## 2 IT/OT Infrastructure in the Coal Mine  
The IT/OT infrastructure is key in managing mining processes, monitoring safety, and optimizing production. Modern systems use advanced IT and OT systems to carry out the precise management of resources, automation of operations, and remote monitoring of machine status and environmental conditions. Figure 1 depicts a typical three-layer industrial control infrastructure in which each layer serves a specific purpose and interacts with other layers. Figure 1: Three-layer industrial control infrastructure. The top layer (or supervisory layer) sets goals, defines strategies, and allocates resources. Information is considered at a high level, without the implementation details. This layer contains the management software responsible for overseeing production schedules, allocating resources, and monitoring performance. Goals and strategies are sent to the intermediate layer, where they are translated into specific tasks and activities. The purpose of the intermediate layer is to coordinate and optimize the performance of the lower-level components. The lower layer (or execution layer) performs specific tasks and actions at the physical level of the lower-level components or subsystems of the system, typically hardware devices, actuators, sensors. The three-layer control structure provides a modular and scalable approach to system design. It is widely used in various fields where complex systems must be controlled and managed efficiently. A good example would be mines, which have highly complex information exchange systems. The considered IT/OT infrastructure used in mines is shown in Figure 2. It is based on the general three-layer industrial control infrastructure shown in Figure 1, with some necessary modifications [37; 38]. Let us enumerate and discuss the main elements of the infrastructure, as follows:  
1. The SCADA systems monitor and control all industrial processes in the mine facility [39]. Additionally, supervision of the entire technical infrastructure and all its elements is performed, both on the surface and underground. Process operators remotely monitor crucial parameters and signal values using the SCADA systems. Furthermore, the condition of the equipment and machinery components is constantly monitored. This helps preserve safe working conditions and prevent failures. 2. Communication networks include wired (e.g., fiber optics) and wireless (Wi-Fi, LTE, 5G, radio) technologies [40; 41; 42; 43]. Specialized wireless networks are typically required underground since they can resist harsh conditions, e.g., high humidity, dust, and vibration. Such networks enable communication between the operators, remote control of the machinery, and high-speed transmission of the data from various sensors and measuring devices. 3. An array of sensors deployed in different parts of the mine provide current values of the key variables, e.g., temperature, methane concentration, oxygen levels, air pressure, and vibration [44; 45]. The obtained data samples are monitored online. In addition to these classical measurements, video monitoring systems comprised of cameras allow for the observation of machinery operation and mining processes and help us to identify potentially dangerous situations, e.g., landslides. Contemporary mines may also use drones to monitor the situation efficiently. 4. Integrated manufacturing execution systems (MESs) and enterprise resource planning (ERP) systems [46; 47; 48; 49] have the objective of integrating data from different sources. These tools optimize the use of resources and processes, leading to cost minimization. The ERP systems are pivotal in coordinating all interactions between the technical departments and management. This would likely make rapid decision-making possible. 5. Automatic control systems, which can operate without direct human intervention, will eliminate the need for humans in remote and dangerous environments and replace humans when fast reactions are necessary and/or impossible for humans [50; 51; 52].