2
permanent stopping locations, fabric stoppings were more
effective closer to blasting areas, and long stone pillars could
perform the same role as a row of stoppings [6, 7]. Under
this research, it was also found that movement of the loader
and trucks lead to increase in airflow at the face, however,
that increase is small [4, 7, 8]. Recently, researchers have
conducted a field study of large-opening underground
mines looking at variations in pressure, relative humid-
ity, and temperature over time [9]. Past research, however,
has not looked into numerical techniques to analyze the
airflow patterns in large-opening mines. A numerical tech-
nique such as computational fluid dynamics (CFD) has
been used for solving airflow problems in mine ventilation
for quite some time. CFD modeling has been widely used
in many areas of airflow and particulate and gaseous con-
taminant modeling from underground mine ventilation to
open-pit ventilation [10–14]. Most recently, Gendrue and
others [15] conducted CFD modeling to find a booster fan
location in a large-opening mine. Watkins and Gangrade
conducted a study using ANSYS Fluent to optimize the
auxiliary fan placement in a large-opening stone mine [16].
Mohamed and others also presented a similar study using
ANSYS Fluent for model airflow in a large-opening under-
ground stone mine to aid the ventilation considering dif-
ferent stopping layouts [17]. However, these studies only
looked at the fan placement and stopping layout. There are
many commercially off-the-shelf and open-source CFD
software programs, such as ANSYS Fluent, Cradle CFD,
COMSOL Multiphysics, and OpenFOAM, that are avail-
able and being used to solve airflow problems in the mining
industry. The majority of these CFD programs are based
on Navier-Stokes equations, the energy equation, the mass
conversion, and transport equations. CFD models have the
potential to provide a pattern of airflow and contaminant
concentration in large-opening underground stone mines.
The main focus of this study is to look at the impact
of movement of truck on the ventilation. This study is a
continuation of the work the authors published on two-
dimensional modeling of a large-opening stone mine where
they used the COMSOL Multiphysics ® CFD modeling
program to understand the influence of truck movement
on airflow in mine [18]. The two-dimensional modeling
study conducted by the authors did show that movement
of truck lead to change in airflow in the mine, however,
the two- dimensional modeling doesn’t provide sufficient
details of airflow patterns a three-dimensional modeling
can provide. Therefore, this paper is on three-dimensional
modeling of the mine geometry to better understand the
airflow patterns with and without a fan and how the airflow
pattern changes with the movement of a truck.
MODEL DESCRIPTION
The geometry for this work was adopted from Grau III
and Krog [7] work to simulate the airflow inside the mine
with four scenarios. The entry of the mine is 15.24 m, and
the dimensions of the pillars are 15.24 m by 15.24 m. The
extent of the model in the x-direction is 441.96 m, and
in the y-direction it is 411.48 m. Figure 1 shows the plan
view of the model geometry. This geometry was previously
used for modeling airflow by the authors [18]. However,
af er considering the influence of outside atmosphere on
the ventilation of the mine, it was decided to modify the
geometry to add outside atmosphere. To modify the geom-
etry, an idealized condition was tested by adding a domain
attached to the openings of the mine. The modified geom-
etry is presented in Figure 2. The outside domain in the
model geometry represents the atmosphere with the inlet at
the top of the rectangular domain and the outlet at the bot-
tom. The side boundary was treated as an open boundary
condition to simulate the interaction with a large volume of
air, i.e., atmosphere. Another reason to consider adding an
outside domain was that the propeller fan near the opening
of the mine is used to ventilate the mine and the assump-
tion of using the main entry as an inlet (as in Figure 1)
might not be a better approximation of airflow due to the
fan near the opening. The dimension of the outside domain
is 457-m long 122-m wide and 30-m high.
In this study, the team followed a similar strategy as
in our previous paper [18] to look at the airflow without
fan and with fan(s) in the model domain. After that, we
simulated movement of a truck coming from the outside
domain into the mine without any fan followed by simulat-
ing a fan with the movement of a truck. This strategy led
the team to simulate four scenarios for this study.
Scenario 1: Model with no Fan
This modeling was done to understand the airflow pattern
when no mechanical ventilation was used in the mine. This
scenario serves as a baseline model to compare models with
fan(s). Boundary conditions used for the model are inlet,
outlet, interior wall, open boundary on top of the outside
domain, symmetry, and wall. The inlet, outlet, and open
boundary are as represented in Figure 2. The interior wall
boundary represents the stopping as shown in Figure 1.
The rest of the geometry represents the wall boundary.
COMSOL Multiphysics has predefined mesh size settings
from very coarse to extremely fine mesh size, and for the
first scenario which is a simple model, we used a finer pre-
defined mesh size setting where the mesh size ranged from
1.69 m to 14.3 m. The smaller size mesh is in the mine
domain and the coarse mesh are in the outside domain.
permanent stopping locations, fabric stoppings were more
effective closer to blasting areas, and long stone pillars could
perform the same role as a row of stoppings [6, 7]. Under
this research, it was also found that movement of the loader
and trucks lead to increase in airflow at the face, however,
that increase is small [4, 7, 8]. Recently, researchers have
conducted a field study of large-opening underground
mines looking at variations in pressure, relative humid-
ity, and temperature over time [9]. Past research, however,
has not looked into numerical techniques to analyze the
airflow patterns in large-opening mines. A numerical tech-
nique such as computational fluid dynamics (CFD) has
been used for solving airflow problems in mine ventilation
for quite some time. CFD modeling has been widely used
in many areas of airflow and particulate and gaseous con-
taminant modeling from underground mine ventilation to
open-pit ventilation [10–14]. Most recently, Gendrue and
others [15] conducted CFD modeling to find a booster fan
location in a large-opening mine. Watkins and Gangrade
conducted a study using ANSYS Fluent to optimize the
auxiliary fan placement in a large-opening stone mine [16].
Mohamed and others also presented a similar study using
ANSYS Fluent for model airflow in a large-opening under-
ground stone mine to aid the ventilation considering dif-
ferent stopping layouts [17]. However, these studies only
looked at the fan placement and stopping layout. There are
many commercially off-the-shelf and open-source CFD
software programs, such as ANSYS Fluent, Cradle CFD,
COMSOL Multiphysics, and OpenFOAM, that are avail-
able and being used to solve airflow problems in the mining
industry. The majority of these CFD programs are based
on Navier-Stokes equations, the energy equation, the mass
conversion, and transport equations. CFD models have the
potential to provide a pattern of airflow and contaminant
concentration in large-opening underground stone mines.
The main focus of this study is to look at the impact
of movement of truck on the ventilation. This study is a
continuation of the work the authors published on two-
dimensional modeling of a large-opening stone mine where
they used the COMSOL Multiphysics ® CFD modeling
program to understand the influence of truck movement
on airflow in mine [18]. The two-dimensional modeling
study conducted by the authors did show that movement
of truck lead to change in airflow in the mine, however,
the two- dimensional modeling doesn’t provide sufficient
details of airflow patterns a three-dimensional modeling
can provide. Therefore, this paper is on three-dimensional
modeling of the mine geometry to better understand the
airflow patterns with and without a fan and how the airflow
pattern changes with the movement of a truck.
MODEL DESCRIPTION
The geometry for this work was adopted from Grau III
and Krog [7] work to simulate the airflow inside the mine
with four scenarios. The entry of the mine is 15.24 m, and
the dimensions of the pillars are 15.24 m by 15.24 m. The
extent of the model in the x-direction is 441.96 m, and
in the y-direction it is 411.48 m. Figure 1 shows the plan
view of the model geometry. This geometry was previously
used for modeling airflow by the authors [18]. However,
af er considering the influence of outside atmosphere on
the ventilation of the mine, it was decided to modify the
geometry to add outside atmosphere. To modify the geom-
etry, an idealized condition was tested by adding a domain
attached to the openings of the mine. The modified geom-
etry is presented in Figure 2. The outside domain in the
model geometry represents the atmosphere with the inlet at
the top of the rectangular domain and the outlet at the bot-
tom. The side boundary was treated as an open boundary
condition to simulate the interaction with a large volume of
air, i.e., atmosphere. Another reason to consider adding an
outside domain was that the propeller fan near the opening
of the mine is used to ventilate the mine and the assump-
tion of using the main entry as an inlet (as in Figure 1)
might not be a better approximation of airflow due to the
fan near the opening. The dimension of the outside domain
is 457-m long 122-m wide and 30-m high.
In this study, the team followed a similar strategy as
in our previous paper [18] to look at the airflow without
fan and with fan(s) in the model domain. After that, we
simulated movement of a truck coming from the outside
domain into the mine without any fan followed by simulat-
ing a fan with the movement of a truck. This strategy led
the team to simulate four scenarios for this study.
Scenario 1: Model with no Fan
This modeling was done to understand the airflow pattern
when no mechanical ventilation was used in the mine. This
scenario serves as a baseline model to compare models with
fan(s). Boundary conditions used for the model are inlet,
outlet, interior wall, open boundary on top of the outside
domain, symmetry, and wall. The inlet, outlet, and open
boundary are as represented in Figure 2. The interior wall
boundary represents the stopping as shown in Figure 1.
The rest of the geometry represents the wall boundary.
COMSOL Multiphysics has predefined mesh size settings
from very coarse to extremely fine mesh size, and for the
first scenario which is a simple model, we used a finer pre-
defined mesh size setting where the mesh size ranged from
1.69 m to 14.3 m. The smaller size mesh is in the mine
domain and the coarse mesh are in the outside domain.