Why the distinction exists
Reporting codes for mineral projects were written after investors lost money on tonnage figures that had little behind them. The codes used on the main exchanges, the JORC Code in Australasia and National Instrument 43-101 with the CIM Definition Standards in Canada, set out which words may be used for which level of knowledge, and who may sign them. They belong to a family of aligned national codes, so the logic below applies widely even where the wording differs.
What an exploration target is
The JORC Code defines an Exploration Target as a statement or estimate of the exploration potential of a mineral deposit in a defined geological setting, quoted as a range of tonnes and a range of grade, relating to mineralisation for which there has been insufficient exploration to estimate a Mineral Resource.
NI 43-101 does not use the same term but allows the same thing: disclosure of the potential quantity and grade of a target for further exploration, provided it is expressed as ranges and accompanied by a statement that the figures are conceptual, that there has been insufficient exploration to define a mineral resource, and that it is uncertain whether further exploration will result in one.
Three features follow. The figures are always ranges, never single numbers. The basis for them must be explained: which drilling, sampling or geophysics they rest on. And they must not be presented, or added to, as if they were resources.
What a mineral resource is
A mineral resource is a concentration of material in the ground with reasonable prospects for eventual economic extraction, whose location, quantity, grade and continuity are estimated from specific geological evidence, including sampling. It is classified by confidence:
- Inferred: quantity and grade estimated from limited evidence; continuity is implied but not verified.
- Indicated: evidence is sufficient to assume continuity and to support mine planning.
- Measured: evidence is sufficient to confirm continuity.
A resource estimate is prepared by, or under the supervision of, a Competent Person (JORC) or Qualified Person (NI 43-101): a professional with defined experience and membership of a recognised body, who takes personal responsibility for it. A mineral reserve is a further step, the economically mineable part of indicated and measured resources, demonstrated by at least a pre-feasibility study.
Side by side
| Exploration target | Mineral resource | |
|---|---|---|
| Status | Conceptual | Estimated and classified |
| Expressed as | Ranges of tonnes and grade | Tonnes and grade by category |
| Data behind it | Too little to estimate a resource | Enough to estimate or assume continuity |
| Economic test | None | Reasonable prospects for eventual economic extraction |
| Use | Justifying and directing further exploration | Basis for economic studies; public reporting |
| Public disclosure | Only with prescribed cautionary language | Under a qualified or competent person’s responsibility |
Why ranges are still useful
A project with twenty holes has no resource and still has decisions to take: whether to drill more, how to describe the opportunity to a partner, which of two zones deserves the next round of funding. A conceptual range answers those questions better than silence and far better than a single optimistic number. Its width shows how much is unknown, and the way it responds to extra holes shows what the next programme is worth.
The discipline is in the handling. The low case and the high case should come from stated assumptions, ideally from more than one geological interpretation. The document should say what the range rests on and what would change it.
Where Gossan's work sits
Tonnage, grade and probability figures produced by Gossan are conceptual. They are decision support, not mineral resource or reserve estimates under NI 43-101 or JORC, and public disclosure requires a qualified person's sign-off.
Our exploitation-potential screening produces ranges of this conceptual kind for internal decisions and private discussions, together with the drilling that would narrow them. When a project approaches the density of data a resource needs, the estimate belongs with a qualified person, and a clean, validated database is the most useful thing to hand over.
This page is a general explanation, not legal or regulatory advice. The codes themselves, and your exchange's rules, are the authority.