What Is a JORC Resource? A Plain-English Guide for ASX Investors
A JORC resource is the estimate behind almost every number an ASX-listed explorer or miner reports about what it has found underground. The JORC Code sets the rules for that estimate, and decides what a company can say before the market takes the claim seriously. QMines (ASX:QML) reports under it at all three of its Queensland projects: Mt Chalmers, Develin Creek and Mt Mackenzie.
Key facts
- QMines (ASX:QML) reports a JORC resource for each of its three Queensland projects, Mt Chalmers, Develin Creek and Mt Mackenzie, under the JORC 2012 Code and a named Competent Person.
- The JORC Code (the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves) is the mandatory ASX disclosure standard for every resource and reserve estimate.
- Three Mineral Resource categories, Measured, Indicated and Inferred, rank geological confidence from highest to lowest. They are not a measure of resource size.
- An Ore Reserve (Proved or Probable) is the portion of a Mineral Resource a feasibility study has confirmed is economically mineable. It does not exist until that study is done.
What Does JORC Actually Stand For?
JORC stands for the Joint Ore Reserves Committee, formed by AusIMM, the Australian Institute of Geoscientists and the Minerals Council of Australia. Its Code is mandatory under the ASX Listing Rules for any company reporting a resource or reserve figure, which is why every QMines project page carries a Competent Person statement.
The JORC Code sets out how a company can classify and disclose what it has found underground: the standard behind every figure in our guide to whether copper is a good investment.
Measured, Indicated and Inferred: What the Three Categories Mean
These three categories rank how confident the Competent Person is in a Mineral Resource, not how big it is. Measured is the highest-confidence category, based on closely-spaced drilling and sampling. Indicated sits in the middle. Inferred is the lowest-confidence category, based on wider-spaced data and carrying the most geological uncertainty.
All three terms apply to a Mineral Resource. An Ore Reserve uses a different pair, Proved and Probable, which is the next distinction worth understanding.
Mineral Resource vs Ore Reserve: Why the Distinction Counts
A Mineral Resource is a geological estimate. An Ore Reserve is a Mineral Resource a feasibility study has tested and confirmed can be mined and processed economically, under a mine plan that works at today’s costs and prices. That test runs through stages, from a Scoping Study to a Pre-Feasibility Study to a Definitive or Bankable Feasibility Study, and a resource only becomes a reserve once it clears the stage that applies. An Ore Reserve is reported as Proved or Probable, mirroring Measured and Indicated, but only once the economics are proven rather than estimated.
QMines’ two most advanced projects sit on opposite sides of that line. Mt Chalmers declared a maiden Ore Reserve of 9.6 million tonnes (Proved and Probable) alongside its Pre-Feasibility Study, announced 30 April 2024. Develin Creek has not reached that stage: its 23 February 2026 resource upgrade states plainly that no Ore Reserves have been reported, a difference in stage rather than in quality.
QMines’ Own JORC Resources: A Worked Example
QMines reports a genuine spread of JORC positions across its three 100%-owned Queensland projects.
Mt Chalmers, the most advanced of the three, holds a JORC Mineral Resource of 11.86 million tonnes at 1.22% copper equivalent (Measured, Indicated and Inferred), 84% of it in the Measured and Indicated categories, and an Ore Reserve, discussed above, of 9.6 million tonnes (Proved and Probable).
Develin Creek holds a JORC Mineral Resource of 4.70 million tonnes, 90% of it now Indicated: 4.22 million tonnes at 0.98% copper and 1.08% zinc. No Ore Reserve has been reported there yet.
Mt Mackenzie holds a JORC Mineral Resource of 5.2 million tonnes at 1.01g/t gold and 6.7g/t silver, for 170,000 ounces of gold and 1.12 million ounces of silver, approximately 70% of the contained gold now Indicated, per its 5 August 2026 resource upgrade.
Line the three up and the spectrum turns from theory into numbers: a declared Ore Reserve at one end, a resource still earning its way toward Indicated at the other.
What JORC Classification Tells an Investor
The category mix in a JORC resource shows how much of a company’s headline number you can act on today, and how much is still a geological opinion waiting on more drilling. A high proportion in Measured and Indicated can support financing discussions and a feasibility-study decision, because the numbers are confident enough to plan around. A resource weighted toward Inferred is not wrong or inflated: it simply means more drilling sits between the company and a mine plan built on those numbers.
In summary
The JORC Code is the mandatory ASX disclosure standard for every resource and reserve figure a listed company reports. Measured, Indicated and Inferred rank how confident that figure is, not how big it is, and a Mineral Resource only becomes an Ore Reserve once a feasibility study proves it can be mined and processed economically. QMines’ three Queensland projects show that spectrum: Mt Chalmers with a declared Ore Reserve, Develin Creek and Mt Mackenzie still building their case through Indicated and Inferred resources. Read the category, not just the number: it tells you where a project sits on the road to a mine.
Frequently Asked Questions
What is the JORC Code?
The JORC Code, the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, is the mandatory public reporting standard for ASX-listed resource companies. It sets out how a company can classify and disclose what it has found underground, and every figure QMines reports for Mt Chalmers, Develin Creek and Mt Mackenzie is estimated and reported under this Code by a named Competent Person.
What’s the difference between Measured, Indicated and Inferred resources?
The three categories rank geological confidence, not size. Measured is the highest-confidence category, based on close-spaced drilling and sampling; Indicated sits in the middle; Inferred is the lowest-confidence category, based on wider-spaced data and carrying more geological uncertainty. A resource with a higher proportion in Measured and Indicated is generally viewed as a stronger basis for financing and development decisions than one weighted toward Inferred.
What’s the difference between a Mineral Resource and an Ore Reserve?
A Mineral Resource is an estimate of what’s in the ground; an Ore Reserve is the portion of that resource a feasibility study has confirmed can be mined and processed economically under current technical and financial assumptions. An Ore Reserve is reported as Proved or Probable, and only exists once a company has done the engineering and economic work to prove it; Mt Chalmers’ maiden Ore Reserve, for example, followed its Pre-Feasibility Study.
What does an ASX company’s JORC resource category mean for investors?
The category mix tells you how much of a company’s headline resource number you can rely on today versus what still needs more drilling to firm up. A high Measured-and-Indicated proportion can support bank or project financing discussions and de-risks the path to a feasibility study, while a resource that’s mostly Inferred signals more drilling is needed before a company can credibly plan a mine around it.
This article is general information only and doesn't take into account your personal objectives, financial situation or needs. Third-party forecasts and JORC estimates referenced here are not guarantees, and past performance is no indicator of future results. Do your own research and speak to a licensed financial adviser before making any investment decision.