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Mining and Extraction (Metals, Minerals and Coal): Key Audit Considerations
Industry-specific audit considerations, tailored procedures, and evidence points for Hong Kong audit teams.
Industry Overview
Last updated: 16 September 2026
Mining and extraction entities bring together operational, geological, commodity-market and environmental information in financial reporting. Audit risk is often concentrated in balances and disclosures shaped by specialist data and forward-looking assumptions, including exploration and evaluation assets, producing mine assets, inventories, revenue arrangements and closure obligations. Teams should obtain a sound understanding of the mine life cycle, products, sales routes, reporting systems and the roles of technical specialists before designing responses to assessed risks.
This article is general technical education for Hong Kong auditors. It illustrates how an audit team can tailor risk assessment and evidence gathering to mining operations under the applicable HKFRS framework and the risk-based concepts in HKSAs, including the evaluation of accounting estimates and relevant controls. The nature, timing and extent of work must remain responsive to the entity's facts, materiality and assessed risks.
Key Audit Issues
Exploration, evaluation and mine-property carrying amounts
Distinguish the project stage and the nature of expenditure when assessing capitalisation, classification and disclosure. Exploration and evaluation assets may require consideration under HKFRS 6, while producing assets require assessment under the applicable standards. Changes in licences, feasibility, reserves, commodity prices, operating performance or financing can indicate that impairment assessment is necessary; the relevant cash-generating-unit assumptions and disclosures can be highly judgemental.
Mineral resources, reserves and unit-of-production measures
Reserve and resource estimates can affect mine-life assumptions, unit-of-production depreciation or depletion, impairment models and rehabilitation estimates. The audit issue is not merely arithmetic: teams should consider the provenance of geological data, the competence and objectivity of the experts involved, the estimate's sensitivity to grade, recovery, cut-off assumptions and mine-plan changes, and whether information used in accounting agrees with approved technical reporting.
Ore, concentrate and finished-product inventories
Physical quantities, grade, recoveries, processing status and allocation of production costs can be material to inventory valuation. Stockpiles and work in progress may be difficult to measure, while net realisable value can move with commodity prices, treatment and refining charges, transport costs and expected recoveries. Cut-off between production, inventory and cost of sales also warrants focused attention.
Sales contracts, provisional pricing and revenue cut-off
Off-take arrangements may include delivery terms, assay-based adjustments, penalties, variable consideration, provisional prices and final settlement mechanics. Under the high-level principles of HKFRS 15, the team should identify the contractual rights and obligations and evaluate when control transfers. Revenue, receivables and subsequent price adjustments may require separate attention where shipment, customer acceptance, assays or pricing periods straddle year-end.
Rehabilitation, restoration and decommissioning obligations
Mine closure and site-restoration obligations commonly depend on permits, legal or constructive obligations, engineering scope, timing, inflation and discount-rate assumptions. The completeness and measurement of provisions under the applicable HKFRS requirements can be affected by revised closure plans, disturbed land, changes in operations and new technical studies. Related asset adjustments, finance-cost accretion and disclosures should be considered together.
Tailored Audit Procedures
Map the operation and reconcile project information
Obtain a project-by-project schedule covering licences, development stage, capitalised expenditure, production status and closure status; reconcile material balances to the general ledger. Inspect a selection of rights, permits, board approvals, feasibility or mine-plan documents and capital authorisations, and compare the operational status evident from these records with management's accounting classification.
Evaluate specialist-supported resource and reserve inputs
For inputs used in material accounting estimates, evaluate the competence, capabilities and objectivity of management's specialists and understand the data, methods and assumptions they use. Trace selected reserve, grade and recovery inputs from approved technical reports into depreciation, impairment or provision models; test the model's mathematical accuracy and investigate material differences from prior approved plans or actual production outcomes.
Attend inventory counts and test quantity and quality data
Where practicable, attend counts at mines, stockpiles, ports, warehouses or processing facilities and perform test counts or survey observations responsive to the risks. Reconcile production, processing, dispatch and inventory records; inspect weighbridge tickets and chain-of-custody records; and assess how assay results, moisture, recoveries and treatment losses are incorporated into recorded quantities and grades.
Test inventory cost and net realisable value
Vouch selected material, labour, processing and freight costs to source evidence and evaluate whether the entity's cost-allocation method is consistently applied. Reperform selected net-realisable-value calculations using year-end or relevant subsequent sales information, contract terms, observable commodity-price data where applicable, expected treatment and refining charges, transport costs and expected recoveries; challenge material departures from historical outcomes or approved forecasts.
Test revenue and provisional settlements around year-end
Select sales before and after year-end and inspect contracts, invoices, bills of lading or other delivery evidence, customer acceptance where relevant, weight and assay certificates, and cash receipts or settlement statements. Evaluate whether the recorded timing of revenue follows the contract's control-transfer terms, recompute selected provisional-price adjustments, and investigate credit notes, returns, final assays and price settlements arising after year-end.
Challenge impairment and rehabilitation estimates
For material models, test data integrity and reperform key calculations. Assess the reasonableness of significant assumptions against approved mine plans, current operating performance, external market inputs and available technical evidence; perform sensitivity analysis for assumptions with high estimation uncertainty. Inspect closure plans, environmental or operational correspondence, engineering estimates and approved budgets, and evaluate whether the provision, related asset effects and disclosures are consistent with the evidence obtained.
Controls and Evidence to Consider
Governed technical-model change management
Consider whether resource and reserve models, mine plans and key assumptions are subject to defined ownership, version control, independent review and documented approval. Useful evidence includes approved technical reports, model-change logs, reconciliation of geological and production data, specialist credentials and minutes recording review of significant revisions.
Production, inventory and assay data integrity
Consider controls linking extraction, processing, weighbridge, dispatch and inventory records, with restricted access to master data and timely investigation of variances. Relevant evidence can include count instructions, signed count sheets, scale-calibration records, assay-laboratory reports, chain-of-custody documentation, stockpile surveys and production-to-inventory reconciliations.
Contract-to-cash and pricing-settlement controls
Consider whether sales contracts and changes to pricing or delivery terms are independently approved, captured in the accounting system and reconciled to shipment evidence and settlement statements. Evidence may include executed contracts, delegated-authority approvals, shipping documents, customer confirmations where obtained, pricing calculations, credit-note reviews and reconciliations of provisional to final invoices.
Closure-obligation monitoring and estimate review
Consider whether management periodically identifies new or changed site obligations and subjects closure-cost models to cross-functional technical and finance review. Evidence may include permits and correspondence, disturbance-area records, approved closure plans, third-party engineering estimates, assumption papers, management review sign-offs and reconciliations between the provision model and the financial statements.
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