5
The analysis highlights the significant stress reductions in
the 3-Entry Y-Y scenario compared to the other designs.
Specifically, there is a 22% reduction in average stress
compared to the 4-Entry scenario and an 8% reduction
compared to the 3-Entry Y-A layout. These findings dem-
onstrate the potential of the 3-Entry Y-Y configuration to
enhance stability by reducing stress concentrations in criti-
cal areas.
STABILITY ANALYSIS
In this section, the focus shifts to evaluating the stability
of the gateroad pillars under the different layout configura-
tions to assess their ability to manage underground stresses
and maintain structural integrity. The analysis compares
the safety factors for three primary scenarios: the 4-Entry
layout, the 3-Entry Y-A layout, and the 3-Entry Y-Y layout
(see Figure 8).
The safety factor analysis reveals notable differences in
pillar stability across the three configurations. After calcu-
lating the weighted average safety factors based on pillar
widths, the results indicate that the 4-Entry configuration
has an average safety factor of 1.3. The 3-Entry Y-A con-
figuration shows a slightly higher safety factor of 1.5, while
the 3-Entry Y-Y configuration significantly outperforms
both, with a weighted average safety factor of 2.3. These
findings underscore the potential of the 3-Entry Y-Y layout
to provide enhanced stability, particularly when consid-
ering pillar widths and the layout’s capacity to distribute
stress more effectively.
Under isolated loading conditions following the sec-
ond-panel mining, the barrier pillar safety factors analysis
revealed essential variations between the three configura-
tions. The 4-Entry layout displayed the lowest safety fac-
tor at 1.1, indicating that it operates closer to its stability
threshold. In contrast, the 3-Entry Y-A layout demonstrated
a more robust safety factor of 1.6, suggesting an improved
capacity to manage the stresses induced by second-panel
mining. The 3-Entry Y-Y layout showed the highest safety
factor at 2.2, offering superior stability under these condi-
tions. These results highlight the ability of the 3-Entry Y-Y
layout to distribute stress better, thus maintaining structural
integrity. The significant increase in safety factor for the
3-Entry Y-Y layout further reinforces its potential increased
effectiveness in mitigating risks associated with mining-
induced seismicity under isolated loading conditions.
CONCLUSIONS
This comparative analysis of gateroad pillar stability in a
deep-cover longwall mine using the LaModel program
provides critical insights into the performance of three dis-
tinct pillar configurations under varying stress conditions.
The results demonstrate reduced stress concentrations and
0
2000
4000
6000
8000
10000
12000
14000
0 50 100 150 200 250 300
Distance Across Pillar (ft)
Total Vertical Stress Profile Across Barrier -Second Panel
4-Entry
3-Entry Y-A
3 Entry Y-Y
Figure 7. Isolated stress profile across the barrier pillars after second-panel mining for the three
scenarios
Total
Verti
l
Stress
(psi)
The analysis highlights the significant stress reductions in
the 3-Entry Y-Y scenario compared to the other designs.
Specifically, there is a 22% reduction in average stress
compared to the 4-Entry scenario and an 8% reduction
compared to the 3-Entry Y-A layout. These findings dem-
onstrate the potential of the 3-Entry Y-Y configuration to
enhance stability by reducing stress concentrations in criti-
cal areas.
STABILITY ANALYSIS
In this section, the focus shifts to evaluating the stability
of the gateroad pillars under the different layout configura-
tions to assess their ability to manage underground stresses
and maintain structural integrity. The analysis compares
the safety factors for three primary scenarios: the 4-Entry
layout, the 3-Entry Y-A layout, and the 3-Entry Y-Y layout
(see Figure 8).
The safety factor analysis reveals notable differences in
pillar stability across the three configurations. After calcu-
lating the weighted average safety factors based on pillar
widths, the results indicate that the 4-Entry configuration
has an average safety factor of 1.3. The 3-Entry Y-A con-
figuration shows a slightly higher safety factor of 1.5, while
the 3-Entry Y-Y configuration significantly outperforms
both, with a weighted average safety factor of 2.3. These
findings underscore the potential of the 3-Entry Y-Y layout
to provide enhanced stability, particularly when consid-
ering pillar widths and the layout’s capacity to distribute
stress more effectively.
Under isolated loading conditions following the sec-
ond-panel mining, the barrier pillar safety factors analysis
revealed essential variations between the three configura-
tions. The 4-Entry layout displayed the lowest safety fac-
tor at 1.1, indicating that it operates closer to its stability
threshold. In contrast, the 3-Entry Y-A layout demonstrated
a more robust safety factor of 1.6, suggesting an improved
capacity to manage the stresses induced by second-panel
mining. The 3-Entry Y-Y layout showed the highest safety
factor at 2.2, offering superior stability under these condi-
tions. These results highlight the ability of the 3-Entry Y-Y
layout to distribute stress better, thus maintaining structural
integrity. The significant increase in safety factor for the
3-Entry Y-Y layout further reinforces its potential increased
effectiveness in mitigating risks associated with mining-
induced seismicity under isolated loading conditions.
CONCLUSIONS
This comparative analysis of gateroad pillar stability in a
deep-cover longwall mine using the LaModel program
provides critical insights into the performance of three dis-
tinct pillar configurations under varying stress conditions.
The results demonstrate reduced stress concentrations and
0
2000
4000
6000
8000
10000
12000
14000
0 50 100 150 200 250 300
Distance Across Pillar (ft)
Total Vertical Stress Profile Across Barrier -Second Panel
4-Entry
3-Entry Y-A
3 Entry Y-Y
Figure 7. Isolated stress profile across the barrier pillars after second-panel mining for the three
scenarios
Total
Verti
l
Stress
(psi)