Cadia Continued Operations Project
Frequently asked questions
Below are some questions received by members of the Cadia community and our key stakeholders. The list of FAQs for the CCOP will be regularly updated to include questions and responses.
If you would like to ask a question, please complete the have your say feedback form. You can also call the Project team on 1800 716 864.
Rehabilitation and Post-Mine Closure
The current overall rehabilitation goal for Cadia is to:
“Generate enduring land value by linking it to ecological and agricultural factors. Cadia's rehabilitation efforts focus on creating safe, sustainable and non-polluting landforms across the mine site, Cadia-owned land, and the broader region.”
This involves restoring mined areas to:
- Enhance the current vegetation corridor program, boosting ecological value.
- Enable future sustainable grazing, where suitable.
- Preserve areas crucial for potential future industry and infrastructure needs.
The current Cadia Rehabilitation Management Plan and Cadia Rehabilitation Strategy can be downloaded from the Environmental Management Plans page on the Cadia website www.cadiavalley.com.au.
The CCOP Rehabilitation Strategy will be aligned to the current Cadia Rehabilitation Strategy and Cadia Rehabilitation Management Plan, and will be submitted as part of the CCOP EIS. The rehabilitation strategy will include conceptual final landforms and closure plans for each of the major facilities proposed for CCOP, such as the Southern Tailings Storage Facility Extension (STSFX) and Southern Water Storage. Cadia will propose a progressive rehabilitation strategy including the timing for implementation.
This is consistent with the Cadia Hill and Cadia East EIS plans where commitments for more than 100 hectares of rehabilitation were made and are substantially complete.
The CCOP Rehabilitation Strategy will be benchmarked against global examples to optimise the closure design and completion criteria.
The proposed CCOP Rehabilitation Strategy will consider all community questions and comments gathered in the lead up to submission of the EIS.
We are preparing a draft plan for a future EIS Technical Q & A Forum which includes our current strategy well as comments we have already received at community workshops and one-on-one meetings. Information shared at the technical forum will be uploaded to the CCOP website. Comments and feedback will be further considered as part of the final proposal and feedback will be made available on the CCOP website prior to EIS submission.
As with all aspects of the EIS, further comments can be made to the Rehabilitation Strategy during the EIS public display period.
There are several on-site locations where progressive rehabilitation has been substantially completed or are in the process of being completed. The map below indicates the main areas North Waste Rock Dump, South Waste Rock Dump, and north of the Cadia Pit (known as Cadia Extended Pit).
Major rehabilitation was undertaken on the main Waste Emplacements in 2008 (South Dump) and in 2014/2015 and 2018 (North and South Dump).
In May and June of 2023, vegetation trials through infill planting of eucalypt species were undertaken on the North Waste Rock Dump (NWRD). The purpose of these trials was to analyse the effectiveness of various tree guards and eucalypt species in terms of performance.
This infill planting focussed on areas of the NWRD that required planting of eucalypt species to achieve the final post mining land use of an open grassy woodland. The trial is ongoing, with results to be reported in the next iteration of the Annual Rehabilitation Report (due 30 September 2024).
Early indications show rehabilitation sites on the South and North Dump have a relatively high diversity of endemic shrubs and juvenile trees. A range of introduced species common to the local agricultural area have successfully colonised large areas of rehabilitation and are playing a particularly important role in the ecological development, function and stability of the sites.
Cadia will continue to manage and improve the rehabilitation in these areas and progress towards completion and sign off.
In mid-2021, the Resources Regulator updated compliance and reporting requirements for rehabilitation. This update requires a Rehabilitation Management Plan and associated Annual Rehabilitation Report, along with a Forward Program for large mines. The most recent versions of these reports can be downloaded from the Environmental Management Plans page on the Cadia website www.cadiavalley.com.au
The 2023 CVO Rehabilitation Report prepared by DnA Environmental presents the results of the ongoing annual rehabilitation program that first commenced in 2008. The monitoring program compares the progress of rehabilitated landforms towards fulfilling long-term land use objectives.
The rehabilitation progress is monitored and assessed through the combination of several environmental monitoring programs, including Waste Rock Dump cover performance monitoring and ecological monitoring on rehabilitation and reference sites.
Reference sites are used as a benchmark for the final rehabilitated landscape and provide a time series record of ecosystem change and development. Since its inception the Cadia monitoring program has adopted this process of comparing rehabilitation areas against reference sites in successive phases and has adapted the methodology with the various revisions of the Departments regulatory guidelines.
Reference sites are used to provide a range of ecological performance indicators or completion criteria against which rehabilitation progress can be compared and provide the ability to monitor ecological indicators of an existing natural ecosystem and changes in that ecosystem as a result of climatic variations and disturbance events (such as drought, fire, flood etc.).
Progressive rehabilitation of mining disturbed lands will be undertaken throughout the life of the CCOP, where practicable. This would allow for the establishment of rehabilitated mine areas where possible well before closure It also allows for rehabilitation trials and testing to achieve rehabilitation goals and encourage self-sustaining growth.
The main phases of rehabilitation where the post mining land use is a native ecosystem are:
- Active Mining
- Decommissioning
- Landform Establishment
- Growth Medium Development
- Ecosystem and Land Use Establishment
- Ecosystem and Land Use Development
- Rehabilitation Completion (sign off).
“Completion criteria targets” are set by the data obtained from replicated reference sites. This data provides upper and lower ecological performance indicator limits. Primary completion performance indicators are those chosen as completion criteria targets and rehabilitation sites should equal, exceed, or show positive trends towards those attributes of the reference sites.
When these primary completion performance indicators have been met or are trending in the right direction, the sites should therefore be eligible for sign off. The CCOP Rehabilitation Strategy will be benchmarked against global examples to optimise the closure design and completion criteria.
A Landform Evolution Model (LEM) considers erosion and deposition on a three-dimensional digital terrain model. These models are used to estimate potential surface water runoff and predict resulting erosion and deposition processes over time. Landform Evolution Modelling informs the design of post-closure landform and erosion protection requirements. When applied to mining landforms, predicting landform erosion helps inform closure design and predict post-closure performance.
Typically, the LEM predictions extend to 1,000 years after closure. A LEM will be prepared for the CCOP proposed design and will be made available prior to EIS submission.
As part of the EIS submission a preliminary concept design for mine closure will be prepared. The final design for mine closure depends on approval of the site-wide Rehabilitation Management Plan, along with regulator, stakeholder and community engagement and input over time.
The final closure design considers the operational performance of the site, outcomes of ongoing vegetation and wetland trials and more detailed investigations of the facilities during operations. All these factors will inform the details of the cover materials, erosion control measures and specific design requirements to achieve a final landform that aligns with the proposed post-mining land use.
Mine closure criteria and the final land use are being optimised to incorporate with existing Tailings Storage Facilities (TSFs). At this point in the process for the conceptual closure, the design includes:
- Stockpiled topsoil placed on the surface of the tailings dam – Southern Tailings Storage Facility Extension (STSFX);
- Rockfill armouring the embankment zones susceptible to erosion;
- Free draining embankments to maintain a low water levels within the stored tailings (phreatic surface level);
- Closure of all spillways to direct filtered, treated water to Cadiangullong Creek through constructed wetlands;
- Topsoil that is vegetated on the embankment slopes to reduce erosion. The embankment slopes are 3.5:1, meaning for every 1 metre increase in height, the horizontal length would go out to 3.5m;
- Reclaim ponds decommissioned once water quality criteria achieved and approved by regulators.
Cadia's rehabilitation efforts focus on creating safe, sustainable and non-polluting landforms across the mine site on Cadia-owned land. This includes restoring mined areas to enhance the current vegetation corridor program, boosting ecological value.
Final land use goals are broadly based on the pre-existing land uses within the Cadia Valley, with these being agriculture (mostly grazing) with scattered paddock trees and woodland conservation.
For the CCOP specifically, proposed potential Post-Mining Land Use (PMLU) includes returning reclaim ponds and stockpiles for grazing, reserving the STSFX footprint for woodland conservation (including native grasslands) and applying aquatic vegetation within ponded areas.
Other post-mining rehabilitation objectives will allow for future needs of the community through retaining key infrastructure where appropriate and pending future negotiations with regulatory bodies and community. This may allow the site to be used for such industries as solar power generation. Cadia will continue to engage with community on options for alternate post-mining land use particularly for the surfaces of the TSFs where these options may be viable.
Cadia’s rehabilitation progress is reported in Section 17 of the Annual Review and the annual Rehabilitation Monitoring Report. Both of these can be found in the Environmental Management Reporting section of the Cadia website https://www.cadiavalley.com.au/newcrest/cvo/environmental-management/reporting.
Cadia’s mining leases and development approval contain rehabilitation conditions. Cadia is required to demonstrate that the rehabilitation of the mine occurs in a manner that achieves sustainable final land uses following the completion of mining.
Cadia has lodged a security deposit with the department that covers the full rehabilitation costs. This requirement ensures that the NSW Government does not incur financial liabilities in the event of a title holder defaulting on their rehabilitation obligations.
The NSW Resources Regulator undertakes inspections of Cadia operations to assess whether Cadia is meeting its rehabilitation obligations under the Mining Act. Where non-compliances are identified, enforcement action may be taken.
The Department of Planning. Housing and Infrastructure (DPHI) can also undertake a similar role in relation to the development approval conditions.
If mine ownership were to change hands, the accountability would be transferred to the new owners of Cadia. The site owners will be accountable to manage the site after operations ceasing until such time as the required conditions have been established – regarding rehabilitation, water management and other environmental measures – to the satisfaction of the regulator. Cadia will be unable to relinquish the site until these conditions are met.
Long-term trials to test methods of capping and rehabilitation of tailings have been undertaken at Cadia. Eight separate research projects focused on the rehabilitation of the TSF have been undertaken at Cadia since 2000. These projects have informed and refined the rehabilitation strategy for the TSFs.
The results from the trials showed that it is feasible to rehabilitate the TSFs at Cadia using native local tree and shrub species and introduced grazing pastures as final land use options. The most successful of the trial treatments included native tree and shrub plantations and introduced pastures when they were sown into topsoil or biosolid substrates.
Under Modification 15 Cadia is seeking approval for the construction of a tailings pilot plant and associated trial sand embankment (known as hydrocyclone sands). The objective of the pilot plant trial is to further evaluate that a suitable sand product can be produced from the tailings generated with Cadia’s typical ore processing rates. Rehabilitation trials will also be undertaken on the sand embankment to inform the rehabilitation strategy for the sand embankments.
Cadia is continuing to undertake rehabilitation of disturbed land which is no longer required for the operation of the mine and monitoring of previously rehabilitated areas. Through the lessons from its ongoing rehabilitation and monitoring activities Cadia continues to refine its rehabilitation techniques and strategy.
In 2023, a consultant (AECOM) was engaged to conduct a pre-feasibility study into using constructed wetlands to manage water runoff from the Tailing Storage Facilities (TSF). The study focussed on the Northern TSF. The study identified that a constructed wetland would be most effective to treat captured leachate from the TSFs, as well as captured surface water flows from the TSF surface. These monitoring programs also take into consideration related monitoring data such as meteorology and water monitoring programs.
Cadia trials to date have verified the success of pasture and woodland ecosystem establishment on the TSF surface (with topsoil or biosolid treatments).
Vegetation trials will continue during operations the outcomes of which will inform the final rehabilitation and closure designs. We will summarise all past and future proposed vegetation trials as part of preparing a rehabilitation strategy for the project, and the progress of these studies will be provided to community prior to submission of the EIS.
All infrastructure, including pipelines, is proposed to be removed once the site achieves the required rehabilitation requirements.
The current Cadia Rehabilitation Management Plan and Cadia Rehabilitation Strategy addresses the rehabilitation of both the NTSF and STSF. It can be downloaded from the Environmental Management Plans page on the Cadia website www.cadiavalley.com.au
We acknowledge that the normal operation of the facility makes this difficult. However, given the community’s feedback on this issue, our engineers are examining what is possible. It may be possible to construct the final footprint wall in some areas, using available excess coarse material. This approach would enable early, progressive rehabilitation of the outer face.
Examples of cyclone sand dam closures are not very prominent as sand dams are often very long-life facilities. However, some examples include: Brenda Copper Mine, British Columbia (BC), Canada (operated by Glencore); and Gibraltar Mine, BC, Canada, (operated by Taseko -partial rehabilitation). CCOP will prepare a factsheet providing further information on these examples of cyclone sand dam rehabilitation, along with images and links.
There are a number of examples of other Tailing Storage Facilities (TSFs) that have been closed that used upstream method construction where the embankments were constructed with coarse segregated tailings that are similar in closure concept to a cyclone sand dam such as the CCOP proposed one. These include: Tyrone Mine, New Mexico, USA, (operated by Freeport McMoRan, closed in 2008); Chino Mine, New Mexico, USA, (operated byFreeport McMoRan -partial closure); Climax Mine, Colorado, USA, (operated by Freeport McMoRan); Morenci Mine, AZ, USA, (operated by Freeport McMoRan).
Newmont will continue to benchmark closures of tailings dams and specifically cyclone sand dams around the world to monitor best practice performance in the industry and incorporate lessons into the rehabilitation and closure design for Cadia.
Due to the long-term operation of the proposed CCOP, there would be areas of the facility which, although not active, are left standing for considerable periods. Cadia is working through the plan to identify any such areas and provide a vegetative cover. This cover will assist to reduce dust liftoff from the dam wall.
Potential methods include mechanical planting for seeding or hydroseeding and hydro mulching (seed + mulch + fertilizer + dye) in conjunction with any progressive rehabilitation that can be completed to maximise dust suppression.
The CCOP mine closure criteria will include restoring water quality to levels agreed with the regulator. The current plan includes closure of all spillways to direct water from the surface of the TSFs through constructed wetlands to enable the water to be filtered prior to release to Cadiangullong Creek.
The aim of the final landform is also to minimise infiltration through the tailings and allow discharge of water off site to the surrounding creeks, ensuring they are of appropriate, approved quality.
These and future monitoring programs also take into consideration related monitoring data such as meteorology and water monitoring programs.
If the CCOP is approved it will identify a closure and rehabilitation plan for the NTSF including the timing.
For the period prior to any closure of the NTSF, Newmont has implemented an irrigation system on the surface of the NTSF to control and mitigate dust emissions from the facility.
The EIS will assess the quality of the tailings used for construction and deposition within the facility and take this into account when recommending a rehabilitation strategy. Preliminary analysis has indicated that the tailings is not acid forming which will allow a wide range of plant species to be used in this program.
As discussed in previous sections Newmont will continue to be engaged with site rehabilitation until issues such as water quality and biodiverse rehabilitation are addressed as adequate and self-sustaining by the regulator.
The results of this work will be presented in future EIS Technical Q & A forums and as part of the Environmental Impact Statement (EIS) display process.
The current Rehabilitation Management Plan (RMP) that Cadia has prepared in reference the NSW Resources Regulator ‘Form and Way’ documentation provides detail on how our ongoing rehabilitation management addresses the risk from fire, pest animals and noxious weeds.
Further, Cadia implements a Land and Biodiversity Management Plan which provides guidance on our approach to feral pest animal and noxious management.
Cadia has developed and implements a bushfire fuel management plan for the operational mining (mining lease) areas. The aim of the plan is to manage fuel loads within operational areas to prevent catastrophic bushfire events. Actions include knockdown spraying, hazard reduction burns (usually conducted during training exercises), maintenance of large fuel free areas and rapid response capabilities.
Mine closure criteria and the final land use are being optimised to incorporate with existing Tailings Storage Facilities (TSFs). At this point in the process for the conceptual closure, the design includes:
- Stockpiled topsoil placed on the surface of the tailings dam – Southern Tailings Storage Facility Extension (STSFX)
- Rockfill armouring the embankment zones susceptible to erosion
- Free draining embankments to maintain low water levels within the stored tailings (phreatic surface level)
- Closure of all spillways to direct water through installed natural filter systems (wetlands), to sustainably treat water entering Cadiangullong Creek.
- Topsoil that is vegetated on the STSFX embankment slopes to reduce erosion
- Reclaim ponds decommissioned once water quality criteria achieved and approved by regulators.
Long-term trials to test methods of capping and rehabilitation of tailings have been undertaken at Cadia. Eight separate research projects focused on the rehabilitation of the TSFs have been undertaken at Cadia since 2000. These projects have informed and refined the rehabilitation strategy for the TSFs.
The results from the trials showed that it is feasible to rehabilitate the TSFs at Cadia using native local tree and shrub species and introduced grazing pastures as final land use options. The most successful of the trial treatments included native tree and shrub plantations and introduced pastures when they were sown into topsoil or biosolid substrates.
Vegetation trials completed in the past and future trials will continue to look at the plant performance and metal uptake in the foliage.
Typically, the ecosystem establishment and development can take 10-25 years to achieve the required completion criteria and is subject to the ongoing outcomes of vegetation trials, performance of the revegetation over time subject to weather conditions and climactic conditions as the ecosystem develops and establishes.
The main phases of rehabilitation where the post mining land use is a native plant ecosystem are:
- Active Mining
- Decommissioning
- Landform Establishment
- Growth Medium Development
- Ecosystem and Land Use Establishment
- Ecosystem and Land Use Development
- Rehabilitation Completion (sign off).
Cadia is required to lodge a security deposit with the NSW Government that covers the full rehabilitation costs. This requirement ensures that the NSW Government does not incur financial liabilities in the event of a title holder defaulting on their rehabilitation obligations.
This process is regulated under the Mining Act 1992 by the NSW Resources Regulator, with Cadia required to complete a Rehabilitation Cost Estimate (RCE) on an annual basis using the RCE tool developed by the Resources Regulator. This RCE includes a detailed costing of all rehabilitation liabilities at Cadia and is prepared in conjunction with the Annual Rehabilitation Report and Forward Program that Cadia is required to prepare annually, with the outcome of the RCE generating the value of the bond or security deposit lodged.
Newmont includes an estimate of the value of this rehabilitation as part of its life of mine plan, which is updated annually to Newmont Standards. Newmont has filed a publicly available technical report with the Securities Exchange Commission in the United States and has included closure costs in that report.
Ongoing, Newmont will conduct progressive rehabilitation where opportunities exist.
As part of CCOP we will be undertaking a Biodiversity Assessment Report (BDAR) to identify the impacts on flora and fauna within the proposed CCOP disturbance area. This process is being informed by multiple field ecology surveys undertaken in recent years. Total impacts on biodiversity will form part of this assessment and the outcomes of the BDAR will be shared with community at a future EIS Technical Q&A Forum.
As part of CCOP we will be undertaking a detailed Soil, Land Capability and Agricultural Resources Impact Assessment including an Agricultural Impact Statement. This will identify the impact of the CCOP on agricultural productivity and identify recommended management and mitigation measures. The outcomes of this will be shared with community at a future EIS Technical Q&A Forum.
Current approvals allow Cadia to place tailings within 10m of the top of the pit. This limit is aligned to the current understanding of impacts on the adjacent Cadiangullong Creek. Cadia is looking at all tailings deposition options including additional storage in the pit.
Achieving a final land form on top of the tailings dams that is suitable for grazing is acknowledged to be a challenging outcome to achieve. Cadia is examining the most suitable resources (soils, clays etc) to ensure the best long-term outcome for rehabilitation. The CCOP assessment process will recommend an achievable rehabilitation plan and if it’s not possible to achieve stock grazing on top of the tailings storage facility, we will be open and transparent about this outcome at a future Technical Q&A Forum.
The requirements of rehabilitation for Cadia are currently outlined in the Cadia Rehabilitation Management Plan which designates the required species types depending on the final land use for each area of the site.
CCOP will prepare an updated Rehabilitation Strategy for the EIS that will outline any changes to the current Rehabilitation Management Plan. In addition, the updated strategy will summarise all past and future proposed vegetation trials as part of preparing a rehabilitation strategy for the Project. The results of these studies will be provided to the community prior to the submission of the EIS.
Cadia has a current bond commitment with the NSW government of approximately $200 million. This will be reassessed if CCOP is approved in line with the relevant NSW Government agency process.
Cadia is required to demonstrate to the regulator that the rehabilitation of the mine has achieved sustainable final land use following the completion of mining before it can declare the site rehabilitated. This includes the requirement to create a sustainable surface water management system which is integrated into the design of the water catchment and vegetation species used on the site. The rehabilitation assessment that will be made available later this year (2024) will provide a more detailed answer however rehabilitation targets, including achieving targeted water quality, can typically take 10-25 years to achieve.
The rehabilitation assessment conducted as part of CCOP will make recommendations on what species of vegetation will be grown. It will use data gathered by Cadia during vegetation trials that have been carried out onsite as well as data from other sites. The recommendations will be shared during the technical sessions process.
Panuara Road Realignment
A realignment of Panuara Road is required due to the proposed construction of an extension to the Southern Tailings Storage Facility (STSFX), which will extend over the current location of the road in some areas. The road realignment will be designed to meet Austroads Guidelines and to minimise inconvenience to road users.
The proposed realignment of the road will increase the distance travelled by road users by approximately 3.7km (two minutes at the current speed limit). The construction of the new sections of Panuara Road will be undertaken while maintaining use of the existing road. There will be times when traffic control will be in place when the new sections of road are joined to the old sections.
The map below shows early suggested options (1a and 1b), and, following community feedback, the current plan (1c) for the proposed realignment of Panuara Road.
The proposed realignment for Panuara Road has been changed several times based on community feedback. Three options were presented at the announcement of CCOP with majority feedback at the time indicating Option 1 was preferred. Further refinements to the proposed realignment continued, with Option 1A presented to the community in May 2023 and Option 1B presented to the CCOP residents workshop in March 2024. Further refinements have since been undertaken to:
- Firmly situate the road to the west of the ridgeline to separate the proposed road from Errowanbang;
- More closely align the road with the existing Meribah Rd in the east; and
- Minimise impact to sensitive vegetation and cultural areas.
Further detailed design will be undertaken to optimise the intersection of Panuara Rd with Cadia Rd.
Feedback gained from community members at community meetings, workshops and face-to-face conversations have influenced the proposed design. Understandably, requests have been made to align the design as close to the Cadia mine site as possible. It has taken time to seek feedback on proposed options as well as aligning the proposals with the Australian Standards for roads. The result is a realignment design that reduces visual and noise impacts for nearby residents, minimises vegetation removal and avoids impacts on culturally significant objects, such as scar trees.
The Panuara Road realignment continues to be revised following the recent workshop and feedback on the alignment. Further detailed design will be required to ensure the road (including the intersection design with Cadia Rd) meets the required Austroad design guidelines.
The design and planning of the road construction will ensure access will be available at all times for Emergency Response traffic.
No, Flyers Creek will not be impacted by the Panuara Road realignment.
The construction work will be carried out during the day with minor impact on local residents, as you would expect for any construction works on any project. The changes, including how it will operate once it’s in place, have been factored into the inputs for the EIS assessments, and will form part of the impact assessment outcomes which will be shared with community prior to EIS submission.
A Visual Impact Assessment will be carried out for the project, including for the Panuara Road realignment. A number of visual montages have been prepared for locations around the mine showing the visual impact of the proposed Southern Tailings Storage Facility (STSFX). Although these do not include the road, there will be an assessment made in relation to the visual impacts of the road.
The proposed Panuara Road realignment has undergone refinement. Once a few small details are sorted out pegs will be installed for viewing. Local residents will then be informed and invited to view and discuss the alignment on site.
Yes, it will be on the western side of the ridgeline separating the road from the Errowanbang valley.
In order to meet a higher safety standard for tailings facilities, Cadia is changing from an upstream lift method to a centreline lift. The final embankment design for the existing Southern Tailings Storage Facility (STSF) is larger than anticipated to meet these higher standards, so a small section of Panuara Rd is required to be moved. This change is proposed as part of Modification 15.
As part of the CCOP, Newmont is seeking a separate, more significant change to the alignment of Panuara Road to accommodate the proposed STSFX. This significant realignment of Panuara Rd is part of the planning and approval process for the CCOP and will not commence until approval of the Project is granted by the NSW Government.
Both options are approximately the same distance. They both add approximately 3.7km additional length compared to current Panuara Rd. This could mean an additional 2-3 minutes of travel dependent on vehicle speeds.
Water Management
Cadia holds Water Access Licences (WAL) under the Water Management Act 2000 for water extraction. The main licenses include pumped extraction from the Belubula River Regulated Water Source under General Security and Supplementary licenses and extraction from the Lachlan Unregulated Water Source including Cadiangullong Creek, Cadia Creek, Copper Gully, Rodds Creek and Flyers Creek.
Cadia will be preparing a water balance for the CCOP which will outline the current water licenses held by Cadia and the proposals for future operations under CCOP. This work is still being undertaken and the outcomes will be presented in future workshops and fact sheets.
A water balance for a mine site is a comprehensive assessment that accounts for all water inputs, outputs, and storages within the mining operation. It involves quantifying water sources, such as licensed extraction from rivers and dams, rainfall, surface water inflows, and groundwater inflows, as well as water uses and losses, including water used for processing, evaporation, seepage and dust suppression.
The purpose of conducting a water balance for a mine site is to ensure sustainable water management practices. It helps Cadia to understand the mine’s water usage patterns, identify opportunities for water conservation and efficiency improvements and comply with regulatory requirements regarding water use and discharge. Additionally, a water balance is crucial for predicting future water needs and ensuring the long-term viability of the mining operation through wetter and drier periods.
Water from the storages onsite is proposed to be used for irrigation. These storages include Upper Rodds Creek Dam (URCD) and the Pit Tailings Storage Facility (PTSF).
The primary control for maintaining a wet surface of tailings which can minimise dust generation is sequenced deposition of tailings. This approach involves strategically layering or sequencing the deposition of tailings around the perimeter of the facility to maintain a wet surface.
By optimizing the deposition sequence, Cadia can reduce the amount of water needed for dust suppression and moisture management. Layers with higher moisture retention properties can help minimize the need for constant water application.
Cadia will be preparing a water balance for the CCOP which will determine the requirements for water across the site and the proposals for future operations under CCOP. This work is still being undertaken and the outcomes will be presented in future workshops and fact sheets.
It is unlikely that Cadia will be seeking additional water licences from river catchments above what is already in place for the operation. Cadia will be preparing a water balance for the CCOP which will outline the current water licences held by Cadia and the proposals for future operations under CCOP. This work is still being undertaken and the outcomes will be presented in future workshops and fact sheets.
The perimeter drain is lined with riprap (rock armour) for erosion protection. Along steep cuts and batters of the drain a non-woven geotextile will be placed beneath the riprap for added protection.
The function of the perimeter drain is to convey construction water, surface water runoff and emergent seepage from the downstream embankment face towards the reclaim ponds.
Cadia routinely monitors and forecasts water efficiency, water supply security and reliability as part of its normal operations. Prolonged drought periods have changed Cadia’s operational practices.
The site water balance reviews enable Cadia to prioritise water re-use over freshwater extraction and to improve water use efficiencies in accordance with the conditions of our approval and our Water Management Plan.
Cadia recognises water as a shared resource. Site water supply is managed with the aim of reducing the demand on high value water sources including the Belubula River. Water supply from external sources is prioritised as follows, subject to available water allocation and on-site storage capacity:
- Priority 1 – treated town effluent from Orange
- Priority 2 – unregulated river and regulated river supplementary and uncontrolled flow events when announced by WaterNSW
- Priority 3 – regulated river general security water from natural tributary flows rather than releases from Carcoar Dam
- Priority 4 – regulated river water from Carcoar Dam releases. Where possible, this extraction is coordinated with WaterNSW to reduce catchment scale transmission losses by combining water orders with downstream water orders.
Cadia maintains a detailed record of site water data which includes:
- Water demand for processing, underground mine operations and other ancillary purposes;
- Water level and stored water volume of water management storages;
- Tailings level of the PTSF, NTSF and STSF (when operational);
- Water transfers to and from water management storages;
- Water transfer to and from underground mine operations;
- Water supply from internal and external sources;
- Environmental flow release from Cadiangullong Dam and Flyers Creek Weir; and
- Total site water storage volume.
The site water records are used to inform:
- Water management decisions made by the Cadia Water Committee;
- Calibration, using models to recreate past conditions and forecasting via the probabilistic site water balance model;
- Calibration and forecasting via the numerical groundwater flow model; and
- Verification of the groundwater inflow predictions.
The site water records are continuously maintained, reviewed and updated to reflect near real-time site conditions.
Information on the results from various monitoring sites is available in Section 3 of this document 12618414-REP-0_Cadia_2022-2023_Surface Water Assessment.docx (caapp.com.au). Monthly samples are taken of water within the PTSF and Upper Rodds Creek Dam (URCD). This data is then independently analysed and forms part of our Annual Review.
Cadia will be preparing a water balance for the CCOP which will outline the current water licences held by Cadia and the proposals for future operations under CCOP. This work is still being undertaken and the outcomes will be presented in future community workshops and fact sheets.
The embankment walls and the drains are designed to be highly permeable. The finger drains and collector drains beneath the proposed hydrocyclone sand dam walls are designed to catch and channel all rainfall and water that permeates the sand dam wall out to the external perimeter drains and then flow to the reclaim ponds where the water is pumped back to the process plant for reuse. This is a key aspect of the dam design as it increases the inherent stability of the facility.
The drains beneath the wall are constructed with a gradated crushed rock fill and sized to convey the operational required flow rates both during construction of the sand dam as well as throughout closure. The drains have been designed to have capacity to convey normal operational seepage as well as construction water realised during hydraulic sand placement.
Migration of hydrocycloned sand overlying the drains is controlled by gradational filters and/or geotextiles. The drain rock material has been specified to be sufficiently durable to continue providing drainage of the STSFX through the post-closure asset life. A safety factor is applied to estimated design flows in calculating required capacity of the gravel drains. See typical collector drain and finger drain illustrations below.
The proposed reclaim ponds have been designed in accordance with ANCOLD Guidelines and more importantly have been designed to ensure that Cadia does not release surface runoff water offsite.
Reclaim ponds are fully lined and sized for a flood storage to suit a 1 in 100-year Annual Exceedance Probability (AEP) 72 hr rainfall event. The emergency spillway has been designed for a 1 in 1000 AEP flood and all water storages are actively managed to mitigate the potential for water release outside the site boundaries.
There are five reclaim ponds located around the perimeter of STSFX. The function of the reclaim ponds is to:
- Collect surface water runoff, construction water and flow from the underdrainage system and emergent seepage for transfer back into the site wide water system;
- to manage the risk of the release of water from the Cadia site to the environment.
The reclaim ponds operate collectively to manage the require volumes of water with a total storage volume of approximately 3,450 ML. A recent design change has been proposed which will remove the Reclaim Ponds 1 & 2 and diverts the water previously designed to be captured by these ponds to a larger Reclaim Pond 3. The overall volumes are expected to be similar, however design for this is still in progress and the individual sizing of each pond will be subject to minor changes.
Any seepage water from the tailings or the sand wall is collected in drains constructed below the sand wall and directed towards the perimeter drains around the facility and then to reclaim ponds where the water is pumped back to the process plant for reuse.
Cadia mine is designed and managed not to affect groundwater in the region.
Cadia monitors groundwater through an extensive network featuring more than 100 monitoring bores, both on site and across the Cadia district. This network was installed to detect any changes to groundwater levels or quality, with a focus on shallow groundwater interactions with local water resources. All data from this monitoring is shared with the local community and relevant government agencies via the Newmont Cadia website to ensure accountability and transparency. Cadia manages and monitors groundwater in conjunction with independent specialists.
Under our Project Approval and Environment Protection Licence (EPL) there are strict compliance requirements for routine sampling and analysis for water chemistry, which is then reviewed by an independent expert. Findings are shared with regulators including the Department of Planning, the Environment Protection Authority (EPA) and Water NSW and also published on the Newmont Cadia website in our Annual Environmental Review.
In the most recent Annual Review the independent expert concluded that any seepage from the TSF is contained to the immediate TSF area, in compliance with the project approval, and does not have an impact on downstream groundwater water receptors.
CCOP has added to this network of monitoring bores to provide data to support the impact assessments and once approved some of these bores will become a part of the monitoring network.
A groundwater and surface water impact assessment are being undertaken and results will be shared with the community prior to submission of the EIS. CCOP has installed a significant number of new bores in recent years years to provide data to support the impact assessments. We would welcome feedback on any requirement for additional bores.
Yes. Cadia’s Annual Review provides details on water monitoring locations and an addendum to the Annual Review – providing a report on two additional monitoring locations (referred to as BRPS & CAWS71) – was uploaded to the Cadia website 3 June 2024 and can be found at 12640002-REP_Cadia Belubula River surface water assessment.docx (caapp.com.au).
These additional monitoring points have been incorporated into the draft Cadia Water Management Plan currently with the department for approval.
As part of the CCOP EIS process, additional monitoring points have been established:
- CAWS70 – will be added to the draft Water Management Plan to represent the most downstream point on Cadiangullong Creek prior to the junction with the Belubula River.
- CAWS81 – CCOP surface water monitoring point upstream from the Belubula River Pumping station monitoring point.
The data from these CCOP monitoring sites is being used to support the surface water and groundwater impact assessments for CCOP. The results will be shared with community as part of future EIS Technical Q&A Forums and are likely to be incorporated into the Water Management Plan if CCOP is approved.
Site selection and Southern Tailings Storage Facility Extension (STSFX)
The current remaining tailings storage capacity aligns with the existing approval timeframe of 2031. However, to continue operations beyond this date, construction of the STSFX is required to commence later this decade to ensure continuity of operations.
As part of the Site and Technology Selection process undertaken, Cadia identified a number of sites that were smaller than the capacity required to cater for the proposed life of CCOP. Whilst a combination of these facilities could potentially meet the required capacity, they would create significantly greater impacts on water catchments, biodiversity, agricultural land and community.
Further details can be found in the Southern Tailings Storage Facility Site and Technology Selection Process report on the CCOP website.
The site and technology selection considered the impacts of each site and technology on surface and groundwater systems. A detailed surface and groundwater impact assessment is being undertaken for the proposed Southern Tailings Storage Facility Extension (STSFX) as part of the preparation of the EIS and, when complete, will be shared with the community for feedback.
Newmont has undertaken a detailed assessment of all site and technology options including the Northern option. The assessments were undertaken against criteria including: the impacts on biodiversity, noise and dust impacts, potential impacts on the quality and quantity of impacted water catchments, changes to visual amenity and technical risks.
Based on these assessments and an assessment of technical risk the southern site has been determined to best meet the community's needs.
The community requested that the Department of Planning, Housing and Infrastructure (DPHI) conduct an independent expert review of this selection. The assessment of the experts was that the selection of the southern site was appropriate. The site and technology selection report and the independent experts report are available on the CCOP website.
The assessment of the northern option highlighted two key technical risks:
- The foundations of the facility wall are required to be built on loosely backfilled material. This creates significant difficulty in constructing the wall with the required stability levels to last in the long term.
- The northern site is exposed to significantly larger catchment and larger water flow in Cadiangullong Creek. This creates significant difficulty in ensuring the facility design is not eroded, remains stable, and that the required water quality leaving the facility can be achieved.
The proposed Southern Tailings Storage Facility Extension (STSFX) is the nominated site based on Newmont’s site selection report and review by independent expert reviewers. Newmont has been transparent and will continue to engage with the community in relation to the site selection process and the factors that were considered in the site selection process.
Willow Park was acquired by Newmont following its public listing and auction. This property will be managed in accordance with the Cadia Farm Strategy.
Hydrocyclone sand dams are used extensively throughout North and South America and are often used in areas that have very high levels of seismicity and that are located on or near fault lines. The design work conducted to date on the proposed STSFX has fully considered the underlying geology of the site including relevant seismic criteria.
The STSFX has also been designed in accordance with Australian National Committee on Large Dams (ANCOLD) Guidelines. Specific design criteria have been adopted in relation to seismicity. From a seismic perspective, a Cadia Mine Seismic Hazard Assessment and Time History Analysis study was undertaken by the Seismology Research Centre for the Cadia site in November 2019. The data from this analysis has been used to inform the design of the STSFX facility under normal operating conditions and post-seismic loading conditions.
There have been several geological studies across the Cadia site including the tailings storage facilities. Geotechnical drilling campaigns conducted over the ground nominated as the footprint for the STSFX to understand the geotechnical conditions have informed the designs to date. Further geotechnical drilling is planned.
The Southern Tailings Storage Facility Extension (STSFX) is planned to manage approximately 650 million tonnes (Mt) of tailings over its life. This includes an area to store excess sand which may ultimately contain 90Mt of excess sand. Cadia is continuing to look at further refinement options in order to reduce this volume of excess sand stored and how it plays a role in early rehabilitation where feasible.
Work is continuing on the refinements to the design of the STSFX and how it integrates with the existing NTSF and STSF. We will share these with the community in future CCOP Forums.
Tailings and Hydrocyclone Sands Technology
Cadia has been investigating different options for the storage of its tailings over a number of years. Multiple technology options have been considered at various phases throughout the selection process.
Detailed assessment has shown hydrocyclone technology to be the preferred option due to the following considerations:
- Less land disturbance from reduced quarrying
- Lower noise levels for affected residents
- No increase above current water requirements
- Increased embankment stability
- Less energy intensive
The Site and Technology Selection Process Report can be found on the CCOP website. In 2023 the Department of Planning, Housing and Infrastructure (DPHI) engaged independent technical experts Dr David Williams and Nils Steward to undertake a review of the Site and Technology Selection Process Report. Their report confirmed that the site and technology selected for the proposed STSFX were the most appropriate for Cadia.
As a key part of the site selection process, a range of potential tailings deposition technologies were investigated across six potential shortlisted TSF sites.
The technologies considered over the multiple studies included:
- Conventional (thickened) slurry – as currently used at Cadia across all current TSFs
- Central thickened discharge;
- Paste;
- Dry stack (filtered tailings);
- Co-disposal of coarse mine waste (cobbles and boulders) with slurry;
- Co-mingling (tailings and coarse waste rock are mixed together within a storage facility or as a single discharge stream);
- Hydrocycloned sand wall embankment.
Hydrocycloning of the tailings waste separates the coarser tailings fraction, hydrocycloned sandfrom the finer tailings, providing a coarse sand material for construction of the new Tailings Storage Facility embankments.
Once separated, the coarse sand (hydrocyclone underflow) is delivered to and hydraulically deposited into cells on the embankment for compaction. The finer fraction is discharged into the facility behind the progressively raised embankment. Water is collected and returned to the process for reuse.
Hydrocycloning of tailings was developed in the 1960s and continues to be used globally as a safe and reliable method of embankment construction.
Hydrocylone sand dams have only recently been explored as an option in Australia. Previously considered construction methods such as upstream lifts are no longer considered acceptable. Cadia’s own experience has highlighted that it is no longer an acceptable design practice. Hydrocylone dams are considered leading practice around the world as an inherently better design, however they are new to Australia and change can take time. Cadia will lead Australia to a better benchmark.
Hydrocyclone sand dams are used extensively throughout North and South America and are often used in areas that have very high levels of seismicity.
The current existing STSF area (including embankment walls) is approximately 500 hectares. The additional surface area of the STSFX at the end of its life (2048-2050) is approximately 650 hectares. The wall height when it reaches its final height will be the same as the current NTSF and at the end of its life will vary around the perimeter from around 30m on the eastern side of the facility to between 60 and 80m on the western side of the facility. Similar to the STSF at the highest point in the southwest in the area of Rodds Creek the wall height from natural ground level is approximately 150m.
Due to the nature of its construction the STSFX is expected to generate less noise and light emissions than existing construction techniques for the tailings facilities at Cadia. Sand will be pumped to the dam wall where it is constructed using either cell construction or downslope construction.
Sand material and the fine tailings will be pumped from the process plant to the STSFX. The sand is deposited as a slurry within constructed cells or directly downslope of the crest. From there dozers are used to push the sand around and compact the surface. This is a considerably smaller fleet than the traditional carting and dumping of rock being used on the existing facilities. For the early construction of the starter embankment which is constructed with rock materials the fleet is expected to be similar to the existing construction techniques.
The hydrocyclones that separate the tailings into coarse sand for construction of the sand embankment wall and the fine tailings will operating 24 hours a day. The sand is deposited as a slurry within constructed cells or directly downslope of the crest is in line with the operation and pumping of tailings to the NTSF and STSF. Dozers and other heavy mining equipment are used to manage the facility and compact the surface. This heavy mining equipment will operate during the day only, as is currently the case for the NTSF and STSF.
In May 2023 we showed the community pictures of the most common practice of cyclones on the wall of the dam. We received clear feedback that this was not acceptable to the community. In response, we first considered relocating the cyclones and pumps to an enclosed facility adjacent to Cadia Rd. Whilst this was an improvement, we have explored alternatives and will now be moving to a facility adjacent to the Cadia Concentrators to minimise the sources of noise and light from the areas around the STSFX.
A detailed geochemical assessment is being undertaken for the both the proposed coarse tailings and fine tailings streams that are produced for the cyclone sands dam. The preliminary results of the assessment indicate that the tailings and sand is non-acid forming (NAF). Further updates will be available once this work is complete.
Groundwater and surface water impact assessments are being undertaken and results will be shared with the community prior to submission of the EIS at a future EIS Technical Q&A Forum. This groundwater impact assessment will consider seepage from the TSF and also transport of dissolved matter through the tailings.
Dust management for the proposed hydrocyclone sand dam includes:
- For the tailings area the primary method for controlling the surface moisture content is the sequenced deposition of tailings. This approach involves strategically layering or sequencing the deposition of tailings around the perimeter of the facility to dampen and maintain a moist surface;
- For the STSFX it is also proposed to include a sprinkler system on the crest of the dam covering portions of the tailings beach from the dam wall for contingency irrigation and difficult atmospheric conditions (hot, dry or windy weather);
- For the sand wall it is proposed to install wind breaks with progressive rehabilitation where advancing the downstream slope of the wall slope has progressed. We are currently investigating using a downslope up approach to enable progressive rehabilitation on the eastern wall of the TSF;
- Consideration will also be given to temporary erosion protection measures for inactive areas during construction/operation including: (seed + mulch + fertilizer + dye, currently in use on STSF), mechanical planter (seeding), synthetic protective solid covers (e.g. geotextile), synthetic protective covers (polymers/sprays).
Cadia is also undertaking additional testing to identify optimal environmental conditions, moisture content and wind conditions that minimises dust lift of tailings and sand. This will enable the operation to proactively respond to the conditions to ensure adjustments to the operations can be made to reduce impacts, such as turning on irrigation sprinklers ahead of a hot dry spell.
As part of the ongoing study into hydrocyclone sands, a pilot plant for cyclone sands has been established to test the process of creating the sand of the correct specifications required for the construction of the cyclone sand wall. The test results show that the correct sand specification for sand dams can be delivered for the proposed STSFX.
The outcomes of the trials are critical to the design development of sand dams and have informed the specific technical details for the wall and tailings impoundment concept design for the STSFX. A consolidated report of the trials was provided to DPHI for their review and has been uploaded to the CCOP website. The Tailings Pilot Plant Phase 2 Trials Consolidated Report can be found on the CCOP website.
A further larger scale trial has been proposed to be carried as part of the Modification15 submission to provide further data to support the engineering design of the facility. Community members will be invited to attend whilst this facility is in operation.
While detailed comparisons of rock quantities between the hydrocyclone sand dam and dry stack technologies have not been made, it is expected that volumes of rock required would be comparable. Both options require rock in the initial construction of starter embankments, and for construction of filter drains and other associated infrastructure.
There are many sand dams in operation around the globe including at various copper/gold mines in both North and South America. Newmont's Peñasquito Polymetallic Mine has a sand dam and produces gold, silver, zinc and lead. Newmont also operates the Red Chris copper-gold mine which also has a sand dam.
A detailed geochemical assessment is being undertaken for both the proposed coarse tailings and fine tailings streams that are produced for the cyclone sands dam. The preliminary results of the assessment indicate that the tailings and sand are non-acid forming (NAF).
The proposed design includes many features to address seepage from the facility. The role of the seepage control system is to minimise losses of construction water, process affected and final tailings pore water into the foundation (and therefore, regional groundwater).
For the STSFX this will be achieved using a system comprised of several seepage mitigation design (SMD) elements.
The SMD components included in the seepage control system are:
- Hydrocycloning of the whole tailings to remove the sand fraction (resulting in lower permeability for the STSFX final tailings compared to those stored within the existing TSFs);
- An underdrainage system beneath the hydrocycloned sand embankment to collect construction water from the hydraulically placed sand and emergent foundation seepage upstream of the embankment toe;
- A perimeter diversion drain beyond the downstream toe that will collect shallow foundation seepage;
- Reclaim ponds (plus the Return Water Pond) downstream of the STSFX embankment that will capture runoff and emergent seepage;
- Clay and geomembrane lining where appropriate;
- A positive foundation cut-off trench through residual soil and extremely weathered rock beneath the upstream toe of the starter embankment;
- Provision for foundation/fault grouting if relatively permeable zones are identified during the proposed Phase 3 site investigation.
Newmont acknowledges the catastrophic impacts of both Mount Polley and Brumadinho tailings dam failures. However, it is important to note that neither dam was a hydrocyclone sand dam. Brumadinho was also an upstream raise construction method that is no longer used in new dam constructions. Mount Polley was a conventional rockfill/earthfill dam, and the failure was attributed to a weak foundation failure.
The proposed STSFX is a centreline/downstream raise construction methodology. The STSFX has been designed in accordance with Australian National Committee on Large Dams (ANCOLD) Guidelines. Specific design criteria have been adopted in relation to wet weather events and seismicity.
For wet weather events Flood Storage Compartments within STSFX are shown in the figure below.
The design criteria for each storage compartment are shown in the table below.
Compartment | Design Criteria | Equivalent Rainfall Depth (mm) | Comment |
---|---|---|---|
Wet Season Storage | 1 in 10 AEP maximum annual pond volume change | 148 | A safety factor of 2 has been applied to this assessment.> |
Extreme Storm Storage | 1 in 100 AEP, 72-hour rainfall | 168 | BOM intensity frequency duration (IFD) AR&R2019 point rainfall depth sourced from lat:-33.52 and long: 149.01 |
Contingency Storage Allowance– Sand embankment | 300 m horizontal beach freeboard | - | Equates to 3 m vertical freeboard assuming a 1% beach slope. |
There are cumulative storm water storage allowances provided for in the design. There is excess water storage within the STSFX during all stages of development, indicating that the flood storage requirements are able to be met. The maximum operating level is the decant pond level at which deposition is required to cease.
From a seismic perspective, a Cadia Mine Seismic Hazard Assessment and Time History Analysis study was undertaken by the Seismology Research Centre for the Cadia site in November 2019 (Seismology Research Centre 2019). The data from this analysis has been used to inform the design of the STSFX facility under normal operating conditions and post-seismic loading conditions.
The slope of the embankment wall is 3.5:1. This means for every 1 metre increase in height, the horizontal length would go out to 3.5m This has been benchmarked against hydrocyclone dams across the world.
The design of the sand dam wall is permeable to allow the free draining of water from the walls to be collected in drains constructed under the wall. The drains channel the water to a perimeter drain which is collected in reclaim ponds. The water is then pumped back to the process plant for reuse.
A detailed geochemical assessment is being undertaken for the both the proposed coarse tailings and fine tailings streams that are produced for the cyclone sands dam.
The results of this work will be presented in future forums.
The STSFX has been designed in accordance with ANCOLD Guidelines. Designing tailings dams to last in perpetuity post-mining involves considering a wide range of factors to ensure their long-term stability, environmental safety, and minimising maintenance. Some of the key factors considered in the design of STSFX include:
- Geotechnical and Structural Stability:
- Detailed geotechnical investigations have been undertaken to assess foundation conditions. Geotechnical work will continue to be done as detail design progresses to ensure the geotechnical properties of the foundation soil and rock are well understood.
- The Seismic Stability: a Cadia Mine Seismic Hazard Assessment and Time History Analysis study was undertaken by the Seismology Research Centre for the Cadia site in November 2019 (Seismology Research Centre 2019). The data from this analysis has been used to inform the design of the STSFX facility under normal operating conditions and post-seismic loading conditions.
- Slope Stability: Ensuring stable slopes for both the dam and the surrounding terrain, using appropriate angles and reinforcement where necessary.
- Water Management Considerations:
- The STSFX has been designed with a key focus on water management and management of seepage mitigation.
- The water management systems include:
- Hydrocycloning of the whole tailings to remove the sand fraction (resulting in lower permeability for the STSFX final tailings compared to those stored within the existing TSFs);
- An underdrainage system beneath the hydrocycloned sand embankment to collect construction water from the hydraulically placed sand and emergent foundation seepage upstream of the embankment toe;
- A continuous 1 to 10 m deep perimeter diversion drain beyond the downstream toe that will collect shallow foundation seepage;
- Reclaim ponds (plus the Return Water Pond) downstream of the STSFX embankment that will capture runoff and emergent seepage.
- Maintaining a central decant pond within the STSFX (reduces gradients near the embankment crest).
- Rehabilitation and closure design forms a key part of creating a safe and sustainable landform post-mining. A detailed rehabilitation strategy will be developed for the CCOP.
- Long-term monitoring and maintenance:
- Instrumentation: installing monitoring equipment to track the dam’s performance over time, including measuring stress, strain, seepage, and other critical parameters.
- Regular inspections: conducting periodic inspections to identify and address any issues early.
- Adaptive management: adjusting management practices based on monitoring data and new insights.
- Case studies and historical data
- The STSFX design has taken into account the latest research and technological advances into the hydrocyclone dam designs and has been benchmarked against several cyclone sand dams around the globe including those at current Newmont operations.
The design of the sand dam intentionally allows air and water to infiltrate the wall. The wall is permeable to allow the free draining of water from the walls to be collected in drains constructed under the wall. The drains channel the water to a perimeter drain which is collected in a reclaim pond. The water is then pumped back to the process plant for reuse.
The sand dam wall is a free draining wall. It is not a concrete consistency.
As part of the Site and Technology Selection process Cadia considered the use of the voids created by the subsidence zones over both Ridgeway and Cadia East underground mines. While underground mining is still in progress, the safety issues associated with depositing tailings, whether thickened or unthickened over working areas of the mine is unacceptable to Newmont.
The sand is pumped to embankment wall as a slurry. As the sand settles and is compacted in the wall, the water freely drains out of the embankment wall and is captured by the underdrainage system beneath the wall. The drains capture the water and direct this to a perimeter drainage channel which takes the water to the reclaim ponds from where it is pumped back to the process plant for reuse.
Newmont will prioritise the control of dust. Meeting the obligations laid out in CCOP is vital to us as a business and vital to the community. Reducing production would form part of a range of responses to meet that commitment and will occur if required.
Cadia tests water to assess for environmental contaminants that could be of concern above certain site-specific guideline values such as pH, electrical conductivity (i.e. salinity) and also for heavy metals.
There have been some studies undertaken into alternate uses for tailings including a University of Queensland study that did some early investigation into the use of tailings in the manufacture of bricks. Cadia will continue to investigate further developments on alternate uses for tailings in the future.
We understand that this is an important topic for the community and nearby landholders. The risk assessment requires a number of other studies to be completed. We will provide an update on this risk assessment later in 2024.
Newmont is a signatory to the GISTM and is committed to its implementation. Newmont communicates progress towards this standard annually in August. The STSFX is being designed to meet GISTM standards.
The Newmont tailings management website provides background information on GISTM and Newmont’s approach to safe tailings governance. (Newmont Tailings Governance) GISTM requires meaningful engagement on tailings management which, for new/expanding facilities, includes discussing design options and incorporating/considering feedback and concerns into the decision-making process.
The Newmont tailings management website includes details on Newmont’s tailings governance systems and processes. This can be found here. The Accountable Executive in Newmont is the Chief Technology Officer.
Cadia uses appropriate experts for its facility designs. These designers have the appropriate qualifications and experience to lead the design of the facilities. Newmont also utilises an independent tailings review board composed of subject matter experts to assist in providing appropriate technical governance as part of the wider governance processes for tailings facilities. The Engineer of Record will prepare and approve the final design prior to construction commencing.
Newmont has a site-specific responsible tailings facility person on each site, supported by enterprise level subject matter experts, operational teams and an independent technical review board.
A detailed geochemical assessment is being undertaken for the both the proposed coarse tailings and fine tailings streams that are produced for the cyclone sands dam. The preliminary results of the assessment indicate that the tailings and sand is non-acid forming (NAF) and is currently being independently reviewed. The results of this work will be presented in future EIS Technical Q&A forums.
We understand the request, it’s been six years since the slump, getting it right is taking more time than we had anticipated. The design of the repair needs careful and diligent work as well as independent oversight from experts. The designs for the NTSF Western and Eastern walls have been completed and these areas have also had their embankment buttressing work completed. An update on the remainder of the NTSF wall repair will be provided to community as soon as it is complete.
Environmental Impact Statement
The current Environmental Management Plans can be downloaded from the Environmental Management page on the Cadia website www.cadiavalley.com.au
On a corporate level, Newmont reports environmental performance annually through Newcrest’s Sustainability Report. At Cadia, we provide an annual summary of our site’s environmental performance through the development of an Annual Review.
The CCOP EIS will provide an updated assessment of the impacts associated with the proposed extension of life of the operation and of the associated infrastructure such as the extension to the Southern Tailings Storage Facility Extension (STSFX), Southern Water Storage Dam, realignment of local roads and increased mining activity in Ridgeway Mine and Cadia East.
The update assessments will include:
- CCOP EIS | Air Quality Impact Assessment
- Assessment of Commonwealth Matters Report
- Cadia LOMT | EIS | Wind Tunnel Analysis
- CCOP EIS | Peer Review of Hydrogeological Conceptual Model Review and Update’
- CCOP EIS | Aboriginal Cultural Heritage Assessment
- Aboriginal Cultural Heritage Assessment
- Air Quality Impact Assessment
- Aquatic Ecology Assessment Report
- Biodiversity Assessment Report
- Bushfire Assessment
- Economic Impact Assessment
- Flood Study and Risk Assessment
- Greenhouse Gas Assessment
- Groundwater Impact Assessment
- Hazard Assessment
- Human Health Risk Assessment
- Land and Agriculture Impact Assessment
- Landscape and Visual Impact Assessment
- Noise and Vibration Impact Assessment
- Rehabilitation Strategy
- Social Impact Assessment
- Surface Water Impact Assessment
- Tailings Geochemistry Assessment
- Traffic and Transport Impact Assessment
Cadia is investigating options for permanent noise monitoring locations and have signalled Newmont’s intention to adopt noise monitoring in Cadia’s submission into the EPA’s Environment Protection Licence review. Currently long-term noise monitoring is being undertaken at locations close to the TSF in relation to the TSF construction works to the east and west of the operation.
A full noise impact assessment will be conducted as part of the EIS. A number of changes have already been made to the project following feedback from community. The hydrocyclones that separate the tailings into coarse sand for construction of the sand embankment wall and the fine tailings that is stored are now proposed to be located at the main process plant following community feedback and assessment by the engineering team. This reduces the noise impacts to the community.
CCOP continues to work on the project details to minimise impacts on biodiversity and agricultural land where possible. Detailed land and biodiversity impacts will be included in the impact assessments for the EIS and the outcomes of these assessments will be shared in future Technical Q&A Forums.
As part of the EIS an Aquatic Ecology Assessment will be undertaken which includes taken a number of samples from the bores on site. This assessment is still in progress and the findings will be shared with community at a future Technical Q&A Forum prior to submission of the EIS.
A detailed Noise Impact Assessment will undertaken for CCOP and a mitigation plandeveloped. Cadia is not seeking any increase in noise limits above our current approvals. The outcomes of the impact assessments will be shared with the community before the EIS is submitted.
Cadia will be preparing a Noise Impact Assessment as part of the preparation of the EIS for the project. This assessment is still in progress and the outcomes of the assessment will include recommendations for mitigation and management measures for affected properties. Once the results of the assessments are known Cadia will engage with potentially affected properties to explore measures to mitigate any impacts.
Cadia is committed to maintaining air quality within the required limits of 50 micrograms per cubic meter of Particulate Matter (PM) 10 and 25 micrograms per cubic meter of PM2.5 for any 24-hour period to assist in minimising the impact that our activities could have on the local community and the environment.
To maintain openness and transparency, we have launched a dedicated real-time monitoring page to display air quality levels around the clock at four strategic locations on and around our site. To view real-time data displayed from Cadia’s monitors, click here Live air quality monitoring.
The NSW Government also reports air quality data from various monitoring stations across the state, including monitors located at Errowanbang, Forest Reefs and Millthorpe. To view real-time data displayed from NSW EPA monitors, click here Air Quality NSW
The Air Quality Impact assessment being conducted considers all available baseline data across the project area and data available from Cadia monitoring sites as well as EPA monitoring sites.
The assessment will also include the improvements made by Cadia over the last 12 months including:
- Installation of a $14 million centre pivot irrigation system on the Northern Tailings Storage Facility;
- Installation of additional dust extraction units;
- Additional monitoring of vent rise emissions;
- Installation of additional dust sampling instrumentation in the underground mine.
Cadia is committed to maintaining air quality within the required limits of 50 micrograms per cubic meter of Particulate Matter (PM) 10 and 25 micrograms per cubic meter of PM2.5 for any 24-hour period to assist in minimising the impact that our activities could have on the local community and the environment.
To maintain openness and transparency, we have launched a dedicated real-time monitoring page to display air quality levels around the clock at four strategic locations on and around our site. To view real-time data displayed from Cadia’s monitors, click here Live air quality monitoring.
The NSW Government also reports air quality data from various monitoring stations across the state, including monitors located at Errowanbang, Forest Reefs and Millthorpe.
A noise and vibration impact assessment will be conducted as part of the preparation of the EIS. Cadia is not seeking any increase in vibration limits above our current approvals. Once the outcomes of this assessment are complete the findings will be shared with the community at a future EIS Technical Q&A Forum.
A detailed Historic Heritage assessment is being conducted as part of the Environmental Impact Statement (EIS) preparation and will include how the project proposes to mitigate impact to identified heritage sites. When this is available we would welcome comments on how it could be improved based on local heritage knowledge.
CCOP will prepare the Historical Heritage Assessment report to identify important sites including structures. A Noise and Vibration Assessment will also review potential impacts to surrounding properties and structures.
The preliminary findings from the Historical Heritage studies and the Noise and Vibration Assessment will be shared with the community at an EIS Technical Q&A Forum. The final investigations from these studies will be shared with the community as part of the preparation of the EIS phase of the Project.
The Historical Heritage Assessment will seek to identify potential impacts. If required Cadia will strengthen or otherwise modify existing structures at its expense to withstand any adverse impacts from vibration caused by Cadia.
The CCOP team has undertaken two rounds of field investigations with Registered Aboriginal Parties (RAPs) and has prepared a draft of the Aboriginal Cultural Heritage Assessment Report (ACHAR), which has been shared with the RAPs.
A culturally sensitive summary outlining the study methodology, approach and preliminary findings of the investigations will be shared with the community at the EIS Technical Q&A Forum. Newmont will also conduct a Cultural Values Assessment in the coming months and will finalise the ACHAR once all feedback has been received from the RAPs.
The Human Health Risk Assessment (HHRA) is one of the final assessments that will be completed as part of the EIS. This is because the HHRA requires outputs from a number of different studies including noise, air quality, surface water and ground water, aquatic ecology and geochemical assessments.
As these studies are still in progress the HHRA will be undertaken once the outputs from these assessments have been completed. We anticipate the HHRA will be finalised in October 2024.
A visual impact assessment is a requirement of the EIS submission and CCOP is currently undertaking a Visual Impact Assessment for the project. In addition to this we have shared with nearby neighbours montages of the project from individual private properties and will continue to work with neighbours to address the visual aspects of the project.
As part of the preparation of the EIS, Cadia is required to undertake a Visual Impact Assessment (VIA). The outcomes of the VIA will be shared with the community ahead of the exhibition of the EIS. Preliminary observations indicate minimal additional impacts from night-time lights from the operation over and above those being currently experienced.
Air quality
This is something that has come up in discussions with the community to date. We will need to look into whether it could be implemented as a successful, or feasible measure.
Yes. We do a calibration exercise to understand the existing measures being implemented. We simulate the existing conditions and test the modelling and the measurements. We seek to understand what has been measured and what is modelled to make sure it is doing the right things at the right times. We do make assumptions to calibrate the model including the effectiveness of management measures.
There are typically two groups of mitigation measures: standard measures (things that happen every day i.e. water carts) and routinely included in the models. The other group are reactive control measures. These measures can be simulated by modelling however, for conservatism, we generally don’t include these in base models in order to assess outcomes without them. Reactive control measures can subsequently be modelled, as required, to test the effectiveness of these controls.
We haven't looked at all of that information but we will look into the effectiveness of measures that have been implemented in the past.
We do act in an auditing role on some mine sites. We are currently undertaking the assessment for the CCOP rather than acting in an advisory role. It's common that a project evolves over time because it needs to meet environmental standards in order to demonstrate that it can reach environmental standards. This also involves advising of any necessary changes to the project.
A plan is important, but I wouldn’t consider a plan to be a mitigation.
A key part of the assessment process is looking at the whole life of the project and identifying scenarios that will form part of the assessment. One of the main scenarios is to look at a worst case and also representative cases. The Secretary’s Environmental Assessment Requirements (SEARs) calls for construction and operational scenarios. We will assess whether modelling final stages is going to be a helpful exercise but generally when there is more rehabilitation occurring, you would expect the dust risk to be lower.
We look at long term records in terms of spatial distribution and time distribution. There is also a test in the assessment process which determines if the project is causing an exceedance, as without any operation in place, there will be exceedances from time to time. We aim to understand if the project is causing an exceedance and consider these in relation to the weather event.
Airen will be looking into this as part of the Air Quality assessment. Meteorological conditions are important for driving what happens at a particular monitoring location and what is in the dust. We will need to undertake those investigations to characterise all the different scenarios at different locations.
(Newmont response)
Part of this process, in collaboration with the air quality specialist, is to determine where to put some additional monitors. We anticipate there will need to be more monitors. When the results some back, if more monitors are needed, we will work with community to discuss the most effective location for additional monitors. Key considerations for the placement of additional monitors include the proposed extension of the Southern Tailings Storage Facility, changes to climatic conditions and taking into account the operations of the mine that have changed and will continue to change over time. Part of Cadia’s submission for a new Environmental Protection Licence, included proposing additional locations for air quality monitors. That EPL is still being considered and we are waiting to receive that. But regardless of the EPL outcomes the Air Quality assessment will likely make more recommendations of where we need monitoring and this report will be shared with community as part of the Environmental Impact Statement public exhibition and in future technical forums.
(Specialist response)
Part of the process is to work out where to put those additional monitors. We welcome feedback and suggestions from the community on potential suitable locations.
Yes, a key part of the assessment is to determine the suitability of the current air quality monitoring network and suggest any necessary changes to this network, both to meet the proposed changes to assets and operations as part of the CCOP and adequately monitor any changes to air quality as a result of the changes to operations proposed under the CCOP project.
(Question on notice – Newmont response)
Yes, Cadia is aware that the monthly air quality monitoring reports were stopped in May 2023. All data is available in a couple of formats – either via the live air quality monitoring page available on the Cadia website : Live Air Quality Monitoring | Cadia Valley Operations | Newmont, or all PM10 and PM2.5 data for the whole year is provided on the website in the EPL reporting. The first option is available in a graph, while the second option is available in a spreadsheet. EPL Monitoring Data | Cadia Valley Operations | Newmont. If you would like any further format, or assistance in interpreting the data, please reach out to the Social Performance team on 1800 063 943.
(Newmont response)
As part of our planning application for the CCOP, Newmont Cadia is required to provide a rehabilitation plan. This includes a schedule for when this will likely take place, which is predicted to be some time in early 2030. This is because the NTSF will be needed until late 2020, as outlined in the Modification 15 plan. As soon as the NTSF is retired from being a tailings dam, Newmont will start the rehabilitation process.
(Newmont response)
The CCOP project team will work in close collaboration with Airen, the technical specialists completing the Air quality assessment, to advise the timing for rehabilitating the NTSF. This information will be added to the air quality monitoring model, which will also take into account the potential noise and dust impacts that are associated with rehabilitating the NTSF site and the reduction in dust when the work is complete. We will tell Shane Lakmaker, the air quality assessment specialist, when we are planning to do the rehabilitation and then he will change his model. We have to account for the noise and the dust that's created as we do it. But then once it becomes rehabilitated, it lowers our dust content and that's put in the model as well.
Groundwater
he question relates to a section in the Scoping Report (6.2.3 Water Resources – Groundwater). We agree that this section is difficult to interpret and we apologise for that confusion. Cadia has checked the data we are using for groundwater models and there are some minor variances. However, as we have added bores this year the data gathering process is using a slight increase in bores against that stated in the Scoping Report. A more fulsome explanation of the bores is listed here:
There are a total of 237 bores that have been drilled at Cadia.
Currently 160 of those remain active.
The remaining 77 bores have been decommissioned or abandoned over time due to various reasons such as:
growth of the cave subsidence zones impacting the bores
bores being covered as tailings areas have expanded
bores that have been replaced with new bores or where bores have been abandoned as they no longer provide useful data
Data from inactive bores will be used until the time they were decommissioned/abandoned.
Of the 160 currently active bores:
ALL are monitored for water level
79 quarterly
28 bi-monthly (effectively 107 quarterly for comparison to the scoping report); and
53 monthly.
115 of the bores are monitored for quality
19 annually,
7 six-monthly,
47 quarterly
28 bi-monthly (effectively 75 quarterly for comparison to the scoping report); and
14 monthly.
(Question on notice - Newmont response)
Cadia’s environmental data was not published annually prior to the Cadia East approval in 2010. Annual publishing of this data commenced at this time and included historical data in the appendices. All prior historical data used for the Cadia East Environmental Impact Statement was published and is available either via the Cadia website or the NSW Department of Planning, Housing and Infrastructure PHI website. Similarly, pre-mining data was published prior to the commencement of Cadia Hill.
Links to this data are below
Cadia East EIS Surface Water Assessment
Cadia East project approval | Cadia Valley Operations | Newmont
Historical Data in Attachment FA
Cadia East EIS Groundwater Assessment
Cadia East project approval | Cadia Valley Operations | Newmont
AMER 2011 Groundwater Assessment
Appendix B groundwater graphs for life of bores
Cadia Hill EIS 1996
Vol 3 Appendix I is Water Quality with pre-mining water data
In this case, we have a lot of data. Our models are calibrated to represent past behaviours of groundwater levels, and quality. We have separate models to forecast. We also define the boundary conditions that allow groundwater and surface water interaction to assess if any base flows could be affected at rivers and creeks.
Yes - the data we have seen includes alkaline bores. We use all relevant data to complete the assessment.
Yes, that is part of the assessment. We need to compile all the information and build the conceptual model. We also conduct a number of analytical calculations to make sure that whatever the numerical model is giving us has physical sense. The risk assessment is a part of the Ground Water Impact Assessment. WIA.
Yes, there are a number of measures that could be undertaken. You can pump water out, treat it and discharge back into the system. Any water treatment plant would need to be specifically designed to suit the specific scope and requirements the scope of a project. There are other measures that can be taken, for instance hydro or geochemical barriers, which consists of trenches filled with reactive material that allows water to change its quality once it gets in touch with those barriers. The water quality at Cadia is variable already partly because it’s flowing through different types of rock and reacts as it naturally flows through it. This explains different water qualities throughout the site.
I understand quite a bit about hydrocyclone sands. If the site is properly designed, it is a safe technique. I have worked in seismic areas where there are high risks of collapse (i.e. Chile) and they have been deemed safe.
We seek to understand the work that has been done, but that doesn’t mean we agree with this work. We don’t replicate what someone did in the past. We start from scratch using raw data and build new models.
We have an internal reviewer who reviews at different steps along the way. This specialist is based in the United State United State and has a PhD in groundwater studies. There is also an independent third party Peer Review of the assessment.
An uncertainty analysis is considered within the assessment process - where we don’t know exacts, the model plays with hydraulic parameters to allow for other combinations of parameters that might produce different but still probable results. This analysis will be included in the Ground Water Impact Assessment.
If our modelling and our predictions say that there is something else that that might be needed, we will propose more measures to be considered in our assessment for CCOP.
(Newmont response)
Our expert reports are saying that any contamination is highly localised and not spreading offsite. We need to go through that with the expert and help the community answer those questions to interpret that data. If there is a spread, obviously we will act. The models will tell us whether or not the mitigation measures we have for the new dams are appropriate to control groundwater impacts. Cadia will not be proposing something that spreads groundwater contamination.
The Project will use liners and a permeability materials. The embankment will also consider a number of measures to capture seepage. Several additional monitoring points are being considered to understand what is happening and to be able to react in time.
We start with a baseline that allows us to understand the water quality and general condition pre mining, and the evolution through time as mining has progressed. Any predicted changes will be compared to pre mining and current conditions.
The 30 years of data we have to date suggests that there are a couple of bores you could say might be impacted with tailings seepage. This hasn't gone any further basically because of the geology. What we have at Cadia is what we call in geotechnology a very competent rock mass, which means very low permeability. The rock has little capacity to transmit water and that's supported by several hydraulic tests that have been done in many areas around the site and that also support a low fractured rock. The small fractures and natural conditions that that we see in Cadia explain why whatever is seeping through the tailings is being contained. There are a number of strategies in place to mitigate the risk of groundwater contamination, including using liners, collector drains, and finger drains installed below the embankment. I believe the most important one is having enough monitoring points, because with those observation points we can understand what's going on and make the right decisions.
We have included these in our models to see if they are to be conductors of groundwater.
The fault lines act as barriers. We have not seen any information that suggests that those are open faults or fracture faults that would allow flow through them, but they're acting as barriers to flow. We have steep hydraulic gradients which suggest faults are containing groundwater flow for a long time in these different compartments, slowing down movement.
We're making sure that we are simulating our models for a long enough time. Because of the very, very low permeability and very low hydraulic conductivity, water travels slowly. Our model will simulate up until 2500.
(Newmont response)
With our bores, we have what’s called trigger action response plans. If groundwater chemistry goes outside of range, then there are certain actions that we take and they’re documented and they’re visible to the EPA as well.
Surface water
The design is not yet finalised, but a sand embankment is planned to confine the tailings. From a surface water perspective, there is more than just the sand embankment and the “sand” isn’t beach sand - it's coarse tailings being separated out. The embankment would be built from that. Surface water would be managed through a series of reclaim dams and drains around the edge of the sand embankment to prevent surface water from going into Cadiangullong Creek and Rodds Creek. The reclaim dams are being engineered to a high standard.
The Surface Water Impact Assessment (SWIA) will address this. My understanding is that they will be lined and sized to capture a large rainfall event. There will also be some very large pumps to reclaim the water, pump it back to a return water pond, which is situated further to the north. This will be documented in the SWIA.
I will take that on notice and address this in the follow up preliminary findings session later this year.
This is certainly something we will address in the assessment. We're looking very closely at that and it's the purpose of the water balance model for the site, to understand how much water Cadia will need to source (and from where) and supply water for the operation both in dry and wet times. Then we will look at licencing implications.
We have secured government water modelling of the Belubula River system. This is the model the government uses to set available water allocations from the river. We are using this to model what Cadia will take out of that and how much is left behind. Your concerns such as these will be directly addressed in our Surface Water Impact Assessment. We are modelling the full range of weather conditions for the last 130+ years including drought and high rainfall periods.
We can modify our model to allow for Regis consumption. We have access to the model and can modify it if we need to. This can and will be considered in the cumulative impact assessment. Part of the scope of the work and part of the Secretary's Environmental Impact Assessment (SEARS) requirements is to look at cumulative impacts.
The surface and groundwater specialists are in contact with one another to make sure something like that doesn’t slip through the cracks. We incorporate groundwater forecasts and how surface and groundwater interact within the Surface Water Impact Assessment. Umwelt also has a dedicated resource ensuring groundwater and surface water are integrated.
Part of CCOP is the south water storage facility to provide a drought proofing reservoir. That's part of the project proposal, to tide Cadia through dry times. There are plans for reducing water consumption, and we are aware that the hydrocyclone sands process produces an excess of water, so improves water recycling.
We compare back to the baseline data period when there were no operations, around 1994-95, as well as considering standards such as the Australian and New Zealand Water Quality Guidelines 2018 (https://www.waterquality.gov.au/anz-guidelines). Cadia's water management system also has site specific trigger values for water quality developed from a long period of monitoring. This will all be included in the Surface Water Impact Assessment and water management plans.
Yes, we have both. Not all data goes back to 1994, but there is a subset that does go back that far, and we will be using that data. Water quality data will be shown as graphs over time in an appendix to our report.
Cadia does do that right now in that there are control releases from the existing Cadiangullong Creek Dam to sustain water flows downstream. You will see in our assessment that's demonstrated by the stream flow monitoring, which occurs downstream as far as at the southern end of Cadia’s lease. That flow is sustained in the Creek even through dry periods and that's planned to continue. Similarly with Flyers Creek, there's no extraction of water from Flyers Creek unless the minimum flow threshold for environmental flows is exceeded.
Yes, it will be as a part of the Environmental Impact Statement, undertaken by a different consultant.
Yes, environmental flows will continue to be released so that we sustain flows in downstream Cadiangullong Creek, which flows into the Belubula River. The assessment will show what the potential impacts on streamflow are.
The water balance is highly complex. We've undertaken a recent update of the water balance calibration. We make sure we're representing the water management system as accurately as possible. No model is 100% accurate. It's the degree of inaccuracy we are trying to minimise. Calibration involves collecting data from all around the site to mimic what has occurred during the Cadia operations phase to date with our model. Then we can replicate what's happening as accurately as possible, so our forecasts can be as accurate as possible. It's not simple but we're not far from completing that work.
We use the most recently available guidelines. These Australian guidelines are available online at https://www.waterquality.gov.au/anz-guidelines. This will tell you the default guideline trigger values. Importantly, these have been developed using data from across the country and that’s why the baseline data is important for this project. It means we can compare to the water in the area before operations began and also at locations that are upstream of Cadia.
We are required by Secretary’s Environmental Assessment Requirements (SEARs) to look at cumulative impacts and this will be done in the Surface Water Impact Assessment.
Traffic and Transport
(Newmont response)
As part of the CCOP, a section of Cadia Road is required to be moved. If the CCOP is approved, it is likely this will occur later this decade as originally forecast in the Cadia East Environmental Impact Statement from 2009. The realignment of a section of Cadia Road is however likely to be further east than outlined in 2009. This is to adequately accommodate the proposed Cadia East subsidence zone.
(Newmont response)
As part of the CCOP, Newmont Cadia would be required to move the powerline at our cost. Newmont Cadia would work with the Owner of Flyers Creek and near neighbours regarding the potential relocation of transmission lines and any potential impacts during construction.
As part of the Noise Impact Assessment for the CCOP Environmental Impact Statement, Independent Specialists are undertaking studies to assess the potential noise impacts of the Project. These noise assessments are in line with government policies and guidelines that outline the acceptable noise levels for a project in construction and operation and outline the potential impact of noise on nearby residents. The assessment also considers the likely potential noise impacts if there are changes to the existing environment, such as the removal of trees, and how potential impacts can be carefully managed and, where possible mitigated. This would include a review of Newmont Cadia’s long term rehabilitation requirements and any additional visual screening to mitigate impacts to affected residents as much as possible.
(Newmont response)
The current approvals allow for a realignment of Cadia Road due to subsidence, however this is yet to take place. With CCOP extending the life of the mine, the cave subsidence has been remodelled and it is anticipated a realignment of a section of Cadia Road near the Cadia East Underground Mine site would be required. The concept design for the Cadia Road realignment is currently being finalised, however, it is anticipated the design would be a bit further to the east to what was predicted at the time of Cadia East approval.
(Newmont response)
The realignment is approximately 500m further east from its current location and 200-300 metres from the previously proposed location (as part of the Cadia East approval).
(Question on notice)
Yes, we have considered the roads around and leading into Cadia including Cadia Road, Errowanbang Road, Panuara Road, Forest Reefs Road, Four Mile Creek Road, Millthorpe Road, Orchard Road and Woodville Road. There is a table in the Traffic and Transport Assessment which will be released to the public at the time of the Environmental Impact Statement that will include information on each road studied and the types of road data used to inform the assessment.
(Newmont response)
The Traffic and Transport Assessment is designed to assess traffic volumes and impacts to roads. Cadia has mechanisms in place to promote appropriate employee and contractor behaviour in line with our values. However, it is fair to say that because it is offsite, (driver) behaviour can be difficult for us to enforce. We welcome any feedback where we can identify poor driver behaviour and help correct it. Cadia has, as part of its site planning, introduced the use of buses to reduce the number of vehicles travelling to and from the site and will launch a driver awareness campaign before the end of the year.
(Newmont response)
We have informed the bus company to make sure that they understand their expectations. We welcome calls on the community line, 1800 063 043. Knowing the identity of the vehicle and/or driver will assist us to manage poor driver behaviour.
The detailed design hasn’t been finalised, however, it will be shared with the community in the near future, as part of the preparation of the Environmental Impact Statement. As part of the preliminary findings from the Traffic and Transport Assessment, it is predicted the proposed realignment of a section of Panuara Road would increase travel time between Four Mile Creek Road and Errowanbang Road by about 1.5 minutes. This will be refined as the detailed design progresses and shared as part of the public exhibition of the Environmental Impact Statement.
Yes. The Traffic and Transport Assessment has shown that, in the long term, there would be no significant change in traffic volumes above current levels and the draft conclusion of the study is that the roads are adequate for the demand.
We've assessed both the conditions now, and in the future with CCOP and what we're finding is that in terms of mid-block capacity, the “worst” sections of road during the Cadia peak hours are at level of service C and will continue at level of service C. As far as the intersections go, they were at level of service A and they've been modelled in a traffic modelling software, and its level of service is A.
(Post meeting note)
Levels of Service definitions are used to translate numerical performance measures (speed and travel time, delay, density, freedom to manoeuvre, traffic interruptions, safety) into a simple stratified system relating to road users’ perceptions of travel of the road. There are six levels of service, A through F, with A representing the best operating conditions from the users’ perspective (free flow) and F being the worst (flow breakdown, unsatisfactory). At Level of Service C, vehicles have a higher tendency to travel in groups, as there may not be opportunities for drivers to overtake or travel at their desired speed.
It is an important distinction that it's not the condition of the road in terms of things like potholes. Through negotiated Voluntary Planning Agreements with Blayney, Cabonne and Orange Shire Councils, Newmont Cadia provides financial contributions, some of which go towards public road maintenance to mitigate the impact of heavy vehicles and other road users travelling to and from the mine site.
There are two types of survey instruments. The first type is where we have the automatic tube counters, and we usually get a week or two of data out of that. Those tubes measure both speed and vehicle type. There's special software that can then work out what size vehicles are using those roads as well. This is called a classified count. The second type of data that we collect is intersection counts. It's usually done with a camera. We put the camera up and analyse the video and count how many cars are going through the intersection, so we know who's turning left, who's turning right and who's going straight through.
Yes, the survey used cameras at all the intersections in the survey. The cameras were removed after the surveys were completed.
The survey data was collected in March 2022, and surveys were conducted in consultation with Cadia regarding their operating conditions at that time. The surveys were delayed until operating conditions at Cadia were considered typical, with workers instructed to be back on-site. At the time the surveys were conducted, no travel restrictions were in place.
Crash data comes from police records. We don’t have a method of collecting near misses, but when there is a crash and it's reported, that's when it goes into the data.
(Newmont response)
The latest traffic surveys were undertaken in March 2022 which was prior to the Cadia Road closure due to Vent Rise 14 which was from July to December of 2022.
We don’t believe that traffic patterns will change as a result of the realignment of sections of Cadia and Panuara roads. During construction we anticipate that the road realignments will be constructed in parallel to the existing roads, to minimise impacts to all road users. A Construction Traffic Management Plan will be prepared to mitigate the impacts of any temporary lane closures to ensure the safety of residents and efficiency of the road network.
(Newmont response)
The intent is not to close the roads. We would anticipate that there will be a few days of interruption when the old and new roads are connected and at that time there will be traffic management but no total closure. Once completed the old section of road will cease to be used and road users will start using the new sections of the realigned roads. Newmont Cadia would notify the local community prior to any road construction work and would provide regular updates as the work progresses.
Any upgrades to road designs such as the intersection of Panuara Road and Cadia Road, would be done in accordance with the Austroads Guide to Road Design. That would include ensuring appropriate sight lines and, if required, a turning lane.
(Post meeting response)
Traffic data was obtained from Cabonne and Blayney Councils and reviewed as part of the study, however the data related to periods when operating conditions at Cadia remained atypical due to Covid restrictions. The survey program was developed to capture traffic conditions at all locations at a consistent time, at which Cadia’s operating conditions are known and typical.
Human Health
The modelling that is being conducted and the reports that we draw upon for our data, are modelled for residential exposure up to a period of 29 years, which is stated in the Environmental Health Risk Assessment – Guidelines for assessing human health risks from environmental health. In Australia we accept that's the average period of time that someone will reside in a single residence. That's not always fit-for-purpose. There is a sensitivity assessment that we do as well, which considers non-standard exposures such as whether somebody has a beef farm and they live purely on their own beef cattle. It can consider people living in residences for longer than 29 years if that's applicable in this community.
From the Air Quality Impact Assessment, we receive an excel file which includes raw data from their model that has every receptor location with an Northing and Easting co-ordinate. It has every single compound that they've modelled, and it has results in micrograms per metres cubed, which is an air concentration. They also have a separate sheet which is a deposition rate, which is how far a compound might move on a particulate and that's how we estimate what might fall onto soil. We also take into account the baseline sampling that's been conducted by the Environmental Protection Authority in NSW.
Meetings have been held with the air quality impact assessment specialists (Airen Consulting) to discuss what is needed to inform the Human Health Impact Assessment studies as well as confirming the compounds in the Secretary’s Environmental Assessment Requirements. We also talked about dam locations and residential property locations.
The ABS data we are looking at has been updated since last year. It's a new lot of data compared to what was previously published. We are also considering the exposures to silica and will have more detailed breakdown of disease. We are looking at respiratory in particular in terms of the baseline community exposures from hospital admissions. We are considering a bigger range than we did in the previous assessment (as part of the Human Health Risk Assessment).
The assessment can't be undertaken on an individual basis. That's not the aim of a health impact assessment. The report is designed to look at human health for the average population. We appreciate there is a wide range of ways people interact with the environment, which is why we are really interested to hear about how you interact with the environment. This is why in the previous study we asked about home grown produce and the way that the conceptual site model is showing how people are exposed from the mine.
We haven't started the process to do the CCOP health impact assessment so I can't comment on what the outcomes will be. When we receive all the studies in the next few months that will then take place. However, there has to be an average base case for a 'typical' resident who lives near the mine, and then a sensitivity assessment which will consider higher than average exposures to certain things such as somebody who has their own chickens and they're eating their own home grown eggs the whole time.
We are more than happy to consider the report rather than the raw data to understand methodology, limitations etc. We are willing and open to receive any information. We prefer to receive it in a report. It's very difficult to receive results in the lab form when we're not understanding how they were collected, the base, quality control. If you are able to share the report via Cadia, we can consider it in our studies.
(Post meeting note: Dr Ian Wright’s study was provided and passed on to Sage Environmental Services for consideration).
Sage is committed to producing independent reports. As we did last time, we were willing to publish a report that showed there was elevated results and risks. Another thing that the Human Health Impact Assessment requires us to do, for the qualitative studies, is to look at the effects to community both positive and negative from the CCOP. That's something we'll be doing in a transparent matter. We go through the report, we then propose mitigation or suggested improvements along with the technical experts of those studies, ways in which it can be turned into neutral or positive outcome for the project. We are looking at the statistical data. We will be comparing the existing community health demographic data to Orange and to the NSW average.
Yes, it's a requirement of the work.
There are no individual case studies done. Any assessment done in NSW, or in Australia, has to be undertaken using a typical resident. It needs to be done in a demonstrated manner in accordance with the frameworks. Those frameworks are set up in the SEARs to meet the Department of Planning requirements to specifically to address assessment of human health impacts to community.
Cumulative impacts are interpreted in a number of different ways. One of these is to look the industries operating concurrently, such as agriculture, forestry and other mines. These industries are added to air quality models, for example, because you cannot just model the mine by itself to understand the potential cumulative effects. Another is to look at potential cumulative impacts on human health through lifestyle factors such back yard soil for growing foods, having chickens and cows, water sources into dams.
Our model will look at the soil conditions in the community before expansion is undertaken. We have some geological information for the area, which we will use. We also have the NSW EPA soil data. We recently had to look at geological soil concentrations for metals and when the NSW EPA data came out, the results were very similar. They married up for the assessment of a baseline. In terms of time, the baseline does not look back to the beginning of mine operations. It starts from now – or most recent studies of air quality, soil quality, etc, ie 2022/ 2023 – and looks at potential cumulative impacts based on what the CCOP is proposing.
No, we will not be considering the mine progress from the first day of operations until now. There is no information available to undertake that kind of study and that is typically not how assessments are done in terms of health impact. Cumulative impacts are taken into consideration by assessing the current status of the environment within and surrounding the mining operation. The future cumulative impacts are then assessed through modelling.
No, we don’t compare other non–mining areas. As we mentioned, the Human Health Impact Assessment is meant to clearly demonstrate what is happening here now, at Cadia and surrounds and any potential impacts with the addition of the CCOP over and above existing mine operations and other existing and proposed industries and activities.
Our assessment has to be done in 2024 based on the current demographics from the community using the latest ABS data. One thing we will look at is the hospital admissions and there'll be an assessment for potential of increases to those types of admissions from the modelled impacts that we get from the air quality impact assessment. Then we do a qualitative assessment for positive/negative impacts to the community wellbeing and health. We will be doing a quantitative assessment of an intake into our body based on the air emissions data from both air and soil and a number of different pathways.
(Newmont response)
In terms of this health assessment, the model takes the current baseline of the air quality from this year and assesses going forward for the 25 to 30 years that are remaining between now and the end of the life of mine extension (CCOP) if approved. Cumulative impacts are taken into consideration by assessing the current status of the environment within and surrounding the mining operation which includes the impacts from Cadia in the past 25 years. The future cumulative impacts are then assessed through modelling.
(Post meeting response from Umwelt)
An assessment of the impacts of the Project on people’s mental health and wellbeing (otherwise known as psychosocial impacts) will be included within the social impact assessment (SIA) as required by the SIA Guideline (DPE, 2023) and also within the SEARs that have been issued for the project. This is also consistent with international SIA practice as documented by the International Impact Assessment Association (IAIA).
These impacts will be further identified, understood and analysed using a combination of social research methods including engagement with community, research into the current community context, review of impacts associated with other project developments in the region and a review of studies on psychosocial impacts of mining projects in Australia. Umwelt will seek to understand wellbeing impacts from the perspective of those affected by the Project and will consider peoples lived and historical experiences and perceptions.