Technical Appendix

USAS Galena Mine – TAIE™ Structural & Endowment Re-Evaluation

Supporting Methods, Assumptions, and Analytical Logic

A1. Purpose and Scope

This Technical Appendix supports the Executive Case Study by documenting the analytical framework, assumptions, constraints, and reasoning applied in the TAIE™ re-evaluation of the Galena Mine.

It is intended for:

  • Technical investors

  • Mining engineers and geologists

  • Due diligence teams

  • Strategic partners

This appendix does not introduce new conclusions. Its purpose is to explain how the conclusions were reached and why they are technically defensible.

A2. Data Sources and Input Classes

TAIE does not require novel or proprietary data to function. The Galena analysis was conducted using existing, independently generated, and publicly available information, integrated within a unified analytical framework.

A2.1 Primary Input Classes

  • Historical mine production data

  • Published geological descriptions of the Galena Mine

  • Structural orientations and vein geometries

  • District-scale geological context (Coeur d’Alene District)

  • Regional tectonic interpretations

  • Publicly available geophysical context (where applicable)

A2.2 What Was Explicitly Not Used

  • Proprietary drill-hole databases

  • Non-public geophysical surveys

  • Speculative grade assumptions

  • Resource estimates beyond public disclosures

This constraint ensures that TAIE’s conclusions arise from interpretation and structural logic, not data advantage.

A3. TAIE Analytical Stack (Galena Configuration)

TAIE operates as a layered system. For the Galena evaluation, the following subsystems were active:

A3.1 Earth-System Context Layer

  • Regional tectonic setting

  • Crustal-scale structural inheritance

  • Long-lived deformation corridors

  • Temporal persistence of fluid pathways

This layer establishes whether vertical continuity is geologically plausible before any mine-scale interpretation is applied.

A3.2 Structural Continuity Layer

  • Orientation coherence of known structures

  • Structural intersection density

  • Persistence of structural trends with depth

  • Absence of termination features at current mining limits

This layer evaluates whether mineralized structures are likely to persist, not whether they have already been drilled.

A3.3 Vertical Zoning Logic Layer

TAIE applies empirically observed vertical zoning patterns from polymetallic systems globally, including:

  • Silver-dominant assemblages commonly occupying upper structural levels

  • Increasing gold enrichment with depth in analogous systems

  • Zoning transitions across predictable pressure–temperature regimes

Zoning logic is applied probabilistically, not deterministically.

A3.4 Actuarial Table (AT) Constraint Layer

TAIE uses actuarial tables derived from global mining analogs to constrain pattern recognition.

These tables define:

  • Expected depth persistence ranges

  • Typical metal zoning sequences

  • Statistical distribution of endowment by system type

Patterns falling outside actuarial bounds are rejected.

A4. Structural Interpretation Methodology

A4.1 From Veins to Systems

Conventional interpretations often treat Galena as a collection of discrete veins. TAIE reframes these as expressions of:

  • A connected structural network

  • Repeated reactivation over geological time

  • Shared fluid pathways

This shift is critical: systems persist where individual veins appear to end.

A4.2 Structural Node Identification

Galena exhibits characteristics consistent with a structural node, including:

  • Converging structural orientations

  • Evidence for repeated mineralization events

  • Sustained grade persistence with depth

In global analog systems, such nodes are statistically correlated with deeper endowment.

A5. Depth Bias and Its Consequences

Historical drilling at Galena was optimized for:

  • Near-term production

  • Known grade envelopes

  • Economic access

As a result:

  • Drill-depth limits are operational, not geological

  • Resource boundaries coincide with development horizons

  • Lack of deep drilling cannot be interpreted as lack of mineralization

TAIE explicitly corrects for this bias.

A6. Silver Endowment Interpretation

TAIE does not assert a revised silver ounce figure beyond current reporting.

Instead, it demonstrates that:

  • Structural continuity remains open at depth

  • No geological exhaustion signal is observed

  • Reported endowment reflects mining strategy rather than system scale

This distinction is critical for valuation analysis.

A7. Gold Potential Logic

Gold potential at Galena is treated as a hypothesis with defined confidence bounds, not a claim.

A7.1 Supporting Indicators

  • Vertical metal zoning logic

  • District-scale analog systems

  • Structural persistence beneath the silver-dominant zone

  • Actuarial alignment with polymetallic systems hosting deep gold

A7.2 What TAIE Does Not Claim

  • Guaranteed gold grades

  • Immediate economic viability

  • Uniform mineralization

TAIE identifies where gold becomes increasingly probable, not how much exists.

A8. Actuarial Table Deviations (>5%)

In accordance with TAIE operating rules, pattern-recognition deviations exceeding ±5% from baseline actuarial expectations were flagged.

A8.1 Observed Deviations

  • Depth persistence probability exceeds baseline expectations for “mature” silver systems

  • Metal zoning aligns more closely with polymetallic gold–silver systems

  • Structural density exceeds median values for comparable deposits

A8.2 Interpretation

These deviations are:

  • Directionally consistent

  • Structurally explainable

  • Not isolated anomalies

Clustering of deviations materially increases confidence.

A9. Economic Modeling Constraints

TAIE does not produce standalone feasibility models.

Economic insights are derived under the following constraints:

  • No assumed increase in mining rate

  • No assumed cost reductions

  • No speculative metal price forecasts

Value uplift arises from optionality, not aggressive assumptions.

A10. Recommended Technical De-Risking Path

TAIE-generated recommendations emphasize capital efficiency:

  • Confirm structural continuity at depth

  • Test zoning transition windows

  • Validate fluid-pathway persistence

Each step is designed to:

  • Answer a specific geological question

  • Minimize sunk cost

  • Preserve optionality

A11. Limitations and Uncertainties

TAIE explicitly acknowledges uncertainty.

Key uncertainties include:

  • Exact depth of zoning transitions

  • Grade continuity at depth

  • Local structural complexity

TAIE does not eliminate uncertainty — it makes it explicit and manageable.

A12. Replicability

The Galena analysis is replicable using:

  • Publicly available data

  • The TAIE analytical framework

  • Comparable system analogs

No proprietary assumptions are required.

A13. Summary

This Technical Appendix demonstrates that the Galena re-evaluation is:

  • Grounded in established geological principles

  • Constrained by actuarial realism

  • Explicit about uncertainty

  • Focused on testable outcomes

The conclusions presented in the Executive Case Study follow directly from this framework.