Reviewed August 2026 against USGS Mineral Commodity Summaries 2025, the Ontario Securities Commission’s NI 43-101 text, and CIM resource/reserve definitions.

Jump to the calculator →

A 43-101 report — properly “NI 43-101,” National Instrument 43-101 — is the technical disclosure document that any mining company listed on a Canadian stock exchange must file before it can publicly describe a mineral property’s size, grade, or economics. It has to be written or supervised by a Qualified Person (QP): an engineer or geoscientist with at least 5 years of relevant experience, per the Canadian Securities Administrators’ rule text. If you’ve searched “43101” or “ni 43-101” trying to find out what the document actually contains, or whether a specific claim in one is credible, this is that answer — not a marketing description of it.

The rule exists because of a specific failure: in 1997, Bre-X Minerals announced a Busang, Indonesia gold discovery that turned out to be fabricated, wiping out a company once valued near CAD $6 billion. Canadian regulators responded with NI 43-101, forcing every public resource estimate to carry a named, accountable, credentialed author. That’s the whole point of the document — it’s a liability instrument as much as a technical one.

Contents

• What a 43-101 Report Actually Is
• Why It Exists: The Bre-X Trigger
• The 7 Required Sections
• Resource and Reserve Categories: What the Numbers Mean
• Reading Ore Grade: What “g/t” Tells You
• US Gold Production Context: Where the Ore Comes From
• The Qualified Person: Who’s Allowed to Sign
• How to Read a 43-101 Report in Under 20 Minutes
• Calculator: Estimate Contained Metal From a Resource Table
• Where the Framework Gets Used Outside Mining
• Where Satellite Data Fits Into a 43-101 Report
• FAQ
• Conclusion

What a 43-101 Report Actually Is

NI 43-101 is a rule administered by the Canadian Securities Administrators (CSA) — the umbrella of provincial regulators that includes the Ontario Securities Commission (OSC). It doesn’t just ask for “a report.” It sets out exactly what a Technical Report must contain, who is legally allowed to write it, and what triggers the requirement to file one: a new mineral resource or reserve estimate, a material change to an existing one, or first-time disclosure of a property’s results. The full rule text is published by the Ontario Securities Commission.

Two things make it different from a normal exploration report. First, someone’s professional license is attached to every number in it — the Qualified Person signs a consent and certificate, and if the estimate turns out to be reckless or fabricated, that’s the person regulators and courts go after. Second, it’s public. Once filed on SEDAR+ (Canada’s disclosure database), anyone — a retail investor, a competitor, a permitting agency — can read the exact drilling data and assumptions behind a company’s resource claim. That combination of named accountability and public access is what “43101” means in practice, more than any specific page count or template.

Why It Exists: The Bre-X Trigger

Before 1997, a Canadian junior mining company could announce a gold discovery with essentially no independent technical review requirement. Bre-X Minerals used that gap to claim one of the largest gold deposits ever found at Busang, Kalimantan — reported at one point above 200 million ounces. The samples had been tampered with; independent drilling later found essentially no gold. The collapse is documented on Wikipedia’s NI 43-101 entry, which traces the direct line from the scandal to the rule.

The regulatory response bakes in three protections that weren’t there before: a named, licensed author for every technical disclosure; a defined chain of custody for samples (QA/QC); and a fixed vocabulary — inferred, indicated, measured, probable, proven — so a company can’t call a rough guess a “reserve.” That vocabulary is what the rest of this article walks through.

The 7 Required Sections

A full Technical Report under NI 43-101 runs through a standard set of items (Form 43-101F1 sets the exact item list; the table below groups them into the seven functional sections most reports organize around). Page counts below are typical ranges seen across public filings, not a regulatory minimum — a report on a single small deposit runs shorter than one covering a multi-zone district.

1. Location & Access

This section fixes exactly where the property is and who has the legal right to work it — claim numbers, lease expiry dates, surface rights, road and utility access. A resource estimate attached to a lapsed claim is worthless, so this is the first thing a QP verifies and the first thing a reader should check. For teams doing this desk-side before a site visit, satellite AOI mapping is the fastest way to confirm boundaries and access routes against public tenure maps — see Map Your Mining Site Here.

2. Geological Framework

This is the technical narrative: host rock types, structural controls (faults, folds), alteration mineralogy, and the deposit model the company is using to justify drilling where it drilled. A weak geological framework section is a red flag before you even reach the resource numbers — if the QP can’t explain *why* the gold is where the drill holes found it, the resource model built on top of that story is guesswork with statistics attached.

Remote sensing tools like Farmonaut’s satellite-based mineral detection platform are increasingly cited in this section as a supporting data source for alteration mapping, ahead of and alongside ground mapping.

3. Exploration Work

This section is the audit trail: drill hole logs, sample intervals, recovery rates, lab chain of custody, and QA/QC — blanks, duplicates, certified reference standards inserted into every batch sent to the lab. Every number in the resource estimate traces back to a row in this section’s data tables. If a report skips QA/QC detail or reports assay results with no detection limits stated, that’s the single fastest way to spot a weak filing.

Pre-drill targeting tools such as Farmonaut’s satellite-driven 3D mineral prospectivity mapping are used ahead of this stage to narrow where expensive drill programs get placed, before a single sample is logged.

4. Resource Estimation

This is the section most readers are actually searching for when they type “43101 report” — the tonnage and grade numbers. It has to state the estimation method (kriging, inverse distance weighting, or polygonal), the cut-off grade applied, the block model parameters, and — critically — which of the three CIM resource categories each tonne falls into. The categories aren’t optional labels; they’re defined precisely (see the next section), and a QP who calls a sparse-data zone “measured” is committing professional misconduct, not just being optimistic.

5. Economic Assessment

Present only when the report is a Preliminary Economic Assessment (PEA), Pre-Feasibility, or Feasibility Study rather than a pure resource estimate. It states metal price assumptions, capital and operating cost estimates, processing recovery rates, and the resulting NPV and IRR under those assumptions. Every input here is a variable the QP chose — a PEA run at $2,400/oz gold looks very different from the same deposit modeled at $1,800/oz, so check the stated price assumption before comparing two companies’ NPVs against each other.

6. Environmental & Social Considerations

Baseline environmental data (water, air, soil, flora/fauna), permitting status against the applicable jurisdiction’s requirements, and stakeholder/community consultation records — including, in Canada, engagement with First Nations where the property overlaps traditional territory. In the US, the analogous permitting layer runs through NEPA review and state-level mining regulations rather than NI 43-101 itself, since the US doesn’t have a direct equivalent statute — US-listed companies with Canadian-exchange listings file 43-101 reports anyway, because the rule attaches to the exchange, not the mine’s location.

7. Risk, Compliance & Recommendations

The closing section names every material risk the QP identified — technical, permitting, market, title — and lays out the next phase of work with a budget and timeline. A report that has no risk section, or one that lists only trivial risks, is a warning sign: every real deposit has open questions, and a QP who doesn’t name any isn’t being thorough, they’re being careless or evasive.

Resource and Reserve Categories: What the Numbers Mean

NI 43-101 defers to the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) for the definitions of these categories — three resource classes and two reserve classes, five terms total, and they are not interchangeable marketing synonyms. The distinction is entirely about confidence level, driven by drill spacing and data density, not about how much gold is physically present.

Source: CIM Mineral Resource and Mineral Reserve definitions. Note the critical distinction: a “resource” is a geological inventory; a “reserve” additionally requires a demonstrated economic case (metal price, cost, and recovery assumptions that produce a positive return) before the tonnage can carry that label. A company can have a large inferred resource and zero reserves — that’s not a red flag by itself, it just means economic viability hasn’t been proven yet.

Reading Ore Grade: What “g/t” Tells You

Grade is reported in grams of gold per tonne of ore (g/t), and the number alone tells you almost nothing without knowing the mining method it’s paired with. An open-pit or heap-leach operation is economic at 0.3–2.5 g/t, because the mining cost per tonne is low. An underground operation needs 4–10 g/t to justify the far higher cost of getting that tonne to surface, per World Gold Council industry benchmarks summarized by Investing News Network. The broader operating-mine average across all methods sits at 1–4 g/t. Above 20 g/t, the industry calls it bonanza-grade — rare enough that it changes the economics of an entire project.

So when a resource table in a 43-101 report states “2.1 g/t indicated,” check the planned mining method in the same report before judging whether that grade is strong. A 2.1 g/t open-pit deposit is comfortably economic; a 2.1 g/t underground deposit likely isn’t, at typical cost structures.

US Gold Production Context: Where the Ore Comes From

US domestic gold mine production totaled 160 metric tonnes in 2024, according to the USGS Mineral Commodity Summaries 2025. That production is heavily concentrated in two states: Nevada alone accounted for 70% of the national total in 2024, and Alaska a further 16% — meaning those two states together produced 86% of all US mined gold, with the remaining 14% spread across the rest of the country.

This matters directly for reading a 43-101 report on a US property: Nevada’s Carlin Trend and similar districts are drilled to a density and geological understanding that most other US gold ground simply doesn’t have, so “indicated” resources there carry a different weight of comparative evidence than the same category label on a first-pass Alaska or Idaho property. The USGS republishes state-by-state production tables every January in the Mineral Commodity Summaries series — check the current edition at pubs.usgs.gov for the latest annual figures rather than relying on this snapshot as the year turns over.

The Qualified Person: Who’s Allowed to Sign

NI 43-101 defines a Qualified Person as an engineer or geoscientist with at least 5 years of experience relevant to the specific type of mineralization and deposit being reported on, who is a member in good standing of a recognized professional association (such as a provincial engineering/geoscience body in Canada, or an equivalent US or international body the CSA recognizes). That’s a narrower bar than “a geologist” — the experience has to match the commodity and deposit style, so a QP with a career in copper porphyries isn’t automatically qualified to sign off on a lithium pegmatite resource.

Practically, this means every 43-101 report carries, usually in an appendix, a signed Certificate of Qualified Person naming the individual, their credentials, their professional membership number, and their specific role in preparing the report. If you’re evaluating a filing, that certificate page is worth reading — it tells you exactly whose name and license are attached to the numbers, and you can independently verify that person’s registration with their professional association.

How to Read a 43-101 Report in Under 20 Minutes

Full technical reports run 100–200+ pages. Nobody reads the whole thing on a first pass. Here’s the order that gets you the load-bearing information fastest:

1. Summary section (Item 1): Every 43-101F1 report opens with a summary restating the resource/reserve table and key conclusions — read this first, it’s the whole report compressed.
2. Certificate of Qualified Person: Confirm who signed it and whether their stated experience matches the deposit type.
3. Resource/reserve table (Item 14): Check tonnage, grade, AND which category (inferred/indicated/measured) each block falls into — not just the headline “total resource” number, which often blends categories together.
4. Effective date: Resource estimates go stale. Check the stated effective date against today — a report dated more than 12–18 months ago on an actively drilled property is missing whatever’s been found since.
5. Risk section (Item 25): What did the QP flag as unresolved? That’s a more honest signal than the executive summary’s tone.

Calculator: Estimate Contained Metal From a Resource Table

Plug in the tonnage and grade figures from any resource table to see the contained ounces implied — the calculation a 43-101 report’s resource section is ultimately building toward.

Assumptions: 1 metric tonne contains grade (g/t) grams of gold; 1 troy ounce = 31.1035 grams. This is a contained-metal arithmetic check only — it does not model cut-off grade optimization, dilution, mining recovery losses, or economic viability, and it is not a substitute for the estimation methods a Qualified Person applies in an actual 43-101 report.

Where the Framework Gets Used Outside Mining

NI 43-101 is a mining-specific rule, but its underlying discipline — named accountable authorship, defined confidence tiers, public auditability — has influenced how adjacent land-use sectors structure their own technical disclosure, even without a directly equivalent statute:

• Agriculture: Where mineral claims overlap active farmland, land managers reference the location/access and environmental sections to understand buffer zones, water use, and soil disturbance commitments before exploration begins.
• Forestry: Timber operators use the same overlap logic — checking claim boundaries and environmental baseline sections against sustainable forestry certification requirements.
• Critical minerals and gemstones: The identical resource-category framework (inferred/indicated/measured) now governs disclosure for lithium, rare earths, and other strategic minerals, not just gold and base metals.
• Infrastructure siting: Where a mineral claim intersects planned infrastructure corridors, the location/access section becomes the reference document for resolving competing land use.

Where Satellite Data Fits Into a 43-101 Report

None of the sections above change because satellite data gets used — the QP still has to verify, classify, and sign off on everything. What changes is how much ground-based work is needed before a company reaches the drilling stage that actually generates the assay data Section 3 requires. Farmonaut’s satellite platforms support two specific pre-drill stages:

• Satellite-based mineral detection — spectral analysis to identify alteration patterns and mineralization indicators across large areas before any ground sampling, informing the Geological Framework section.
• 3D mineral prospectivity mapping — combining spectral, structural, and topographic data into drill-target ranking, narrowing where the expensive Exploration Work stage actually happens.

This doesn’t shortcut the regulation — a satellite anomaly map has no standing in a 43-101 filing until it’s been drilled, sampled, and assayed under proper QA/QC. What it does is help exploration teams spend drilling budgets on higher-probability targets, which is a cost and timeline lever, not a disclosure shortcut. For teams scoping a program, Contact Us or submit details through the mining query form to discuss a specific property.

FAQ

What is a 43101 report?

It’s the standard shorthand for an NI 43-101 Technical Report — the mandatory disclosure document a Canadian-exchange-listed mining company must file, prepared or supervised by a Qualified Person, whenever it makes a new or materially changed resource/reserve claim public.

What is a 43101 report used for, specifically?

It’s the evidentiary basis investors, regulators, and potential acquirers rely on to check a company’s claims about a property’s mineral tonnage, grade, and economic viability before committing capital or approving permits.

How is “43-101” different from a standard exploration report?

The difference is legal accountability. Any geologist can write an exploration summary; only a Qualified Person meeting the CSA’s experience and credential bar can sign a document that legally counts as an NI 43-101 Technical Report, and false or misleading statements in it carry professional and securities-law consequences.

Do US-based mining companies need a 43-101 report?

Only if they’re listed on a Canadian exchange (TSX, TSX-V, CSE) — the requirement attaches to the listing venue, not the mine’s location. A large share of gold explorers operating in Nevada and Alaska are TSX-V-listed and file 43-101 reports even though the mine itself is entirely on US soil.

What’s the difference between “inferred,” “indicated,” and “measured”?

They’re CIM-defined confidence tiers based on data density, not on how much metal is actually there. Inferred is the lowest confidence (limited drilling); measured is the highest (dense, validated drilling sufficient for mine design). See the resource categories table above for the full breakdown.

Where can I find a company’s actual 43-101 filing?

Public filings are searchable on SEDAR+, Canada’s disclosure database, under the issuer’s name — every TSX/TSX-V listed miner’s technical reports are there, free to read in full.

Conclusion

A 43-101 report earns its weight by making one thing checkable: whose license is attached to the resource number you’re reading, and how much drilling actually backs it up. The seven sections — location and access, geological framework, exploration work, resource estimation, economic assessment, environmental and social considerations, and risk and recommendations — exist because a fabricated Indonesian gold deposit in 1997 showed regulators what happens without them.

The durable check, regardless of which year you’re reading this in: open the Certificate of Qualified Person, confirm the signer’s credentials match the deposit type, check the effective date against today, and read the resource table by category — not just the blended total. That process doesn’t expire; only the specific numbers in any one filing do.

To scope a property using satellite pre-drill analysis, Contact Us, request a quote through the mining query form, or map a site directly at mining.farmonaut.com.