9
its gob will remain unaffected by gas released from wells
located on the tailgate side. However, for a given ventila-
tion layout, increasing gas inflows from breached wells will
lead to higher gas concentrations at key monitoring loca-
tions. A linear positive correlation between gas inflows and
gas concentrations at each monitoring location has been
established using the VentSim model. This will assist mine
operators in understanding the capacity of their ventilation
system in the event of a gas well breach.
LIMITATIONS
The findings and conclusions of this study are based on
hypothetical gas breach scenarios, and no known gas well
breach has occurred to date. One key limitation is that the
gas simulation in the network model has not been validated
using field data, which may introduce some inaccuracies
in the results. Additionally, in-situ gas in the mine was not
considered, as the primary focus of this study was on the
impact of breached gas. The gas concentrations obtained at
each location represent the added gas, on top of any in-situ
gas present.
It is worth nothing that the linear equation is specific
to this particular ventilation system and is not generaliz-
able. If the ventilation system or gas source model changes,
the equation would need to be recalibrated. In addition, the
gas concentrations discussed here are exclusively from the
breached gas our simulations did not account for in-situ
gas as those from the face or other mine areas.
REFERENCES
Ajayi, K.M., Z. Khademian, S.J. Schatzel, E. Watkins, and
V. Gangrade (2021). Numerical modeling of longwall-
induced permeability under shallow cover. Tukkaraja
(Ed.), Mine Ventilation, 2021: p. 389–397.
Ajayi, K.M. and S.J. Schatzel (2020). Transport model for
shale gas well leakage through the surrounding frac-
tured zones of a longwall mine. International Journal
of Mining Science and Technology, 2020. 30(5):
p. 635–641.
Ajayi, K.M., Z. Khademian, and S.J. Schatzel (2022).
Evaluation of parameters influencing potential gas flow
to the mine in the event of a nearby unconventional
shale gas well casing breach. Mining, Metallurgy &
Exploration, 2022. 39(6): p. 2333–2341.
Commonwealth of Pennsylvania, Department of mines
and mineral industries, oil and gas division. Joint coal
and gas committee, gas well pillar study. Harrisburg,
Pennsylvania 1957.
Dougherty, H., E. Watkins, R. Kimutis (2022). A network
model analysis of an unconventional gas well breach
above an underground coal mine, Pre-print of SME
Annual Meeting, Feb.27-Mar.02, 2022, Salt Lake City,
UT.
Gangrade, V., S. Harteis, and J. Addis. Development and
applications of a scaled aerodynamic model for simu-
lations of airflows in a longwall panel. in Proceedings
of the Sixteen North American Mine Ventilation
Symposium. Golden, CO. 2017.
Harris, M., S.J. Schatzel, K.M. Ajayi, M. Van Dyke, P.
Zhang, V. Gangrade, J.D. Addis, H. Dougherty, E.
Watkins (2023). Permeability determination for
potential interaction between shale gas wells and the
coal mine environment due to longwall-induced defor-
mations under deep cover Underground Ventilation.
2023, CRC Press. p. 499–506.
Kimutis, R.A., Harris, M.J., Schatzel,S.J., Addis, J.D.,
Mazzella, M.M., Guitard, M., Ganagrade, V. Mine
Ventilation Pathway Simulation on a Hypothetical
Shale Gas Well Breach Utilizing the Longwall
Instrumented Aerodynamic Model (LIAM). Society
for Mining, Metallurgy and Exploration Inc. 2023.
Mine Safety and Health Administration, MSHA (1996)
Bleeder and Gob Ventilation Systems. Ventilation
Specialist Training Course. Revised 2002.
Su, D. W. (2017). “Effects of Longwall-Induced Stress and
Deformation on the Stability and Mechanical Integrity
of Shale Gas Wells Drilled Through a Longwall
Abutment Pillar.” International Journal of Mining
Science and Technology 27(1): 115–120.
Su, D. W., P. Zhang, M. Van Dyke and T. Minoski
(2018). “Effect of Cover Depth on Longwall-Induced
Subsurface Deformations and Shale Gas Well Casing
Stability.” 52nd U.S. Rock Mechanics/Geomechanics
Symposium, OnePetro.
Su, D., P. Zhang, H. Dougherty, M. Van Dyke, T. Minoski,
S. Schatzel, V. Gangrade, E. Watkins, J. Addis and
C. Hollerich (2019a). “Effects of Longwall-Induced
Subsurface Deformations and Permeability Changes
on Shale Gas Well Integrity and Safety Under Shallow
Cover.” 53rd U.S. Rock Mechanics/Geomechanics
Symposium, OnePetro.
Su, D., P. Zhang, S. Schatzel, V. Gangrade and E. Watkins
(2019b). “Longwall-Induced Subsurface Deformations
and Permeability Changes—Shale Gas Well Casing
Integrity Implication.” Proceedings of the 38th inter-
national conference on ground control in mining.
Su, D. W., P. Zhang, M. Van Dyke and T. Minoski (2019c).
“Effect of Longwall-Induced Subsurface Deformations
on Shale Gas Well Casing Stability Under Deep
its gob will remain unaffected by gas released from wells
located on the tailgate side. However, for a given ventila-
tion layout, increasing gas inflows from breached wells will
lead to higher gas concentrations at key monitoring loca-
tions. A linear positive correlation between gas inflows and
gas concentrations at each monitoring location has been
established using the VentSim model. This will assist mine
operators in understanding the capacity of their ventilation
system in the event of a gas well breach.
LIMITATIONS
The findings and conclusions of this study are based on
hypothetical gas breach scenarios, and no known gas well
breach has occurred to date. One key limitation is that the
gas simulation in the network model has not been validated
using field data, which may introduce some inaccuracies
in the results. Additionally, in-situ gas in the mine was not
considered, as the primary focus of this study was on the
impact of breached gas. The gas concentrations obtained at
each location represent the added gas, on top of any in-situ
gas present.
It is worth nothing that the linear equation is specific
to this particular ventilation system and is not generaliz-
able. If the ventilation system or gas source model changes,
the equation would need to be recalibrated. In addition, the
gas concentrations discussed here are exclusively from the
breached gas our simulations did not account for in-situ
gas as those from the face or other mine areas.
REFERENCES
Ajayi, K.M., Z. Khademian, S.J. Schatzel, E. Watkins, and
V. Gangrade (2021). Numerical modeling of longwall-
induced permeability under shallow cover. Tukkaraja
(Ed.), Mine Ventilation, 2021: p. 389–397.
Ajayi, K.M. and S.J. Schatzel (2020). Transport model for
shale gas well leakage through the surrounding frac-
tured zones of a longwall mine. International Journal
of Mining Science and Technology, 2020. 30(5):
p. 635–641.
Ajayi, K.M., Z. Khademian, and S.J. Schatzel (2022).
Evaluation of parameters influencing potential gas flow
to the mine in the event of a nearby unconventional
shale gas well casing breach. Mining, Metallurgy &
Exploration, 2022. 39(6): p. 2333–2341.
Commonwealth of Pennsylvania, Department of mines
and mineral industries, oil and gas division. Joint coal
and gas committee, gas well pillar study. Harrisburg,
Pennsylvania 1957.
Dougherty, H., E. Watkins, R. Kimutis (2022). A network
model analysis of an unconventional gas well breach
above an underground coal mine, Pre-print of SME
Annual Meeting, Feb.27-Mar.02, 2022, Salt Lake City,
UT.
Gangrade, V., S. Harteis, and J. Addis. Development and
applications of a scaled aerodynamic model for simu-
lations of airflows in a longwall panel. in Proceedings
of the Sixteen North American Mine Ventilation
Symposium. Golden, CO. 2017.
Harris, M., S.J. Schatzel, K.M. Ajayi, M. Van Dyke, P.
Zhang, V. Gangrade, J.D. Addis, H. Dougherty, E.
Watkins (2023). Permeability determination for
potential interaction between shale gas wells and the
coal mine environment due to longwall-induced defor-
mations under deep cover Underground Ventilation.
2023, CRC Press. p. 499–506.
Kimutis, R.A., Harris, M.J., Schatzel,S.J., Addis, J.D.,
Mazzella, M.M., Guitard, M., Ganagrade, V. Mine
Ventilation Pathway Simulation on a Hypothetical
Shale Gas Well Breach Utilizing the Longwall
Instrumented Aerodynamic Model (LIAM). Society
for Mining, Metallurgy and Exploration Inc. 2023.
Mine Safety and Health Administration, MSHA (1996)
Bleeder and Gob Ventilation Systems. Ventilation
Specialist Training Course. Revised 2002.
Su, D. W. (2017). “Effects of Longwall-Induced Stress and
Deformation on the Stability and Mechanical Integrity
of Shale Gas Wells Drilled Through a Longwall
Abutment Pillar.” International Journal of Mining
Science and Technology 27(1): 115–120.
Su, D. W., P. Zhang, M. Van Dyke and T. Minoski
(2018). “Effect of Cover Depth on Longwall-Induced
Subsurface Deformations and Shale Gas Well Casing
Stability.” 52nd U.S. Rock Mechanics/Geomechanics
Symposium, OnePetro.
Su, D., P. Zhang, H. Dougherty, M. Van Dyke, T. Minoski,
S. Schatzel, V. Gangrade, E. Watkins, J. Addis and
C. Hollerich (2019a). “Effects of Longwall-Induced
Subsurface Deformations and Permeability Changes
on Shale Gas Well Integrity and Safety Under Shallow
Cover.” 53rd U.S. Rock Mechanics/Geomechanics
Symposium, OnePetro.
Su, D., P. Zhang, S. Schatzel, V. Gangrade and E. Watkins
(2019b). “Longwall-Induced Subsurface Deformations
and Permeability Changes—Shale Gas Well Casing
Integrity Implication.” Proceedings of the 38th inter-
national conference on ground control in mining.
Su, D. W., P. Zhang, M. Van Dyke and T. Minoski (2019c).
“Effect of Longwall-Induced Subsurface Deformations
on Shale Gas Well Casing Stability Under Deep