K1: Research Roundup Exposure Assessment/Noise and Hearing Loss Prevention

With the increasing sophistication of real time monitoring devices, research to objectively assess their performance is a priority. The International Sampler Comparison Group (ISCG) has embarked on a series of projects in association with various international research groups. In Australia, a workplace sampler comparison study has commenced the collection of conventional and real time samples of inhalable and respirable dust, from host sites in the Western Australian mining industry. The selected samplers are placed on a specially designed Workplace Atmosphere Multi-sampler (WAM) device which can host up to 12 samplers simultaneously, rotating at 3 revolutions a minute to reduce sampling biases.

We report on the initial findings of matched pairs of each sampler, run for a minimum of 6 hours, over 28 sample days. Results will be presented from a series of conventional versus real time monitors including SKC IOM, HazDust 7204 with IOM Inlet, TSI AM520 with Respirable dust Cyclone, IOM + Foam plug PVC, Zefon DRS + Foam plug PVC, UPAS v2+ direct reading sampler + 37mm filter, Nanozen 9000, Dust Canary with foam insert and Trolex XD1+. 

Noise exposure is ubiquitous, and exists in all industries, but can be a particular cause for concern in heavy commercial and industrial settings including construction, manufacturing, and mining. Workers in the mining sector have been found to have rates of hearing loss far exceeding general industry with almost a quarter of the occupational population experiencing more than 25 dB of hearing loss averaged over the 1, 2, 3, and 4 kHz audiometric frequencies.

To better understand noise exposures in the mining industry and identify patterns of exposure between mine types and occupational designation over time, data were collected from the Mine Safety and Health Administration (MSHA) from 1979 to 2025. Descriptive statistics and two fixed-effect linear regression models were developed to predict the average noise exposure by job title; one model predicts exposure using the MSHA permissible exposure limit (PEL) (i.e., 90 dBA limit, 90 dBA threshold) and the other uses the MSHA action level (AL) (i.e., 85 dBA limit, 80 dBA threshold).

Overall, 8-hr TWA noise levels decreased significantly (p<0.05) over time, albeit the decrease was not strictly linear, nor consistent across different job titles. This presentation will explore this variability and provide information on job titles that have sufficiently reduced noise exposure and those that need more work. These results will help further noise control efforts in the mining industry.