What is the difference between a PEA, a Pre-Feasibility Study, and a Feasibility Study?

After a PEA, projects advance through two more rigorous studies:

• Pre-Feasibility Study (PFS): demonstrates, with reasonable confidence, that a project is economically viable. It must be based on Indicated and Measured resources (no Inferred) and is the minimum required to declare a mineral reserve.
• Definitive / Bankable Feasibility Study (DFS/BFS): the highest-confidence study, with engineering detailed enough (typically ±10–15% cost accuracy) to raise construction financing and support a board's build decision.

Each step costs more and takes longer, but converts geological and economic uncertainty into something a lender will underwrite. Key outputs to read: post-tax NPV and IRR (and the discount rate and metal-price assumptions behind them), initial capex, AISC, mine life, and payback.

For investors, the study stage is a proxy for de-risking: PEA = concept, PFS = credible, DFS = financeable. Watch for capex inflation and metal-price assumptions that look generous versus spot.