6
in the J-3 panel began at cross-cut 37, which is located 12
breaks inby the instrumented pillar P3. In the study mine,
the pillar retreat sequence typically progresses from right to
left, starting with the closest pillar to the previously mined
J-2 panel. However, an exception was made for the pillars
situated between cross-cuts 24 and 26, where the retreat
sequence was reversed to proceed from left to right. This
adjustment was necessary to allow the instruments to con-
tinue monitoring when retreating the instrumented pillar.
Once the pillars in the study sites were retreated, the con-
ventional right-to-left retreat sequence was restored.
INSTRUMENTATION RESULTS AND
VISUAL OBSERVATIONS
The roof, floor, rib, and caving conditions at the study site
were thoroughly assessed when the pillar line was located
two breaks inby the instrumented pillar P3. Observations
revealed that the roof effectively caved inby the pillar lines
(see Figure 12a), with significant roof overhanging occurring
only at Entry No. 1 and Entry No. 6 (see Figure 12b). This
overhang was attributed to the presence of solid barrier pil-
lars, which helped sustain the roof overhang in those areas.
The favorable caving conditions in the roof contributed to
Figure 11. Pillar retreat sequence and retreat dates, in the
top, along with overburden contours at the study site
Figure 12. Photos taken outby the pillar retreat line
in the J-3 panel began at cross-cut 37, which is located 12
breaks inby the instrumented pillar P3. In the study mine,
the pillar retreat sequence typically progresses from right to
left, starting with the closest pillar to the previously mined
J-2 panel. However, an exception was made for the pillars
situated between cross-cuts 24 and 26, where the retreat
sequence was reversed to proceed from left to right. This
adjustment was necessary to allow the instruments to con-
tinue monitoring when retreating the instrumented pillar.
Once the pillars in the study sites were retreated, the con-
ventional right-to-left retreat sequence was restored.
INSTRUMENTATION RESULTS AND
VISUAL OBSERVATIONS
The roof, floor, rib, and caving conditions at the study site
were thoroughly assessed when the pillar line was located
two breaks inby the instrumented pillar P3. Observations
revealed that the roof effectively caved inby the pillar lines
(see Figure 12a), with significant roof overhanging occurring
only at Entry No. 1 and Entry No. 6 (see Figure 12b). This
overhang was attributed to the presence of solid barrier pil-
lars, which helped sustain the roof overhang in those areas.
The favorable caving conditions in the roof contributed to
Figure 11. Pillar retreat sequence and retreat dates, in the
top, along with overburden contours at the study site
Figure 12. Photos taken outby the pillar retreat line