Dust monitoring and control efficiency measurement in longwall mining

Occupational hygiene has been an integral part of the mining industry for centuries; however its importance has grown with developments in mechanisation. While the focus in the past has quite correctly been on improving the controls on dust exposure, the future lies in identifying the efficiency of installed controls on operating longwalls, evaluating them through robust and quantitative sampling methods to ensure the most effective controls are in place to prevent occupational disease from occurring. The current statutory testing regime identifies the exposure levels of personnel on an operating face, which gives a snapshot of the dust that these persons will be exposed to over the duration of a mining shift. Although this testing process clearly determines exposure levels, it does not give mine operators any indication of where dust is produced, how much dust is produced nor how efficient the installed controls are at mitigating produced dust. This paper proposes a new testing methodology to determine installed control efficiency for both respirable and inhalable dust and reports the initial dust measurement results based on this methodology. The main objective of this sampling method is to identify dust loads at independent sources of dust generation on longwall faces and quantify the efficiency of installed controls for the mitigation of produced dust. The use of this new methodology will provide mine operators with a complete dust production signature of their operating longwall and allow the implementation of more efficient controls at independent sources of dust generation.