Environmental review document

K+S Group is an international resources company with headquarters in Germany. It is considering the possibility of developing and operating a green field solar salt Project (the proposed Ashburton Salt Project; Proposal) on the Western Australian coast, approximately 40 km south-west of the township of Onslow, within the Shire of Ashburton. The Proponent of the Project is K+S Group's Australian Entity: K plus S Salt Australia Pty Ltd (K+S).

K+S proposes to construct and operate a 4.7 million tonne per annum (Mtpa) solar salt farm.

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K+S has followed the Ministerial Council on Mineral and Petroleum Resources (MCMPR) Principles for Engagement with Communities and Stakeholders (2005) to undertake stakeholder engagement. The principles emphasise open, transparent, two-way, and appropriate communication, inclusiveness, and a cooperative and collaborative approach to seek mutually beneficial outcomes.

Since 2016, K+S has consulted with all stakeholders affected by or interested in the Proposal, including decision-making authorities, state and Commonwealth government agencies, local government authorities, the local community, and environmental non-government organisations.

K+S has maintained regular interactions with Traditional Owners through Buurabalayji Thalanyji Aboriginal Corporation (BTAC) regarding heritage and environmental values. A project agreement with the Thalanyji People was signed in 2023.

Stakeholder consultation activities have included providing information on the Proposal, key environmental studies, and seeking feedback on relevant environmental impacts. Communication methods have included media briefings, meetings, website publications, correspondence, newspaper advertising, and community information days.

All consultation is ongoing.

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The environment has been carefully studied through 28 comprehensive studies. The Proposal has been iteratively re-designed to minimise impacts to the environment, ensuring any proposed disturbance is localised and impacted areas are well-represented regionally..

Important processes have been maintained so that local and regional environmental values are protected. With mitigation measures it is predicted that some significant residual impacts will remain, however offsets are proposed to improve or maintain marine and terrestrial values around the local area, in collaboration with (but in addition to) State Government programs. These offsets are considered to be of an adequate scale to counterbalance the impacts. With the implementation of these offsets, it is considered that the EPA objectives for each relevant Environmental Factor will be met.

In 2020, the Western Australia Minister for Environment requested strategic advice from the EPA on potential cumulative impacts on Exmouth Gulf. The report identified the Gulf as a multi-use area with various pressures across different sectors. No key values were in very poor condition, most were in good or very good condition, however, the EPA acknowledged that key values of the Gulf are likely to degrade without improved management.

K+S considered cumulative pressures on Exmouth Gulf in its assessment and determined that the combined Proposal impacts on marine fauna were significant. K+S re-designed the Proposal to reduce impacts to tidal samphire mudflats habitat, algal mat, and mangrove habitat. Research and management offsets were proposed to counterbalance the remaining impacts.

The Proposal targeted areas of unvegetated supratidal flats to limit vegetation clearing. Cumulative clearing pressures on vegetation in the surrounding area are limited, with over 90% of pre-European extent remaining. The EPA advised that all future salt proposals on the West Pilbara Coast need to assess potential regional and cumulative impacts to habitats.

K+S notes that the EPA considers that the clearing of native vegetation and impacts on other associated environmental values in the Pilbara IBRA bio region is significant where the cumulative impact may reach critical levels if not managed. While the Proposal lies just outside the Pilbara IBRA bioregion, K+S has assessed vegetation loss in a similar manner, with the loss of Good to Excellent vegetation being considered to be a significant residual impact. Offsets are proposed to counterbalance those impacts, targeting the management of weed infestations in the region, in collaboration with State Government programs.

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The environment has been carefully studied through 28 scientific, technical studies, which are appended to the ERD (Table 4). These studies have informed the project design, with the Proposal being iteratively re-designed to minimise impacts to the environment based on the findings.

Proposed disturbance is localised to the project site. Important environmental processes have been maintained and impacts avoided and minimised so that local and regional environmental values are protected. Several management plans are also proposed. These can be read in Appendix BB.

The Proposal meets EPA objectives to ensure residual impacts to the environment are acceptable. Table 5 summarises potential impacts, proposed mitigation and predicted outcomes for all environmental factors relevant to the Proposal.

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To maintain the geophysical processes that shape coastal morphology so that the environmental values of the coast are protected, comprehensive studies were undertaken. These studies align with the EPA’s requirements.

The studies found that the project outcome is not expected to be any significant residual impacts once the closure activities have been implemented.

The proposed infrastructure for the project, including a seawater intake, solar evaporation ponds, crystallizer ponds, and a salt export jetty, has been designed to minimise any direct impacts on coastal processes and morphology. The seawater intake has been positioned on the banks of Urala Creek South, which has a deeper channel than Urala Creek North, to minimise erosion and fluvial morphology impacts due to seawater pumping.

The jetty is designed as a pile support transmissive structure, which means that it does not impede water flows and has minimal effects on local currents. The footprint of the piles is also too small to generate any material impact on the nearshore hydrodynamic or longshore sediment transport conditions in such a low energy environment.

The overall Project is predicted to have minimal impact on tidal inundation due to its position largely on the supratidal salt flats beyond the reach of most tides. At the completion of the proposed project, the site will be rehabilitated to reinstate the existing environment, and all buildings and structures will be removed from the site.

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The Proposal is unlikely to result in significant impacts on the marine environment, however the predicted water quality impacts occur within marine areas that are Biologically Important Areas (BIAs) and/or critical habitat for some marine fauna species. As a result, even localised water quality impacts may contribute to significant residual impacts to BCH and marine fauna.

The Proposal is expected to have localised impacts on the marine environment, primarily through the discharge of bitterns. An ecotoxicology assessment showed that the material is likely to present a very low risk of ecotoxicity in the marine environment outside the bitterns discharge mixing zone. Once the metals within the bitterns plume are diluted to meet the nominated species protection level, they present very low risk of ecotoxicity or bioaccumulation.

Mitigation strategies include the use of a transhipping approach for salt product export, which eliminates the need to dredge a shipping channel to the berth at the jetty, and the discharge of bitterns to the ocean via a specifically designed and aligned diffuser, designed to promote mixing. The alignment of the jetty has been shifted to deeper water to reduce dredging and improve the mixing of bitterns.

Pre-dilution of bitterns will be carried out before discharge through a diffuser designed to optimise dilution and mixing. The dredge spoil will be disposed of on land, and excavated spoil from the seawater intake will be contained in embankments and managed in accordance with the Acid Sulfate Soil and Sediment Management Plan. The diffuser design has been optimised to minimise its impact on the marine environment.

Proposed management plans include a Marine Environmental Quality Monitoring and Management Plan, a Dredging and Sediment Management Plan, a Waste Management Plan, and an Acid Sulfate Soil and Sediment Management Plan.

These mitigation strategies will minimise the impact of the project on the marine environment and ensure its sustainability. While the project could have some impacts on critical habitats for marine fauna species, overall, it is not expected to have significant negative effects on the marine environment.

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The Ashburton Salt Project aims to maintain the biological diversity and ecological integrity of benthic communities and habitats (BCH) by minimising direct and indirect impacts during construction and operation. The project is expected to have minimal impacts on subtidal benthic communities and avoid ecotoxicity risk for biological communities.

The direct impacts are expected to be proportionally small, with a disturbance of approximately 36 ha of intertidal BCH and 2.6 ha of subtidal BCH. The indirect impacts are also predicted to be localised, affecting 5.52 ha of intertidal BCH and 223.77 ha of subtidal BCH.

The cumulative impacts are estimated to be a very small proportion of regional extent, with the development predicted to increase mangrove loss by 0.02%, algal mat loss by 0.06%, and samphire loss by 0.5%.

Even without the project, modelling indicates sea-level rise will cause natural loss of some mangroves and algal mats after about 50 years. However, the project seeks to create ongoing habitat for these species during closure planning, providing protection from sea-level rise behind rock-armoured embankments.

The pond system has been redesigned eight times to minimise its footprint, with alignment of the western boundary moved further east to avoid the direct loss of algal mats and provide a setback from mangrove areas. The area and volume of sediment to be dredged were minimised to reduce impacts to subtidal habitats. Modelling predicts that local plumes of elevated turbidity will not persist for more than a week following the cessation of dredging activity.

The project will obtain and comply with appropriate approvals and implement various plans, including the Introduced Marine Pest Monitoring and Management Plan, the DSMP, and the MEQMMP. Appropriate monitoring measures will be undertaken to minimise residual groundwater impacts to BCH, and an Oil Spill Response Plan will be developed.

At the completion of operations, all buildings and structures will be removed, and the pond areas may be selectively reconnected to the existing tidal flat system. The MCP will establish which embankments to breach, allowing inwards tidal movement to enhance the habitat values of the ponds to BCH and fauna post-closure.

The closure activities of the project are predicted to have very small and indirect disturbances. The effect of sea-level rise will be considered during the closure planning process, however there are not expected to be any significant residual impacts once the closure activities have been implemented.

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K+S has incorporated extensive avoidance and minimisation measures into the Proposal design and operational processes.

The project will focus on the unvegetated Supratidal salt flats to minimise the disturbance footprint, resulting in only a small portion of the total project footprint occurring within marine fauna habitat. However, the project will still result in water quality impacts over 232.2 ha of marine fauna habitat, which is significant for several marine fauna species, particularly when evaluated with other direct and indirect impacts. The residual impacts of the project include the loss of nearshore BCH, mangroves, and tidal creeks, as well as significant fauna behavioural responses and potential injury or death associated with seawater intake, dredging, or vessel strike. Overall, the project has incorporated measures to minimise its impact on the environment, but significant impacts are still predicted. To counterbalance these significant residual impacts, offsets are proposed.

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To avoid significant impact on vegetation and flora, the project has been designed to place most disturbance on supratidal salt flats that are devoid of vegetation and reduced the size of salt ponds to minimise groundwater seepage and salt crust impacts.

No significant flora records are expected to be significantly impacted by the project. The vegetation communities to be disturbed are not considered threatened, with over 90% of their original extent remaining – making it unlikely that the project will impact the biological diversity and ecological integrity of vegetation at a regional scale.

The proposed project will directly disturb around 1,265 ha of vegetation, which is 5% of the study area. 333ha is deemed degraded – poor condition. Offsets are proposed to manage degraded land in the surrounding area to counterbalance the loss of vegetation.

Industry best-practice management measures for flora and vegetation will be implemented, and all appropriate approvals sought. Rehabilitation plans include reinstating the flora and vegetation at the completion of the project, using locally endemic native species to establish a self-sustaining ecosystem with similar biological diversity and ecological integrity. The project will monitor potential changes to tidal inundation regimes and implement appropriate controls to reduce the risk of impact from unintentional brine pipeline spills.

The project is long-term and may not close this century, requiring consideration of altered ocean hydrodynamics and climate change.

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To protect terrestrial fauna so that biological diversity and ecological integrity are maintained, K+S has implemented measures to mitigate its impact on the environment, particularly on fauna habitats.

Direct impact on significant fauna habitats is considered relatively low due to several reasons, such as minimal vehicle traffic between ponds, jetty and coastal corridors, low embankments with shallow walls in concentrator and crystalliser ponds, and the accommodation camp being relatively small.

The project is not expected to attract or increase introduced fauna species, and seepage from the ponds is predicted to be small, with adequate freeboard and overflow features to minimise the risk of unplanned overflows and wall breaches. A hierarchy of waste controls will be adopted and provide new habitat for migratory shorebirds within the ponds. The predicted cumulative impact to significant fauna habitat is proportionally small, representing only 4.27% of such habitat locally and 0.66% regionally.

There will be direct and indirect impacts on habitats for listed fauna species that will be addressed through the Fauna Management Plan (FMP).

Annual migratory shorebird surveys will be conducted, and the usage of concentrator and crystalliser ponds by fauna species will be recorded. K+S will design and construct concentrator and crystalliser ponds that are safe and stable according to DMIRS requirements and will implement appropriate controls to reduce the risk of impact from unintentional brine pipeline spills. At the completion of the project, the site will be rehabilitated to reinstate the terrestrial fauna, and locally endemic native species will be used to establish a self-sustaining ecosystem with similar biological diversity and ecological integrity to that which existed prior to project implementation.

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K+S has implemented appropriate mitigation measures to avoid any significant residual impact on the environment. Potential contaminants such as salt product, bitterns, hydrocarbons, and general site wastes could impact the environment, so approaches have been developed to address and deal with potential scenarios.

K+S is taking the necessary precautions to ensure that the development does not have any significant residual impacts on the environment.

All potential sources of ongoing contamination (bitterns, bitterns pond, crystallisers, salt stockpiles) will be removed and rehabilitated.

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Hydrological assessments indicated the Project will have only minor impacts on local hydrological processes, including surface flow and groundwater systems. Direct disturbance will be only 1.7% of the local catchment and 0.2% of the Ashburton River catchment.

Indirect impacts are primarily related to minor surface water flows, which will be mitigated through infrastructure placement and diversion channels.

Monitoring and management plans will be implemented during the design phase to ensure that impacts remain within modelled predictions. Overall, the direct and indirect impacts on hydrological processes are not significant.

Infrastructure areas have been located outside the flood zone where possible, and flows have been diverted around key infrastructure areas that intersect flow paths. The conveyance of surface water flows under the main access road into the site will be ensured, and surface water flows into downstream receptors will not be impeded. Culvert locations and sizes have been identified to maintain flow connectivity, and drainage diversions have been designed to remove floodwaters from the salt flats and allow flow to the ocean.

Two management plans, a Surface Water Management Plan and a Groundwater Monitoring and Management Plan, will be developed to ensure that measures to minimise impacts to surface water flow have been implemented, and groundwater seepage and mounding impacts are monitored and managed.

After completion, the site will be rehabilitated to reinstate hydrological processes, and structures will be removed. The evaporation ponds will be left in situ to become fauna habitat for shorebirds.

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The Project is not expected to have any direct impact on inland water environmental quality. However, accidental spills or inappropriate waste disposal could disturb ASS and result in spillages of product, brine, waste, or hydrocarbons.

K+S has developed management plans to prevent, mitigate, and remediate such incidents. Appropriate engineering controls will prevent erosion, scouring, or disturbance of sodic and/or dispersive soils, which could cause increased turbidity and sediment loading of surface waters.

Highly conservative modelling predicts a local post-development proportional reduction in nitrogen flows into the Proposal catchment. Tidal inundation modelling show that the alignment of salt pond outer levees is not expected to modify tidal flows, and the tidally moderated salinity levels within shallow groundwater beneath the mangroves are expected to be unaffected.

To minimise the Project footprint, eight iterations of the pond design were undertaken, and the alignment of the western boundary of concentration ponds was moved further east to avoid seepage and salinity-related impacts to mangroves. The proposal is located mostly in the supratidal zone to avoid interference with tidal inundation that moderates shallow groundwater salinity vital for mangroves. The surface water engineering measures were designed to maintain connectivity of the local and regional surface water flow paths to minimise overland nutrient pathways' impact.

After completion, the site will be rehabilitated to reinstate the inland waters' environmental quality, and all buildings and structures will be removed from the site. The management plans will minimise impacts on surface water and groundwater, prevent, mitigate, and remediate incidents that could disturb ASS and result in spillages of product, brine, waste, or hydrocarbons.

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The Project has minor direct and indirect impacts on the social surroundings, and it is unlikely that there will be any significant residual impacts.

The disturbance of areas that may contain Aboriginal heritage sites is proportionally small in the study area, and consultation with the Thalanyji people has occurred to mitigate the impact of potential disturbance. K+S will continue to work with the Thalanyji people to ensure that impacts to Aboriginal Heritage and broader cultural values are minimised during the final design, construction and operation of the Project.

Recreational activities in the wider area are not expected to be impacted given the Project’s limited interface with Exmouth Gulf and relatively low number of vessel movements.

The area of habitat within the seawater intake area of influence is proportionally low compared to the entire nursery habitat of the Exmouth Gulf Prawn Managed Fishery. Jetty construction, bitterns discharge, dredging, underwater sound, artificial lighting, and alteration of nutrient pathways are considered unlikely to significantly impact the prawn fisheries.

Management measures will be in place for noise and dust, and these will be further assessed during the works approval and licensing process under Part IV of the EP Act. The closest site is 8km away, so impact is considered minimal.

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The Project is expected to generate minimal dust and low noise emissions during construction and operation.

During construction, standard dust suppression measures will be implemented to minimise dust emissions, such as using water carts and sprinklers, and applying water or dust suppressant to disturbed areas. The project's remote location, with the nearest sensitive receptor (Urala Homestead) approximately 8 km away, makes it unlikely to have significant dust impacts on the community.

The project's future workforce health and safety issues related to dust inhalation will be assessed and managed via the CEMP and OEMP. During operation, noise emissions will be low due to the solar evaporation process, and minimal night work will be undertaken due to site terrain. The project will comply with EP Act Noise Regulations and will be further assessed by DWER during the works approval and licensing process. The CEMP and OEMP will establish appropriate dust management and monitoring measures and address any potential impacts from naturally occurring heavy minerals.

The Project is not expected to generate any significant air emissions.

The Project aims to minimise its contribution to greenhouse gas emissions. The project relies on solar and wind energy for salt evaporation, and the energy requirements are expected to be minimal. The electricity required will be provided by an offsite natural gas-fired power station, and power lines will be constructed to supply electricity to the project site.

The project will consider the effects of sea-level rise during the closure planning process and may create a "niche" environment for mangroves and algal mats.

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K+S has conducted various environmental surveys and studies to determine the key values that require protection, including significant fauna and flora habitats, areas of cultural value, and marine life. Changes to the proposal design have been made to avoid and minimise significant impacts on these values. K+S has assessed the residual impacts of the proposal against the WA Environmental Offsets Guidelines (2014) and the results are presented in Table 114, summarising the predicted significant residual impacts on environmental values.

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K+S submitted a Referral to the Department of Climate Change, Energy, the Environment and Water (DCCEEW) under EPBC Act (Reference: EPBC 2016/7793) on 7 October 2016. The WA EPA will assess the proposal as an ‘accredited assessment’ on behalf of DCCEEW due to potentially significant factors such as listed threatened species and communities, listed migratory species, and Commonwealth marine areas.

Table 119 in the ERD lists all flora and fauna that are considered Matters of National Environmental significance and may be impacted by the proposal.

Environmental surveys have been conducted to identify values that require protection, including significant fauna and flora habitats, areas of cultural value, and marine life. The residual impacts of the proposal have been assessed against EPBC Offsets Guidelines, and the predicted significant residual impacts on environmental values are summarized in Table 114.

The proposal is separated from the Ningaloo Coast World Heritage Area by significant distances across marine waters and land, and is unlikely to impact the area. The proposal is also unlikely to impact the National Heritage Place, the Ningaloo Coast, and the Ramsar Wetland. Flora and vegetation surveys indicate that no threatened ecological communities are present, and only one potentially vulnerable flora species has been identified. This has been addressed through mitigation measures.

With effective management measures and offsets detailed in Sections 9.7, 10.7, and 11.7, residual impacts on EPBC listed threatened and migratory species from the proposal are expected to be appropriately counterbalanced.

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