Real-time diesel particulate monitor for underground mines

Abstract

The standard method for determining diesel particulate matter (DPM) exposures in underground metal/ nonmetal mines provides the average exposure concentration for an entire working shift, and several weeks might pass before results are obtained. The main problem with this approach is that it only indicates that an overexposure has occurred rather than providing the ability to prevent an overexposure or detect its cause. Conversely, real-time measurement would provide miners with timely information to allow engineering controls to be deployed immediately and to identify the major factors contributing to any overexposures. Toward this purpose, the National Institute for Occupational Safety and Health (NIOSH) developed a laser extinction method to measure realtime elemental carbon (EC) concentrations (EC is a DPM surrogate). To employ this method, NIOSH developed a person-wearable instrument that was commercialized in 2011. This paper evaluates this commercial instrument, including the calibration curve, limit of detection, accuracy, and potential interferences. The instrument was found to meet the NIOSH accuracy criteria and to be capable of measuring DPM concentrations at levels observed in underground mines. In addition, it was found that a submicron size selector was necessary to avoid interference from mine dust and that cigarette smoke can be an interference when sampling in enclosed cabs.

Promoting early exposure monitoring for respirable crystalline silica: Taking the laboratory to the mine site

“…The monitoring solutions developed for respirable coal dust [1, 2] diesel particulate matter, [3] and respirable dust enhanced by video features [4] are aimed at gathering near real-time information of the aerosol concentration levels during the shift. Unfortunately, these solutions do not address the monitoring of respirable crystalline silica (RCS) in the mining environment.…”

Particulate matter characteristics, dynamics, and sources in an underground mine

“…Nowadays, PM and elemental carbon (EC) concentrations in mines can be determined by real-time measurement techniques (Kimbal et al 2012;Noll et al 2013), but traditionally, the mass and composition of particles have been investigated by collecting particles on filters or impactor substrates, and the mass and chemical species have been determined in the laboratory (Verma et al 1994;McDonald et al 2002). Advanced online methods, such as aerosol mass spectrometers (AMS; Jayne et al 2000), have originally been developed for investigation of the chemical composition of atmospheric submicrometer particles.…”

Sources and Characteristics of Particulate Matter at Five Locations in an Underground Mine

“…Regarding BC, 4-12% of measured BC was attributed to blasting at the sites excluding the blasting area where 45% of BC was associated with blasting. Traditionally, BC has been used as a tracer for diesel emissions in the mines (Noll et al, 2007(Noll et al, , 2013, but as shown in the present study, also blastings can produce BC in the mines. However, the contribution of blasting to the BC concentrations was significant only at the blasting site.…”