7
November 2023 point cloud was registered to the March
2024 point cloud and provides an original floor height. The
comparison with the initial point cloud shows a heave of
1.4 ft (0.4 m) outby the face.
The heave magnitudes between the model and the
LiDAR scans cannot be directly compared because the
model is psedo-2D, and thus the heave profiles are related
to the completion of panel 1. However, the LiDAR scans
were taken around the instrumented pillars right before
face mined by. However, the in-mine observation of the
authors showed that heave further increased inby the face.
We also took scans of Entry #2 and 3 in Panel 2 tail-
gate side that can be directly compared with the modeling
results, but at the time of writing this paper the LiDAR
scan results were not fully processed.
The comparison between the modeling results and
BPCs and LiDAR scans showed the model could have pre-
dicted the pillar pressure and floor heave. With this confi-
dence, we evaluated alternative mine layouts with respect to
floor heave and load transfer.
Alternative Layouts
Two alternative layouts were studied. One yield-stable-bar-
rier and one yield-yield-barrier. Figure 11 shows the model
geometry for the current and alternative mine layouts as
constructed in the 3DEC software program.
The results for average pillar pressure across the pil-
lars between the two panels are plotted in Figure 12. In
Figure 12, YYB design increased barrier pillar pressure by
4%, while YSB design increases the barrier pillar pressure
by 9%. Although YYB design has a wider barrier, the yield
pillars transferred all loads to the barrier increasing its aver-
age load slightly higher than the current design.
In terms of load transfer to the panel 2 tailgate side,
YYB design increases the transferred load by 11%, but YBS
design reduces it by 5%. For load transfer calculation, the
pillar pressure in pillar 2T in Figure 12 was the reference.
Figure 13 shows the floor heave after panel 1 was
mined. The minimum floor heave in Entry 2H was for the
current design. YYB and YSB led to the entry closure with
the mining height of 7 ft (2.1 m). The minimum heave in
the Entry 1H was for the YSB design, reducing the cur-
rent heave by 72%. The largest heave is for the YYB design
where the heave was almost doubled (85% increase from
the current design).
Figure 10. Floor heave profile from LiDAR scan in Entry
2H ~400 ft (121.6 m) outby the face
Figure 11. Current and alternative mile layouts constructed
in 3DEC models
Figure 12. Average pillar pressure in different mine layouts
November 2023 point cloud was registered to the March
2024 point cloud and provides an original floor height. The
comparison with the initial point cloud shows a heave of
1.4 ft (0.4 m) outby the face.
The heave magnitudes between the model and the
LiDAR scans cannot be directly compared because the
model is psedo-2D, and thus the heave profiles are related
to the completion of panel 1. However, the LiDAR scans
were taken around the instrumented pillars right before
face mined by. However, the in-mine observation of the
authors showed that heave further increased inby the face.
We also took scans of Entry #2 and 3 in Panel 2 tail-
gate side that can be directly compared with the modeling
results, but at the time of writing this paper the LiDAR
scan results were not fully processed.
The comparison between the modeling results and
BPCs and LiDAR scans showed the model could have pre-
dicted the pillar pressure and floor heave. With this confi-
dence, we evaluated alternative mine layouts with respect to
floor heave and load transfer.
Alternative Layouts
Two alternative layouts were studied. One yield-stable-bar-
rier and one yield-yield-barrier. Figure 11 shows the model
geometry for the current and alternative mine layouts as
constructed in the 3DEC software program.
The results for average pillar pressure across the pil-
lars between the two panels are plotted in Figure 12. In
Figure 12, YYB design increased barrier pillar pressure by
4%, while YSB design increases the barrier pillar pressure
by 9%. Although YYB design has a wider barrier, the yield
pillars transferred all loads to the barrier increasing its aver-
age load slightly higher than the current design.
In terms of load transfer to the panel 2 tailgate side,
YYB design increases the transferred load by 11%, but YBS
design reduces it by 5%. For load transfer calculation, the
pillar pressure in pillar 2T in Figure 12 was the reference.
Figure 13 shows the floor heave after panel 1 was
mined. The minimum floor heave in Entry 2H was for the
current design. YYB and YSB led to the entry closure with
the mining height of 7 ft (2.1 m). The minimum heave in
the Entry 1H was for the YSB design, reducing the cur-
rent heave by 72%. The largest heave is for the YYB design
where the heave was almost doubled (85% increase from
the current design).
Figure 10. Floor heave profile from LiDAR scan in Entry
2H ~400 ft (121.6 m) outby the face
Figure 11. Current and alternative mile layouts constructed
in 3DEC models
Figure 12. Average pillar pressure in different mine layouts