Antimony, Tungsten, REEs and the Defence Buyer's Sourcing Problem

China cut antimony exports in September 2024. That single decision sent trioxide prices past $25,000 a tonne, and I watched a few procurement people who'd never returned my emails suddenly want a call.

That's the thing about defence critical minerals. Nobody cares where the antimony comes from until they can't get any. Then it's the only thing anyone talks about.

I run GBX Resources. We hold 16 concessions across Gilgit-Baltistan in northern Pakistan, and three of the minerals in that portfolio — antimony, tungsten and the rare earths we're chasing in the Karakoram batholith — sit on the US, EU and UK critical-minerals lists at the same time. Which is not a coincidence. Those three are the ones the defence supply chain quietly panics about.

Let me walk through why, because the demand side is what makes the geology worth your time.

Antimony is the one people underestimate

Honestly, I got this wrong at first too. I thought of antimony as a lead-battery hardener and a flame retardant. Boring industrial stuff.

But antimony munitions and ordnance applications are where it earns its critical-minerals badge. Antimony trisulphide goes into primers. Antimony metal hardens the lead in armour-piercing rounds and shrapnel. It's in tracer compositions, in night-vision components, in the flares that pull heat-seeking missiles off aircraft. There's no drop-in substitute for a lot of that. You need the actual element.

And here's where it gets uncomfortable for Western defence planners. China plus Tajikistan plus Russia control the overwhelming share of mined antimony and refining. When one country runs roughly 48% of global mine output and an even larger slice of refining, that's not a supply chain — that's a chokepoint with three actors, two of which a NATO buyer can't touch.

So when a defence prime maps its antimony exposure and finds it runs through Beijing, somebody in that building starts making phone calls. Pakistan isn't a NATO member, I'll be straight with you. But it's a workable, non-sanctioned origin, and our stibnite showings in Gilgit-Baltistan are real — we've got vein antimony that assays well above cut-off in our sampling, and we're building out the drill picture now. I won't quote a resource figure I haven't earned yet. But the geology is there.

Tungsten and the aerospace problem

Tungsten defence supply is the one European buyers ask me about most, and I understand why.

Tungsten carbide cuts everything. Tungsten metal goes into kinetic penetrators — the long-rod ammunition that punches through armour — and into the machining tools that make basically every other defence component. High melting point, extreme density, and the West essentially stopped mining it decades ago because Chinese supply was cheap and reliable.

Until it wasn't. China put tungsten on its export-control list in early 2025, and the same buyers who'd shrugged at concentration risk for twenty years suddenly needed a spreadsheet of alternative sources.

We've got tungsten and molybdenum associations in the Karakoram — skarn and greisen-style occurrences tied to the granite intrusions that also give us our architectural block. Scheelite and wolframite are what we're sampling for. It's early-stage on tonnage, but the mineralising system that produces tungsten here is the same one that's produced it in the Alpine-Himalayan belt for a long time. This isn't wishful geology. It's the right rock in the right place.

What I'll say to any serious tungsten buyer: come look at the concentrate potential before you commit to a number. I'd rather show you a real sample than sell you a story.

Rare earths are the long game, and I won't pretend otherwise

Here's the honest part. Our rare earth work is exploration-stage. We're seeing what looks like promising REE indications in the batholith — the kind of alkaline and pegmatitic signatures that host them elsewhere — but I am not going to sit here and tell you we've got a defined deposit. We don't. Yet.

Why it matters anyway: rare earths run the guidance systems, the radar, the electric-drive motors in newer platforms. Neodymium and dysprosium magnets are in the actuators and the sensors. And roughly 90% of processed rare-earth output has run through China for years. When a supply chain is that concentrated, defence ministries stop treating it as a commercial matter and start treating it as a national-security one.

So even early-stage REE exploration in an allied-adjacent, non-sanctioned country gets attention it wouldn't have got in 2015. The bar has dropped, because the alternative — depending entirely on a strategic competitor for magnet feedstock — is unacceptable to anyone planning past this decade.

What "allied sourcing" actually means for you

Look, I want to be careful with the word "allied." Pakistan is not a Five Eyes country and I'm not going to dress it up as one. But strategic sourcing for defence isn't only about formal alliances. It's about diversification away from a single adversarial supplier, and it's about origin you can document, ship and audit.

On that front we're straightforward. Our concessions are licensed through the Gilgit-Baltistan mineral authority — real titles, not letters of intent. Export moves overland to Karachi and out by sea; I've written before about what that costs and how the logistics actually run, so I won't repeat it. The point is the route works and it doesn't pass through anyone's sanctions regime.

What I can't offer is speed at defence-grade purity tomorrow. Antimony trisulphide for primer stock needs refining specs I'd want to hit through a JV partner who already does that processing. Tungsten to APT (ammonium paratungstate) is a conversion step, not a mine-gate product. If you're a prime or a trader thinking off-take, the smart structure is joint venture — you bring the processing and the qualification, we bring the ground and the concentrate.

The defence buyers who move early on this get something the latecomers won't: a documented second source, locked before the next export ban makes it a bidding war.

Because there'll be another one. There always is. The only question is whether you've got a phone number to call when it happens — or whether you're the one emailing me at $25,000 a tonne.