The Drilled Gold Bars Filled With Tungsten

I have to admit that I really do like this story. Over the weekend there's been some rather breathless speculation about how a gold bar has been found, one that has been drilled out and filled with tungsten. Given that I'm actually in the metals trade, albeit not bullion or tungsten (I have handled both but they're not my specialty) I thought I'd have a closer look.

The first mainstream report that I saw was by Felix Salmon at Reuters. And there's two parts to that story.

Firstly, I wouldn't be surprised if someone has attempted to do the substitution. It's been known for a long time that the densities of tungsten and gold are close enough that in theory, drilling out a hallmarked gold bar and replacing the interior with tungsten could fool all but the most sophisticated of tests.


But as I've said, in theory this sort of thing is possible even if it would be very difficult to do in practice. Further, I'm not really sure that the economics of it quite work out either. Sure, tungsten is vastly cheaper than gold but this would be very skilled work with a low success rate and the gross profits are a few thousand $ per 1 kg bar so treated. It's most certainly not a 5 minute job either. Nor mechanisable. Just not sure that it would be worth it.



The answer to this comes from a commenter there:



I would take that even further. Even the ingots in central banks, or in gold vaults, sometimes get sent off to be refined. For the very same reason those vaults are regularly vacuumed for the trace amounts of gold that have rubbed/been chipped off the ingots. It's absolutely true that gold doesn't oxidise or decompose, but as bars are moved around then they inevitably get bumped and after enough of that they are likely to get sent of for refining so as to maintain their good delivery characteristics. And no, a tungsten filled bar would not be refined without someone noticing.

If I were to assign percentages here I'd say that someone trying to drill out a bar and fill it with tungsten would be up near 100%. I'm sure the idea has occurred to lots of people independently. As to this being a common occurrence among good delivery bars I'd put it down somewhere near zero. There's just too much turnover of bars through the refineries for this to be possible.

Update: I should have added that the first people to raise concerns about the veracity of this story were the guys and gals at the Screwtape Files. As to who was first to find out about MKS, well, by the time I phoned them at lunchtime (European time) Monday they were already obviously bored with answering the questions so I know I wasn't first to do so even if I did do so.

