1
24-034
Enhancing Ventilation and Development Planning in
Underground Stone Mines: Insights from a CFD-Based Study
Khaled Mohamed
CDC NIOSH, Pittsburgh, PA
Marcia Harris
CDC NIOSH, Pittsburgh, PA
Vasu Gangrade
CDC NIOSH, Pittsburgh, PA
Jim Addis
CDC NIOSH, Pittsburgh, PA
Kumar Vaibhav Raj
CDC NIOSH, Spokane, WA
Snigdha Sarkar
KETIV Technologies, Brea, California
ABSTRACT
The National Institute for Occupational Safety and Health
(NIOSH) conducted a ventilation assessment for a recently
established underground room-and-pillar stone mine
implementing split-mine ventilation. The primary objec-
tive was to examine the impact of the length of the in-place
stone stoppings on face ventilation efficiency. These stone
stoppings serve to separate the intake and exhaust entries
and align with the mining direction. To achieve this, com-
putational fluid dynamics (CFD) modeling was utilized.
The appropriate turbulence model was selected, and a mesh
convergence analysis was conducted for the CFD model.
Following that, the CFD model was validated using the
conducted ventilation surveys.
Two configurations of in-place stone stoppings, des-
ignated as Layout-I and Layout-II, were simulated using
the validated CFD models. Layout-I featured a shorter
in-place stone stopping, while Layout-II had a longer one.
The results obtained from the CFD models demonstrated
that the increased length of the in-place stone stopping in
Layout-II resulted in a notable enhancement in ventilation
efficiency at the advanced faces (last stopping), elevating
it from 4% in Layout-I to 8.4% in Layout-II. However,
no significant impact of the in-place stopping layouts was
observed at other faces. In general, Layout-II exhibited a
greater circulation of air at the outby stoppings.
INTRODUCTION
Stone mines produce a wide range of raw material such as
basalt, granite, limestone, marble, etc. for the construc-
tion industry needed for infrastructure development. As
of 2020, there are 4,248 stone mining operations with
110 underground operations in the United States (NMA,
2020).
Underground stone mines come with a unique set of
challenges, of which ventilation is often the primary chal-
lenge. Ventilation of these mines is challenging because
of the large entry sizes leading to low airflow velocities
and increased natural ventilation effects (Watkins and
Gangrade, 2022). To establish effective ventilation in such
mines, it typically necessitates delivering the required air
volumes and effective planning and positioning ventilation
control equipment, such as auxiliary fans and stoppings
(Grau and Krog, 2009).
Throughout the 2000s, NIOSH conducted an exten-
sive research initiative dedicated to investigating ventila-
tion in large-opening mines. This research emphasized a
significant ventilation challenge faced by these mines, spe-
cifically the effective planning of airflow direction (Grau
et al. 2006). Studies assessing the effectiveness of various
ventilation stoppings within large-opening stone mines
revealed that in-place stone stopping could fulfill the same
function as a series of stoppings (Krog et al., 2004). Testing
24-034
Enhancing Ventilation and Development Planning in
Underground Stone Mines: Insights from a CFD-Based Study
Khaled Mohamed
CDC NIOSH, Pittsburgh, PA
Marcia Harris
CDC NIOSH, Pittsburgh, PA
Vasu Gangrade
CDC NIOSH, Pittsburgh, PA
Jim Addis
CDC NIOSH, Pittsburgh, PA
Kumar Vaibhav Raj
CDC NIOSH, Spokane, WA
Snigdha Sarkar
KETIV Technologies, Brea, California
ABSTRACT
The National Institute for Occupational Safety and Health
(NIOSH) conducted a ventilation assessment for a recently
established underground room-and-pillar stone mine
implementing split-mine ventilation. The primary objec-
tive was to examine the impact of the length of the in-place
stone stoppings on face ventilation efficiency. These stone
stoppings serve to separate the intake and exhaust entries
and align with the mining direction. To achieve this, com-
putational fluid dynamics (CFD) modeling was utilized.
The appropriate turbulence model was selected, and a mesh
convergence analysis was conducted for the CFD model.
Following that, the CFD model was validated using the
conducted ventilation surveys.
Two configurations of in-place stone stoppings, des-
ignated as Layout-I and Layout-II, were simulated using
the validated CFD models. Layout-I featured a shorter
in-place stone stopping, while Layout-II had a longer one.
The results obtained from the CFD models demonstrated
that the increased length of the in-place stone stopping in
Layout-II resulted in a notable enhancement in ventilation
efficiency at the advanced faces (last stopping), elevating
it from 4% in Layout-I to 8.4% in Layout-II. However,
no significant impact of the in-place stopping layouts was
observed at other faces. In general, Layout-II exhibited a
greater circulation of air at the outby stoppings.
INTRODUCTION
Stone mines produce a wide range of raw material such as
basalt, granite, limestone, marble, etc. for the construc-
tion industry needed for infrastructure development. As
of 2020, there are 4,248 stone mining operations with
110 underground operations in the United States (NMA,
2020).
Underground stone mines come with a unique set of
challenges, of which ventilation is often the primary chal-
lenge. Ventilation of these mines is challenging because
of the large entry sizes leading to low airflow velocities
and increased natural ventilation effects (Watkins and
Gangrade, 2022). To establish effective ventilation in such
mines, it typically necessitates delivering the required air
volumes and effective planning and positioning ventilation
control equipment, such as auxiliary fans and stoppings
(Grau and Krog, 2009).
Throughout the 2000s, NIOSH conducted an exten-
sive research initiative dedicated to investigating ventila-
tion in large-opening mines. This research emphasized a
significant ventilation challenge faced by these mines, spe-
cifically the effective planning of airflow direction (Grau
et al. 2006). Studies assessing the effectiveness of various
ventilation stoppings within large-opening stone mines
revealed that in-place stone stopping could fulfill the same
function as a series of stoppings (Krog et al., 2004). Testing