Cadia gold mine
The NSW EPA is working to ensure that Newcrest’s Cadia Holdings Pty Ltd mine is operating in compliance with its environmental obligations, in a way that minimises impacts from their operations, and to safeguard the community and the environment.
Cadia Valley Operations are required to comply with site specific conditions and controls aimed at minimising the impacts from their operations on the environment and community. These conditions are outlined in an environment protection licence issued by the EPA to Cadia Holdings Pty Ltd and are legally enforceable. The licence is available on the EPA's public register.
The EPA has launched prosecutions in the NSW Land and Environment Court against Newcrest Cadia Holdings.
- The EPA commenced proceedings in August 2023 alleging that in March 2022 the mine exceeded the standard of concentration for solid particles (total) as a result of operating surface exhaust fans attached to Ventilation Rise 8. Newcrest Cadia Holdings plead guilty to this alleged breach in September. The sentence hearing date has been set for 28 March 2024.
- The EPA launched four further prosecutions against Newcrest’s Cadia Holdings for alleged air pollution and solid particle exceedances from the Cadia gold mine in October 2023. This includes two offences relating to an exceedance of the standard of concentration for solid particles (total) as a result of operating mine surface exhaust fans attached to Ventilation Rise 8 (VR8) in November 2021 and May 2023, and two offences relating to air pollution incidents in October 2022 from the surface of Cadia’s tailings storage facilities.
The EPA will continue active investigations into Cadia’s mining operations and licence compliance and will take necessary regulatory action, including prosecutions, where appropriate.
Regular vent emission monitoring
Cadia is continuing to undertake vent emission monitoring regularly and provide a monthly report on dust discharges from one of its main vents. Since June 2023, these levels have been found to be compliant with the standard of concentration for solid particles (total). Results for fortnightly sampling of metals in vent stack emissions are provided to the EPA. All levels for metals were below Clean Air Regulation emission limits with metals such as selenium below laboratory detection levels. The EPA will continue to receive and review these reports.
Independent health risk analysis
The EPA required Cadia to provide an independent health risk analysis in the form of a human health impact assessment to the EPA. Cadia sought peer-review and has made the report available on the Cadia website.
The EPA has reviewed the Air Quality Impact Assessment, which is a key input to the human health impact assessment, and identified a number of issues.
The EPA has required the Air Quality Impact Assessment to be revised and resubmitted.
Tailings dam dust mitigation
The EPA also required Cadia to provide a report on all reasonable and feasible dust mitigation options to manage the risk of dust from the tailings dam and conduct sampling. In response, Cadia has provided the report on options to manage the risk of dust from the tailings dam to the EPA. The EPA is reviewing the report.
Once the EPA’s review of the options report has been completed, we will engage with Cadia to progress the most appropriate options.
The EPA has required Cadia to undertake dust emissions monitoring on Vent Rise 8 (VR 8) every fortnight and is receiving fortnightly reports on dust monitoring as required under the licence conditions.
All reports and information received by the EPA are being reviewed and will inform the EPA’s regulatory activities.
On 21 June 2023, the EPA said Cadia must comply immediately with the Protection of the Environment (Clean Air) Regulation 2022 (the Clean Air Regulation), the Protection of the Environment Operations Act 1997, and its Environment Protection Licence (EPL), or face further regulatory action by the EPA.
This follows test results showing that the mine’s main vent is releasing an unacceptable level of dust. If Cadia does not take all necessary steps to ensure dust emissions are significantly reduced, the EPA will take appropriate action which could include suspension of the licence, seeking court orders or issuing further directions.
Several new conditions have been added to the licence to address community and environmental concerns about impacts on air quality. The new conditions require Cadia to do the following:
- Undertake vent emission monitoring regularly and provide a monthly report on dust discharge from one of its main vents.
- Provide additional reports on lead dust fingerprinting research, analysis of dust impacts and sources, an independent health risk analysis, and an updated Air Quality Impact Assessment.
- Undertake works to manage dust generation underground, in addition to conditions issued in April to manage the risk of dust from the tailings dam.
- Provide monthly reports on works undertaken in relation to the dust suppression plan for the tailings dam that Cadia has implemented under the conditions issued in April.
Cadia responded with initial actions including adjusting their underground operations in order to be compliant. Cadia has also taken a number of actions in addition to lowering dust production levels including
- installing additional dust sprays and spray curtains
- re-configuring the dust extraction systems
- sampling of the vent rise emissions as required by the latest variation to the mine’s licence
- installing additional dust sampling instrumentation
- accelerated additional dust filtration units currently on order
There is still more work to be done and we will be monitoring compliance closely.
Read the media release issued 30 June for more information.
On 29 May 2023 the EPA issued Newcrest’s Cadia Holdings Pty Ltd’s Cadia mine with a final pollution Prevention Notice regarding the management of emissions of dust and other air pollutants. A draft licence variation was also issued on 19 May 2023 as part of a new investigation commenced by the EPA.
Cadia mine has submitted a proposed modification application and scoping letter to the Department of Planning and Environment, with a current estimate of August 2023 for lodgement. For more information, go to the NSW Planning Portal.
The EPA’s monitoring programs
Many residents in the area surrounding Cadia mine rely on rainwater tanks for their domestic water supply.
Information on rainwater tank management and cleaning can be found on the NSW Health website.
In response to community concerns, the EPA offered water tank testing for residential properties which are rainwater dependant as part of a broader monitoring program.
We have collected samples from 97 residential properties to check the concentration of metals in water. Our specialist officers worked to a sampling plan to make sure samples were collected at each property using consistent methodology. Water samples were collected from kitchen taps at residences by letting the tap run to release one litre of water, before we collected the sample in a container supplied by our National Association of Testing Authorities (NATA) accredited laboratory. We sampled water from residents’ rainwater tanks, bores, dams, creeks and downpipes. We also took sediment samples from rainwater tanks where possible.
All samples were analysed for metals. Residents’ kitchen tap water was also analysed for total dissolved solids, total hardness, colour, turbidity, pH, nitrate, nitrite, sodium, fluoride and iodine.
We have received the results for samples collected from the 97 properties sampled. We have compared the results of the water testing to the national guidelines for drinking water, known as the Australian Drinking Water Guidelines (ADWG).
The majority of results from kitchen tap samples showed metals concentrations below the health-based guideline values.
At three properties, the levels of lead in samples collected from the kitchen tap were at or marginally above the health-based guideline value for lead on the day of sampling. The level of lead in the tank water samples from these three properties did not exceed the health-based guideline value.
At one property, the level of nickel in the sample collected from the kitchen tap marginally exceeded the health-based guideline value for nickel. Nickel was not detected in the water tank sample from this property.
Some water tank samples had levels of lead (14 properties) or cadmium (two properties) or antimony (one property) above the health-based guideline values. Samples taken at the corresponding kitchen tap on these properties did not detect the same metals above the health-based guideline value.
Other metals in tank water samples were below the respective health-based guideline values on the day of sampling.
Some samples also recorded pH in kitchen tap and tank water tap samples outside the range described in the Australian Drinking Water Guidelines, on the day of sampling. This range is based on minimising corrosion and encrustation of plumbing fittings and pipes rather than a risk to human health.
There were some mixed results for aesthetic values (including zinc, colour, copper, total dissolved solids, turbidity, hardness, iron and aluminium) in kitchen tap and tank water samples outside the range described in the Australian Drinking Water Guidelines, on the day of sampling. An aesthetic guideline value is the concentration below which the water quality is considered acceptable to the consumer, for example, appearance, taste and odour.
These results indicate the importance of maintaining tanks and tank water distribution systems in accordance with guidance provide by NSW Health. Property owners might also consider installing filtration and/or first flush systems to reduce potential contamination of their drinking water.
Sediment in rainwater tanks
We understand testing sediment from rainwater tanks is important for the community. We took samples of sediment from rainwater tanks where it was safe to do so. To get safe access, sediment samples were collected from first flush system or with a sampling device direct from the bottom of the rainwater tank. We took samples from 52 properties; 41 samples had sufficient volume for metal analysis.
The EPA analysed 41 sediment samples. The results have been compared to results of other studies of sediment in Australian water tanks. All key metals measured were within typical concentrations found in Australian tanks, with the exception of nickel which was exceeded in two samples. For these two samples nickel did not exceed the health-based guideline value at the kitchen tap.
There are no relevant guideline values comparable to the sediment samples. The Australian drinking water guidelines provide a basis for determining the quality of water to be supplied to consumers in all parts of Australia to ensure safety at the point of use. The Australian and New Zealand sediment quality guidelines are targeted to the protection of aquatic ecosystems and livestock (ANZG 2018). In the absence of suitable guideline values, we compared the concentrations of metals in tank sediments collected around Cadia Valley Operations to those measured in other parts of Australia.
We are providing individual test results to property owners and offering an opportunity for them to discuss the findings with the EPA.
Expressions of interest for water sampling closed on Friday 4 August 2023.
The test results from our sampling programs, have been broadly compared with sampling results previously undertaken by NSW Health, industry and independently by the community and with other Australian rainwater tank studies.
The EPA’s Expert Panel has reviewed the summary reports on the results of the water tank water and sediment sampling programs and advised that the conclusions are supported by the data. Isotope testing of a subset of sediment samples, surface and subsurface soils in Cadia Valley, and vent emissions and tailings from the mine is being undertaken. The lead isotope ratios in the soil and sediment samples will be compared to those in the vent emissions and tailings, to help identify the potential source of lead in sediment and soils.
Community-based smart sensors
The EPA sought expressions of interest from community members interested in having a smart sensor, also known as a PurpleAir monitor, installed on their property as part of our broader monitoring program. Expressions of interest for smart sensors have now closed.
We have deployed 35 smart sensor air monitors at properties in the Cadia Valley for community-based air monitoring.
Smart sensors measure airborne particulate matter (PM). Particulate matter describes solid particles suspended in air, including dust, smoke, pollen, and other organic and inorganic particles.
The sensors use laser particle counters that count particles in the air in a range of sizes. These particle counts are then used to estimate the PM2.5 air quality index (AQI). Data from the sensors is made available to the public in real-time via an online map. You can see on the map the sensors that we have already installed in the Cadia Valley reporting data in real-time.
These sensors will provide us with a picture of regional dust however they will not identify the source or composition of any dust. We are deploying additional monitoring equipment and a range of monitoring techniques to provide a robust and comprehensive understanding of the air quality in the region.
The sensors will provide indicative information about air quality and dust movement in the Cadia Valley. It should be noted that the data provided by the sensors can be impacted by smoke from BBQ’s, wood heaters, extraction fans and air conditioners, and when foggy the sensors may measure water droplets in fog as particles, giving an incorrect reading.
More information about the smart sensors, including how to use the PurpleAir map, is available on the Environment and Heritage website
Measurement of metals in air and particles in air
The EPA is also installing a comprehensive network of high-volume air samplers and multi-channel DustTraks in the Cadia Valley. These provide scientifically robust insights into air quality.
DustTraks are an air monitoring device for reporting total suspended particles, PM10 and PM2.5 with a 1-hour averaging period. Go to the Air Quality NSW website for more information about current air quality for parts of the Central Tablelands.
High-volume air samplers are a device for sampling a relatively large volume of air, through a filter paper to determine gravimetrically the amount of trapped particulate matter. The collected matter is analysed for total suspended particles and will be reported regularly.
More high-volume air samplers and DustTraks will be added to this network.
The information provided by the sensors and high-volume air samplers will be used to inform the EPA's regulatory activities.
Continuous monitoring of other air pollutants
In addition, the department has established an air monitoring station at Millthorpe. This station continuously measures particles, visibility, some gaseous pollutants (carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide), as well as meteorological variables. Data from the station is reported hourly as air quality category (AQC) ratings and are included in our Central Tablelands regional summary. Please visit our air quality page to check the current air quality in Millthorpe.
This network is run by the Department of Planning and Environment on behalf of the EPA.
More information about this program is available on the Environment and Heritage website.
The EPA sampled surface soils at 30 public sites within the Cadia Valley region on 12-14 July 2023. Soil at 0.5 metres was also sampled at these locations where possible.
All samples were analysed for lead, copper, cadmium, arsenic, nickel, zinc and selenium. We compared the results of the soil monitoring to the national health-based levels for public open space and residential land with accessible gardens and to soil metal concentrations prior to commencement of the operation of the Cadia gold mine.
No soils samples, at surface or at depth, had levels of metals above national health-based levels for public open space or residential land with accessible gardens.
Metal concentrations were at a similar level to those observed prior to the operation of the Cadia gold mine.
This suggests that dust deposition from the mine has not increased metal concentrations in soil in the area.
The EPA’s Expert Panel has reviewed the report and advised that the conclusions were supported by the data.
No further soil sampling is proposed.