ASX mining announcements explained: how to tell a great result from a good one

Australia is the lucky country – it’s blessed with some of the largest deposits of natural resources anywhere in the world. And Aussie investors love their mining companies – I’d bet you own a few, and I’d bet every investor you’ve ever chatted with owns a few, too. That love affair is as strong now as it was when Poseidon hit it big in 1969. Another thing that hasn’t changed is that mining announcements are written in a dialect all their own.

That’s why I published the first edition of this guide way back on 14 November 2023. Since then, it’s racked up tens of thousands of views, but it’s time for a refresh for two main reasons. What constitutes a “good grade” in a drill result changes with the prices of commodities. An uneconomic result at $X an ounce might be an acceptable one at 2 × $X an ounce. The table below shows how much the prices of gold, silver, copper, and other commodities have changed since the first edition.

The prices of these staple commodities of Aussie mining investor portfolios may have changed (um, well perhaps not for nickel or lithium!), but there are also some major changes brewing regarding how mining companies must report their reserves. The Joint Ore Reserves Committee has spent the past two years redrafting the JORC Code, the rulebook that governs how every ASX-listed miner reports what it thinks it has in the ground. It isn’t in force yet. But it’s close, and the changes are worth knowing before they land.

In addition to updating these changes, I’ll also take on the entire mining journey: from a geologist kicking over rocks in the desert to first production. Along the way, you’ll learn all the key jargon so that you can read ASX mining company announcements with confidence. Let’s dive in!

Kicking over rocks in the desert stage

Every mining company starts here – a company at this point owns a tenement, a hunch, and a great deal of hope. Step one is to try to work out what might be underneath that ground or hill 450km north-east of Kalgoorlie. These are the most common terms you’ll hear from mining companies at this stage:

Rock chip sampling: a geologist collects surface rock from the exploration site and has it analysed. Quite often they’ll bash at a few of these rocks with their trusty hammer and hope that one reveals something shiny. Clearly, it’s a very early stage of exploration, but I’ve seen speccy (speculative) mining stocks double on a report of “visible mineralisation in rock chip sampling”. Consider that this might say more about that speccy’s audience than the quality of its announcement!

Geochemical survey: geologists test soil and water for the chemical fingerprints a buried deposit leaves behind. More advanced than rock chip sampling, but still very early stage.

Geophysical surveys: typically airborne, seismic, electromagnetic, or gravity – which use electronic equipment and software to read and analyse the physical properties of the rock from a distance. These are generally looking at the density or conductivity of rocks on and under the surface that says something interesting is going on. This step guides the drilling, which is where the big results, and the big share price reactions, come from.

Drilling stage

If you’ve kicked over enough of the right rocks, and identified some promising targets from your surveys, you’ll want to drill. The drill brings up a core – a cylinder of rock – which gets “assayed” in a laboratory to determine its chemical composition. That assay is where the numbers in an ASX announcement come from, and they’ll be written in a shorthand that looks like this: 20 metres at 2.5 g/t Au from 100 metres.

Read it backwards and it’s straightforward. From 100 metres below the surface, the drill passed through 20 continuous metres of rock, and that rock carried gold at an average concentration of 2.5 grams per tonne. Three things make a result like that valuable – it’s long, it’s high grade, and it’s shallow – and each has its own bit of jargon:

Intercept: the length of the mineralised section, the 20 metres. Longer is better, because it means more rock carrying metal in a single hit.

Grade: the average concentration of the target metal through that intercept, the 2.5 g/t. Higher is better, and I’ll come back to what “high” actually means in a moment.

Depth: where the intercept starts, the “from 100 metres”. Shallower is better, and by more than investors tend to credit. Rock 100 metres down is vastly cheaper to retrieve than rock 800 metres down.

Open at strike, open at depth: the first means drilling hasn’t found the edge of the deposit along the direction it’s running; the second means it hasn’t found the bottom. Both are ways of saying: there may be more down there, we just haven’t found it yet.

💡 PRO TIP: What counts as a “good grade”? ⛏️

There isn’t a single answer, and any mining exec who hands you one is probably trying to sell you the strength of their own grade! A grade only means anything against a “cut-off” – the concentration at which rock is worth mining rather than leaving where it is. And a cut-off is a calculation, not a constant: commodity price, costs, metallurgical recovery, and depth all feed in. Move the price, and tonnes of rock that were once waste become ore.

With that caveat firmly attached, here’s roughly where the market’s head is at today:

Gold: the answer depends entirely on how the ore comes out of the ground. Big Australian open pits run on remarkably little metal – Evolution Mining’s (EVN) Cowal books reserves at 0.78 g/t and Capricorn Metals' (CMM) Karlawinda at 0.8 g/t – because they move enormous tonnages cheaply, so anything approaching 1.5 g/t in a pit is good. Underground has to pay for the development and averages nearer 5 g/t, though plenty of mines work fine at 2 to 3 g/t. Double-digit reserve grades barely exist in production: even Agnico Eagle's (NYSE: AEM) Fosterville, our byword for high grade, books 5.0 g/t. And watch which number you’re being shown – Bellevue Gold’s (BGL) 8.9 g/t resource became a 4.7 g/t reserve, which became a 4.0 g/t head grade at the mill.

Copper: 1% is the number usually quoted, and for the big open-pit porphyries that supply most of the world’s copper it is a genuinely high bar – the US Geological Survey puts the median porphyry deposit at 0.44%, and Cerro Verde (0.35%) (Freeport McMoRan (NYSE: FCX)), Quellaveco (0.49%) (Anglo American (LSE: AAL)) and Escondida (0.59% reserve grade) (BHP (BHP) and Rio Tinto (RIO)) all sit under it. That bar has moved a long way: the world average mined grade was above 4% a century ago. But 1% is low for the orebodies Aussie investors actually own, because underground and sediment-hosted deposits clear it routinely – BHP milled 2.03% at Olympic Dam last financial year and 1.34% at Carrapateena.

Uranium: first, watch the units. Grades are quoted as U3O8, or yellowcake, which is about 85% elemental uranium, so a grade given as %U is roughly 18% higher once restated as %U3O8. The World Nuclear Association puts most ore feeding conventional mines above 0.10% U, or about 1,180 ppm U3O8, but that figure is dragged up by Canada’s freakish Athabasca Basin, where Cameco’s (NYSE: CCJ) Cigar Lake reserves grade 16.3%. Most of what’s on the ASX is far leaner and perfectly economic: Boss Energy’s (BOE) producing Honeymoon at 738 ppm, Paladin’s (PDN) Langer Heinrich reserve at 437 ppm, Deep Yellow’s (DYL) Tumas at 298 ppm. Bulk scale, low strip ratios and leach recovery do the work that grade does elsewhere.

Lithium: for a hard-rock spodumene deposit, around 1% Li2O is the working range and above 1.5% is genuinely strong – only IGO's (IGO) Greenbushes (1.9% reserve grade) and Wesfarmers' (WES) Mt Holland (1.57%) clear that bar, while Pilgangoora (PLS Group (PLS)), Wodgina, Mt Marion (both Mineral Resources' (MIN)) and Kathleen Valley (Liontown (LTR)) all sit between 1.1% and 1.4%. The cut-offs run well below that, 0.3% to 0.75%, so don’t dismiss a sub-1% intercept on grade alone. And don’t confuse any of it with SC6, the 6% concentrate the industry prices off – that’s the product, not the rock. Pure spodumene is only 8.03% Li2O, so the concentrator is doing a four-fold upgrade, and most Australian mines actually ship 5.0% to 5.5% and get paid pro-rata.

One last habit, and it’s the most useful in this whole guide: every resource statement discloses the cut-off it was calculated at. Go and find it. Raising the cut-off flatters the headline grade while quietly shrinking the tonnes – and a company that needs a good number knows that.

Mineral Resource stage

Drill enough holes, and a company can start describing what’s in the ground as a “Mineral Resource”. The JORC Code sets out three categories, and the only thing separating them is confidence:

Inferred: the lowest confidence, with geology and grade estimated from limited sampling. An educated guess, but one with drilling behind it.

Indicated: enough confidence to support mine planning. The drill spacing is tight enough to reasonably assume the rock between the holes resembles the rock in them.

Measured: the highest confidence, with quantity, grade, shape, and density all established by detailed work.

That ladder matters because of what each rung allows. An Inferred Resource cannot become a reserve at all. An Indicated Resource can become a “Probable Ore Reserve”, and only a Measured Resource can become a “Proved Ore Reserve”. 

Which brings us to the distinction investors most often blur:

Resource versus Reserve: a Resource is what’s in the ground. A Reserve is the part of it the company intends to mine, and it has shown that it can be mined economically. Resource is what’s there, Reserve is what’s worth getting out, and the gap between the two is often where the real story lies.

A few other things separate a good resource from an also-ran. A single contiguous deposit beats the same tonnage scattered in pockets. Stable jurisdictions beat volatile political environments – governments have nationalised mineral resources before, and shareholders ended up with nothing. And don’t underestimate the value of the term “close to infrastructure” in a mining company report. Road, rail, port, water, and power are often the difference between a deposit and a mine.

Reserve stage (scoping and feasibility studies)

We’re now several years on from that first rock chip sample. Drilling continues to build out the Resource, but from here on you’re looking at the companies serious about actually building a mine.

Converting a resource into a reserve means proving the economics, and that happens through a sequence of studies of increasing rigour:

Scoping Study and Pre-Feasibility Study (PFS): the first serious looks at whether this is worth doing at all – costs, production estimates, processing options. A scoping study is indicative and can’t support a reserve on its own. A PFS is the first study that can.

Definitive Feasibility Study (DFS): the detailed version. Specific processing methods, mine engineering, mine life, a production profile, and project economics you could actually build from.

Bankable Feasibility Study (BFS): in practice the distinction between a DFS and a BFS has largely dissolved. Both are the document you take to your bankers and shareholders to raise construction funding. Read the contents, not the title.

The DFS and BFS will often map out a timeline to production, and assuming the next steps all go well, it could be two to three years from here – with at least half of that spent on construction and commissioning…

The money to mine stage

A study that stacks up is one thing, a mine is another. Once the geology is settled the argument becomes one about money, and three bits of jargon carry most of it:

Net Present Value (NPV): the total value of the project in today’s dollars, taking every future cash flow – revenue, operating costs, capital – and discounting it back at a specified rate. It’s the headline number from any feasibility study.

All-In Sustaining Cost (AISC): a per-unit measure covering the cost of production plus the sustaining capital needed to keep a mine running. It began as a World Gold Council standard for gold miners and spread by analogy, so it compares better within a commodity than across them. Lower is better.

Front-End Engineering and Design (FEED): the detailed construction design work that turns a study into a build. It’s where you’ll hear about “procuring long lead time items” – ordering the equipment that takes a year to arrive.

I like to compare a project’s NPV against the company’s market capitalisation, to see how much of the potential is already in the price. There are many, many reasons a market cap can sit below an NPV, but as a rough rule the two should converge as a single-project company works through the stages.

Two cautions. First, the commodity price assumption does enormous work. An NPV built on a price well above where the market expects to be at first production isn’t worth much, so check the vintage of any study you’re reading. Second, discount rates aren’t standardised. A higher rate is more punitive, so two NPVs struck at different rates compare nothing at all.

After FEED comes funding, construction, production, and processing – with the latter preferably done on site, because the economics are better that way.

💡 What the new JORC Code will change

The JORC Committee has been at this since 1971, and its Code has governed reporting since 1989, most recently in the 2012 edition. A replacement went out for consultation on 1 August 2024, and as I write it still isn’t finished – JORC reported in August 2026 that the draft remains in legal review with the ASX, ASIC, and the parent bodies, and a mandatory ASX consultation on the corresponding listing rule changes has to run before anything takes effect. JORC 2012 remains the operative code today, and a transition period is expected to follow, as it did in 2012. What’s coming is still worth knowing now:

The Competent Person gets far more visible: the geologist or engineer who signs off an estimate will need a CV of record and mandatory induction training, and public reports will carry a summary of their relevant experience. A Competent Person will also be able to lean formally on named specialists.

ESG moves into Table 1: material environmental, social, and governance considerations become a modifying factor in assessing whether a deposit has reasonable prospects for economic extraction, disclosed across the whole project life, from exploration through to closure.

“Eventual” disappears: the familiar phrase “reasonable prospects for eventual economic extraction” loses its most elastic word, and Competent Persons will have to complete a formal assessment justifying their assumptions on an “if so, why so” basis.

More gets disclosed: royalties, litigation, permitting, and rehabilitation guarantees all come into scope, alongside a new requirement to reconcile actual production against previously reported estimates – accountability that continues after the announcement.

None of this changes the geology. It changes how much you get told about it, and I’d read that as a clear net positive for investors.

All stages: cash is king!

Almost every explorer and developer is burning cash, because it’s spending money and not yet selling anything. As the cash runs down, it raises more, usually by issuing new shares, since banks charge dearly to lend to a company with no revenue. Those raisings are typically priced at a discount, and steep discounts hurt existing holders. If you take one thing away from this article, let it be this: it pays to know when a capital raise is coming.

You can work that out yourself from the Appendix 5B, a cash flow report every ASX mining explorer files each quarter. There are three main sections:

Section 1: net cash used in operating activities. This is the burn.

Section 5: cash and cash equivalents at the end of the quarter. This is what’s left.

Section 8: the arithmetic already done for you, as quarters of funding remaining. Any company with fewer than two quarters of funding left has to explain how it intends to fix that.

Personally, I start watching for a raise when a company is inside one year of funding.

Reading between the lines

Mining companies want their results read in the best possible light – it lifts the share price, and a higher share price makes the next capital raising cheaper. That’s not cynicism, it’s just the reality of the mining company life cycle: no funding, no life!

Which is why the jargon is worth learning. A Resource isn’t a Reserve, an Inferred ounce isn’t a Measured one, an NPV is only as good as the assumptions behind it, and a good grade is only good against its cut-off.

Get these concepts straight, and the next announcement that lands for your favourite explorer stops being a wall of acronyms and starts being information you can actually use to make an informed investing decision.

Parts one and two of the original guide were published on Market Index on 14 and 21 November 2023. This article draws on the JORC Code 2012 edition and JORC’s published updates on the code review (August 2026), ASX Listing Rules Appendix 5B, gold, silver  and uranium price data from TradingView, base metals data from Norgate Data, and lithium carbonate price data from SMM and the author's own data — all as at 9 September 2026. Grade figures are drawn from company Mineral Resource and Ore Reserve statements (Northern Star, Evolution, Capricorn Metals, Agnico Eagle, Bellevue Gold, IGO/Talison, Albemarle, Pilbara Minerals, Mineral Resources, Liontown, Boss Energy, Paladin Energy, Deep Yellow, BHP), the US Geological Survey porphyry copper database, the World Nuclear Association, and Cameco.