Page 148 - Advances In Productive, Safe, and Responsible Coal Mining

132 Advances in Productive, Safe, and Responsible Coal Mining

Fig. 8.13 Layout of primary EW node about 2400ft inby the portal and the nearest secondary
EW node.

signals passing through them. Antennas on the secondary EW are placed on either side
of these air lock doors. These antennas are connected to FMN 202 by coaxial cables.
This enables avoidance of signal attenuation due to the air lock doors.
Fig. 8.12 shows mine features in the area of FMNs deployed about 1600ft inby the
portal on the primary EW. The FMN on the secondary EW several crosscuts outby is
also shown. These nodes provide network links in long straight sections of these
entries. FMN 104 on the primary EW is 900ft from the next FMN outby, FMN
103. FMN 203 is 700ft from the next FMN outby, FMN 202, on the secondary EW.
Fig. 8.13 shows the FMN layout 2400ft inby the portal on the primary EW. Of
interest is the primary EW detour to Entry 4 for two crosscuts and then back to Entry 5.
This detour goes around a pair of airlock doors providing vehicle access to the belt
entry. Two related stoppings block Entry 5.
SCSR caches are designated as “strategic areas” by the operator. More accurate
tracking is warranted in these areas, and accordingly a beacon is placed at the cache
shown in Fig. 8.13. In the Test System, mobiles radios carried by mine personnel
report receipt of signals from nearby tracking beacons via communications links
afforded by FMNs.