Proximity Detection Systems (PDSs) are used in the mining industry for protecting mine workers from striking, pinning, and crushing injuries when they work in close proximity to heavy machines such as continuous mining machines (CMMs). Currently all PDSs approved by the Mine Safety and Health Administration (MSHA) are magnetic field based systems which can be influenced by the presence of steel wire mesh that is commonly used for supporting roof and ribs in underground coal mines. In this paper, researchers at the National Institute for Occupational Safety and Health (NIOSH) characterized the influence of the mesh on the performance of magnetic PDSs by measuring the magnetic field difference around a CMM caused by the presence of the mesh. The results show that the magnetic fields are generally enhanced by the mesh which causes PDS detection zones to be increased correspondingly. It was discovered that the fields around the joints of two mesh sections have the greatest enhancement and thus deserve more attention. In addition, it was found that the presence of mesh can also cause a variation in the generator current. The experimental results show that the generator current variation and thus the magnetic field change caused by the mesh can be significant (on the order of ten) when the mesh is extremely close to the generator (e.g, less than 1 cm) and is negligible when mesh is relatively far (greater than 0.15 m). The findings in this paper can be used to develop guidelines and best practices to mitigate the influence of mesh on PDSs.
Bruce G. Whisner,
Jacob L. Carr,
"Influence of Steel Mesh on Magnetic Proximity Detection Systems: an Experimental Study," Progress In Electromagnetics Research M,
Vol. 90, 89-97, 2020. doi:10.2528/PIERM19082004
1., Proximity Detection Systems for Continuous Mining Machines in Underground Coal Mines, MSHA, 2015.
2. Qing, X. and Z. N. Chen, "Proximity effects of metallic environments on high frequency RFID reader antenna: Study and applications," IEEE Transactions on Antennas and Propagation, Vol. 55, No. 11, 3105-3111, 2007. doi:10.1109/TAP.2007.908575
3. Dobkin, D. M. and S. M. Weigand, "Environmental effects on RFID tag antennas,", 135-138, 2005.
4. D'hoe, K. and V. Nieuwenhuyse, "Influence of different types of metal plates on a high frequency RFID loop antenna: Study and design," Advances in Electrical and Computer Engineering, Vol. 9, No. 2, 3-8, 2009. doi:10.4316/aece.2009.02001
5. Otteni, G., "Plane wave reflection from a rectangular-mesh ground screen," IEEE Transactions on Antennas and Propagation, Vol. 21, No. 6, 843-851, 1973. doi:10.1109/TAP.1973.1140609
6. Hill, D. A. and J. R. Wait, "Electromagnetic surface wave propagation over a bonded wire mesh," IEEE Transactions on Electromagnetic Compatibility, No. 1, 2-7, 1977. doi:10.1109/TEMC.1977.303515
7. Yamaguchi, Y., T. Honda, and M. Sengoku, "Reduction of wave propagation loss by mesh in rectangular tunnels," IEEE Transactions on Electromagnetic Compatibility, Vol. 37, No. 1, 88-93, 1995. doi:10.1109/15.350245
8. Yamaguchi, Y., T. Honda, M. Sengoku, S. Motooka, and T. Abe, "On the reduction of wave propagation loss in tunnels," IEEE Transactions on Electromagnetic Compatibility, Vol. 34, No. 2, 78-85, 1992. doi:10.1109/15.135619
9. Carr, J. L. and J. P. DuCarme, "Performance of an intelligent proximity detection system for continuous mining machines," SME Annual Meeting, 1-6, Denver, CO, 2013.
10. Carr, J. L., C. C. Jobes, and J. Li, "Development of a method to determine operator location using electromagnetic proximity detection," 2010 IEEE International Workshop on Robotic and Sensors Environments (ROSE), 51-56, Phoenix, AZ, 2010.
11. Noll, J., J. Ducarme, J. Li, R. J. Matetic, M. Reyes, J. Srednicki, and C. Zhou, "Electromagnetic interference with proximity detection systems,", 2018.
12. Li, J., J. Carr, J. Waynert, and P. Kovalchik, "Environmental impact on the magnetic field distribution of a magnetic proximity detection system in an underground coal mine," Journal of Electromagnetic Waves and Applications, Vol. 27, No. 18, 2416-2429, 2013. doi:10.1080/09205071.2013.852487