Underground mining is expected to lead the mining industry in the near future. Due to the advance of electronic devices and communications technologies, new safety regulations must be accomplished in order to operate underground mines safely and optimally. In 2006, the US government updated safety policies and introduced the PUBLIC LAW109-236. As a result, underground tracking is nowadays mandatory for underground mine operations. This new regulation establishes that current, or immediately pre-accident location of all underground personnel must be delivered over ground. Despite the recent advances of tracking and positioning systems for indoor environments, underground mines are a unique scenario which poses different and highly demanding constraints for current technologies. Throughout this manuscript an extensive survey on underground mines’ positioning technologies is provided. The main characteristics of current localization systems in underground mines are analysed for their implementation from a user’s requirements point of view. Furthermore, the main constraints and opportunities of the existing indoor positioning systems to deliver underground tracking are presented. Finally, future research directions are highlighted.

This paper proposes two solutions based on angle diversity receivers (ADRs) to mitigate inter-cell interference (ICI) in underground mining visible light communication (VLC) systems, one of them is a novel approach. A realistic VLC system based on two underground mining scenarios, termed as mining roadway and mine working face, is developed and modeled. A channel model based on the direct component in line-of-sight (LoS) and reflections of non-line-of-sight (NLoS) links is considered, as well as thermal and shot noises. The design and mathematical models of a pyramid distribution and a new hemi-dodecahedral distribution are addressed in detail. The performances of these approaches, accompanied by signal combining schemes, are evaluated with the baseline of a single photo-diode in reception. Results show that the minimum lighting standards established in both scenarios are met. As expected, the root-mean-square delay spread decreases as the distance between the transmitters and receivers increases. Furthermore, the hemi-dodecahedron ADR in conjunction with the maximum ratio combining (MRC) scheme, presents the best performance in the evaluated VLC system, with a maximum user data rate of 250 Mbps in mining roadway and 120 Mbps in mine working face, received energy per bit/noise power of 32 dB and 23 dB, respectively, when the bit error rate corresponds to ${10}^{-4}$ , and finally, values of 120 dB in mining roadway and 118 dB in mine working face for signal-to-interference-plus-noise ratio are observed in a cumulative distribution function.

A new visible light communication (VLC) system is proposed for localization in underground mining. Existent systems, such as global positioning system (GPS) and systems based on mobile communication, are generally not useful in underground mining. The proposed system is based on a three-dimensional trilateration VLC localization scheme. This articles offers an evaluation of the proposed system in different evaluation scenarios in terms of the average localization error. The proposed algorithm localizes the source with an average localization estimation error of less than (16.4 cm), based on the source location. The average error is (3.5 cm) for subjects that are very close to the light-emitting-diode (LEDs).The obtained results show the superiority of the proposed method in comparison with traditional short range radio frequency technologies such as RFID, Wi-Fi and Zigbee, making it a feasible system for localizing objects in underground mining.

In this paper we present a new system that uses new technology that has the ability to transmit data using light emitting diodes (LED) and a photodetector (PD) capable of sensing very soft changes of light. The system developed in conjunction with the trilateration technique can be used for localizing personnel as well as machinery in underground mining tunnels. Simulations are performed, and comparisons are made with other well-known techniques in terms of the location estimation error. Overall, it is shown that the proposed system is a viable option for localization in underground mining tunnels.

Chile is the largest copper producer in the world. In the world, almost 40% of copper is produced underground and it is expected that the activity will reach the 60% of the total mining activity. Because of this, there will be new challenges in terms of safety and productivity. Visible Light Communications (VLC) is a new technology capable to provide illumination and communication at the same time. This technology has shown high accuracy in localization and tacking for indoor scenarios. Nevertheless, most of the applications that can be found in literature assumes square rooms, no tilt receivers, and Line of Sight (LOS) link. In this paper we will address the problem of enabling Visible Light Communications (VLC) based Indoor Positioning System (IPS) in underground mines. Feasible link configurations and positioning topologies are studied throughout this paper. In addition to this, different localization methods are classified in two groups, i.e., range based and range free methods. Their performance in terms of accuracy and robustness as well as the constraints of each method will be analyzed for its usage in underground mines.