Arrival 

Mines and Environment Welcome 

Queensland’s mine rehabilitation expectations are increasingly focused on the design and performance of constructed soil systems, particularly where natural topsoil resources are limited or highly variable.

The Queensland Mine Rehabilitation Commissioner (QMRC) has advanced guidance on manufactured soil blending criteria to improve consistency, functionality and long-term rehabilitation success across mining projects.

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These criteria are shaping how operators design growth media using combinations of topsoil, subsoil and overburden materials to achieve defined physical, chemical and biological performance outcomes. There is growing regulatory emphasis on ensuring that reconstructed soils are not only stable, but capable of supporting self-sustaining ecosystems aligned with post-mining land use objectives under PRCP frameworks.

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This session examines the practical application of QMRC blending criteria in mine rehabilitation design and how they are influencing soil construction approaches across Queensland operations.

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Key Discussion Areas:

• QMRC manufactured soil blending criteria and design intent
• Managing variability in spoil, subsoil and limited topsoil resources
• Engineering functional growth media for long-term plant establishment
• Soil structure, chemistry and biological requirements for rehabilitation success
• Integration of blended soils into PRCP rehabilitation commitments
• Performance monitoring and validation of constructed soil systems

​Queensland’s critical minerals sector is operating under increasingly stringent environmental and rehabilitation conditions, reflecting heightened government focus on long-term land outcomes and environmental accountability. Alongside expanded project development, regulatory settings are placing greater emphasis on rehabilitation assurance, compliance performance and enforceable environmental conditions.

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This is driving closer scrutiny of how rehabilitation commitments are delivered in practice, including the performance of constructed soil systems and their ability to meet approved land use outcomes. Emerging policy direction also signals stronger enforcement mechanisms, including financial penalties linked to non-compliance with rehabilitation and environmental obligations, increasing the importance of defensible design and delivery frameworks.

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This session explores the regulatory and financial implications of Queensland’s evolving critical minerals framework, with a focus on rehabilitation liability, compliance risk and the role of soil system performance in regulatory enforcement outcomes.

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Key Discussion Areas:

• Queensland critical minerals policy direction and rehabilitation expectations
• Strengthening compliance frameworks and enforcement mechanisms
• Financial risk and penalty exposure linked to rehabilitation performance
• Link between soil system performance and regulatory liability outcomes
• PRCP alignment with critical minerals environmental conditions
• Implications for closure planning, assurance and long-term risk management

Plenary Panel, Q & A  

Morning Tea 

High-rainfall mining regions present significant engineering challenges for maintaining stable landforms and controlling erosion during both construction and rehabilitation phases. Intense rainfall events, high runoff velocities and concentrated flow paths can rapidly compromise exposed surfaces if not adequately engineered and managed.

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Within mine closure and rehabilitation environments, erosion control is increasingly being assessed as a performance outcome, requiring robust design, construction quality and verification that landforms can physically withstand storm events without failure or excessive sediment loss.

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This session focuses on the engineering and operational controls required to manage erosion risk and ensure landform stability in high rainfall environments. It examines how design methodologies and construction practices are being applied to reduce erosion failure and improve long-term surface stability.

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Key Discussion Areas:
• Erosion mechanisms in mined and rehabilitated landforms (sheet, rill, gully and mass failure processes)
• Sediment mobilisation pathways and downstream environmental impacts
• Drainage design for high-intensity rainfall and concentrated flow control
• Soil placement, compaction and surface protection techniques
• Erosion and sediment control structures (channels, basins, energy dissipation systems)
• Engineering approaches to landform stability verification and performance testing
• Monitoring, inspection and early detection of erosion-driven instability

Climate variability and extreme weather events are increasingly reshaping mine closure planning, rehabilitation design and regulatory expectations across Queensland’s mining sector.

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These changing conditions are placing greater emphasis on long-term performance, requiring operators to demonstrate that closure designs remain robust under future climate scenarios rather than historical assumptions. This includes increasing attention on rainfall intensity, flood risk variability, prolonged dry periods and their implications for rehabilitation success.

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As PRCP frameworks evolve, climate resilience is becoming a core consideration in closure approvals, influencing how landforms, soil systems and post-mining land uses are designed and assessed.

This session examines how climate risk is being embedded into mine closure planning and what it means for long-term rehabilitation strategy, design assumptions and regulatory compliance.

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Key Discussion Areas:

• Integration of climate change projections into mine closure and PRCP planning
• Impacts of rainfall variability, flooding and drought on closure assumptions
• Regulatory expectations for future-focused (non-historical) design criteria
• Climate resilience in landform and rehabilitation strategy development
• Long-term stability considerations for post-mining land uses
• Evolving closure risk frameworks in a changing climate

Soil is increasingly recognised as a living system rather than a structural medium in mine rehabilitation, with microbial communities playing a critical role in driving nutrient cycling, carbon sequestration and long-term ecosystem stability.

Disturbance from mining significantly alters soil biology, carbon dynamics and microbial diversity, often limiting the ability of rehabilitated landscapes to achieve self-sustaining ecological function.

As closure expectations evolve, there is growing regulatory and scientific focus on restoring not just soil structure, but the biological processes that underpin ecosystem resilience.

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This session explores the role of soil microbiology in rebuilding functional ecosystems post-mining, with a focus on carbon recovery, microbial re-establishment and soil health as a measurable indicator of rehabilitation success. It will examine how advances in soil science are informing closure design, improving vegetation outcomes and supporting long-term landscape function.

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Key Discussion Areas:

• Role of soil microbiology in ecosystem recovery after mining
• Carbon cycling, sequestration and recovery in rehabilitated soils
• Impacts of mining disturbance on soil biological function
• Microbial re-establishment strategies in mine closure
• Linking soil health metrics to rehabilitation success criteria
• Soil function as a driver of long-term ecosystem resilience

Soil is increasingly recognised as a critical performance system in mine closure, underpinning vegetation establishment, ecosystem recovery and long-term land stability.

Traditional approaches focused on topsoil replacement are being replaced by more sophisticated soil reconstruction strategies that address soil structure, chemistry and biological function as integrated systems.

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Regulators are now placing greater emphasis on whether rehabilitated soils can support self-sustaining ecosystems and meet post-mining land use objectives over long timeframes.

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This session explores modern approaches to soil reconstruction and how functional soil systems are being designed for long-term rehabilitation success.

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Key Discussion Areas:
• Topsoil stripping, handling and storage best practice
• Subsoil reconstruction and soil profile design
• Soil chemistry, structure and nutrient balance in rehabilitation
• Microbial and biological soil restoration approaches
• Functional soil performance and ecosystem establishment
• Measuring soil health and long-term land capability

Panel Session, Audience Engagement 

Lunch and networking 

Soil contamination and geochemical disturbance remain critical challenges in mine rehabilitation across Queensland, particularly in legacy operations and increasingly complex critical minerals projects. Acid mine drainage, metal(loid) mobilisation, hydrocarbon impacts and saline or sodic spoil materials continue to influence long-term land stability and post-mining land use outcomes.

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Under Queensland’s Progressive Rehabilitation and Closure Plan (PRCP) framework, there is growing emphasis on identifying, characterising and managing contaminated or potentially contaminated soils early in the mine life, rather than deferring treatment to closure.

This shift is driving more risk-based approaches to soil classification, containment design and rehabilitation planning, with increased scrutiny of long-term environmental liability.

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At the same time, regulators are placing greater weight on whether contaminated materials can be safely contained, remediated or reclassified into non-use management areas, particularly where full soil restoration is not technically feasible.

This is reshaping how closure risk, residual contamination and rehabilitation success are assessed across Queensland mining operations.

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This session explores modern approaches to managing soil contamination in mine rehabilitation, with a focus on risk-based design, regulatory expectations and long-term land stability outcomes.

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Key Discussion Areas:

• Types and sources of soil contamination in Queensland mining environments
• Acid mine drainage, metal mobility and geochemical instability in waste materials
• Risk-based soil classification and rehabilitation decision-making under PRCP
• Containment, encapsulation and treatment strategies for contaminated soils
• Long-term monitoring and stability of rehabilitated contaminated landforms
• Linking contamination risk to residual liability and closure approvals

Mine closure expectations are shifting beyond compliance-based rehabilitation toward nature-positive outcomes that restore ecosystem function, biodiversity value and landscape resilience.

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Soil reconstruction, vegetation establishment and hydrological restoration are increasingly being integrated to support functional ecological systems rather than simple landform stabilisation.

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This shift is driving new approaches to measuring closure success, with greater emphasis on ecological performance and long-term environmental value.

This session explores how nature-positive principles are being applied in mine closure design and implementation.

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Key Discussion Areas:
• Shift from compliance rehabilitation to nature-positive closure
• Ecosystem function and biodiversity outcomes in closure design
• Soil and vegetation integration for ecological recovery
• Hydrological restoration and landscape connectivity
• Measuring ecological success beyond vegetation cover
• Alignment with ESG and sustainability frameworks

Tailings, by products from extracting economic minerals are the largest environmental challenge facing the world’s mining industry.

Conventional method to cover the tailings using geomembrane is not only expensive but unsustainable.

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This presentation introduces a nature-based ecological engineering approach developed through more than 15 years of field-based, industry-partnered research across multiple climate zones.

The methodology enables the systematic mineralogical, geochemical, and biophysical transformation of bio-toxic tailings and mine wastes (e.g., bauxite residue) into a productive soil system resembling natural lateritic soils.
 
Through carefully designed ecological processes, the treated tailings develops stable soil structure, supports diverse microbial communities, and establishes self-sustaining nutrient cycling without the need for ongoing fertiliser inputs.
The resulting eco-engineered soil can be harvested within 2-3 years for use in the remediation of severely degraded landscapes, or utilised in situ to construct stable landforms with functional soil profiles.
 
Field trials demonstrate the development of persistent vegetation cover and long-term ecosystem function, supported by ongoing natural bioweathering processes and stable interfaces between engineered soil layers and underlying residue.

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By moving beyond containment-focused approaches, this work demonstrates how nature-based design can transform tailings rehabilitation, enabling more sustainable mine closure outcomes and creating new opportunities for land restoration and post-mining land use.

Panel session, Audience engagement 

Afternoon tea 

Securing sufficient quality topsoil remains one of the most persistent challenges in progressive mine rehabilitation across Australia.
In many Queensland operations, topsoil depths vary significantly, and available volumes are often inadequate to support final landform objectives.

Additionally, both topsoil and subsoil resources may contain physical and chemical constraints that limit vegetation establishment.

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This presentation introduces a structured, evidence-based framework for developing manufactured growth media to address topsoil deficits and support achievement of the proposed Post-Mining Land Use (PMLU).

Initiated by the Queensland Office of the Mine Rehabilitation Commissioner, the project combines insights from an industry survey of environmental professionals with an extensive literature review to identify common soil constraints and practical amelioration strategies.

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The session outlines a five-stage approach:
•    Defining the PMLU and determining soil performance requirements
•    Identifying and characterising available growth media resources
•    Developing tailored growth media strategies, including constraint identification and amelioration design
•    Trialling amendment strategies under site conditions
•    Implementing ongoing monitoring and adaptive management
•    The framework emphasises early material characterisation, strategic soil inventory management, and site-specific amendment design to transform subsoil and spoil into functional growth media.

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By shifting from reliance on scarce topsoil to engineered growth systems, operators can reduce closure risk, improve vegetation outcomes, and enhance regulatory confidence.
The approach provides a practical, scalable pathway to achieve resilient landforms and sustainable PMLU outcomes where natural topsoil resources are limited.​

Not all disturbed mining areas can be returned to a pre-mining or productive post-mining land use, requiring long-term management of Non-Use Management Areas (NUMAs).

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These areas present ongoing challenges for soil stability, contamination control and environmental risk management, particularly where final voids or permanent landforms remain.

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Regulators require clear justification and long-term management strategies for these areas under PRCP frameworks, with ongoing liability considerations.

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This session examines how NUMAs are being assessed and managed within modern closure planning.

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Key Discussion Areas:

• Definition and regulatory treatment of NUMAs
• Final voids and permanent landform management
• Soil and surface stability in non-use areas
• Long-term environmental risk considerations
• Justification requirements under PRCP frameworks
• Ongoing monitoring and management obligations

Audience engagement 

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