Dust pollution hazard and harmful airborne dust exposure assessment for remote LHD operator in underground lead-zinc ore mine open stope

Abstract

Underground mines have several occupational hazards, including airborne dust generated from various mining operations. Line-of-sight remote LHD mucking is adopted to draw the blasted muck from unsupported stopes in underground metalliferous mines. Investigation on particulate matter (PM) at remote operator location is crucial for assessing the operator exposure and devising appropriate dust control measures. This paper identifies the potential dust pollution hazard for remote LHD operator by simulating different mucking scenarios in open stope. PM generated due to mucking in a long-hole open stope by line-of-sight remote LHD during downcast airflow are measured using real-time aerosol spectrometers. The particulates concentration at upstream and downstream of dust source are analysed for various particle sizes including occupational dust types, such as alveolic and thoracic. The study revealed that the airborne dust concentrations of ≤10 μm, ≤5 μm, and ≤1 μm sizes in downstream, near the operator location, are measured 71.3%, 28.5%, and 3.0%, respectively. Moreover, the alveoli and thoracic dust fractions, respectively are determined 25.1% and 74.2%, in downstream and 48.9%, and 84.6%, in upstream total airborne dust concentration (311±246 μg/m3). The differential concentrations of 15.0-20.0 µm, 10.0-15.0 µm 5.0-10.0 µm, and 0.23.0-5.0 µm are analysed, and empirical relations of these sizes in total airborne dust are established. Moreover, dilution of airborne dust at remote LHD operator location is studied. This study enhanced the understanding on exposure potential of harmful dust during remote LHD mucking in open stopes. Moreover, it emphasised adoption of tele-remote-operated LHD and automated mucking operation in open stopes.