A promising drill intercept is evidence of mineralization—not proof of a mine, a mineral resource, a reserve, or an economically viable project. To evaluate a mining company’s announcement, identify its reporting framework and project stage, check the quality and context of the data, distinguish exploration results from resources and reserves, and examine the technical, economic, legal, environmental, social, and execution factors that could prevent development.
First, identify what the company is actually reporting
Mining announcements use terms that describe very different levels of evidence. Read the formal estimate or study label, not promotional phrases such as “project inventory” or “mine potential.” The applicable disclosure rules depend on the jurisdiction, exchange, and reporting framework. CRIRSCO’s International Reporting Template is a cross-code reference; the SEC’s mining guidance describes the U.S. framework. Their terms and filing requirements should not be assumed to match in every jurisdiction.
| Disclosure or study stage | What it tells you | What it does not establish by itself |
|---|---|---|
| Exploration results | Observations such as drill-hole assays, an outcrop, or geophysical survey data that may help test for mineralization. | A resource estimate, mineable tonnage, reserve, or project economics. |
| Exploration target | A conceptual indication of the potential quantity and grade of a mineralized system, where reported under applicable rules. | A mineral resource or reserve. CRIRSCO cautions that targets must not be presented in a way that misrepresents them as either. |
| Mineral resource | An estimate of mineralization with reasonable prospects for eventual economic extraction, classified by geological confidence. | A reserve or proof that extraction is economically viable. |
| Preliminary economic assessment or initial assessment | An early-stage study of a project’s potential under stated assumptions. | The level of certainty or technical detail of a pre-feasibility or feasibility study. Under SEC guidance, a qualified person may include a cash-flow analysis in an initial assessment, but is not required to do so. |
| Pre-feasibility or feasibility study | A study stage used to assess project development; a feasibility study is more comprehensive than a pre-feasibility study. | Certainty that the project will be built or that its assumptions will hold. |
| Mineral reserve | The economically mineable portion of indicated or measured resources after relevant modifying factors have been applied and evaluated. | Freedom from risk: costs, permits, markets, infrastructure, and execution can still affect a project. |
Check the effective date of every estimate and study, then look for later company announcements or filings that may have changed the numbers, assumptions, or project stage. CRIRSCO says companies should review and report results, resources, and reserves at least annually and promptly report material changes.
How to read a drill result without overvaluing it
Start with the full announcement and its technical context rather than a headline intercept. A long interval or high grade may be encouraging, but neither can be interpreted in isolation. Its significance depends on the deposit’s geometry and style, continuity between observations, cut-off assumptions, potential dilution, and the distribution of drilling.
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Check the context for each reported interval
- Which hole produced the result, and where is it located relative to other holes and the interpreted mineralized zone?
- What were the hole’s orientation and depth? Does the announcement explain how the reported interval relates to true width?
- Are the full assay intervals and geological interpretation available, or does the headline emphasize only selected highlights?
- What sampling and analytical methods were used, and what quality-control information is reported?
- Is recovery adequate, and are the results representative of the wider system?
- How many observations support the interpretation, and are they distributed well enough to say anything about continuity?
CRIRSCO’s International Reporting Template identifies poor sample recovery, poor assay or laboratory repeatability, and limited bulk-density information as examples of issues that can weaken confidence or reliability. If material data are uncertain or inadequate, look for an explanation of that limitation in the announcement or supporting report.
There is no universal grade threshold that turns an intercept into a valuable deposit. CRIRSCO also warns that exploration results alone should not be used to derive tonnage and grade. An attractive result is a reason to examine what further work is needed—not a standalone estimate of a project’s value.
What resource categories mean—and what they do not mean
Mineral resources are classified by increasing geological confidence: Inferred, Indicated, then Measured. The category reflects confidence in the geological evidence; it does not, on its own, establish that the material can be mined economically.
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| Category or term | Practical reading | Important boundary |
|---|---|---|
| Inferred resource | Lower geological confidence than Indicated or Measured. | Under the SEC framework, inferred resources cannot be converted into reserves. Do not treat them as established economic inventory. |
| Indicated resource | Higher geological confidence than Inferred. | It may be considered for conversion to a reserve only after relevant modifying factors are applied and evaluated. |
| Measured resource | Higher geological confidence than Indicated. | It does not automatically become a proven reserve. CRIRSCO notes that uncertainty in modifying factors can result in conversion to a probable reserve instead. |
| Reserve | The economically mineable portion derived from Indicated or Measured resources after applying modifying factors. | It is a different statement from a resource estimate, and it remains subject to project risks and assumptions. |
Do not equate geological confidence with economic certainty. A resource estimate is not simply all mineralized intervals drilled or sampled: it also depends on reasonable prospects for eventual economic extraction. Under SEC guidance, inferred material cannot be converted into a reserve.
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Check who is responsible for the technical disclosure
Find the named Competent Person or Qualified Person, their qualifications and professional affiliations, relevant experience, relationship to the issuer, sign-off, and the report date. Under CRIRSCO’s template, a Competent Person must have at least five years of relevant experience for the style of mineralization and the activity being undertaken. The SEC guide describes a Qualified Person requirement that includes at least five years of relevant experience and membership or licensure in good standing with a recognized professional organization.
For SEC registrants, the SEC guide says a dated and signed technical report summary is required when mineral resources or reserves are first disclosed or materially changed; the applicable filing details depend on the filing. Check the underlying technical report for its data, assumptions, limitations, and any reliance on information provided by the issuer. A press release may summarize a technical basis rather than replace it. If the report is absent, stale, or hard to reconcile with later statements, treat that as a reason to investigate the claim more closely.
Test the risks between a resource and a mine
Modifying factors are the bridge between geological evidence and a reserve estimate. CRIRSCO lists mining, metallurgical, economic, marketing, legal, environmental, social, and governmental considerations. SEC guidance also enumerates infrastructure, compliance, and arrangements with local individuals or groups. The questions below are a practical checklist; the factors that matter most, and the evidence needed to assess them, vary by mineral, project, location, and development stage.
| Risk area | Questions to investigate |
|---|---|
| Mining and geology | Is the deposit geometry understood? What assumptions are made about continuity, mining method, dilution, recovery losses, geotechnical conditions, and water management? |
| Processing and metallurgy | Is testwork representative? What recovery and product quality are assumed? Are impurities, concentrate specifications, and process performance at a suitable scale addressed? |
| Infrastructure | Are power, water, roads or rail, port access, workforce, and construction needs understood? Who must build and pay for required infrastructure? |
| Economics and markets | What capital and operating costs, commodity prices, royalties, taxes, financing assumptions, contracts, and offtake terms underpin the analysis? Is there sensitivity analysis? |
| Legal and tenure | Are title, claims, access rights, permits, agreements, litigation, and other relevant obligations clear? |
| Environmental and social | What baseline work, impact assessment, closure obligations, community agreements, consultation, resettlement risks, or unresolved conflicts are identified? |
| Government and execution | What approvals are needed and on what schedule? How exposed is the project to regulatory or fiscal change, security issues, or gaps in construction capability? |
A risk that is not quantified in a study is not necessarily immaterial. Look for what the study actually evaluates, which matters it leaves unresolved, and whether the project’s next steps depend on approvals, infrastructure, financing, or technical work that is not yet complete.
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Stress-test the study’s economics and assumptions
Read a study in light of its stated stage and scope. Under SEC guidance, a pre-feasibility or feasibility study supporting reserve disclosure includes economic analysis; commodity price assumptions and the basis for selecting those prices must be disclosed. A feasibility study is more comprehensive than a pre-feasibility study, but neither makes uncertain future conditions certain.
Compare the base case with downside cases for commodity price, capital and operating costs, recovery, schedule, exchange rates, and financing. Ask whether infrastructure and permitting costs are included, whether the schedule assumes approvals that have not been obtained, and whether the company appears able to finance the work needed to advance the project. These are ways to test the assumptions, not universal investment thresholds.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Judge whether the disclosure is balanced and comparable
CRIRSCO says exploration-result reports should give enough information for a considered, balanced judgment and should not unreasonably imply that potentially economic mineralization has been discovered. It also calls for material information affecting economic value, including material changes to resources or reserves, to be reported.
Compare an announcement’s headline with its full text and technical report. Check whether the account gives enough context to identify uncertainty, non-contiguous results, low recovery, incomplete metallurgical work, dependence on assumptions, or material changes in cost, permits, ownership, or schedule. This is a way to read disclosure critically, not evidence that a particular company has omitted information.
When comparing companies or projects, record the effective date and compare like with like: reporting framework, project stage, resource and reserve category mix, data quality, geology, metallurgy, infrastructure, capital and operating assumptions, price sensitivity, permits and tenure, environmental and social obligations, financing runway, execution capability, and disclosure quality. No single score resolves those trade-offs, and a ranking based only on headline grade or total resource tonnage can hide important differences.
What to conclude from an exploration announcement
Use an exploration result to decide what evidence to examine next, not to assume that a mine exists. The strongest evaluation traces a clear path from the reported data, through a dated and technically supported resource estimate, to study assumptions and modifying factors. If a company’s claim jumps across those stages without showing the supporting work, the evidence presented does not establish the missing steps.
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