Managing Air and Water Quality at Cadia Valley Operations
Mining responsibly is what the community expects of us, and what we demand of ourselves. We remain firmly committed to rebuilding trust and confidence in our operations with the community and regulator, so we can continue to support jobs, regional investment, and the energy transition.
In late February this year, a small number of residents living in the district informed Cadia that they had self-tested the quality of water in their water tanks and found elevated levels of contaminants, including lead. This information was very concerning, and in response, Cadia commissioned and completed several independent scientific studies.
Independent Scientific Studies and Reports
SAGE Environmental Human Health Risk Assessment
The assessment determined the potential risks to human health within the community surrounding Cadia from operating emissions (modelled from January 2022 – February 2023) and environmental sample data collected from a residential drinking water sampling program. The report reaffirms that Cadia is not responsible for lead or heavy metals where elevated risks have been identified.
The report states building materials and drinking water system maintenance practices as the key source of metals.
The findings of the Human Health Risk Assessment conducted by SAGE Environmental shows that Cadia is operating within established health standards, and the potential risk of emissions to human health is low.
When assessing the report in collaboration with all other independent studies, it confirms that there is no impact on human health from metals in dust from Cadia's mine site.
ANSTO 12-month Air Quality Report
This study, undertaken by independent air quality investigator - Australian Nuclear Science and Technology Organisation (ANSTO), assessed if dust from Cadia was leaving site and affecting residents in the district.
It found that while Cadia's dust could be detected in the sampling, it was a very minor proportion of the dust samples and that the total dusts sampled were well below national guidelines.
Importantly, the levels of substances like lead, chromium and selenium were all well below national guidelines. The report also supported Cadia's record of operating in accordance with its project approval air quality impact assessment criteria.
Isotope Interpretation Report
Results from a lead isotope analysis and dust fingerprinting study show no evidence linking Cadia to the lead sampled in the district's rainwater tanks.
For this study, 88 sludge samples that were collected by Cadia during the district water sampling program were examined against samples taken from Cadia's ore body, and other soil and rock samples from the surrounding area.
74 of the samples found no correlation with Cadia ore.
While there were similar characteristics between the Cadia orebody and district soil samples in the remaining 14 samples, the amount of lead recorded in these 14 samples were at the lowest concentration of lead amongst all the sludge samples and at a level that is considered immaterial. Despite this fact, some media continue to suggest Cadia as the source of lead.
The results of this isotope fingerprinting study correlates with the results from the district drinking water sampling program undertaken earlier this year in response to community concerns, the findings from the ANSTO 12-month air quality study, and current and historical monitoring data.
Community Drinking Water Sampling Program
144 residences participated in Cadia’s Independent Community Water Sampling program.
Eight residences return readings above Australian drinking water guidelines, with seven residences’ results attributed to building and/or plumbing materials.
95% of households had water that meets the Australian Drinking Water Guidelines.
No clusters were identified or links determined to Cadia.
The results of Cadia’s community drinking water program aligns with sampling conducted by NSW Health and the NSW EPA.
These results also indicate the importance of maintaining tanks and tank water distribution systems in accordance with guidance provided by NSW Health.
Todoroski Air Quality Dispersion Model
Cadia has released an updated Air Quality Dispersion Model conducted by Todoroski Air Sciences.
The report presents air dispersion modelling for Cadia during the period January 2022 to February 2023.
Using actual sampling data from the Cadia and ANSTO monitoring networks, the Air Quality Dispersion Model showed that site boundary and receptor point compliance levels are met, and no evidence linking Cadia to lead or metals sampled in community rainwater tanks.
Monitoring Air Quality at Cadia
We monitor air quality at key locations on and adjacent to our mine site on a 24-hour basis. Our Air Quality Monitoring Program is managed in accordance with the Cadia Air Quality Monitoring Program, which was approved by the NSW Department of Planning and Environment (DPE). Cadia reports monthly on Air Quality and these reports are uploaded to our website.
What we monitor
PM10 and PM2.5 Ambient Air Quality Monitoring – BAMs (Beta Attenuation Monitors) provide continuous PM10 and PM2.5 particulate concentration measurements using the industry proven principle of beta ray attenuation. Eight BAM’s are in continuous operation at various locations around the Cadia district.
Dust Deposition Gauges - (DDG’s) are located at eleven sites around the Cadia District and the Cadia Dewatering Plant. The DDGs are analysed monthly for metals and total dissolved and insoluble solids.
Visual Dust Monitoring - Visual dust is monitored during routine inspections and when complaints are received. Where excessive dust generation has been identified, mitigation measures are implemented.
Meteorological Monitoring - We also utilise our on-site weather stations as part of our air quality monitoring program.
Data gathered from our monitors is used, in conjunction with weather forecasts, to plan each day’s operational activities. We change or reduce the operation of equipment to avoid or minimise potential contribution to elevated dust conditions on a case-by-case basis.
Monitoring Vent Emissions
Cadia conducts routine emissions testing at the surface ventilation system, which analyses the air quality of the exhausted air from our underground operations.
The latest monitoring results show that we are operating in full compliance with clean air regulations – the direct action we have taken to comply and curtail emissions from the mine's ventilation rise is having a positive effect and we intend to maintain this compliance.
These results have been provided to the NSW EPA and we continue to maintain regular contact with them on our actions to maintain compliant emissions from the vent rise.
The hot and humid conditions underground result in exhausted air being warm and saturated with moisture. On chilly mornings, the condensation from the exhaust air is often visible on the surface.