Mining Project: Electromagnetic Interference and Electromagnetic Compatibility Considerations in Underground Mines

Research Summary

Electrical devices and electronic equipment emit electromagnetic energy. This energy can sometimes negatively impact the performance of electronic safety systems and have unintended consequences that may create additional hazards for mine workers. While EMI issues have been widely investigated on the surface and a variety of EMI standards have been developed to overcome them, there has been very limited EMI research conducted to examine the EMI issues in the underground. This project is designed to identify the prevalence of EMI specifically in mining, to develop measurement methodologies to characterize the mining environment, to develop mitigation strategies to promote EMC, and to enable solutions to address current and potential EMI/EMC problems.

The effects of EMI/EMC have been suspected in numerous incidents in which control systems failed, causing ships to run off course, aircraft to crash, and medical devices such as pacemakers and defibrillators to malfunction. The effects of EMI have also been implicated in cases such as the 1967 explosion on the USS Forrestal in which a rocket was accidentally fired due to an electrical power surge. These cases highlight the critical need to consider EMC/EMI in the design and integration of electronic devices into any given environment, including the mining environments.

The underground mine environment presents several unique challenges related to the types of equipment used, the operating frequencies of devices that are integrated into daily operations, the strata surface and composition which surrounds the environment, and the physical dimensions of the entries through which signals propagate. This research will focus on unique operating frequencies of intended and unintended sources of EMI, safety factors for electronic components, and performance degradation implications of electronic safety systems such as proximity detection systems (PDS) and atmospheric monitoring system (AMSs). Mining Program researchers will focus on identifying EMI challenges within the mining industry, developing strategies to mitigate these challenges, and promoting EMC moving forward.

This project research will address these needs by way of five research aims and related tasks, as summarized below.

1. Characterize underground mining environments in the context of radiated energy to define the electromagnetic emissions spectrum and the interaction of electronic devices that may increase the potential for EMI. Researchers will develop and execute test protocols to survey the mine environment for radiated emissions and collect samples of the mining environment and mining tasks that present a potential to introduce EMI. This information will be used to generate profiles for mine environment characteristics to identify device interactions that may create EMI to determine if they will be evaluated during the laboratory testing phase.
2. Develop/validate methodologies to assess the radiated emissions and susceptibility related to electromagnetic interference. Researchers will perform root cause and risk prioritization matrix analyses to characterize the high-risk, high-severity interaction of devices in underground mines, with the goal of identifying specific cases and devices that will be prioritized for laboratory evaluations. A key source of information will be the list of products approved by the Mine Safety and Health Administration (MSHA).
3. Develop guidelines for the integration of electronic-controlled miner-wearable safety components with other electronic safety systems utilized within their interference range. Researchers will identify the applicable standards, acquire the necessary instrumentation, and develop an experimental plan to perform EMI testing of appropriate mining devices under controlled laboratory conditions.
4. Develop mitigation strategies that can be applied to existing electronic devices to enhance immunity and reduce susceptibility potential. Previously developed administrative and engineering controls that reduce a device’s susceptibility to EMI will be evaluated in the laboratory and validated in mines to ensure their effectiveness in mitigating EMI issues in the mining environment while maintaining their intended functionality.
5. Develop mining-specific recommendations centered on the adaptability of existing test protocols, validation of test methodologies, and increased functionality testing to mitigate the interference issues encountered with respect to existing and future electronic safety systems. Researchers will develop guidelines and recommendations to overcome EMI issues encountered in underground mines, focusing on the methodologies and administrative/engineering controls proposed through the previous tasks.

The primary anticipated outcome of this project is that mining-specific guidelines and recommendations will be developed and disseminated to the mining industry. These outputs will take the form of peer-reviewed journals, conference proceedings, trade publications, and workshops. The outcomes of this research will be used to promote and facilitate the standardization of EMI/EMC in underground mines.