Electromagnetics theories and design of antennas and communication systems are being used in numerous applications in the mining industry, aiding in various aspects. Amng those are exploration techniques, mine safety, equipment monitoring and control, environmental monitoring, ground stability monitoring, and automation and robotics. Solutions of Maxwell’s equations in differential form in time and frequency domains are used to help in mapping geological structures and identifying potential mineral deposits and magnetic ore bodies such as iron ore deposits. Electromagnetic waves are used to detect the presence of underground metallic objects, ensuring safety by preventing accidents like collisions with buried infrastructure. Ground penetrating Radar is one system that is commonly used for these applications.  Electromagnetic sensors are used in many aspects inside underground mines. They are used for sorting and identifying valuable ore from waste rock based on their electrical conductivity or magnetic properties. Other sensors are used to monitor the efficiency and performance of crushers, grinding mills, and conveyor belts for faults or irregularities, ensuring continuous operation and preventing downtime. Electromagnetic sensors can help monitor pollution levels and assess environmental impact on miners. Electromagnetic positioning systems enable the navigation of autonomous vehicles within mines, improving efficiency and safety in operations. Overall, electromagnetics plays a crucial role in various aspects of the mining industry, ranging from exploration and resource assessment to safety monitoring and environmental protection.

In this presentation two recent mining applications conducted by the Antennas, RFID and Computational (ARC) electromagnetics research group at Colorado School of Mines will be addressed. The first application is related to hazardous dust concentrations in underground mines. Miners are required to identify where in the mine the high dust concentrations occur.  To do this, they wear dust monitoring units to track the amount of dust in the regions they move in and record their locations by hand.  This is an extremely time-consuming process for large underground mines, making an automated localization system a necessity.  The first application describes a wearable system that uses a combination of IMU dead reckoning, reverse passive RFID trilateration, and map matching to localize a user in both an indoor and/or underground mine where GPS operation and signals are not available.  The only infrastructure required for the system to operate are clusters of passive RFID tags sparsely placed throughout the area.  IMU dead reckoning localizes the user in between tag clusters while the RFID tag clusters reset the drift errors accrued by the IMU. Map matching projects the dead reckoned values onto a path, sacrificing a user’s lateral distance from the path for a massive increase in accuracy. The developed system is presented successfully in localizing a user at Colorado School of Mine’s Edgar experimental mine. The second application is related to improving the excavation/digging process while considering the safety of miners. Routine maintenance of digging equipments is necessary. Because the mining environment could be unsafe for miners to get closer to these equipments during operation, sensor-based measurements on cutting tools with real time data being available allows for determining when maintenance might be needed. This limits work stoppages and prevents equipment from reaching the failure point. Deteriorating equipment can pose risks to both workers and personnel as well as to the machine itself. Continuous mining machines utilize a large, horizontal, rotating drum with a number of teeth, called pick cutters to dig into a mine site wall. If these pick cutters are worn out, they will require more force to operate, generate more dust, and extract rock less efficiently. Force sensors on the picks can help determine when it is time to replace them. These sensors require a support system to operate on the rotating drum while the machine is operating. This is designed to be as small as possible to be placed on the drum and to transmit data to a remote station, where systems with more powerful computing power can be used to analyze and interpret the data. A prototype on-drum wireless data relay system is developed. The system is capable of assembling force data from multiple sensor-enabled pick cutters (“smart bits”) and transmitting the data to a remote station. High gain circularly polarized antennas are designed, fabricated, and tested to act as transmit and receive endpoints for the radio frequency transmission signals.  The working environment of the antenna is often subject to violent vibrations, dust, debris, and even water. For these reasons, a high gain antenna design is required with a protective cover to avoid the system being damaged by the harsh environment while supporting the desired contentious transmission performance.