Researchers at NIOSH are developing methods for characterizing ultrafine aerosols in workplaces. One method includes the detailed analysis of collected particles using electron microscopy (EM). In order to collect samples for EM at remote workplaces including mining and manufacturing facilities, researchers have developed a handheld electrostatic precipitator (ESP) particle sampler capable of collecting airborne particles including nanoscale materials, for subsequent EM analysis. The handheld ESP has been tested in the laboratory and is currently undergoing beta testing in the field. Gross collection efficiencies were measured with a CPC and net efficiencies by EM analysis of collected samples. Using laboratory-generated NaCl aerosols in the 30-400 nm size range at a flow rate of 55 cc/min and ESP operating voltages between 5.6-6.8 kV, both gross and net efficiencies were measured and showed a similar correlation with voltage, with maximum efficiency of approximately 86% at 6.4 kV. EM images from samples were also used to estimate particle size distributions of the original aerosols and the size-dependent deposition was evaluated for upstream versus downstream locations on the sample media. Results suggest that the number concentration and particle size distribution of sampled aerosols may potentially be estimated from a single ESP sample, but that the accuracy and repeatability of such quantification need to be investigated and refined. NIOSH is planning to license the ESP sampler for commercial manufacturing.

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Since the passage of the Mine Improvement and New Emergency Response Act (MINER Act) of 2006, several electronic tracking systems that inform personnel on the surface of a coal mine about the location of miners underground have become commercially available. These systems can be broadly categorized into technology groups that are described in this paper.In addition, several other technologies have been identified by the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) that show promise to increase location accuracy, reduce installed infrastructure, or otherwise improve the performance of existing systems. This paper will describe tracking system technologies currently installed in US coal mines and discuss some emerging technologies.

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The through-the-earth (TTE) wireless communication system, in which the RF signal can directly penetrate the earth separating a transmitter and receiver, is likely to survive a mine disaster because it requires no cabling between the surface and underground. One of the biggest challenges for TTE communication is that the ambient electromagnetic (EM) noise can be significant and impose a limitation on the reception sensitivity. Both underground and surface RF noise characteristics were obtained and analyzed from experimental data collected at several coal mines. The results show the surface has a higher noise level than underground. Moreover, the parameters obtained in an empirical noise model can be used to predict a TTE system's performance at a specific mine site.