Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Carr JL[original query] |
---|
Influence of steel mesh on magnetic proximity detection systems: An experimental study
Zhou C , Whisner BG , Carr JL , Srednicki J . Prog Electromagn Res M Pier M 2020 90 89-97 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. |
A method for estimating the low frequency coupling characteristics of a ferrite-cored rod antenna to a long conductor
Li J , Carr JL , Zhou CJ , Reyes MA , Noll JD . Prog Electromagn Res M Pier M 2018 75 193-203 Magnetic proximity detection systems (PDSs) used in underground mines occasionally generate false alarms when the miner-wearable component (MWC) is close to nearby conductors such as power cables. This is because the signals from the generators (antennas) of the PDS wirelessly couple to nearby cables, travel along these cables, and then couple back from the cable to a distant MWC to cause a false alarm. In order to manage such a false alarm, it is necessary to understand the basic near-field coupling characteristics from a generator to a long wire. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have developed a method to measure such coupling characteristics for a ferrite-cored antenna to a straight wire. The method is introduced in this paper along with the test results. |
Design of intelligent proximity detection zones to prevent striking and pinning fatalities around continuous mining machines
Bissert PT , Carr JL , DuCarme JP , Smith AK . Trans Soc Min Metall Explor Inc 2016 340 (1) 75-81 The continuous mining machine is a key piece of equipment used in underground coal mining operations. Over the past several decades these machines have been involved in a number of mine worker fatalities. Proximity detection systems have been developed to avert hazards associated with operating continuous mining machines. Incorporating intelligent design into proximity detection systems allows workers greater freedom to position themselves to see visual cues or avoid other hazards such as haulage equipment or unsupported roof or ribs. However, intelligent systems must be as safe as conventional proximity detection systems. An evaluation of the 39 fatal accidents for which the Mine Safety and Health Administration has published fatality investigation reports was conducted to determine whether the accident may have been prevented by conventional or intelligent proximity. Multiple zone configurations for the intelligent systems were studied to determine how system performance might be affected by the zone configuration. Researchers found that 32 of the 39 fatalities, or 82 percent, may have been prevented by both conventional and intelligent proximity systems. These results indicate that, by properly configuring the zones of an intelligent proximity detection system, equivalent protection to a conventional system is possible. |
Proximity detection zones: Designs to prevent fatalities around continuous mining machines
Bissert PT , Carr JL , DuCarme JP . Prof Saf 2016 61 (6) 72-77 Mine workers in an underground coal mine are exposed to many hazards and potential hazards on a daily basis such as unstable mine openings, coal and rock dust, high noise levels, fires and explosions, and heavy machinery. While many engineering and process controls have been established to mitigate the risks of these hazards, working with and in proximity to large, mobile equipment remains a significant risk to miner safety. Some of the most hazardous jobs for an underground coal miner involve operating or working in the vicinity of continuous mining machines (CMMs). Since 1984, 39 miners have been killed when struck or pinned by a CMM (MSHA, 2015). In Brief: 1. Underground coal extraction commonly utilizes remote-controlled crawler-mounted heavy equipment known as continuous mining machines that cut coal from the solid formation. 2. Miners working with or near these machines are regularly exposed to the risk of serious injury from being struck or pinned. 3. Based on an analysis of 39 fatalities involving continuous mining machines, it is estimated that proximity detection systems can help prevent such injuries by preventing hazardous machine movements. 4. Design of proximity detection zones significantly affects the effectiveness of intelligent proximity detection systems. |
Comparison of magnetic field distribution models for a magnetic proximity detection system
Li J , Jobes CC , Carr JL . IEEE Trans Ind Appl 2013 49 (3) 1171-1176 Magnetic proximity detection technology is rapidly advancing as a promising method of protecting underground mine workers from striking and pinning hazards associated with mobile mining machines. A magnetic proximity detection system requires a magnetic distribution model to estimate the proximity of the sensor to the generators. This paper presents a comparative analysis of magnetic flux density distribution models in three different field distribution design patterns. The accuracy of these models is determined with a laboratory magnetic proximity detection system. These field distribution design patterns are spherical, ellipsoidal, and sphere-cosine, respectively. The analyses show that the sphere-cosine model is the most accurate model for the proximity system followed by the ellipsoidal and spherical models. |
- Page last reviewed:Feb 1, 2024
- Page last updated:May 06, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure