Open Cut » Environment
Fine particulates are considered to be a health risk to humans and are therefore a potentially significant issue for open cut coal mines. Little data is available in relation to fine particulate concentrations in the vicinity of mines, and stringent new air quality goals were promulgated in 1998 that could potentially affect open cut mining operations.
This study investigates the potential risks posed by fine particulate emissions for open cut mines, and assesses alternative monitoring techniques to facilitate rapid response sampling in a cost effective manner.
Particle size distribution data for a range of open cut mining activities are presented. These data demonstrate that fine particulates constitute a smaller proportion of overall dust emissions for open cut mines than for urban environments in Australia.
The composition of the fine particulates from open cut mines is predominantly soil, with coal particles comprising a relatively small percentage. The soil particulates are likely to be sourced from both activities within the mine such as overburden or topsoil removal and agricultural activities external to the mine.
Fine particulate concentrations are shown to have a potential to exceed the new air quality goals at sensitive receptors at distances of 3 km or less from coal mines. At distances of 1 km or less, it is probable that the fine particulate air quality goal will be exceeded on a substantial number of days per year.
Existing dust control costs for open cut coal mines are of the order of $ 0.30 to $ 0.60 per tonne of saleable coal. The new air quality goal could increase these costs significantly and alternative control measures may be required for mines constrained by close proximity to receptors as a result.
Fine particulate monitoring is currently undertaken at a small number of open cut coal mines. It is possible that significant additional monitoring costs will be incurred in the future due to the need to demonstrate compliance with fine particulate air quality goals.
A relatively low cost monitoring alternative was investigated as part of this study. Although the technique appears suitable for screening surveys, the data obtained during this study indicated that it does not comply with the relevant Australian Standard performance requirements. Existing sampling methods were also found to operate outside the appropriate performance range. It is therefore considered necessary to establish on a national basis appropriately tested monitoring instrumentation for fine particulates.
This report is an important step is managing fine dust generated by coal mining.