Feasibility Studies

A feasibility study (FS) examines a selected development option in technical and economic detail. CRIRSCO's advisory June 2024 Template requires assessment of modifying and operational factors, with financial analysis sufficient to support development or financing decisions. Confidence exceeds that of a pre-feasibility study; national or regional rules govern public disclosure.^[1]

The practical question is whether the proposed mine can be delivered and operated on the stated basis, with an understood risk profile. A useful FS connects its recommendation to the engineering evidence, implementation arrangements and assumptions on which the conclusion depends. It also identifies the work that remains after the investment decision.

Defining the Selected Development Case

The study needs a clearly identified case: what will be mined, how it will be treated or sold, which facilities are included and how the development is expected to proceed. The preferred alternative from earlier work is the starting point, but its selection should remain open to challenge if subsequent evidence changes the basis.

McCarthy's discussion of mining feasibility studies identifies the final study's roles as demonstrating technical and economic viability, supporting detailed design and helping secure finance. It also cautions that further optimization and substantial engineering can follow study completion. A finished report therefore does not mean that every design choice has been exhausted or every construction document has been produced.^[2]

For an internal review, define the limits of the proposed commitment explicitly. A new mine, an extension of an operating mine and a replacement processing facility create different interfaces. The report should state which existing facilities or outside services the case relies on and which are included in the proposed expenditure. That distinction prevents assumptions about shared infrastructure from disappearing between disciplines.

Checking Technical Consistency

A common technical baseline allows designs, estimates and schedules to refer to the same project. The US Government Accountability Office's 2020 cost guide describes this connection between technical definition, assumptions and cost credibility. Although written for programme cost assessment, the principle is useful for reviewing a mining study's internal consistency.^[3]

Applied to a mine, a consistency review can follow the physical chain from the geological interpretation to the planned product. The following are examples of review questions, not a universal deliverables checklist:

Process confidence deserves particular attention where feed properties vary. CIM's 2022 mineral-processing guidance links sampling and variability testing with expected plant feed, product characteristics and process performance. It calls for increasing investigation as project definition advances, especially where the deposit or technology is complex. An average recovery assumption alone does not describe that evidence.^[4]

Definition maturity must be checked across dependent packages. AACE notes that a well-defined process plant may still face major change if connected utilities are less developed. The review therefore needs to identify lagging interfaces before treating the combined estimate as ready for the decision.^[5]

Economics, Cost Basis and Confidence

The financial model translates the engineering and production case into cash flows through time. Its basis includes production quantities, grades and recoveries, product prices, capital and operating expenditure, taxation and the treatment of financing. Nell and Burks describe these as connected inputs when assessing development cases.^[6]

Economic indicators should be read with their underlying basis. State the currency and valuation date, the treatment of escalation and discounting, and whether a result describes the project before financing or the return to a particular investor. Comparing indicators built on different bases can confuse a change in financing or assumptions with a change in the underlying development case. These are matters for the study's economic specialists to explain and reconcile.

Estimate class and accuracy also require qualification. AACE's 2022 guidance identifies scope-definition maturity as the primary classification criterion and explains that class does not uniquely determine accuracy. A study title therefore cannot justify a fixed, universally applicable error range.^[5]

The cost basis should make omissions visible. For example, a package priced to supply equipment may leave installation, access, temporary services or commissioning support elsewhere in the estimate. An effective review asks where each necessary activity has been included and whether the corresponding time and resources appear in the execution plan. A contingency allowance needs an explained risk basis; it should not be used to make an undefined package appear complete.^[6]

Showing How the Project Can Be Delivered

Constructability examines how the proposed design can be built under the conditions of the project. Calienes' account of mining constructability work connects design with capital estimation, the master schedule, procurement and the execution plan. It also identifies access, climate, interactions between disciplines and interference with an existing operation as relevant concerns. These are practical issues to investigate during study development, not simply after a construction contract is placed.^[7]

A delivery review can work backwards from the intended production start. What has to be commissioned? Which utilities and access arrangements must be available first? What procurement or construction activities depend on completing investigations or design packages? Which interfaces involve parties outside the project team's direct control? The answers should be consistent with the schedule used in the economic evaluation.

For an expansion, the review also needs to distinguish the proposed facility's performance from the operating mine's ability to accommodate the change. A technically workable connection can still require an interruption, temporary arrangement or revised commissioning sequence. These consequences belong in the evaluated case when they are material to its implementation.

Environmental and Social Commitments

Environmental and social provisions need an implementation basis as well as an assessment. For IFC-financed projects covered by its Performance Standards, the 2012 Performance Standard 1 connects identified risks with management actions, responsibilities, resources and measurable outcomes. It also provides for changes in circumstances and feedback from monitoring. This is a financing framework with a defined scope, not a universal substitute for the requirements of the host jurisdiction.^[8]

In the FS, a useful review follows consequential commitments into the engineering and economic case. If an assessment depends on a particular water-management arrangement, transport route, construction sequence or closure outcome, identify the corresponding design provision, schedule assumption and cost. Record the actual status of required decisions and agreements. Planned, submitted, conditional and completed items should remain distinguishable so that a reviewer can understand what the investment conclusion still depends on.

Risk, Review and the Investment Recommendation

Sensitivity analysis examines the effect of changing selected inputs. It does not, by itself, describe the combined uncertainty of all inputs. GAO's guidance distinguishes sensitivity work from risk and uncertainty analysis and emphasizes that tested variations need a basis in the technical assumptions. A collection of arbitrary percentage changes is a weak substitute for identifying the reasons the case could differ.^[3]

An illustrative delivery scenario is a later-than-assumed external power connection. The consequence may extend beyond a delayed utility milestone to temporary supply arrangements, commissioning sequence and revenue timing. The purpose of examining the scenario is to trace those linked effects and identify what evidence or arrangement could reduce the uncertainty. It does not imply a particular technical solution or numerical loss.

The recommendation should distinguish the study team's conclusion from the owner's approval and a lender's financing decision. The description bankable does not guarantee that a lender will provide funds; financing also depends on considerations outside the study team's control.^[2]

A useful decision record identifies the evaluated case, material assumptions, remaining work and conditions attached to the recommendation. Reviews should leave a trace of significant challenges and how they were resolved. If new information changes a consequential premise, the affected engineering, costs, schedule and economic conclusion need reconsideration together. The FS then serves as an accountable basis for commitment and subsequent change, with its limitations visible to those relying on it.