Inferred mineral resources rarely appear in discounted cash flow models — yet they routinely drive 20–40% of a junior explorer's market capitalisation. This disconnect between financial modelling convention and market pricing creates both opportunity and disclosure risk. Understanding how to bridge that gap is one of the most practically valuable skills a QP can offer a capital-markets-facing client.
This post examines what "Inferred" actually means under the major reporting codes, why markets price inferred inventory the way they do, how to communicate it responsibly to financially literate audiences, and where the securities-law exposure lies for companies that get it wrong.
What "Inferred" Actually Means Under the Codes
All three major codes — NI 43-101/CIM, JORC 2012, and SK-1300 — define an Inferred Mineral Resource as a quantity and grade estimated on the basis of limited geological evidence and sampling, sufficient to imply continuity but not to verify it. The CIM Definition Standards (2014) are explicit: the level of confidence is insufficient to apply any modifying factors and must not be converted to a mineral reserve.
The phrase "insufficient to apply modifying factors" is technically precise and practically important. It means that a QP has concluded there is not enough information to assess whether the material can be economically extracted under any defined set of operating conditions. This is not a statement that the material is uneconomic — it is a statement that the data do not support economic analysis at this stage.
The distinction matters enormously for how the resource should be communicated to investors. An inferred resource is a geological statement of potential, not an economic statement of value.
Under NI 43-101 and JORC 2012, it is a disclosure violation to include Inferred resources in a mine plan, cash flow model, or any statement that implies economic extraction has been demonstrated. The QP's certificate covers this obligation — and the QP is liable if the issuer's disclosure breaches it.
Why Markets Price Inferred Resources
If inferred resources cannot be modelled in a DCF, why do they move stock prices? The answer lies in optionality theory and the way mining capital markets think about exploration upside.
A junior explorer's equity value can be decomposed into two components: the net present value of the project's currently Measured and Indicated inventory (the "known" value, approximated by a DCF), plus the value of the option to discover and define additional resources. Inferred inventory is the most tangible proxy for the second component: it tells the market that there is a geological system of some scale, that initial drilling has encountered the expected mineralisation, and that there is a credible pathway to upgrading the inventory with additional work.
Buy-side analysts who cover juniors routinely use EV/oz or EV/lb metrics applied to inferred inventory at a discount to Measured/Indicated — typically 25–50% of the M&I in-situ value. This is not a rigorous valuation methodology; it is a market convention that prices the probability of upgrade. The magnitude of the discount reflects the geological complexity, the quality of the historical data, and the amount of work required to achieve Indicated classification.
"The market is not pricing inferred resources as if they are real. It is pricing the probability that they will become real — and that probability is a function of geological quality, not just tonnage."
How to Communicate Inferred Resources to Investors
The QP's job in communicating inferred inventory to a financially literate audience is to give them the information they need to assess the upgrade probability — without crossing into economic statements the code does not permit. In practice, the following disclosures accomplish this:
Geological Continuity Narrative
Describe the deposit model and the evidence for geological continuity at the scale of the inferred inventory. What drill spacing does the inferred classification reflect? What is the variogram range in the primary direction of continuity? Has the system been drilled to closure or does it remain open? A deposit that is open in three directions at the inferred resource boundary has higher upgrade potential than one constrained by geological limits — and the market should be told this.
Upgrade Pathway and Work Programme
Under NI 43-101 Item 25 (Recommendations), the QP is expected to describe the work required to advance the project. For a deposit with significant inferred inventory, this should include an explicit statement of the infill drill spacing required to achieve Indicated classification, the estimated number of holes and metres, and the geological basis for that spacing recommendation. This is not an economic guarantee — it is a technical roadmap that allows investors to assess the cost and timeline of upgrade.
Classification Sensitivity
A sensitivity table showing resource tonnage and grade at multiple cut-off grades — clearly labelled by classification — gives financially literate readers the information to build their own EV/unit-metal scenarios without the QP making economic claims. This is standard practice in well-written NI 43-101 technical reports and should be extended to the executive summary where the inferred component is material.
Securities Law Exposure: Where Companies Get Into Trouble
The most common securities disclosure failures I have seen in inferred resource communications fall into three categories:
- Implicit economic statements. Press releases that describe inferred resources using language such as "represents significant future cash flow" or "supports a mine plan extension" are making economic claims that the classification does not support. This language, appearing in a TSX-listed company's press release, is a potential NI 43-101 and securities-law violation — even if the QP's technical report is compliant.
- Aggregating classifications without distinction. Reporting "total resources of X million ounces" without clearly separating Measured, Indicated and Inferred quantities violates the disclosure requirements of both NI 43-101 and JORC. Markets have learned to look for this aggregation as a potential red flag of grade or tonnage padding.
- Converting to metal equivalents without code compliance. Metal-equivalent calculations applied to inferred inventory require the same economic assumptions that the classification expressly does not permit. QPs should refuse to prepare or endorse metal-equivalent tables for inferred-only resources without a clear disclosure of the assumptions and their limitations.
Responsible Communication: A Practical Framework
The QP who helps their client communicate inferred inventory responsibly and compellingly provides significant value. The framework I recommend:
- Always lead with classification: "X Mt at Y g/t Au (Inferred)" — never aggregate without breakdown
- Follow immediately with the geological context: deposit type, continuity evidence, open directions
- State the upgrade requirement explicitly: "Achieving Indicated classification would require infill drilling to approximately 25×25m centres over the core zone"
- Include a standard disclaimer referencing CIM Definition Standards and the prohibition on economic conversion — not as boilerplate but as a genuine disclosure
- Avoid adjectives that imply economic value: "significant," "robust," "high-value" are all problematic when applied to inferred inventory without supporting economic analysis
The market will apply its own valuation methodology to a responsibly disclosed inferred inventory. The QP's obligation is to ensure the geological basis for that valuation is transparent — not to inflate the perception of value, and not to suppress it either.
JNA Resource Advisory provides independent resource estimation and investor-facing technical communication support under NI 43-101, SK-1300 and JORC. Contact us to discuss your project valuation needs.