
4.5 Center Cutting Method and Face Blast
explosive requirement. Drilling must be correct,
Pattern Design Used in the Study
otherwise, the results will be undesirable.
4.5.1 Parallel Cutting Method
4.5.2 Large Hole Parallel Cutting
There are two different types of parallel
The difference from Burn-Cuts is that the
cuts. These; burn-cuts and large blank parallel
diameter of the unloaded holes is larger than the
hole cut. The characteristic of the hollow hole cut
loaded holes. Large-diameter holes (76-175mm)
is that the holes are the same length and parallel
are drilled by expanding with the adapted
to each other. Empty decay holes with a larger
expansion drill bit like the drill bits produced for
diameter than the diameter of these holes are
drilling other holes. The purpose of the hollow
drilled near the blast holes in the middle drawing.
holes is to provide a free surface to which the
Exploding holes explode into decay holes. The
center cutting holes can orient when they first
purpose of the rot holes is to give the initial free
burst.
surface to the blast. Timed capsules are used in
the application of parallel cutting. By giving
sufficient time to the cutting holes, the
translation towards the decay holes is ensured.
The cutting area can be relocated to avoid areas
damaged in the previous blast. Empty holes are
drilled as close as possible. Small deviations (For
example: 100mm/1m) adversely affect the
cutting and the entire chuck. (Uyar, Güzin Gülsev,
2017)
4.5.1.1 Advantages and Disadvantages of
Parallel Cutting Method
Figure 14 Examples of parallel cutting with
large hollow holes (Zou, Dingxiang, 2017)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
If the cut fails due to pre-compression, the
We can see examples of parallel cutting with
loaded holes should be spread farther apart.
large hollow holes from Figure 14.
Adding
more
narrowly
spaced
holes
will
exacerbate the problem and unnecessarily
4.5.3 On the Concept of Freezing in Medium
Cutting
Two of the problems that can arise in
blasting with parallel hole cuts are sympathetic
increase costs.
In soft or fragmented rock, adjacent loaded holes
with separate lags should be drilled at least 30cm
apart.
detonation and dynamic pressure desensitization,
as the cut holes will be narrowly spaced and
Parallel bore cuts with a sufficient volume of
contain a high amount of explosive. The explosive
uncharged discharge holes should be preferred to
used, with nitro-glycerine in its compositions
successfully shoot shots deeper than 2.5 meters.
With a high degree of sensitivity, such as those
with a high degree of sensitivity, it is inevitable to
see a sympathetic explosion in the two adjacent
For throws exceeding 2.5 meters, the empty hole
area must be at least 25% of the total center
cutting area.
cut holes. Dynamic pressure desensitization can
Supplementary charged holes can be placed
occur in many types of explosives. A water-based
below the empty decay holes to further assist the
emulsion or water gel explosives are the most
central cut to discharge towards the gallery
susceptible to dead-press error when used in
space. These charges should be delayed so that
close-range holes. (Zou, Dingxiang, 2017)
the loaded holes in the shear are detonated
4.5.3.1 Things to Do to Minimize Freezing in
In general, it is necessary to ensure that the rock
Medium Cutting
•
from each hole or group of holes has sufficient
Make sure the holes are parallel by drilling
them carefully and measuredly.
•
immediately after ignition.
time to be cut and removed before the
subsequent holes are fired. Long delays should be
Drilling more or larger rot holes to create
used to ensure sufficient time.
a free surface to pull the blasted rock out.
•
Reducing the explosive charge per square
cutting area. When this occurs, there is a loss of
meter in cutting.
•
Changing the geometry or spacing of cut
Giving a delay with sufficient time
between
them
feed in other areas drilled to the same length. To
minimize this lost feed, the cutting holes should
and rot holes.
•
Finally, some preload builds up in the middle
to
cause
sequential
bursting of holes in the cutting area.
be drilled 15-30 centimeters more than the drill
steel (rod) allows. If this extra drilling for a few
holes produces an equal feed for the entire face,
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
the result is worth the extra drilling cost. (Zou,
n: number of large holes
Dingxiang, 2017)
The loaded holes closest to the large holes are
called shear holes.
In general, the center-to-center distance between
the large hollow hole and the cutting hole should
4.5.4 Design of Parallel Cut Hole Pattern
There are many minor variations of the
parallel hole cut, but the basic pattern is always
one created by drilling one or more large
diameter hollow holes at or near the center of
be about 1.5 times the diameter of the large
hollow hole. This means the load distance
(burden) of the cutting holes. (Zou, Dingxiang,
2017)
𝑣=1,5 × 𝑑𝑓
(3)
of cutting begins to be used more and more.
𝑣= 1,5 × 𝑑𝑙 ×√𝑛
(4)
Large diameter hollow holes vary in the range of
For two or more large hollow holes, the distance
65-175mm.
is
v must be calculated for black-filled blastholes in
important to consider the following three
the following cutting patterns. The remaining
parameters in order to get good results.
holes are added to obtain a square system. U.
• Diameter of large hollow holes
Langefors and B. Kilhström stated that the v-
the cut. As drilling equipment develops, this type
When
designing
cutting,
it
• Distance of blast holes to empty holes (the
burden)
distance should not be more than 1.7×df in order
to
achieve
fragmentation
and
satisfactory
movement of the rock. Fragmentation conditions
• Charge amount
vary greatly depending on the type of explosive,
4.5.4.1 Diameter and Number of Holes
the rock properties, and the distance between
It has been proven that the diameter of the large
hole should depend on the blasthole depth used.
the charged holes and the large hollow hole.
(Zou, Dingxiang, 2017)
An “equivalent” hole diameter can be calculated
to achieve an acceptable feed at 95% of the
blasthole depth.
𝑑𝑓 ≈ (3,2 ×𝑙)2
(1)
Figure 15 Burden samples in one or more decay
holes (Zou,Dingxiang, 2017)
𝑑𝑙 = 𝑑𝑓/√𝑛
df: equivalent hole diameter (mm)
dl: diameter of the big hole
l: length of blast hole (m)
(2)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
Figure 17 The relationship between hole depth
Figure 16 Results of an empty hole at different
and hollow hole diameter according to the drill's
distances and diameters (Langefors U, Kihilström
feed percentage (Olofsson, Stig O,1988)
B, 1978)
As can be seen in Figure 17, 90% progress
When we examine Figure 16, the fracture angle is
very small for loads larger than 2 × df and plastic
deformation occurs between the two holes. Since
accuracy is very important when drilling these
will be possible for a hole diameter of 102 mm
and a hole depth of 4 meters. For more than one
hollow hole, the equivalent hole diameter df
should be based on the equation dl = df/√𝑛.
holes, for cases where the drilling deviation is
more than 1%, v should be calculated as follows.
Cutting
(Zou, Dingxiang, 2017)
𝑣1 = 1,7 × 𝑑𝑓 – 𝐸𝑝
𝑣1 = 1,7 × 𝑑𝑓 − (𝛼 × 𝐿 + é)
4.5.5 Four-Section Design for Parallel Hole
(5)
(6)
Ep: Drilling error (m)
α: Angular deviation (m/m)
Auxiliary cut holes are needed to achieve
a clearance sufficient to blast the dredge holes.
Four
square
sections
were
created
to
accommodate these auxiliary holes around the
cutting holes. The four-section cut is an empirical
L: Depth of blast hole (m)
method
é: Collaring error (deviation of the tip from the
excavations and tunnels. This method is generally
center, braceleting) (m) When we examine
used for excavating tunnels with a cross-sectional
Olofsson's sources, we see that he takes
area of more than 10 m2. (Olofsson, Stig O, 1988)
for
blast
design
in
underground
Langefors and Kiliström as a reference.
Figure 18 Four-section cutting method (P.D.,
Sharma, 2009)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
We can see Four-section cutting method design
The charge concentration required for different
from Figure 18.
C-C distances between the decay hole and the
Table 2 Design equations of the four-section
nearest blasthole can be found in Figure 19 for
model (P.D., Sharma, 2009)
the decay holes of different diameters. An
increase in the C-C distance between the holes
will cause an increase in the concentration.
A guideline for the charge concentration of the
cutting holes closest to the Langefors and
The four-section model equations for the parallel
Kihlström decay holes is given in Table 3.
cutting method are given in Table 2. When
Table 3 Charge concentration in kg/m (U.,
different cutting designs are applied as in Figure
Langefors, B., Kihlström, 1978)
15, calculation with B1 (6) equation will give close
to optimum results.
4.5.6 Charge Calculation for First Square Cut
Extreme care should be taken when filling
the holes closest to the empty holes. A very low
Φ: Diameter of rot holes
charge concentration in the hole may not break
D: Diameter of blast holes
the rock, while a very high charge concentration
will hurl the rock towards the large hole at high
a: Distance between the rot hole and the nearest
loaded hole
speed, creating compaction. In this case, the
expected yield cannot be obtained. (Olofsson,
Weight strength of explosive (s) = 1.0
4.5.7 Charge Calculation for Other Squares
Stig O, 1988)
The calculation method for the remaining
frames of the cut is essentially the same as for
the first frame. The difference is that the
refraction is towards a rectangular opening rather
than a circle. In the other squares, the angle of
refraction should not be narrow. It can be
compensated by
providing
a
high charge
concentration. Normally, the load distance (B) for
Figure 19 Minimum charge amount (kg/m)
the remaining squares of the section is equal to
required according to the maximum load distance
the width (W) of the opening. (Olofsson, Stig O,
of different decay hole diameters (Olofsson, Stig
O,1988)
1988)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
We can see blasting into a narrow opening’s
model from Figure 21.
Table 4 shows the charge concentrations for the
dredge holes proposed by Langefors and
Kihlström. The load distance of the stoping holes
should not be greater than the distance in the VFigure 20 Maximum charge distance (burden) and
recommended minimum charge concentration
(Olofsson, Stig O, 1988) for spans of different
widths
pillar. (Zou, Dingxiang, 2017)
Table 4 Charge concentrations for various charge
distances and extension of the free face (U.,
Langefors, B., Kihlström, 1978)
The charge concentration to be determined from
Figure 20 belongs to the column of the hole. To
break the collapsed bottom, a subcharge of twice
the charge concentration and 1.5 × B in length
should be used. The clamping length is 0.5 × B.
(Olofsson, Stig O, 1988)
4.5.8 Blasting Design and Charge Calculation for
Stoping Holes
The best way to decide the location of hatching
holes is to use the rectangle principle. Figure
A free surface must be created where the rest of
22(b) shows the firing sequence to be used in this
the blasting can take place. The purpose of the
way. A stoping hole arrangement to be created in
stoping
satisfactory
this way minimizes the tearing in the surrounding
fragmentation and to allow the entire section of
rock. Consequently, model (a) should be avoided.
the gallery to be loosened during advancement. It
(Zou, Dingxiang, 2017)
holes
is
to
achieve
is also ensured that a smooth mirror section is
left for the next blasting job.
Figure 22 Arrangement of dredging holes, (a)
Figure 21 Blasting into a narrow opening (Zou,
Dingxiang, 2017)
incorrect application (b) correct application (Zou,
Dingxiang, 2017)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
The graph in Figure 23 can be used for the load
4..5.9 The Design of Floor Holes
distance and bottom charge of the stoping holes.
The design of the bottom holes is similar to the
step blasting, by taking the gallery progression
instead of the step height, the load distance of
these lift bottom holes, in other words, the slice
thickness can be calculated. (Zou, Dingxiang,
2017)
(7)
The design of the bottom holes is similar to the
step blasting, by taking the gallery progression
instead of the step height, the load distance of
these lift bottom holes, in other words, the slice
thickness can be calculated. (Zou, Dingxiang,
Figure 23 Bottom charge concentration and
2017)
charge distance according to different explosives
and hole diameters (Olofsson, Stig O, 1988)
When the load distance (B), hole depth (H) and
If B ≥ 1.4 m, then c= c+0.05 is taken.
If B < 1.4 m, c= c+ 0.07/B is taken.
bottom charge (lb) are known, Table 5 will allow
For the next shot, attention should be paid to the
us to create the geometry of the holes. (Olofsson,
base holes to be drilled angled towards the
Stig O, 1988)
gallery wall. The instructions set out in heading
4.1 should be followed.
Table 5 Equations for stoping holes bottom
charge, column charge, and stemming (Olofsson,
It is usually drilled at an angle of 3 degrees for 3
Stig O, 1988)
meters. This creates a distance of 6 cm per meter.
(Zou, Dingxiang, 2017)
The number of base holes can be determined by
the following equation;
(8)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
The stemming is fixed at T= 10 ×d1.
The load distance is 1.25 times the distance
d1: Hole diameter
between the holes. Svanholm et al give the
The linear charge concentration is practically the
minimum linear charge concentration for smooth
blasting as; 𝑤 = 90 × 𝑑2
same as for stoping holes. However, the specific
charge is higher than the stoping holes as the
w: linear charge concentration in kg/m of Anfo
charge distance and spacing are less. Table 5 can
equivalent explosive
be used for the charge concentration of the
d: Hole diameter (Zou, Dingxiang, 2017)
bottom holes.
Rock quality seriously affects the result of
blasting. In Table 3.9, recommendations are given
for the surrounding hole spacing and the load
distance depending on the rock quality. These
recommendations are generalized conditions.
Optimum values should be determined according
Figure 24 Geometry of floor holes (C.L., Jimeno,
1995)
to the preliminary results to be taken in the light
of this information according to the state of the
rock conditions. (Zou, Dingxiang, 2017)
We can see geometry of floor holes from Figure
24.
4.5.10 The Design of Border Holes and Ensuring
Smooth Blasting
Contour holes, especially ceiling holes, also called
perimeter holes in gallery blasts, are blasted
using the smooth blasting method.
Figure 25 Design pattern for border holes (Zou,
Dingxiang, 2017)
If a smooth blast is not needed, it can be
We can see design pattern for border holes from
designed using the base hole equations. When
Figure 25.
there is no need for smooth blasting, the values
should be taken as follows. (Zou, Dingxiang, 2017)
ƒ = 1.2
B/W= 1.25
Table 3.7 can be used for charge concentration.
In smooth blasting, the distance between the
holes is usually 15-16 times the hole diameter.
Table 6 Smooth blasting parameters suggested by
(Svanholm et al.) (ISEE, 1998)
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
It is seen from Figure 16 that the calculation
Table 7 Recommended hole distance, charge
coefficient of B1 should be 1.5 and the slice
distance and charge concentration for
thickness should take a value between 150-250
environment-controlled blasting in gallery (ISEE,
mm.
1998)
Face design was made with the formulas in Table
2.
When we consider the three decay holes in the
charge calculation for the cutting holes, as in the
first calculation, we consider a for 190mm.
5. Results
If the mirror cross-sectional area is 40 m2 or
more, it is seen that the throw distance is at most
4 m. The ore mirror that we will design is 5
meters wide and 5 meters high, and the mirror
According to its value, the charge amount
becomes 0.55 kg/m. When Table 3 is looked at
and interpolated for 190.5 mm, the values will be
close to each other.
cross-sectional area is approximately 25 m2. The
From here, the amount of explosive material
maximum throw distance for this area is taken as
required for the 4 blast holes in the first section
4 m.
was calculated.
From the graph in Figure 5, the specific charge
Although the calculation method for the second
was found to be 1.9 kg/m3.
section is the same for the first square, the first
From Figure 8, 51 mm hole diameter was found
suitable for a specific charge of 1.9 kg/m3 and a
square explodes into a circular void, while the
second square explodes into a square void. In this
region, the distance between the slice thickness B
cross-sectional area of 25 m2.
and the holes X (W) is considered equal. Since
In Figure 12, the number of holes was found to be
35.
B2= 269.4077 mm, the charge concentration will
be approximately 0.32 kg/m. From here, the total
Equivalent hole diameter and 1 hollow hole
explosive charge for the four holes was
diameter were calculated by replacing the
calculated.
“formula (1) formula (2)” values in the formulas
of equivalent hole diameter and diameter of large
The fourth section can be evaluated as stoping
holes and Table 3 can be used.
holes.
In the calculation of the holes other than the
center cutting holes, different tables and graphics
According to the bit sizes produced in Figure 17,
are mentioned in section (4.5.8 – 4.5.9 – 4.5.10).
the
Calculation of auxiliary holes is divided into 3
127
mm
hollow
improvement of 90-94%.
hole
provides
an
stages as bottom charging, column charging and
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
squeezing. Since there may be application
Table 9 Ignition sequences, number of capsules
differences, even if the squeezing calculation is
and delay amounts.
made, the squeezing is not done, and this part
can be left blank. In most of today’s applications,
bottom charging and column charging are
accepted as a whole, and sensitive packaged
emulsion explosive is placed in the capsule to
enable blasting to be carried out at the bottom of
the hole.
Table 8 Calculated values for cut holes, stoping
and border holes.
6. Conclusions
In this study, it has been revealed that the
underground production method, the drilling
machinery equipment suitable for this method,
and the determination of the materials to be
used in blasting are directly dependent on the
physical conditions, mineralogical and chemical
properties of the rock, according to the literature
research and the data obtained from the drillingblasting applications of an example underground
mining operation. has been placed. The Cut-Fill
method, which is produced in the gallery method
and is widely used today, has been explained, and
an exemplary drilling-blasting design has been
created by examining the previous studies on this
Figure 26 Ignition sequence
We can see our ignition sequence from Figure 26.
method. In the creation of the design, a method
like
the
blast
hole
arrangement
in
the
Efemçukuru underground mining operation was
used.
The Four Section Parallel Cutting Method was
used, and when the results obtained are
compared, it is seen that the drilling-blasting
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
design differs considerably according to the
Bilgin, H.A., 1996. Recent Developments in
changes in rock parameters. As a result, the
Blasting Science and Technology, 2. Drilling and
parameters determined by the data obtained
Blasting Symposium, MADENMO, Ankara, 23-27
from the researches should be accepted as a
Dağçimen, A., 2006. A Computer Program
starting reference point, and the data obtained
Developed
from the trial blasts of different designs to be
Undergraduate
determined according to the location conditions
Adana, 131
for
Blasting
Thesis,
Design,
Çukurova
High
University,
encountered should be acted upon. Trial shots
and part size analyses should be carried out
continuously
according
to
the
changing
conditions at the point of creating the final
drilling-blasting design, considering the desired
amount
of
progress,
blasting
cost,
and
Dirikolu, A., 2009. Drilling-Blasting in KayseriPınarbaşı Toruntepe Underground Chrome Plant
Design and Implementation of Activities, Master
Thesis, Cumhuriyet University, Sivas, 234
Dönmez, Y., 2014. Instruction for Filling Mirrors
occupational safety conditions.
with Explosives, TÜPRAG, Izmir,1-14
The correct determination of the initial reference
Erkoç, Ö.Y., 1990. Rock Blasting Technique, 2nd
points to be taken will reduce the number of trial
Drilling and Blasting Symposium, MADENMO,
shots and ensure that the result is reached with
Ankara, 63-131
the least cost and the production proceeds
Erkoç, Ö.Y., 1996. Drilling, Method and Cost in
efficiently.
Rock Blasting Technique Comparison, 2nd Drilling
and Blasting Symposium, MADENMO, Ankara,
193-201
References
Abdullahoğlu, A.E., 1993. Properties and Selection
of Commercial Explosives, Turkey XIII. Mining
Gustafsson, R, 1973. Swedish Blasting Technique,
SPI, Gothenburg, 323
Hustrulid W.A., Bullock, R.L., 2001. Underground
Congress, 137-144
Arı, H., 1996. Selection and Importance of Shot
Length in Drilling and Blasting Technique, 2nd
Mining Methods: Engineering Fundamentals and
International Case Studies, SME, 728
Drilling Blasting Symposium, MADENMO, Ankara,
Kahriman, A., 1999. Rock Blasting Technology
113-117
Education in Open Mines and Quarries Seminar,
Atlas
Copco,
2007.
Mining
Methods
in
Underground Mining, Second edition, 144
Aydıner, K., 2017. Underground Production
Methods, Basic Mining Information, Mayeb, 888949
Istanbul, 20-38
Kahriman, A., 2003. Mining Investment Projects
Investment Preparation Principles and Cost
Analysis
Seminar,
Foundation, Istanbul
IU
Aid
and
Research
Research Article of Scientific Research Techniques and Publication Ethics Lecture – Dokuz Eylül University
Kibar, T., 2013. Jumbo Drilling Instructions,
TÜPRAG, İzmir, 1-8
Langefors, U., Kihlström, B., 1978. The Modern
Technique of Rock Blasting, Wiley,New York, 438
Olofsson, S., 1990. Applied Explosives Technology
for Construction and Mining, APPLEX, Arla,303