The Rock DoesNot Lie
Physical-Financial Reconciliation and the audit of deferred stripping in open-pit mining
Conventional audit tests financial records against other financial records. Because the taxpayer authors every document in a stripping computation, that method is structurally blind. This paper makes the ore body the primary object of audit and reduces the financial claim to a testable hypothesis.
Why ledger auditing cannot work here
Deferred stripping — capitalising waste-removal costs under IFRIC 20 — is among the largest recurring discretionary judgements in extractive taxation, and among the least auditable. It rests on quantities that originate outside the financial system: strip ratios, component boundaries, bank cubic metres.
Because the taxpayer controls the generation of every document, a rational misstater produces a set that is internally consistent by construction. Conventional tests detect only errors of execution. Detection requires an anchor outside that control — and a modern mine supplies several: dispatch logs built for maintenance, surveys that certify contractor payments, metered diesel disclosed as scope-1 emissions, and a pit photographed from orbit every few days.
What IFRIC 20 requires
A stripping asset may be recognised only where three conditions hold together. Each is also a manipulation surface — the paper catalogues twelve schemes (F1–F12), of which four are operationalised here.
Probable future benefit
Improved access to ore must be probable. The boundary against ordinary production cost is where F7 operates — booking post-production cost as development stripping.
An identifiable component
Access must relate to a specific component. Define it as the entire final pit and amortisation stretches across decades; re-slice opportunistically and the base moves at will.
Reliably measurable cost
Costs must be measured, then split between inventory and asset on the excess of actual over expected strip ratio (¶13–14). Both pool and ratio are manipulable — F4 and F3.
Headline result
On a physically consistent synthetic mine-year with four manipulation schemes injected at realistic intensities, the engine identifies every scheme with quantified, evidence-cited adjustments — while returning zero findings on an honest control derived from identical physics.
Seven of nine indicators fail, one warns. Five findings issue, each citing rule, uncertainty and evidence. Risk score 0.99.
zero findings, risk score 0.23
The specificity result matters as much as the sensitivity one. Administrations fear wrongful assessment; taxpayers purchasing assurance fear the opposite error. The engine leaves a clean position alone.
The mountain keeps better books than the CFO.
Four channels, one physics
PFR asks one question: does there exist an excavation history consistent with all admissible evidence under which the claim is true? Verification builds a maximum-likelihood reconstruction — the pit digital twin — with propagated uncertainty, then tests the claim against the supportable set it implies.
Each channel is generated by a different function of the firm, for a non-tax audience. Co-ordinated falsification of all of them is assumed infeasible; partial falsification shows up as cross-channel residuals, and those residuals are the detection signal.
Survey differencing
Monthly surfaces yield excavated solids with error-propagated confidence intervals. These surveys certify contractor payments — falsifying them means underpaying your own contractors.
Satellite DEM differencing
Public archives observe the pit directly and are not producible by the taxpayer at all — an independent volume check that also dates the excavation.
Haul-energy feasibility
Diesel consumed against the haul energy the claim requires. Fuel reconciles to supplier invoices and ESG disclosures, so the figure carries exposure elsewhere.
Block model tribunal
Conditional simulation over the taxpayer's own block model yields the distribution of supportable expected ratios — testing the assertion against the mine's own geology.
The money identity
Total disallowed deductions decompose exactly into three independently evidenced components. Each maps to one scheme and one finding, and the findings tie arithmetically to the recomputation — the property that survives objection and appeal.
F4 pool stuffing
ledger ontology
F5 phantom volume
survey / satellite / energy
F3 ratio inflation
block-model tribunal
Each term rests on a different channel, so a finding cannot be defeated by attacking one source. The split is exact by construction, and the acceptance-test suite asserts the tie-out.
Findings on the fraudulent case
One mine-year of the synthetic Kavarra pit: a 60×40×24 block model on 10 m benches, calibrated so the Stage 3 pushback's true life-of-component ratio is 4.9:1, with twelve months of excavation, monthly surveys, fleet cycles at 218 t payload and physics-derived diesel.
From that single truth, two submissions are derived — one honest, one with four schemes injected. Surveys, satellite, fuel and dispatch reflect true physics in both.
The honest control
Run identically, the honest submission passes all nine indicators. Supportable ratio recomputes to 4.8:1 (95% interval 4.6–4.9) against the 4.9:1 used — the 90th percentile of its own geology, aggressive but inside tolerance. Risk 0.23. Zero findings, K0.0M proposed.
| Finding | Scheme | Adjustment | Basis |
|---|---|---|---|
| DS-2026-014 | F3 ratio inflationASSERTED 6.8:1 VS TRUE 4.9:1 | K17.3M | Recomputed κs K59.3M vs K42.0M claimed |
| DS-2026-015 | F5 phantom volume38.5M BCM CLAIMED VS 35.3M MINED | K12.5M | 3.2M BCM unsupported, at pool unit cost |
| DS-2026-009 | F4 pool stuffingDEWATERING, CAMP, COMMUNITY COSTS | K11.8M | Ineligible content, IFRIC 20 ¶12 |
| DS-2026-011 | F7 boundary abuseBOOKED AT A SATELLITE PIT | K7.4M | Ramp-curve commercial-production test |
| DS-2026-017 | F8 consequential | K4.5M | Amortisation base vs component reserves |
| Total | Risk score 0.99 | K53.5M | First three tie exactly to the money identity |
Table 1. Fixed seeds, fully reproducible. Engine wall time under one second per case, excluding the Monte Carlo tribunal (~15s at 1,500 realisations).
Claim exceeds the rock
3.2M BCM above survey-differenced volume, corroborated by satellite DEM differencing and a 16.8 ML diesel shortfall against the haul energy claimed.
Outside its own geology
The asserted 6.8:1 ratio lies above the 99.9th percentile of the distribution built from the taxpayer's own block model.
Two ledgers disagree
Material moved per the sustainability report contradicts the tax computation; the component register's metadata post-dates the year it governs.
Evidentiary posture and limitations
Deterministic first. The machine-learning layer prioritises but never asserts. Every finding carries a rule citation, an uncertainty statement and an evidence reference.
Thresholds in standard-error units. Measurement-noise objections are answered in advance rather than litigated afterwards.
Adversarial cost multiplies. Coherent deception now requires co-ordinating surveys, fuel records, dispatch data, investor-facing reserve statements — and a satellite record that cannot be manipulated at all.
No systems integration required. No data leaves the administration; the jurisdiction rule pack is authored with, and retained by, counterpart staff.
Detection requires an anchor outside the taxpayer's control — or outside its practical capacity to co-ordinate.
Research agenda
Selected references: IFRIC 20 (2011) · Journel & Huijbregts (1978) · Chilès & Delfiner (2012) · Nigrini (2012) · IGF/OECD BEPS in Mining · TADAT Field Guide · Maitra (2026), MDRIA MWP-2026-01.
Availability. Platform design document, reference implementation with acceptance tests, interactive demonstrations, evidence-request register and deployment package available from the author. All results reproducible with fixed seeds. © 2026 Maitras.ai.