Borroloola and Devils Spring Study
In 2015 McArthur River Mine (MRM) was instructed by the Northern Territory Environment Protection Authority (NTEPA) to operate air quality monitoring stations at the Borroloola and Devils Spring communities to monitor the concentration of sulphur dioxide (SO2) in ambient air. Consequently the stations were installed, commissioned and then operated between June 2015 and August 2016. During that 14 month period, all SO2 concentrations measured in Borroloola and Devils Springs were well below the National Environment Protection Measure (NEPM) triggers, which are the national standards for air pollutants in Australia. The NEPM are designed to protect the health of the general population and are normally applicable to residential locations where there may be elderly, frail or sick adults and babies in residence.
MRM engaged the services of independent air quality specialists to produce monthly performance reports (link at the right of this page). The role of the air quality specialists was to validate, analyse and interpret data from the air quality monitoring, including wind speed, direction and temperature and to compare the ambient concentration of SO2 against the NEPM standards.
The NEPM standards are available from:
The air quality specialists identified non mine related potential sources of SO2 emissions in the Borroloola and Devils Spring communities that may be measured by the air quality monitoring stations. These sources included the combustion of fuel from vehicles and generators and from bushfires.
Potential sources of SO2 can be found at:
MRM Operational Performance
In September 2016, the NTEPA was satisfied that the results of the AQMS study showed there was no risk of harm to the Borroloola and Devils Spring communities from SO2 generated at MRM. Accordingly, the NTEPA authorised MRM to decommission the air quality monitoring sites.
However, as part of continuous environmental improvement, MRM installed an air quality monitoring station adjacent the Carpentaria Highway near Northern Overburden Emplacement Facility (NOEF) to monitor SO2 concentrations as shown on the map at the right of this page. The data from the new monitoring location allows real-time detection of small and isolated sulphur dioxide emission events, thereby allowing the mine to respond appropriately.
NEPM standards apply to residential areas. For this reason MRM has developed operational performance triggers for SO2 concentrations measured at the new monitoring location, which is far removed from any residential areas.
The operational management triggers are used as part of an adaptive management system at MRM and assist in the management of SO2 emissions by providing an early warning SO2 emissions. MRM also continues to work closely with an air modelling expert to model potential SO2 impacts at community receptors. The modelling shows that the estimated maximum SO2 concentration at the Devils Spring and Borroloola communities are notably lower than the NEPM standards.
The AQMS measures the following data at five minute intervals:
- The concentration of SO2 in the air in parts per billion (ppb)
- The wind speed in metres per second (m/s)
- The wind direction shown as degrees from north
- Sigma o Sigma Theta is the standard deviation of the horizontal wind direction fluctuations over the averaging period in degrees
SO2 concentrations are not collected between 1am and 2am each day due to the self-calibration completed by the AQMS. The raw data from this monitoring station is available using the link at the right of this page (you must click the acknowledgement to see the link).
This data must be used with caution. It must be validated and interpreted by an air specialist using accredited methods and Australian standards.
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