Mining Studies · Stage 3
Definitive feasibility studies (DFS)
An investment-grade, bankable study providing the detailed technical and financial basis for a decision to mine, project financing and execution planning.
Stage 3 · −10% / +15% accuracy
The bankable basis for a decision to mine
A definitive feasibility study — also called a bankable feasibility study (BFS) — is the most detailed and rigorous study stage. It develops the preferred case selected at PFS into a fully engineered, costed and scheduled project, to a level of confidence that supports a final investment decision and external project finance.
At DFS, estimates are built from detailed designs, firm quotations and test work, and the financial model is robust enough for lenders and investors to rely upon. The output is not just a verdict — it is an execution-ready plan.
A DFS answers the last question: not just “can this be built?” but “exactly how, at what cost, and with what return?”
Scope
What a DFS delivers over a PFS
Detailed design
Final mine designs, layouts, access and infrastructure engineered for construction and operation.
Final schedule
A fully integrated production and development schedule reconciled to equipment and people.
Bankable estimates
Capital and operating costs to −10% / +15%, built from detailed quantities and firm quotes.
Financial model
An auditable discounted cash-flow model with valuation, funding and sensitivity analysis.
Risk & execution
Risk register, implementation plan, contracting strategy and path to first production.
Ore Reserve
A Reserve statement to the standard required to support disclosure and financing.
Outcome
Decision-ready and execution-ready
- A comprehensive, auditable DFS report suitable for board and financier review
- Capital and operating cost estimates to bankable accuracy (−10% / +15%)
- A financial model robust enough to support project finance and investment decisions
- An Ore Reserve statement signed by a Competent Person
- An implementation plan, schedule and risk register to move into execution
FAQ
Definitive feasibility studies, answered
Is a DFS the same as a bankable feasibility study?
In practice yes. DFS and bankable feasibility study (BFS) both describe an investment-grade study with about minus 10 to plus 15 per cent cost accuracy, based on detailed engineering, firm supplier quotations and confirmed metallurgical test work — robust enough for project financiers to lend against.
What accuracy does a DFS provide?
Approximately minus 10 to plus 15 per cent. That band is achieved through detailed engineering design, firm quotations for major equipment and contracts, confirmed geotechnical and metallurgical test work, and an auditable basis of estimate for every major cost item.
What do I get at the end of a DFS?
An auditable study report, bankable capital and operating cost estimates, a robust financial model and valuation, a JORC-compliant Ore Reserve statement, and an implementation plan — the complete technical basis for a final investment decision and project financing.
Sources: JORC Code 2012 (jorc.org) · AusIMM Study Processes Handbook — Monograph 35 (2024)
Related services
Build on your DFS
Heading for a decision to mine?
A DFS gives boards and financiers an investment-grade basis. Tell us your timeline and we will scope the work and the Competent Persons.