Gravity Survey for Mining in Pakistan: What It Costs and When to Skip It (For Now)

A gravity meter isn't cheap to move around Gilgit Baltistan. I learned that the hard way in 2022, when I paid for a crew to haul equipment up a slope near Skardu that, it turned out, had nothing worth measuring underneath it. The data came back clean. Boring, actually. And I'd just spent the equivalent of two months of survey work to confirm empty ground.

That's the thing nobody tells you about gravity surveys. They work. They're accurate. But they answer a question you should already have a rough answer to before you spend the money.

So let me walk through what a gravity survey for mining in Pakistan actually involves, what it costs, and — honestly — when you're better off starting with satellite data instead.

What a gravity survey actually measures

Gravity isn't the same everywhere on the ground. Denser rock pulls slightly harder. A gravity meter picks up these tiny differences — we're talking millionths of the normal pull — and from that you can figure out what's sitting below the surface.

Dense stuff pulls more. Chromite, massive sulphides, iron-rich bodies. Less dense stuff (like a buried void, or a granite intrusion, or a salt deposit) shows up as a weaker pull. So a gravity survey is really good at spotting things that are noticeably heavier or lighter than the rock around them.

That's why chromite explorers in Muslimbagh and copper-gold teams around the Chagai belt care about gravity. Those targets have a density signature.

But here's a limit people forget. Gravity won't tell you gold is there. Gold occurs in such small amounts that it barely moves the needle. What gravity does is find the structure — the buried fault, the intrusion, the contact zone — where gold tends to sit. You're mapping the geology, not the metal.

There are two main flavours you'll get quoted for in Pakistan:

• Ground gravity survey. A crew walks a grid, takes a reading at each station, moves on. Slow, precise, boring in a good way. This is what most local geophysical survey mining contractors offer.
• Gravity gradiometry. Measures the rate of change of gravity, not just the value. Sharper picture of edges and small bodies. Usually airborne, usually expensive, usually not available domestically without flying in a rig.

Most of the work happening on the ground in Balochistan and GB right now is the first kind.

What it costs (real numbers, not brochure numbers)

People ask me the gravity survey cost in Pakistan like there's one figure. There isn't. It swings wildly based on terrain, station spacing, and how far your site is from a road.

Rough guide, and I mean rough:

A ground gravity survey on accessible, flatter ground might run you somewhere in the range of PKR 180,000 to 400,000 per line-kilometer once you fold in the crew, the meter rental, GPS control, and processing. Tight station spacing (say every 50m instead of every 200m) multiplies that fast. Denser data, higher bill.

Now put that same survey in the mountains. No road. Porters or helicopter access. Weather delays. I've seen the effective per-day cost triple, and I've had crews sit idle for four days waiting for a pass to clear near one of my sites at around 3,400m elevation. You pay them anyway.

So when someone quotes you a flat gravity survey cost, ask them what elevation, what spacing, and what happens if the weather kills three days. If they don't flinch, they haven't worked GB.

Add data processing on top. Terrain correction alone (removing the effect of the mountains themselves from your readings) is real work in Pakistani topography. It's not a rounding error here — it's often the biggest source of noise in the whole dataset.

Why I tell most people to start from space

Look, I own 15 mines. I'm not against gravity work — I've paid for plenty of it. But I got the order wrong for years, and I want to save you that money.

Here's the sequence that actually makes sense.

Before you put a single crew in the field, you run satellite analysis over the whole license area. At GeoMine we pull Sentinel-2 and ASTER for surface mineralogy, SRTM DEM for structure and elevation, and SAR for ground stability. Our Breeze geo mineral analysis takes all of that and flags where the interesting geology is — the alteration zones, the fault intersections, the density-worthy structures — across thousands of hectares. In days. For a fraction of what one week of ground gravity costs.

Then you take those flagged zones and that's where you send the gravity crew.

See the difference? Satellite work narrows a 5,000-hectare license down to maybe three high-priority blocks. The gravity survey then goes deep on those three, instead of grinding across ground that a satellite could've told you was dead.

My Skardu mistake in 2022 was doing it backwards. I sent the gravity crew first, on a hunch, over ground that surface data would've flagged as low-probability. If I'd run the satellite pass first, I'd have spent that budget somewhere it mattered.

The rough math on my own sites: satellite-first cut my ground geophysical survey mining costs by around 40 to 55% per license, because we stopped surveying blanks. On one chromite prospect it was closer to 60%.

This isn't satellite versus gravity. It's satellite then gravity. Geo mining works best when the cheap, wide tool goes first and the expensive, deep tool confirms.

When gravity is genuinely worth it up front

A few cases where I'd skip straight to a gravity survey:

You've already got surface data pointing at a buried target — something you can't see from the surface because it's under cover. Gravity is one of the few tools that sees through overburden. If Breeze or an old report already tells you there's a hidden structure, gravity is the right next call.

Or you're chasing a genuinely dense target — chromite, massive sulphide — where the density contrast is strong and gravity gives you a clean answer nobody can argue with in a funding room.

Or you need bankable data. Investors and government mining departments trust ground geophysics because someone physically stood there. A satellite report opens the door; a gravity survey often closes the deal.

What I'd push back on is treating gravity as a discovery tool across a whole license. It's not a search engine. It's a microscope. Point it somewhere first.

If you're sitting on a license right now and wondering whether to book a crew, ask yourself one question — do you actually know where on your ground the interesting geology is? If the honest answer is no, that's your first spend. And it isn't a gravity meter.