A mine's financial model can be arithmetically correct while combining assumptions from different technical cases. The risk grows as geologists, engineers and commercial advisers update separate files. Before an investment committee relies on the result, the owner should demonstrate that quantities, feed, recovery, products, costs and dates all describe the same version of the proposed operation.
Establish a controlled input register
The register should identify each material input, its source document, effective date, responsible author and status. A modelled value, a supplier quotation and an observed result should remain distinguishable. CIM's estimation and processing guidance supports transparent assumptions and technically grounded cost inputs. The owner should specify which study release governs the decision. A hypothetical new mining schedule should not be combined silently with a plant forecast developed for a different feed. Investors need enough provenance to understand which inputs are provisional and which parts of the conclusion would need reconsideration if those inputs change during the continuing development programme.
Trace one period through the physical system
The team should be able to follow the material mined, material delivered to processing, recovery and products for a representative period. Stockpile changes and internal transfers need a consistent account. A lifetime total may reconcile while individual periods do not. The owner should compare the technical schedules with the financial model's timing. A hypothetical product quantity arriving before the feed is available exposes a schedule mismatch even if annual totals look plausible. The review should investigate the mechanism behind differences rather than insert a balancing quantity that makes the spreadsheet appear complete without resolving the physical or commercial inconsistency.
Follow the product into receipts
Sales assumptions should use the same product specification, quantity and delivery boundary as the technical case. Pricing adjustments, transport and payment timing need the corresponding commercial evidence. The model must also distinguish revenue recognition from cash receipt under its chosen accounting and planning approach. Appropriate professional advisers should assess the actual transaction. Investors should examine whether customer acceptance or a shipment delay changes working capital. Owners can preserve scenarios that alter linked assumptions together, avoiding a combination of favourable individual sensitivities that no coherent operating plan could simultaneously achieve under the actual constraints being investigated.
Use a change log to explain the conclusion
A revised forecast should state which inputs changed and why, with material consequences attributed where practical. The committee can then distinguish new evidence from corrections or changed preferences. Owners should allocate enough time for this reconciliation before a financing presentation is released. Investors gain a clearer account of the study's maturity and remaining uncertainty. The objective is not an elaborate spreadsheet for its own sake. It is a decision record in which each significant figure connects to an identifiable technical or commercial assumption, allowing the next expenditure or commitment to be assessed against the project the team actually intends to develop.
