## 1 Introduction  
Mining has always involved the use of new technologies to increase productivity and safety, reduce environmental impacts, and lower operational costs. The industry faces various operational challenges, such as declining ore grades, complex deposit structures, and volatile commodity prices. These objectives are driving factors for digitalization in mining. The vision for digitalization in mining is a connected and autonomous mine with real-time data-based decision-making [1].  
The authors of [1] have systematically identified digital key technologies in the mining industry, which can be categorized as Automation and Robotics, IoT, Big Data and Real-Time Data, AI and Machine Learning, 3D Printing, Connected Workers, Drone Technology, Electrification, and Simulation Modelling.  
Autonomous driving is for example implemented for long-haulage trucks in surface mining [2] or driverless vehicles underground [3]. Exchanging information on machinery positions is crucial to prevent incidents and optimise processes. Loading processes are not yet automated due to the lack of real-time data regarding, e.g., rock conditions and material positions [2, 4].  
IoT in mining is one of the basic requirements enabling remote operations and advanced automation [5]. It can be used to gather status information on mobile machines [4], relay data in emergency situations [6] or provide monitoring data on, e.g., rock stability [7].  
Analysing (Big) Data with machine learning and AI tools can improve mining operations, for example, in predictive maintenance for conveyor belts [8].  
Most of these key technologies rely on the transmission or exchange of (real-time) data, in other words on communication. Communication is a key enabling technology in the automation and digitalisation of mining operations connecting workers, mobile machinery, stationary equipment and mine operation centres. Wireless communication infrastructure must be deployed regardless of the kind of operations to leverage on the technological advancement but is especially difficult in underground mining.  
Picking, testing and integrating communication technologies is not only challenging due to the number of possible existing technologies and their technological, physical and legal limits, but also due to the varying mining environments, operational constraints and applications. Mining operations have an enormous amount of variety due to the natural geologic structure and connected mining methods, level of mechanization and automation, as well as size of the operation [9]. In this paper, we will evaluate existing communication applications that range from the transmission of minimal data via ZigBee to the use of digital radio in areas without general infrastructure, to fully remote operations via 5G.  
The main drivers for establishing a communication infrastructure that enables advanced mining operations are to (1) improve the efficiency and operations of equipment across the mining value chain, (2) increase safety, (3) reduce costs, and (4) lay the foundation for innovation, all while minimizing (5) environmental impact as an integral part of advanced mining operations [1,10,11].  
The aim of this paper is to provide an overview of selected current and potential wireless communication technologies used or suitable for use in mining, as well as existing applications, to assist with selecting and testing the appropriate technology and improving mining operations. Communication networks are already in use in a variety of use cases, enabling different automation and digitalization applications towards interoperability of mine production [11].  
The structure of this paper is summarized in Figure 1.