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Comment by dsq | Hacker News Reader

How would xraying the cargo find gold? Because its denser than steel? Is that a routine inspection?

They probably got tipped off by something else that triggered a deeper investigation. It is not economical to do x-ray spectrometry on every single machine part leaving HK.

Or they noticed the weight of it was unusually high for what it was supposed to be

I wonder if gold will alloy with something that would reduce it down to "normal density".

When Nazi Germany occupied Denmark during World War II, Niels Bohr and George de Hevesy dissolved Max von Laue's and James Franck's Nobel Prize medals (entrusted to Bohr for safekeeping) in aqua regia. After the war, Hevesy found the flask of dissolved gold undisturbed, and precipitated the gold for the medals to be recast.

https://www.aip.org/history-programs/news/invisible-prize

Sure, but would it still be enough to make converting, transporting, and converting it back to purer gold economically viable?

I mean by that logic you could also have a couple of mules wear expensive jewelry or watches or the like; if it's convincing enough that someone wears a $500K watch as personal effect then they wouldn't be flagged for inspection.

In theory anyway, I don't know how these things work in reality. I wonder if someone's financial status is pulled up at passport control.

I don't believe it's uncommon for rich people to travel coach though.

Can you tell the difference between a $500K watch and a $50 knockoff? You don't need to be rich to wear an imitation watch.

The problem is a $500k watch is only like $20k in gold, even if it were solid gold. You'd have to wear a lot of watches.

Also the amateurish paint job.

This is what happened with a similar operation where cocaine was disguised in rubber ground mats for tents.

It's not economical to have a person walk up to every package with an XRF gun, but it feels like it ought to be possible to do this in bulk. Maybe use high intensity XRay to quickly capture an overview image / tomograph of each container and then follow up with lower intensity on areas of interest to tease out the spectrum. Is the best way to capture X-Ray spectra still to choke down intensity to the single-photon regime, watch the size of each scintillation event in the detector, and assemble a histogram? In any case, the best way can't be worse than the old way, and the old way is probably viable as a second automatic step in a two step process.

Come to think of it, airport luggage inspection happens at high throughput. Surely they could scale that up from suitcases to containers?

Of course, "physically possible" doesn't mean "politically possible given the budgets involved" which in turn doesn't mean "has actually happened." I'm mostly fishing here to see if anybody knows things about high-throughput X-Ray screening.

There are several paths to discovery here, none perfect, but is a swiss cheese hole method for tripping suspicion.

\0 Social tipoff - did somebody snitch in advance?

\1 Behavioural - is the sender a regular dealer in machine goods | compressors | etc .. a financial accountant suddenly transfering compressors is a behavoural spike.

\2 Consistencey WRT thousands of items per day ... does this load weigh the same as other loads on a pallet with the same Bill of Loading?

\3 Actual Tomography - it's easier than many might think to calculate a rough volume at speed via either X-Ray and|or paired oblique laser scans .. combine that with conveyer weight sensor and you have a density ... see \2.

All these things raise flags .. depending on the number and types of flags per hour, things may or may not get a closer look.

X-raying cargo is a routine activity on the EU's land and sea borders. I assume they do it for air freight and luggage too.

Here's an example x-ray [1].

At the land borders there are large pillars which the lorry driver must drive between (and the same by railway tracks).

I don't know if that's enough to detect steel replaced by gold. It would seem too small to notice.

[1] https://www.smithsdetection.com/press-releases/smiths-detect...

That link is to vapor detection of narcotics, not x-ray.

And those vertical towers are almost certainly radiation detectors.

Pretty sure he was just linking for the picture on that page which is a full vehicle x-ray produced from a system like https://www.smithsdetection.com/products/hcvg/

> The system’s high-performance imaging capability provides the operator with detailed radioscopic images of container or vehicle and its contents, with organic and inorganic material discrimination and colourisation based on atomic number, allowing for rapid and reliable results in a single scan.

It colorizes the x-ray based on the atomic composition of the materials so this system could probably detect a bunch of solid gold parts.

The parts of the turbine look too janky. It has imperfections and irregularities on the surface. So looks like a total piece of junk. Then it’s a bit odd to pay to ship that on a cargo plane.

Gold is also pretty heavy so if they handled any parts they could tell, too.

I think where they screwed up was shipping something heavy and not particularly valuable or obviously necessary to send by air freight via air freight. If it had gone the slow way on a few pallets via LCL ocean freight as mundane industrial machinery it probably wouldn't have been noticed.

Yes. Gold is about 2.5x as dense as steel; gold is about 19.3 g/cc while steel is about 7.8 g/cc.

So, I'd expect it to show up as significantly more opaque in x-ray imaging. I wonder if it would have been noticed if they made all the components out of gold (so they all show up with similar density) or if the operator or a feature of the imaging software would notice that the whole thing was unusually dense.

I also expect that they might have noticed the units were exceptionally heavy, if all the components were gold.

Not an easy problem to solve, as our protagonist smuggler found out.

It would have been much harder to fabricate, but tungsten would be the ideal cover for this as it's almost the exact same density as gold. It's often used in fake gold bars even, where tungsten rods or slugs are cast into a bar in a way that's undetectable without either breaking it open or using a ultrasound technique.

I think tungsten carbide is less dense though, so making fake drill bits wouldn't work.

You could make fake bucking bars, commonly used in metalworking. The whole point of them is to be small enough to fit in your hand but dense enough to backstop a rivet gun, so they are very heavy for their size. Perfect form factor for gold bars, too.

It doesn’t matter if it’s gold, tungsten, or lead.. the x-ray can’t see through it.

If the x-ray can’t see through it, it’s going to get inspected as a possible place where drugs are being smuggled.

Sounds more like a cover for parallel construction.

Agreed. Are inspectors really looking for smuggled gold vs drugs, bombs, etc?

$10 million in gold is only ~130kgs. Feels very plausible to intermingle that among of material in a cargo shipment.

I would guess, this was not x-ray photography, but spectroscopy: https://en.wikipedia.org/wiki/X-ray_spectroscopy

There are these slick handheld units that exist, where you basically point them at something, and they tell you what elements are in something!

https://www.youtube.com/watch?v=LWPSrXB2OZw

I am curious about this as well. Maybe the details on how this was discovered are intentionally missing, so that would-be smugglers don't know how to avoid being discovered.

They obscure in order to secure? Interesting strategy.

> They obscure in order to secure? Interesting strategy.

I mean we do it all the time.

The US government has nuclear submarines so no one knows where they are in the world.

We hide things all the time to keep them from others.

This is a practice that practically everyone does.

There is something that has always felt off about “security through obscurity is no security at all”. There is no reason to give a malicious actor a guide to your operations.

> This is a practice that practically everyone does.

I don't find that a strong argument. I doesn't sound true, but even if it were it wouldn't make it a good idea. Furthermore, there is a difference between hiding a detail (submarine location) and hiding a process (the fact that there are submarines, that they have ICBMs, that they slink around waiting to avenge).

So, in this case, the process would be the existence of customs checks. The hidden detail might be "we've got an informant in the smugglers' organization".

Sure! And it's a matter for debate, but I would draw the line somewhere between what kinds of customs checks there are (e.g. we scan everything leaving a foreign vessel with an MRI and 10% at random with a mass spectrometer) and something covert and sensitive like an informant.

Isn't it well known for example that banks have some rules or algorithms that flag potentially illegal activity, and those rules are secret? Revolut just tells you your transaction is suspect and it will take more time to go through, or just tells you you are suspect, and your account is being closed. They don't tell you what the rules are and which one you broke.

Or if Google thinks you are cheating on ads somehow, they just ban you with no information. Intentionally, so you can't construct a cheat that avoids the cheat detection algorithms. This has been discussed at nauseam, and you're saying it doesn't sound true.

More importantly, what exactly do you think "secret" in "secret service" means? Or "classified" information? Are you actually arguing that these things don't exist? Do you think while the location of secret agents is a secret, the hiring rules and the training and the infiltration strategies are public? Go try to find them.

Yes; I'm convinced most intercepts are not reported on except maybe in end of year statistics.

That said, they do seem to report on large catches. I'm not sure if that's effective, given it means they will just change tactics. I see this mainly with drugs.

But also, I keep thinking if they intercepted this one $100M worth of cocaine, how much did actually pass by?

It's a routine random inspection of commercial freight. Gold is extremely dense. It's about the same density as Uranium and Plutonium (which is a big reason why they and/or software look for it in the x-rays).

at $2k the ounce of gold thatd be 312lb(142kg)...not easy to disguise

> that be 312lb(142kg)...not easy to disguise

I think that’s a cube about 8 inches (~19cm) per side.

Tough to disguise if carrying it solo, but maybe not so tough to hide in a cargo plane somewhat inconspicuously.

The pictures in the article show them as being shaped like machine parts.

Yeah, gold is not quite twice as dense as lead. It's weirdly heavy, but few people handle it in large enough quantities to notice.

Uncle is a goldsmith. I once held a decently sized bar of gold (I'd say 30x10x2cm) in my hand and you're absolutely right, it really is weirdly heavy in a way you'd not expect.

If anyone wants to try it, Sovereign Hill in Ballarat, Australia does daily forgings of a gold bar. They melt it down, pour into a mold, let it cool for a minute or two, and then guests can hold it. I've got a picture of my kids almost dropping ~$300k onto the floor.

https://www.sovereignhill.com.au/events/gold-pour/

Seems to fit in 1 truck:

  10,000,000 / 2,000 = 5,000 ounces
  1 ounce = 28.35 grams
  5,000 * 28.35 = 141,750 grams
  1 cm^3 = 19.3 grams gold
  141,750 / 19.3 = 7,345 cm^3 gold
  % Truck bed volume: .4%
  % Truck bed volume: 16%

https://www.ford.com/trucks/f150/models/f150-xl/

  Base model:
  Cargo box volume: 52.8 cu. ft. = 1,495,129.5 cubic centimeters
  Cargo box weight limit: 1,785 lbs = 809,662.38 grams

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