3
Watkins [12] through a CFD model. The researchers chose
the insertion points based upon the CFD plume graph.
The location Test Series D has an inflow value of 500 cfm
inserted at the mine roof at 30 location points (8 inser-
tion points located in the tailgate corner gob behind the
tailgate shields and 22 insertion points were located inby
the tailgate pillar extending towards the tailgate BEP). The
sampling and insertion locations are shown in Figure 2.
Breached gas inflow values (340, 400, and 500 cfm)
were used in the testing scenarios and for simulating
breached gas moving through the mine roof fractures into
the mine ventilation system. During testing, SF6 is inserted
into the LIAM at the mine roof level for 15 to 16 min-
utes. A mass flow controller regulates the inflow. At each
sample location, a vacutainer tube sample is taken every
30 seconds for the first 5 minutes and then every 60 sec-
onds for the next 10 minutes, and then at 17.5, 25, and 40
minutes. Samples are analyzed by gas chromatography and
results are converted to methane concentrations in ventila-
tion air using conventional tracer gas methods for the test
inflow rates. Critical sampling locations were determined
by locations in an operating longwall panel where electrical
Figure 2. Insertion points and sample locations are shown on the LIAM
Table 1. Inflow rates and insertion points for the various test series
Test
Series
Inflow Rate
(cfm) Insertion/Breach Points
A 340 8 in the tailgate corner gob behind the tailgate shields
22 inby the tailgate pillar extending towards the tailgate BEP
B 400 14 in the tailgate corner gob behind the tailgate shields
16 inby the tailgate pillar extending towards the tailgate BEP
C 400 6 in the tailgate corner gob behind the tailgate shields
24 inby the tailgate pillar
D 500 8 in the tailgate corner gob behind the tailgate shields
22 inby the tailgate pillar extending towards the tailgate BEP
Watkins [12] through a CFD model. The researchers chose
the insertion points based upon the CFD plume graph.
The location Test Series D has an inflow value of 500 cfm
inserted at the mine roof at 30 location points (8 inser-
tion points located in the tailgate corner gob behind the
tailgate shields and 22 insertion points were located inby
the tailgate pillar extending towards the tailgate BEP). The
sampling and insertion locations are shown in Figure 2.
Breached gas inflow values (340, 400, and 500 cfm)
were used in the testing scenarios and for simulating
breached gas moving through the mine roof fractures into
the mine ventilation system. During testing, SF6 is inserted
into the LIAM at the mine roof level for 15 to 16 min-
utes. A mass flow controller regulates the inflow. At each
sample location, a vacutainer tube sample is taken every
30 seconds for the first 5 minutes and then every 60 sec-
onds for the next 10 minutes, and then at 17.5, 25, and 40
minutes. Samples are analyzed by gas chromatography and
results are converted to methane concentrations in ventila-
tion air using conventional tracer gas methods for the test
inflow rates. Critical sampling locations were determined
by locations in an operating longwall panel where electrical
Figure 2. Insertion points and sample locations are shown on the LIAM
Table 1. Inflow rates and insertion points for the various test series
Test
Series
Inflow Rate
(cfm) Insertion/Breach Points
A 340 8 in the tailgate corner gob behind the tailgate shields
22 inby the tailgate pillar extending towards the tailgate BEP
B 400 14 in the tailgate corner gob behind the tailgate shields
16 inby the tailgate pillar extending towards the tailgate BEP
C 400 6 in the tailgate corner gob behind the tailgate shields
24 inby the tailgate pillar
D 500 8 in the tailgate corner gob behind the tailgate shields
22 inby the tailgate pillar extending towards the tailgate BEP