From Cradle to Forever: The Reality of ‘Post-Closure’ When There’s No Real End Date

The closure plan was approved in 2008. It showed a clear timeline:

- Final deposition: 2023 - Active closure works: 2024-2028 - Post-closure monitoring: 2029-2038 (10 years) - Relinquishment: 2039 - Total closure liability: $47 million

The mine could see the finish line. Bond would be released. Obligation would end. They could walk away.

Then the 2020 Dam Safety Review asked an uncomfortable question: “What happens after year 2039 if the facility still requires management?”

The engineering team initially dismissed this. “We’ve designed for passive closure. No ongoing management needed.”

But the reviewer pressed: “Your seepage model shows water treatment needed for 15-20 years. Your geochemical model has high uncertainty. Your climate projections show increasing precipitation. Your monitoring shows behavior you don’t fully understand yet. On what basis do you conclude management will be unnecessary after 2039?”

Long pause.

“That’s… when our financial model ends. That’s when we can afford to close.”

The reviewer’s response was blunt: “Your financial planning horizon doesn’t determine the facility’s actual closure timeline. Nature doesn’t care about your spreadsheet.”

That uncomfortable conversation led to three years of re-analysis. The conclusion, finally acknowledged in 2023:

This facility will require monitoring and potential intervention indefinitely. Not 10 years. Not 50 years. Forever.

Updated closure liability: $180 million (perpetual care trust fund)

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This scenario—or variations of it—is playing out at mining operations worldwide.

The industry is slowly, reluctantly, coming to terms with an uncomfortable truth:

For many tailings facilities, “post-closure” isn’t a phase that ends. It’s a permanent condition.

GISTM requires designing for “safe closure” but doesn’t explicitly define what “closed” means or when responsibility ends.

Let’s talk about what the mining industry doesn’t want to acknowledge: Some tailings facilities will never truly be “closed” in the sense of walk-away relinquishment.

And what that means for how we design, operate, finance, and think about these structures.

The Myth of the Clean Exit

How We’ve Traditionally Thought About Closure

The conventional closure narrative goes like this:

Phase 1: Operations (10-30 years)

• Mine ore, process it, deposit tailings
• Active management, full staffing, operational expenditure

Phase 2: Closure Construction (3-5 years)

• Stop depositing tailings
• Implement closure design (cover, drainage, revegetation)
• Decommission infrastructure
• Significant capital expenditure

Phase 3: Post-Closure Monitoring (5-20 years)

• Monitor performance
• Minor maintenance
• Verify closure success
• Declining expenditure over time

Phase 4: Relinquishment (Year X)

• Demonstrate closure objectives achieved
• Regulator agrees facility is stable and self-sustaining
• Legal obligations transferred or ended
• Bond released
• Walk away
• Expenditure: $0 forever

This narrative is appealing because:

• It has a definite end
• Financial liability is bounded and calculable
• Company can exit cleanly
• Regulators can declare success and move on
• Land can return to other uses

There’s just one problem: For many facilities, this narrative is fiction.

Why the Clean Exit Is Often Impossible

Tailings facilities that may never achieve walk-away closure:

Type 1: Perpetual Water Management Facilities

Characteristics:

• Located in humid climates (water inputs exceed evaporation)
• Sulfidic tailings generating acidic, metal-laden seepage
• Seepage quality exceeds environmental standards
• Treatment required to protect receiving environment

The reality:

• Geochemical reactions may continue for centuries (sulfide oxidation is slow but persistent)
• Even with cover systems, some infiltration occurs
• Treatment may be needed indefinitely
• “Passive treatment” systems still require maintenance

Real example (anonymized):

Copper mine in eastern Canada:

• Closed 1995 after 30 years operation
• Closure plan: Install cover, establish passive wetland treatment, monitor for 10 years
• Reality: 29 years later (2024), still treating water
• Passive wetland helps but insufficient—active treatment still needed
• Seepage chemistry modeling suggests treatment needed for at minimum another 50-100 years, possibly indefinitely

Original closure budget (1995): $8M Actual costs to date (2024): $47M and counting Projected additional costs: $200M+ (perpetual care trust fund established)

Type 2: Perpetual Stability Maintenance Facilities

Characteristics:

• Built on challenging foundations (compressible, seismically active, permafrost)
• Climate change affecting design assumptions (permafrost thaw, changing hydrology)
• Erosion potential requiring ongoing management
• Structural elements requiring monitoring and maintenance

The reality:

• Conditions change over time in ways that prevent passive stability
• Monitoring detects issues requiring intervention
• Maintenance becomes perpetual
• Can’t confidently predict when (if ever) monitoring can cease

Real example:

Mine in northern Canada (permafrost region):

• Facility built on permafrost, designed for long-term frozen conditions
• Climate warming faster than predicted
• Permafrost degrading beneath facility
• Ongoing settlement and deformation requiring monitoring
• Intervention capability must be maintained in case instability develops
• No foreseeable date when monitoring can end (as long as climate continues warming and permafrost is transitioning)

The facility technically “closed” in 2015 but requires indefinite care.

Type 3: Consequence Classification Forces Perpetual Care

Characteristics:

• Downstream population/infrastructure (High, Very High, or Extreme classification)
• Even with excellent design and demonstrated stability, consequences of failure too severe to abandon
• Regulatory and social expectation of ongoing vigilance

The philosophical question:

• If 10,000 people live downstream, can you ever truly “walk away” even if facility is demonstrably stable?
• What’s the acceptable failure probability for abandonment? 1 in 10,000 per year? 1 in 100,000? 1 in 1,000,000?
• When consequences are catastrophic, can risk ever be low enough for zero monitoring?

Real policy example:

Some jurisdictions now require: Facilities with Very High or Extreme consequence classification must maintain monitoring indefinitely, regardless of demonstrated stability.

Rationale: Public safety stakes are too high to assume facility will remain stable without verification.

Result: No relinquishment possible. Perpetual care obligation.

Type 4: Uncertainty Prevents Confident Closure

Characteristics:

• Novel tailings technologies (limited long-term performance data)
• Complex geochemistry (hard to predict long-term behavior)
• Climate change uncertainty (don’t know future conditions)
• Large facilities (behavior not fully understood)

The reality:

• Engineers can’t confidently predict facility will be stable/passive forever
• Can’t eliminate all monitoring without accepting unknown risks
• Regulatory requirement: Demonstrate closure success before relinquishment
• But how do you “prove” something will be stable for centuries?

The precautionary approach: Keep monitoring indefinitely until sufficient confidence develops (which may be never).

The Financial Time Bomb: When Closure Costs Extend Forever

The Math That Doesn’t Work

Traditional closure financial assurance calculation:

Closure Liability = Construction Costs + Monitoring Costs (Years 1-N) + Contingency

Example:
- Closure construction: $30M
- Monitoring ($500K/year × 15 years): $7.5M
- Contingency (25%): $9.4M
- Total bond: $46.9M

This math works IF monitoring actually ends at Year 15.

But what if it doesn’t?

The Perpetual Care Problem

If facility requires perpetual care:

True Closure Liability = Construction Costs + NPV of Perpetual Care

Example:
- Closure construction: $30M
- Annual care costs: $500K/year forever
- Discount rate: 3% real (after inflation)
- NPV of perpetuity: $500K / 0.03 = $16.7M
- Total: $46.7M

But what if discount rate is 2%? 
- NPV = $500K / 0.02 = $25M
- Total: $55M

What if annual costs are higher ($1M/year) and discount rate is 1.5%?
- NPV = $1M / 0.015 = $66.7M
- Total: $96.7M

The liability is extremely sensitive to assumptions about:

• Annual cost (how much does perpetual care cost?)
• Discount rate (what return can fund earn?)
• Inflation (how do costs escalate over time?)

And there’s another problem: Who manages this fund? What if they fail?

Real-World Examples of the Financial Challenge

Example 1: Orphaned mine in Montana (US)

• Mining ended 1998
• Company declared bankruptcy 2003
• State took over site management
• Annual care costs: ~$800K (water treatment, monitoring, maintenance)
• No end date in sight
• Funded by state environmental trust (i.e., taxpayers)
• Total liability over next 100 years: $80M+ (not accounting for discount)

The state is effectively the permanent owner of a facility requiring perpetual care.

Example 2: Gold mine in Australia

• Closed 2015 with $28M closure bond (based on 10-year monitoring)
• Year 5 post-closure (2020): Water quality not improving as predicted
• Year 8 (2023): Clear that treatment needed indefinitely
• Company still solvent, renegotiating closure obligations
• Establishing perpetual care trust: $45M additional
• Total: $73M (2.6× original estimate)

The company had the financial capacity to address this. But what if they hadn’t?

Example 3: Multiple mines in Sweden (government-mandated review)

• 2019 government review of closure financial assurance for all mines
• Found: Most calculations assumed 20-30 year post-closure period
• Assessment: For many sites, perpetual care more realistic
• Result: Required financial assurance increased by average of 60% across industry
• Industry pushback: “This makes projects uneconomic”
• Government response: “Then the true cost exceeds the value, and the project shouldn’t proceed”

Uncomfortable but logical conclusion.

The Generational Ethics Problem

Who Bears the Cost When Monitoring Spans Generations?

Scenario to consider:

Tailings facility built 2025:

• Mine operates 2025-2045 (20 years)
• Closure works 2045-2050
• Post-closure monitoring required indefinitely

Timeline of responsibility:

2025-2045: Current generation builds facility, extracts economic benefit, pays taxes/royalties, provides employment

2050-2100: Next generation (children of workers/communities) inherits monitoring obligation. They got some economic benefit (their parents had jobs), but they bear ongoing cost/risk.

2100-2200: Generation 3-4 removed from original mining. Received no direct economic benefit. Still responsible for monitoring facility their great-great-grandparents built.

2200+: Generation 7+ monitoring a facility built 175+ years ago by people whose names are forgotten. Still bearing cost/risk.

The ethical question: Is this acceptable?

Arguments FOR Long-Term Societal Responsibility

Argument 1: “Benefits were societal, so costs should be too”

• Mining provided metals for societal benefit (infrastructure, technology, etc.)
• Not just the mining company/community benefited—society globally used the metals
• Therefore society should bear long-term costs
• Analogy: We maintain Roman aqueducts—why not 21st century tailings facilities?

Argument 2: “This is the price of resource extraction”

• We need metals for modern civilization
• Extraction has environmental costs, some of which are long-term
• This is knowable upfront and should be factored into project economics
• If project can’t generate enough value to cover perpetual care, it shouldn’t proceed

Argument 3: “Future generations inherit all infrastructure, good and bad”

• They inherit roads, buildings, knowledge, technology, wealth (good legacy)
• They also inherit environmental impacts, contaminated sites, nuclear waste (bad legacy)
• This is simply the reality of intergenerational transfer
• Each generation deals with previous generations’ legacies and leaves their own

Arguments AGAINST Long-Term Societal Responsibility

Argument 1: “This isn’t fair to people who received no benefit”

• Company and shareholders captured profit
• Workers received wages
• Community received some economic benefit
• But generations 100+ years out got nothing—why should they pay?

Argument 2: “This incentivizes bad behavior”

• If companies know society will ultimately bear perpetual care costs, they have less incentive to design for truly passive closure
• Becomes a form of socialized risk (privatized profits, socialized long-term costs)
• Creates moral hazard

Argument 3: “We don’t know what future societies will value or be capable of”

• Maybe technology in 2200 will make closure easier/cheaper
• Maybe society will have different risk tolerances
• Maybe the facility won’t need monitoring (our models are wrong)
• Committing future generations to specific actions may be misguided

What Other Industries Do We Have Precedent From?

Nuclear waste:

• Spent fuel requires isolation for 10,000+ years
• No society in human history has maintained institutions for that long
• Current approach: Deep geological repositories designed for passive safety
• Monitoring plans span centuries but don’t require active management
• Key difference: Failure mode is gradual contamination, not catastrophic release

Dams for water supply/flood control:

• Many large dams are essentially permanent infrastructure
• Require perpetual maintenance
• Society accepts this as cost of water/flood management
• Ownership typically government (municipalities, states, federal)
• Key difference: Providing ongoing benefit (water supply), not just managing legacy

Contaminated industrial sites:

• Many Superfund sites (US) require perpetual care
• Groundwater plumes requiring eternal pump-and-treat
• Capped landfills requiring eternal monitoring
• Funded by government (i.e., taxpayers) when responsible parties gone
• Similarity: Legacy industrial facilities requiring perpetual management

The closest analogy is contaminated sites—and there, we’ve accepted that some require perpetual care at public expense.

Is the mining industry prepared to accept that framing for tailings?

What “Perpetual Care” Actually Looks Like

The Institutional Requirements

Perpetual care isn’t just “someone checks on it occasionally.”

It requires:

1. Monitoring Program

• Physical stability (survey, inclinometers, settlement)
• Seepage quantity and quality
• Vegetation/cover performance
• Erosion and drainage function
• Seismic activity
• Frequency: Monthly to annually depending on parameters

2. Maintenance Activities

• Vegetation management (fire breaks, invasive species control)
• Erosion repair
• Drainage cleaning
• Instrumentation calibration and replacement
• Access road maintenance
• Security/fencing

3. Intervention Capability

• Engineering expertise available
• Equipment/contractors on standby
• Emergency response capability
• Authority to act if problems detected
• Funding immediately accessible

4. Data Management and Institutional Knowledge

• Continuous record of monitoring data
• Facility history and design documentation
• Lessons learned from past issues
• Transfer of knowledge as personnel change

5. Regulatory Interface

• Regular reporting to authorities
• Participation in regulatory reviews
• Permit renewals/modifications as regulations evolve
• Coordination with emergency management agencies

Estimated annual cost for typical large tailings facility:

• Routine monitoring and maintenance: $300K-$800K/year
• Periodic major maintenance: $100K-$500K/year (averaged)
• Engineering/management: $200K-$400K/year
• Regulatory compliance: $50K-$150K/year
• Total: $650K-$1.85M per year

For 100 facilities requiring perpetual care globally: $65M-$185M per year, forever.

Who pays for this in perpetuity?

The Institutional Permanence Challenge

Organizations that must persist for perpetual care:

Option 1: Mining company maintains responsibility

• Problem: Companies don’t last forever (average Fortune 500 company lifespan: ~20 years)
• Mergers, bankruptcies, name changes
• What happens in 200 years when company is long gone?

Option 2: Transfer to government

• Problem: Governments change, priorities shift, budgets cut
• Agency reorganizations, changing mandates
• Intergenerational political pressure to reduce spending

Option 3: Independent trust/foundation

• Endowment funds perpetual care
• Independent board governs
• Problem: How do you ensure institutional permanence for centuries?
• What prevents mission drift, corruption, or dissolution?

Historical reality: Very few human institutions persist for 100+ years unchanged. Churches, universities, some governments—but even these evolve dramatically.

Yet we’re creating obligations spanning centuries.

Real Example: The Church’s Approach to Perpetual Care

Medieval European churches/monasteries:

• Established with endowments for perpetual maintenance
• Some have survived 500-1,000+ years
• Key factors in their success:
  • Multiple revenue streams (not just endowment—also community support)
  • Intrinsic value to community (spiritual, cultural, architectural)
  • Adaptability (evolved with society while maintaining core mission)
  • Physical durability (stone buildings last)

What tailings facilities lack:

• Intrinsic ongoing value (produce nothing, serve no purpose except managing their own risk)
• Community affection (liability, not asset)
• Physical durability without maintenance (require active care)

The comparison is sobering: Tailings facilities require permanence without the factors that enabled churches to persist.

Design Implications: If Forever, Then What?

If we accept that some facilities require perpetual care, how should this change design?

Design Philosophy Shift: From Passive to Resilient

Old approach (passive closure):

• Goal: Facility needs no intervention after closure
• Design for static stability and passive water management
• Minimize ongoing care requirements

New approach (resilient closure):

• Goal: Facility remains manageable with reasonable intervention
• Design for adaptability and easy maintenance
• Accept that ongoing care is needed; make it efficient and robust

What this means in practice:

1. Design for Inspectability

• Access for personnel and equipment (forever)
• Instrumentation designed for easy replacement
• Monitoring systems adaptable to evolving technology
• Physical access doesn’t degrade (permanent roads, not temporary)

2. Design for Maintainability

• Erosion controls that can be repaired easily
• Drainage that can be cleaned/rehabilitated
• Vegetation that can be managed (not monocultures that may fail)
• Components modular and replaceable

3. Design for Adaptability

• Systems can be upgraded as technology improves
• Water treatment can be expanded if needed
• Cover can be enhanced if climate changes
• Monitoring can be intensified if issues emerge

4. Design for Knowledge Transfer

• Comprehensive documentation
• Design rationale clearly explained
• Failure modes and response plans documented
• Institutional knowledge not dependent on specific individuals

Real example of resilient design approach:

Gold mine in northern Canada (2018 closure design):

Rather than optimizing for “passive stability requiring no intervention,” they designed for “manageable perpetual care.”

Key features:

• All-season road access maintained (not decommissioned)
• Monitoring system designed for 100+ year life (fiber optic, redundant)
• Water treatment system modular (can be expanded or modified)
• Established perpetual care trust fund with governance structure
• Documented “adaptive management framework” for post-closure (specific triggers for different interventions)

Cost: ~35% higher than equivalent “passive” design

Justification: “Passive” design had low confidence of success; this design acknowledges reality and manages it explicitly

The Financial Structure: How to Actually Pay for Forever

Traditional Financial Assurance Doesn’t Work for Perpetual Care

Current approaches:

• Surety bonds (insurance companies guarantee funds)
• Letters of credit (bank guarantees)
• Restricted cash (money set aside)
• Corporate guarantees (parent company promise)

None of these work for perpetual care because:

• Insurers/banks don’t issue century-spanning guarantees
• Cash set aside today erodes with inflation
• Corporations don’t exist for centuries

What Actually Works: The Perpetual Care Trust Model

Structure:

1. Company establishes trust fund
2. Fund capitalized with endowment sufficient to generate perpetual income
3. Independent trustees manage fund
4. Investment returns fund ongoing care costs
5. Trust documents specify governance, adaptation mechanisms, and beneficiaries

Critical design elements:

Element 1: Adequate Capitalization

Need to calculate:

• Annual care costs (best estimate with inflation adjustment)
• Real investment return (after inflation)
• Risk buffer (what if returns lower than expected?)

Example calculation:

• Annual costs: $1M/year (in today’s dollars)
• Assume 2% real return on conservative investment portfolio
• Required endowment: $1M / 0.02 = $50M

But add risk considerations:

• What if returns only 1.5%? Need $66.7M
• What if costs escalate faster than inflation? Add 25% buffer = $83M
• What if major intervention needed? Add $20M contingency = $103M

Realistic perpetual care trust for major facility: $75M-$150M

This is 3-5× typical closure bonds calculated with finite timelines.

Element 2: Governance That Can Adapt

Trust must be able to:

• Adjust spending as costs change
• Modify care activities as conditions evolve
• Hire new contractors/consultants as old ones cease to exist
• Respond to regulatory changes
• Adapt to technological improvements

Trust documents must allow flexibility while preventing misuse.

Real example of trust structure:

Diamond mine in Northwest Territories (Canada):

• Established C$120M trust for post-closure perpetual care
• Trustees: 2 government appointees, 1 Indigenous appointee, 1 industry expert, 1 financial expert
• Investment mandate: 40% fixed income, 40% equities, 20% alternatives; must achieve 3% real return over rolling 10-year period
• Spending rule: Limited to 75% of actual investment earnings (other 25% retained to grow principal for inflation protection)
• Review every 5 years: Actuarial assessment of fund adequacy, adjustment of principal if needed

The structure is sophisticated because the obligation is eternal.

Element 3: Regulatory Backstop

Even with trust, need regulatory oversight:

• Government monitors trust performance
• Can require additional funding if inadequate
• Can step in if trust fails to perform care
• Ultimate guarantor if everything fails

But this creates societal obligation—which brings us back to the generational ethics question.

What If the Trust Fails? The Societal Backstop

Realistic scenario:

• Trust established with $80M
• Economic crisis devastates investment returns for a decade
• Trust depleted to $40M
• No longer generates sufficient income for care
• Company long bankrupt

Who pays?

In practice: Government (i.e., taxpayers) becomes responsible.

This has happened repeatedly with contaminated sites. It will happen with tailings facilities.

The question is whether we acknowledge this upfront and plan for it, or pretend it won’t happen and deal with crisis later.

GISTM and Perpetual Care: What the Standard Does (and Doesn’t) Say

What GISTM Requires

Requirement 5.7: Closure design must demonstrate feasibility with “sufficient detail to demonstrate the feasibility of the closure scenario”

Requirement 10.7: Financial capacity for closure must be reviewed periodically and “conclusions of the review shall be publicly disclosed annually”

Principle 14: Prepare for long-term recovery in event of catastrophic failure

What these requirements imply but don’t state explicitly:

• Must honestly assess closure feasibility (including whether passive closure is achievable)
• Must provide adequate financial assurance (including perpetual care if needed)
• Must prepare for very long-term management if required

What GISTM Doesn’t Address

Silent on:

• How long is “post-closure”? (10 years? 100 years? Forever?)
• What defines “safe closure” that allows relinquishment?
• What’s acceptable probability of failure for walk-away closure?
• Who bears responsibility if perpetual care needed?
• How to structure financial assurance for unlimited timeline?
• What happens when company no longer exists?

Why the silence?

Likely because:

• These are jurisdictional/regulatory policy questions, not technical standards
• International standard can’t dictate financial/legal structures (vary by country)
• Industry wasn’t ready to confront perpetual care reality in 2020

But the gap in the standard means operations can claim compliance while avoiding the hard questions about perpetual care.

How to Interpret GISTM for Perpetual Care Context

Good faith interpretation:

Requirement 5.7 (“demonstrate feasibility of closure”):

• If honest assessment shows passive closure infeasible, design should acknowledge perpetual care requirement
• Feasibility means technical AND institutional feasibility for entire timeline

Requirement 10.7 (“adequate financial capacity”):

• Must include perpetual care costs if that’s the reality
• Can’t define “closure complete” at arbitrary date if management still needed

Requirement 14 (long-term recovery):

• “Long-term” should be interpreted honestly (decades to centuries, not just 5-10 years)
• Recovery planning includes institutional arrangements for perpetual management

The spirit of GISTM requires honesty about actual closure timelines and costs, even when uncomfortable.

The Uncomfortable Conversations We Need to Have

Conversation 1: With Regulators

Question to ask: “What conditions must be satisfied for you to release our closure bond and allow relinquishment?”

Follow-up: “If those conditions can’t be satisfied because perpetual monitoring is needed, how do we structure ongoing responsibility?”

Many jurisdictions haven’t clearly answered this. Push for clarity.

Conversation 2: With Investors and Boards

Statement: “Our closure liability calculation assumes 15-year post-closure monitoring. But engineering assessment suggests monitoring may be needed indefinitely.”

Question: “Do we disclose this uncertainty? Do we revise financial provisions? Do we change project economics?”

Many companies know their closure estimates are optimistic but haven’t acknowledged it publicly. This is material financial risk.

Conversation 3: With Communities

Honest message: “We’re designing this facility to be stable and safe. But we can’t guarantee it will never need monitoring or intervention. Even in 100 years, someone may need to check on it.”

Question: “Are you comfortable with that reality? If so, what institutional arrangements do you want in place to ensure it’s done right?”

Most community consultations present closure as finite process. This isn’t honest.

Conversation 4: With Society

Question: “As a society, do we accept that some resource extraction creates perpetual obligations?”

Follow-ups:

• “If so, how do we structure responsibilities across generations?”
• “Do we prohibit projects that require perpetual care?”
• “Do we require trust funds sufficient for perpetual care as condition of approval?”
• “Do we acknowledge that taxpayers will ultimately backstop when private entities fail?”

This is fundamentally a values question that mining industry alone can’t answer.

Practical Guidance: What to Do Tomorrow

If you’re an Accountable Executive facing potential perpetual care:

Step 1: Commission Honest Assessment

Ask your EOR and closure team:

• “Under what conditions could we achieve walk-away closure where no monitoring or intervention is needed?”
• “What’s the realistic probability we achieve those conditions?”
• “What’s our honest assessment of how long monitoring might be needed?”
• “What could go wrong that would require perpetual intervention?”

Demand honest answers, not optimistic answers.

Step 2: Engage Regulator Early

Don’t wait until closure to discover regulator won’t allow relinquishment.

Ask now:

• “What are your criteria for closure bond release?”
• “If perpetual monitoring is needed, how do you want that structured?”
• “What financial assurance is acceptable for unlimited timeline?”
• “What’s your process for reviewing and updating closure plans as understanding evolves?”

Step 3: Assess Financial Implications

Calculate two scenarios:

Scenario A (optimistic): Passive closure achieved, 15-year monitoring, relinquishment Scenario B (realistic): Perpetual monitoring and maintenance required

Compare financial provisions:

• Current bond/assurance
• Required for Scenario A
• Required for Scenario B (perpetual care trust)

If gap is large, this is material financial risk that needs disclosure and management.

Step 4: Consider Design Modifications

If perpetual care likely:

• Is current design optimal for perpetual care scenario?
• Should you design for maintainability rather than passive stability?
• Should you maintain more robust access and infrastructure?
• Should monitoring systems be more durable/adaptable?

May be worth higher upfront cost for design better suited to long-term reality.

Step 5: Establish Governance for Uncertainty

You can’t know today whether perpetual care will be needed.

But you can establish process:

• Regular reassessment (every 5 years) of closure timeline assumptions
• Explicit triggers for when to establish perpetual care arrangements
• Stakeholder engagement process for major changes in understanding
• Financial planning that accommodates range of scenarios

Adaptive management for closure timeline uncertainty.

The Bottom Line: Honesty About Forever

Some tailings facilities will require management for periods longer than human institutions typically survive.

This is uncomfortable. It challenges the way we’ve always done mining. It makes projects less economically attractive. It raises questions we don’t want to answer.

But denying it doesn’t make it untrue.

GISTM requires safe closure. For some facilities, “safe” means “perpetually managed.”

The question isn’t whether this is fair or desirable. The question is whether we’re honest about it.

Are we:

• Designing appropriately for long-term realities?
• Providing adequate financial assurance for actual timelines?
• Creating governance structures that can persist?
• Engaging stakeholders honestly about perpetual obligations?
• Accepting societal responsibility for intergenerational impacts?

Or are we:

• Designing for optimistic scenarios we hope are true?
• Providing financial assurance based on desired timelines, not realistic ones?
• Assuming institutions will persist without planning for it?
• Telling stakeholders what they want to hear?
• Pretending future generations won’t inherit our obligations?

The difference between these two paths is the difference between responsible stewardship and intergenerational burden-shifting.

Your grandchildren’s grandchildren may still be monitoring the facility you’re building today.

What legacy are you leaving them?

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