How to Finance Carbon Mineralization, Progressive Rehabilitation, and Long-Term Tailings Risk Reduction in Western Australia

Illustrative case study. This proposal is modeled on the characteristics of ultramafic nickel tailings in Western Australia. It does not describe an existing transaction or imply the participation of any particular mine operator, regulator, carbon purchaser, or investor.

Executive Summary

Mine tailings are ordinarily treated as long-term environmental liabilities. Operators must manage physical stability, seepage, dust, water quality, rehabilitation, monitoring, and post-closure risks, potentially for decades after production ends. Governments retain additional contingent exposure if an operator becomes insolvent or a mine is abandoned.

Some ultramafic mine tailings contain magnesium-bearing minerals that react with carbon dioxide to form stable carbonate minerals. This process, known as mineral carbonation, can occur naturally and may be accelerated through changes in tailings handling, aeration, water management, particle exposure, or the controlled introduction of concentrated carbon dioxide.

Research at the Mount Keith nickel mine in Western Australia estimated that its tailings were naturally capturing approximately 39,800 tonnes of atmospheric carbon dioxide annually at the time of the study, equivalent to approximately 11 percent of the mine’s reported annual greenhouse-gas emissions. Researchers identified carbon-dioxide ingress as a constraint on the reaction rate, suggesting that changes in tailings management could accelerate carbonation. These findings demonstrate geological potential, not commercial performance, and cannot be extrapolated to another facility without site-specific testing. Australian National University

The proposed structure uses a dedicated project vehicle to finance pilot testing and, if successful, integrate mineral carbonation into progressive rehabilitation. Its financial architecture has three layers:

1. Minimum Viable Transaction: A mine operator purchases an approved carbonation and rehabilitation service, while a carbon-removal buyer purchases independently verified net mineralization.
2. Carbon Price Participation Layer: Additional parties contribute capital, services, infrastructure, purchase commitments, or risk-bearing capacity in exchange for transferable claims on qualifying future carbon-price value.
3. Broader Beneficiary Map: Governments, lenders, insurers, mineral purchasers, communities, and other institutions may benefit without being treated as underwritten payers unless they enter enforceable contracts.

Investors participate through Outcome-Linked Prevention Shares, or OLPS. Essential operations and senior distributions are supported by contracted operator payments. Performance distributions depend on carbon mineralization, progressive rehabilitation, environmental performance, and formally recognized remediation savings.

Carbonation does not eliminate the operator’s legal rehabilitation obligations or substitute for safe tailings management. The investable asset is a contracted rehabilitation and mineralization service, not the tailings themselves, their theoretical carbon capacity, or an unverified reduction in a balance-sheet provision.

The Structural Problem

Mining companies recognize closure and rehabilitation obligations throughout the life of a mine. Yet conventional mine finance generally treats expenditure on tailings closure as a cost to be minimized rather than an investment capable of generating environmental services and reducing future liabilities.

This creates a timing problem. Expenditure that could reduce future remediation costs is required today, while the resulting savings may not become observable for years. Operators may also hesitate to fund an emerging process whose performance depends on mineralogy, climate, water chemistry, engineering integration, reaction kinetics, and future regulatory recognition.

Governments face a related problem. Western Australia’s Mining Rehabilitation Fund provides pooled funding for abandoned mines when operators fail to meet their obligations. However, the fund does not absolve operators of their legal responsibility to rehabilitate their sites. Its levy is based on reported disturbance rather than the operator’s actual site-specific closure cost. A carbonation project therefore cannot assume that lower modeled risk automatically reduces either the operator’s legal obligation or its MRF contribution. Any financial recognition would require an approved change in rehabilitation status or another formal regulatory determination. Government of Western Australia

The financing distinction is fundamental:$$\text{Potential economic value}=\text{carbon removal}+\text{lower remediation expenditure}+\text{lower residual environmental risk}$$Potential economic value=carbon removal+lower remediation expenditure+lower residual environmental risk

But:$$\text{Investable value}=\text{enforceable service payments}+\text{contracted carbon purchases}+\text{formally recognized shared savings}$$Investable value=enforceable service payments+contracted carbon purchases+formally recognized shared savings

The first equation explains why the intervention may be valuable. The second determines whether investors can finance it.

Why Ultramafic Nickel Tailings?

The case study focuses on an illustrative Western Australian nickel operation whose tailings contain potentially reactive magnesium-bearing minerals.

The suitability of an individual facility would depend on:

• Brucite, serpentine, olivine, and other reactive mineral content
• Tailings grain size and reactive surface area
• Existing carbonate content
• Sulfide content and acid-generation potential
• Porewater chemistry and alkalinity
• Nickel and other metal mobility
• Tailings deposition method
• Water availability and evaporation rates
• Facility geometry and physical stability
• Remaining mine life and closure schedule
• Access to suitable low-carbon carbon dioxide

Theoretical carbon capacity cannot be treated as a financeable outcome. A deposit may be capable of reacting with a substantial quantity of carbon dioxide in theory while delivering only a fraction of that potential under operational conditions.

The Defined Intervention

The project would begin with one eligible mine, one operator, and a controlled tailings cell. Depending on pilot results, the intervention could include:

• Thin-layer tailings deposition
• Periodic turning or aeration
• Controlled wetting and drying
• Adjustment of tailings-water chemistry
• Improved drainage and water recirculation
• Carbon-dioxide delivery into selected tailings cells
• Carbonation of rehandled material in engineered heaps or reactors
• Integration with approved closure covers
• Dust suppression and surface stabilization
• Continuous porewater, seepage, and geotechnical monitoring
• Long-term mineralogical and carbonate sampling

Suitable carbon dioxide might come from passive atmospheric uptake, captured mine emissions, nearby industrial sources, biogenic sources, or another verified low-carbon source. Capture, purification, compression, transportation, pumping, and rehandling emissions would be deducted from gross mineralization.

Carbonation would not substitute for dam safety, drainage, seepage control, water treatment, emergency planning, closure covers, or post-closure monitoring. The Global Industry Standard on Tailings Management applies a lifecycle approach to tailings safety, environmental protection, governance, monitoring, and affected-community engagement. The project should align with those principles whether or not formal certification is required. UN Environment Programme

What Carbonation Might Prevent

Successful carbonation could generate several categories of value, but none should be assumed before testing.

Durable Carbon Storage

Carbon dioxide reacts with suitable minerals to form solid carbonate minerals. Properly characterized carbonates may provide highly durable storage compared with biological carbon pools.

Only incremental mineralization beyond the expected business-as-usual rate would qualify as a project outcome. Naturally occurring carbonation that would have happened without the intervention cannot be sold again as additional removal.

Future Remediation Expenditure

Depending on site chemistry and engineering design, carbonation may reduce some future requirements for:

• Tailings rehandling
• Reactive-material treatment
• Dust suppression
• Imported cover materials
• Water treatment
• Seepage management
• Long-term chemical stabilization
• Post-closure monitoring

These savings would be recognized only after independent engineering analysis and regulatory acceptance. A reduction in a modeled cost is not automatically a reduction in an accounting provision, statutory obligation, financial-assurance requirement, or MRF contribution.

Residual Environmental Risk

Carbonation can change pH, mineral volume, pore structure, permeability, and metal mobility. Some changes may be beneficial; others may create additional risk. The project receives no environmental-performance payment unless testing demonstrates acceptable performance under expected closure conditions.

Public Contingent Exposure

If progressive rehabilitation reduces the work remaining when a mine closes, it may also reduce the consequences of future operator failure. This creates potential value for government and the Mining Rehabilitation Fund.

Public participation should pay only for incremental public outcomes. It should not subsidize work the operator was already legally required to perform.

Layer One: The Minimum Viable Transaction

The minimum viable transaction is deliberately narrower than the complete beneficiary map. It finances one commercial demonstration using a limited number of enforceable contracts.

Project Scope

The first transaction finances a controlled commercial demonstration cell at a single operating ultramafic nickel mine. Commercial expansion occurs only after the demonstration verifies:

• Incremental carbon mineralization
• Net-negative lifecycle emissions
• Acceptable water chemistry
• No adverse increase in metal mobility
• Acceptable permeability and volume changes
• Continued physical stability
• Compatibility with the approved closure plan
• A reproducible measurement and verification protocol

Required Parties

Only five parties are essential:

1. Mine operator: Purchases the carbonation and rehabilitation service.
2. Project vehicle: Finances and administers the intervention.
3. Carbon-removal purchaser: Buys verified net removal at a contracted price or price floor.
4. Independent technical administrator: Verifies carbon, rehabilitation, and environmental outcomes.
5. Regulatory authority: Approves integration into the applicable environmental and closure framework but is not assumed to make payments.

The Anchor Payer

The mine operator is the anchor payer.

Under a Carbonation and Progressive Rehabilitation Services Agreement, the operator makes a fixed availability or service payment for treating eligible tailings and delivering approved rehabilitation functions. The payment can be calibrated against work the operator would otherwise need to perform, including tailings placement, surface management, dust control, drainage, water management, monitoring, and closure preparation.

The operator payment must be sufficient to cover:

• Essential project operations
• Safety and environmental monitoring
• Required maintenance
• Corrective-action reserves
• Contracted senior OLPS distributions

Senior capital is therefore not dependent on a future carbon price, a reduction in the operator’s accounting provision, or participation by multiple indirect beneficiaries.

The Contracted Outcome Buyer

A carbon-removal purchaser supplies the second payment stream.

The purchaser enters a long-term offtake covering only independently verified net carbon removal. The agreement could include a fixed price, a price floor with market-linked upside, or a prepayment for a conservatively estimated quantity of future removals.

Carbon-removal revenue supports:

• Incremental carbonation equipment
• Measurement and verification
• Pilot and scale-up costs
• Performance OLPS distributions
• Expansion into additional approved tailings cells

If no credible purchaser will sign an enforceable agreement at financial close, forecast carbon revenue is assigned a base-case value of zero.

Base-Case Underwriting

Potential revenue	Included in base case?	Treatment
Operator rehabilitation-service payment	Yes	Supports operations, reserves, and senior OLPS
Contracted carbon-removal floor price	Yes, if executed	Supports incremental costs and performance OLPS
Forecast remediation savings	No	Recognized only after independent and regulatory approval
Accounting-provision reduction	No	Cannot be assumed before auditor acceptance
Reduced financial assurance	No	Included only after formal reassessment
Reduced MRF contribution	No	Not assumed
Insurance-premium savings	No	Potential future shared savings
Low-carbon nickel premium	No	Potential future revenue
Future statutory carbon price	No	Governed by the participation layer
Public outcome payments	No	Available only for verified incremental public benefits

Base-case cash flow is therefore:$$C{F}_t^{base}=OS{P}_t+CR{O}_t^{floor}$$CFtbase​=OSPt​+CROtfloor​

Where:

• $OS{P}_t$OSPt​ is the operator service payment
• $CR{O}_t^{floor}$CROtfloor​ is the enforceable carbon-removal offtake payment

Layer Two: Carbon Price Participation

The minimum viable transaction can close without a future global carbon price. A separate participation layer allows additional parties to contribute today in exchange for contingent rights to future carbon-price value.

Carbon Price Participation Window

For a defined period during pilot development and early operation, the project vehicle would accept qualifying contributions from additional participants.

Contributions could include:

• Project capital
• First-loss protection
• Carbon-removal prepayments
• Carbon dioxide supplied below market cost
• Equipment provided on deferred terms
• Carbonation technology licensed at a reduced initial fee
• Long-term nickel-purchase commitments
• Credit enhancement
• Data, testing, or verification services
• Operator payments exceeding the minimum contracted amount
• Public demonstration funding, where legally authorized

In exchange, the contributor receives Carbon Price Participation OLPS. These units carry a defined claim on future net carbon-price value generated by the project.

The participation layer creates a simple incentive:

Parties that help finance or de-risk the intervention before a global carbon price exists receive a claim on part of the value if that price is later created.

An institution may benefit environmentally without participating. It cannot, however, receive the project’s carbon-price distributions unless it makes a qualifying contribution or purchases the relevant OLPS from an existing holder.

Potential Participants

Mine Operator

The operator may contribute more than the minimum required service payment in exchange for retaining a larger share of future avoided compliance costs or statutory carbon revenue.

Carbon-Dioxide Supplier

A supplier could finance capture, conditioning, or transportation infrastructure in exchange for future participation rights. It might also accept a lower initial mineralization fee in return for OLPS.

Technology and Equipment Providers

A technology provider could defer part of its fee or accept performance-based compensation. Its participation rights would vest only if the equipment contributes to verified outcomes.

Nickel Purchasers

A manufacturer or commodity buyer could enter a long-term offtake agreement for lower-carbon nickel. In exchange for early commitment or a product premium, it could receive a defined share of future product-carbon value, subject to anti-double-counting rules.

Carbon-Removal Buyers

A purchaser that prepays for removals or accepts early methodology risk could receive contractual price protection or participation in value created if the removal later becomes eligible in a compliance market.

Lenders and Specialist Investors

Lenders could provide favorable financing terms, subordinated capital, or longer maturities in exchange for OLPS participation. Any claim would remain separate from the lender’s ordinary security and repayment rights.

Government and Public Programs

A public demonstration program could receive a recycling interest in future carbon-price revenue, where legally authorized. This allows successful projects to repay or replenish public innovation capital rather than permanently retaining both public support and the full regulatory windfall.

Participation Share Allocation

Participation shares could reflect:

• Capital contributed
• Duration of commitment
• Technology or infrastructure provided
• Contracted removal purchases
• Carbon dioxide supplied
• Risk absorbed
• Performance achieved
• Timing of participation

Earlier participants could receive more favorable conversion ratios because they assume greater technical, market, and policy uncertainty.

A participant’s rights could be expressed as:$$s_i=\frac{\alpha K_i+\beta R_i+\gamma O_i+\delta T_i}{\sum _j(\alpha K_j+\beta R_j+\gamma O_j+\delta T_j)}$$si​=∑j​(αKj​+βRj​+γOj​+δTj​)αKi​+βRi​+γOi​+δTi​​

Where:

• $K_i$Ki​ is capital or economic value contributed
• $R_i$Ri​ is risk absorbed
• $O_i$Oi​ is contracted operating or purchase commitment
• $T_i$Ti​ represents timing and duration
• The coefficients determine the relative importance of each contribution

The formula would be fixed in the transaction documents before participants commit.

Vesting and Transferability

Participation rights would vest over time according to continued performance. A technology provider whose equipment fails to meet contractual standards would not retain the full future claim. A nickel buyer that terminates its purchase commitment early could forfeit unvested units.

Vested OLPS could be sold to eligible investors through a controlled registry. This allows participants to realize some of the contingent value before the carbon-pricing event occurs, provided a buyer is willing to assume the policy and performance risk.

The Global Carbon Pricing Event

The transaction documents would define a Qualifying Carbon Pricing Event to include:

• Introduction of an internationally coordinated carbon tax or trading system
• Linkage of Australian carbon markets with an international system
• Recognition of mine-tailings carbonation as an eligible removal
• Acceptance of mineralized carbon for compliance purposes
• Introduction of a carbon-removal purchasing obligation
• A border or product-carbon regime producing an assignable low-carbon nickel premium
• A change in Australian law allowing mineralization to reduce a covered facility’s compliance obligation

A price on emissions does not automatically create revenue for this project. The applicable regime must recognize the removal, create an assignable avoided compliance cost, or produce another legally transferable benefit.

Carbon Price Participation Account

Eligible incremental carbon value would be calculated as:$$NC{V}_t=N{R}_t^{eligible}\times P_t^{qualifying}-V_t^{existing}-C_t^{compliance}-C_t^{MRV}-D{C}_t$$NCVt​=NRteligible​×Ptqualifying​−Vtexisting​−Ctcompliance​−CtMRV​−DCt​

Where:

• $N{R}_t^{eligible}$NRteligible​ is mineralization legally recognized by the regime
• $P_t^{qualifying}$Ptqualifying​ is the applicable global or linked price
• $V_t^{existing}$Vtexisting​ is carbon value already paid through existing contracts
• $C_t^{compliance}$Ctcompliance​ represents registry, tax, and transaction costs
• $C_t^{MRV}$CtMRV​ represents additional measurement and verification expense
• $D{C}_t$DCt​ removes duplicated or incompatible claims

The remaining value enters a ring-fenced Carbon Price Participation Account.

Carbon-Price Distribution Waterfall

Revenue in that account would be applied in the following order:

1. Taxes, verification, and compliance expenses
2. Replacement of any carbon-offtake payment displaced by the new regime
3. Required reduction or repayment of public support
4. Long-term environmental stewardship reserve
5. Carbon Price Participation OLPS distributions
6. Community and affected-party benefits
7. Expansion into additional tailings cells or mines

Each participant receives:$$Distributio{n}_{i,t}=s_i\times NC{V}_t^{distributable}$$Distributioni,t​=si​×NCVtdistributable​

OLPS upside would be capped where necessary to prevent excessive windfalls from publicly supported infrastructure.

No Double Counting

A tonne of mineralized carbon cannot simultaneously be:

• Sold as a voluntary removal
• Surrendered as a compliance unit
• Used fully to reduce the operator’s statutory obligation
• Claimed fully in the carbon intensity of nickel
• Paid for again through a public outcome contract

Compatible claims may be allocated among different parties only where the relevant standards permit it and the allocation is clearly disclosed.

Layer Three: The Broader Beneficiary Map

The project may create value across numerous institutions. Mapping that value is necessary for understanding the intervention, but it does not mean every beneficiary becomes a payer.

Beneficiary	Potential value	Transaction status
Mine operator	Rehabilitation service and potentially lower closure expenditure	Anchor payer
Carbon-removal purchaser	Verified durable removal	Contracted outcome buyer
Parent company	Lower residual group exposure	Potential support provider
Carbon-dioxide supplier	Mineralization capacity and future carbon value	Optional participation-layer contributor
Technology provider	Commercial validation and future performance revenue	Optional participation-layer contributor
Nickel purchaser	Lower product carbon intensity	Optional participation-layer contributor
Government of Western Australia	Lower abandoned-mine exposure	Non-paying beneficiary unless separately contracted
Mining Rehabilitation Fund	Lower potential residual exposure	Not an assumed payer
Financial-assurance provider	Lower expected claim severity	Potential future co-payer after formal reassessment
Environmental insurer	Lower expected remediation exposure	Potential future co-payer
Lenders	Lower closure and environmental credit risk	Non-paying beneficiary unless financing terms change
Affected communities	Improved monitoring and environmental performance	Governance participant and non-paying beneficiary
OLPS investors	Contracted project distributions	Capital provider

Additional institutions become payers only when their benefits are measurable, legally assignable, and supported by enforceable contracts.

The Tailings Carbonation and Closure Vehicle

A ring-fenced Australian project company or trust would be established as the Tailings Carbonation and Closure Vehicle.

Its principal agreements would include:

Carbonation and Progressive Rehabilitation Services Agreement

The operator grants site access and pays for specified services. The agreement defines eligible tailings, operating constraints, minimum availability, payment terms, measurement requirements, safety responsibilities, and termination provisions.

Regulatory Interface Deed

The operator, project vehicle, and relevant authorities establish how verified results may be incorporated into the approved mine-closure plan. No reduction in liability, financial assurance, monitoring, or rehabilitation requirements occurs automatically.

Carbon-Removal Offtake Agreement

The purchaser pays for verified net removal. Delivery shortfalls reduce carbon revenue but do not reduce the operator’s safety or rehabilitation obligations.

Measurement and Assurance Agreement

An independent administrator verifies mineralization, lifecycle emissions, progressive rehabilitation, water quality, and physical performance.

Environmental-Attribute and Participation Deed

This agreement establishes ownership, vesting, transfer, retirement, and distribution rules for carbon attributes and Carbon Price Participation OLPS.

Community and Stewardship Deed

The vehicle funds disclosure, community engagement, monitoring access, grievance procedures, and long-term environmental stewardship.

The mine operator retains its permits, tenements, statutory obligations, and legal responsibility for the tailings facility. OLPS holders receive contractual cash-flow rights but do not own the tailings or control safety-critical operations.

If the mine is sold, the project agreements would require novation to an approved successor. Vested OLPS remain outstanding, supported by change-of-control protections and replacement credit support.

Outcome-Linked Prevention Shares

The project vehicle could issue four classes of OLPS.

Senior Rehabilitation Prevention Shares

Senior shares receive priority distributions from the operator’s fixed service payment. Their returns depend on service availability, compliance, and satisfactory rehabilitation performance.

Carbon Mineralization Performance Shares

Performance shares receive distributions from verified carbon-removal revenue and recognized remediation savings.

Carbon Price Participation Shares

Participation shares receive distributions from the Carbon Price Participation Account following a Qualifying Carbon Pricing Event. They do not receive value merely because market participants expect a future carbon price.

Stewardship Shares

A public, Indigenous, community, or environmental trust could hold stewardship shares whose distributions fund monitoring, local capacity, and post-closure protection.

The Outcome Score

Annual performance would be determined using a composite score:$$Q_t=w_C{C}_t+w_R{R}_t+w_W{W}_t+w_S{S}_t+w_M{M}_t$$Qt​=wC​Ct​+wR​Rt​+wW​Wt​+wS​St​+wM​Mt​

Where:

• $C_t$Ct​ is verified net incremental carbon mineralization
• $R_t$Rt​ is approved progressive rehabilitation
• $W_t$Wt​ is water-quality and seepage performance
• $S_t$St​ is physical stability, erosion, and dust performance
• $M_t$Mt​ is monitoring and regulatory compliance

Water quality, physical stability, and regulatory compliance operate as mandatory gates. Carbon mineralization cannot generate a performance distribution if the project causes unacceptable environmental or safety outcomes.

Measuring Carbon Removal

Verified net removal would be calculated as:$$N{R}_t=G{M}_t-B{C}_t-E_t^{capture}-E_t^{energy}-E_t^{transport}-E_t^{handling}-D_t$$NRt​=GMt​−BCt​−Etcapture​−Etenergy​−Ettransport​−Ethandling​−Dt​

Where:

• $G{M}_t$GMt​ is gross carbon incorporated into newly formed carbonate minerals
• $B{C}_t$BCt​ is expected business-as-usual carbonation
• The $E$E terms represent project-generated lifecycle emissions
• $D_t$Dt​ represents uncertainty, leakage, dissolution risk, and conservative deductions

Measurement could combine:

• Quantitative mineralogy
• Carbonate mass balance
• Stable and radiocarbon isotope analysis where appropriate
• Tailings and porewater sampling
• Gas-flux measurement
• Process-energy and transportation records
• Reactive-transport modeling
• Independent laboratory analysis
• Periodic third-party audits

The project credits actual mineral formation, not the theoretical reaction capacity of the tailings.

Measuring Avoided Remediation Liabilities

Avoided remediation value would be calculated separately:$$A{R}_t=(E[C_{\text{approved baseline}}]-E[C_{\text{carbonation closure}}])\times a_t\times h_t$$ARt​=(E[Capproved baseline​]−E[Ccarbonation closure​])×at​×ht​

Where:

• $E[C_{\text{approved baseline}}]$E[Capproved baseline​] is the expected cost of the approved existing closure plan
• $E[C_{\text{carbonation closure}}]$E[Ccarbonation closure​] is the expected cost of the approved carbonation-integrated plan
• $a_t$at​ is the proportion formally recognized at that stage
• $h_t$ht​ is a conservative uncertainty haircut

Four categories remain legally and financially distinct:

1. Reduction in expected physical closure expenditure
2. Reduction in the operator’s accounting provision
3. Reduction in required financial assurance or MRF-related payments
4. Reduction in the government’s contingent exposure

Recognition of one category does not automatically change the others.

Shared-Savings Mechanism

If the carbonation-integrated closure plan produces verified savings, the operator and project vehicle divide them according to a predetermined schedule.

The operator would retain the first portion of savings to ensure participation remains economically rational. The project vehicle could receive a capped share to reward successful innovation, while another portion funds long-term environmental stewardship.

Forecast savings cannot be distributed as if they were already realized. Savings are released only after the underlying rehabilitation milestone is completed, independently verified, and recognized under the applicable closure framework.

Current Carbon-Market Treatment

As of July 2026, the Australian Clean Energy Regulator’s list of current ACCU methods does not include a dedicated mine-tailings mineral-carbonation method. The base case therefore assigns no value to future ACCUs unless an eligible method is created or the project qualifies through another formally approved pathway. Clean Energy Regulator

Private carbon-removal purchases may still be possible if buyers accept the methodology and associated claims. Such removals cannot be represented as statutory Australian compliance units unless they acquire that legal status.

Capital Structure

The phased capital structure could include:

1. Operator capital: Funds legally required rehabilitation and the operator’s share of the demonstration.
2. Research or demonstration funding: Supports methodology development and public-interest research.
3. First-loss innovation capital: Absorbs pilot and scale-up risk.
4. Carbon-removal prepayments: Finance a conservative portion of expected delivery.
5. Senior rehabilitation OLPS: Supported primarily by operator service payments.
6. Carbon performance OLPS: Supported by carbon offtake and verified shared savings.
7. Carbon Price Participation OLPS: Supported only by qualifying future carbon-price value.
8. Stewardship reserve: Funds long-term monitoring and corrective measures.

Senior institutional capital enters only after the project demonstrates repeatable mineralization, acceptable environmental performance, and enforceable payments.

General Project Cash-Flow Waterfall

Annual project revenue outside the Carbon Price Participation Account would be applied in the following order:

1. Taxes and statutory charges
2. Essential operations and maintenance
3. Water-quality, geotechnical, and environmental monitoring
4. Corrective-action and remediation reserves
5. Long-term stewardship reserve
6. Senior rehabilitation OLPS distributions
7. Carbon performance OLPS distributions
8. Community benefits and project expansion

Safety-critical expenditure always ranks ahead of investor distributions.

Implementation

Phase One: Screening and Baseline

The project characterizes mineralogy, water chemistry, metals, natural carbonation, closure obligations, remediation costs, and regulatory requirements.

Phase Two: Controlled Pilot

Field cells compare passive carbonation, enhanced aeration, controlled water management, and concentrated carbon-dioxide delivery. The pilot monitors net removal, water quality, metal mobility, permeability, volume change, dust, and physical behavior.

Phase Three: Minimum Viable Transaction

The operator signs the rehabilitation-services agreement, a carbon purchaser signs the offtake, the verifier approves the methodology, and the regulator approves the intervention’s integration into the closure program.

Phase Four: Participation Window

Additional parties contribute capital, services, infrastructure, purchase commitments, or risk-bearing capacity in exchange for Carbon Price Participation OLPS.

Phase Five: Commercial Expansion

Following successful verification, the project issues senior and performance OLPS and expands into additional approved tailings cells.

Phase Six: Closure and Stewardship

Monitoring continues through the required closure and post-closure periods. Reserves remain protected until environmental and regulatory milestones are satisfied.

Principal Risks

Risk	Primary mitigation
Insufficient reactive mineral content	Mineralogical screening and minimum eligibility thresholds
Carbonation slower than projected	Phased deployment and payment for measured results
Lifecycle emissions eliminate removal	Full capture, energy, transport, and handling accounting
Adverse metal mobility	Pilot testing, environmental gates, and corrective reserves
Geotechnical or volume effects	Independent engineering and restricted deployment zones
Closure savings are not recognized	Exclusion from base-case underwriting
Carbon methodology is unavailable	Operator service payment remains the anchor revenue
Carbon purchaser defaults	Credit support, replacement rights, and conservative senior leverage
Future carbon regime does not recognize mineralization	Participation OLPS receive no distributions
Operator insolvency	Parent support, reserves, security, and successor obligations
Double counting	Environmental-attribute registry and third-party assurance
Community opposition	Early engagement, disclosure, grievance mechanisms, and stewardship participation
Tailings-facility failure	No liability transfer and full operator safety responsibility

Why This Is Structurally Different

Conventional mine-closure finance reserves capital for a future obligation. Conventional carbon finance asks whether a project can generate marketable tonnes of carbon removal.

This structure connects the two while preserving their legal and financial separation. The operator purchases an actual rehabilitation service. A carbon buyer purchases verified mineralization. Investors receive additional returns only when evidence demonstrates successful rehabilitation, additional carbon removal, or formally recognized reductions in expected closure expenditure.

The structure also recognizes that a future global carbon price may influence behavior before it exists. Parties that contribute capital, equipment, carbon dioxide, purchase commitments, or risk-bearing capacity today receive transferable participation rights in the value that may be created later.

The project does not require every beneficiary to sign a contract. It separates the small coalition required to finance the initial intervention from the larger group that may choose to join once future carbon-price value is made assignable.

Arctica Advisory Insight

Ultramafic mine tailings can simultaneously represent industrial waste, a long-duration environmental liability, and a potentially reactive mineral resource. That does not make every tailings facility a carbon-removal asset, nor does mineral carbonation eliminate the operator’s legal and engineering responsibilities.

The opportunity arises where three conditions coincide:

1. The tailings mineralize carbon at a verified net-negative lifecycle rate.
2. Carbonation improves, or at minimum does not compromise, approved rehabilitation outcomes.
3. An operator and carbon purchaser convert those outcomes into enforceable payments.

The three-layer financial architecture makes that opportunity investable without relying on an implausibly large coalition.

The Minimum Viable Transaction finances the intervention through a mine operator and contracted carbon purchaser. The Carbon Price Participation Layer allows additional institutions to exchange present contributions for contingent future value. The Broader Beneficiary Map identifies the full distribution of economic benefits without mistaking every beneficiary for a payer.

Outcome-Linked Prevention Shares connect these layers. They create transferable claims on contracted rehabilitation payments, verified mineralization, formally recognized remediation savings, and qualifying future carbon-price value while preserving safety gates and the operator’s legal responsibility.

The essential innovation is not simply using mine tailings to remove carbon dioxide. It is converting current rehabilitation expenditure and the possibility of future carbon value into a disciplined financial structure that rewards early participation without depending on speculative policy outcomes or shifting environmental liabilities away from the mine operator.