3
of a strain-softening constitutive law is for the purpose of
future work where different designs will be evaluated based
on their seismic hazard maps.
INSTRUMENTATION SITES
In total, six instrumentation sites were selected for moni-
toring stress and deformation during the first panel mineby,
including two sites on the first panel headgate, two sites
on the second panel tailgate, and two sites on the third
panel tailgate. In this paper, the focus is on two sites: site
#2 which is in the headgate of the first panel (panel 1) and
site #4 in the tailgate of the second panel (panel 2) as shown
in Figure 2. Overburden depth at these two sites is 1920 ft
(584 m). Borehole pressure cells (BPC) were used for moni-
toring pillar pressure. A BPC is crafted from two steel plates
welded along their edges and casted in concrete in a cylin-
drical form. The gap between the two plates is filled with
hydraulic fluid, pressurizing the borehole. Stainless steel
tubing connects the BPC to a pressure gauge and pressure
transducer outside the borehole (Minoski et al., 2024). To
install BPCs, 2-¼-inch (57 mm) boreholes were drilled
into pillar ribs to the center of the pillar if not deeper than
Modeled cross section
Site #4
BPC 3
BPC 2
BPC 1
BPC 6
BPC 5
BPC 4
BPC 9
BPC 8
BPC 7
Figure 2. Mine layout, instrumentation sites, and modeled cross section
Site
#2
Site
#4
Site
#6
of a strain-softening constitutive law is for the purpose of
future work where different designs will be evaluated based
on their seismic hazard maps.
INSTRUMENTATION SITES
In total, six instrumentation sites were selected for moni-
toring stress and deformation during the first panel mineby,
including two sites on the first panel headgate, two sites
on the second panel tailgate, and two sites on the third
panel tailgate. In this paper, the focus is on two sites: site
#2 which is in the headgate of the first panel (panel 1) and
site #4 in the tailgate of the second panel (panel 2) as shown
in Figure 2. Overburden depth at these two sites is 1920 ft
(584 m). Borehole pressure cells (BPC) were used for moni-
toring pillar pressure. A BPC is crafted from two steel plates
welded along their edges and casted in concrete in a cylin-
drical form. The gap between the two plates is filled with
hydraulic fluid, pressurizing the borehole. Stainless steel
tubing connects the BPC to a pressure gauge and pressure
transducer outside the borehole (Minoski et al., 2024). To
install BPCs, 2-¼-inch (57 mm) boreholes were drilled
into pillar ribs to the center of the pillar if not deeper than
Modeled cross section
Site #4
BPC 3
BPC 2
BPC 1
BPC 6
BPC 5
BPC 4
BPC 9
BPC 8
BPC 7
Figure 2. Mine layout, instrumentation sites, and modeled cross section
Site
#2
Site
#4
Site
#6