Page 140 - Advances In Productive, Safe, and Responsible Coal Mining

124 Advances in Productive, Safe, and Responsible Coal Mining

different components that provide network resources. The system uses fixed nodes
that are powered by mine power with battery backups. This backbone has tracking
beacons that are used to supplement tracking calculations. Tracked devices are the
same radios or handsets that are used for communications in many mines. The system
does have tracking only devices, i.e., ones that have no voice or text capabilities; how-
ever, these devices were not used in the data presented.

8.3.1 Example Mine layout
Testing was performed in a West Virginia mine (the Example Mine) that is typical of
central Appalachian coal mines in both dimension and mine design. This mine has
been actively producing for several decades. The area studied was at the mine’s portal,
a 10-entry system with four returns, which were excluded. Communications and track-
ing system hardware (the Test System) was installed using guidelines obtained from
the manufacturer. Infrastructure placement was based on designs provided by the
manufacturer and estimates generated by the author.
In this study, only the Mains section of the Example Mine was considered as shown
in Fig. 8.1. The portal is indicated on the right side of the map along with some key
ventilation controls such as stoppings, equipment doors, and regulators. Other key
infrastructure often shown on mine maps (including some shown later in this chapter)
includes power transformers (red dots) and existing tracking units (yellow dots). Other
symbols include ventilation controls (blue lines), ventilation air splits (red arrows for
return air), conveyor belts (green line), and track haulage (orange line).
Current regulations require that the mine track miner locations in primary and sec-
ondary escapeways (EWs) and in designated areas to which miners are trained to go in
emergencies. Areas of the mine not normally occupied by workers and areas that
are not places a worker would go to in an emergency are not required to be covered.
In the Example Mine, the area in which coverage was tested is the blue-shaded region
in Fig. 8.2.
The installed tracking system was a radio frequency identification (RFID) tag sys-
tem with readers located at the portal and the turn. This provides a small active TCA
that indicates the transient presence of a tracked entity, but leaves a majority of the
Mains area as an inferred TCA.

Fig. 8.1 Map of mains area.