## 6 Tracking and Tracing
### Technology Description  
#### 6.2.1 Bluetooth  
Bluetooth was introduced in 1998 and, via continuous development and version control, grew to one of the most used communication methods in commercial and industrial applications. The technology is based on ultra-high frequency radio waves in the ISM bands, meaning 2.402 to 2.48 GHz. Bluetooth gained this high status as the Bluetooth Special Interest Group (SIG) improved the specifications, such as data rates, signal reach and protocol features, including low-energy transmission and direct beacon pairing. These upgrades in the form of Bluetooth versions with backwards compatibility allowed the technology to be kept in the fast-evolving field of commercial electronics. The resulting refinement of this communication option is a key aspect alongside the general specifications for its use in mining [70].  
This size and market representation make the technology extremely interesting for the integration of new systems into the Internet of Things or into local area networks. When this technology is considered in the context of tracking and tracing, there are a number of opportunities that arise even in the harsh environment in underground mines [66; 71].  
Proximity warning systems (PWS) have already been mentioned as one of the tracing cassettes. This application is intended to signal an imminent collision between the nodes and thus their carriers via mounted or carried network nodes. In [66; 67; 68; 69], a PWS network by means of Bluetooth beacons in dedicated devices on people and machines is tested. The test series in the Yeonhwa underground tunnel was considered conclusive and successful.  
The scientists in [72] set up a Bluetooth beacon-based underground navigation system, a so-called BBUNS, in a limestone mine. This is an advantage of a mine section equipped with tracing and tracking, as it leads to the analysis and optimization of operational processes. The route optimization and the decision on the route is applicable in the three forms of mining cycle, human-driven teleoperation, and automated conveyance. This information is important in all three situations, and the beacon network and data analysis are used to reproduce an ideal line on the display of the driver. Cost and implementation proved to be practical and robust. Precision and accuracy were also sufficient for the critical situations of a PWS. Due to the large number of mobile nodes on machines and workers, the coverage is given in the concept of Dynamic Coverage. This coverage can be implemented with mesh-type networks, as described in [73]. In this paper, the researchers have developed a monitoring system based on a portable Bluetooth device. It is used for health monitoring and tracking in a standard working situation or in an extended emergency mode in the event of an accident. Data is collected and transmitted through a mesh network of the devices themselves.  
Still to be considered are the technical parameters of the data rate, data type and range, which are clear from the experiments for a sufficient application at local medium to short ranges [66; 67; 68; 69].  
Bluetooth is an extremely widespread and developing wireless communication standard that is already being used successfully in various applications for local data transmission, tracking and tracing, which is also finding its way into application in advanced mining operations.