Bronze age Britain and the tin trade

[Imperial Dave]

https://theconversation.com/bronze-age-britain-traded-tin-with-the-mediterranean-shows-new-study-settling-a-two-century-debate-256005

The more I read the less I am surprised at this...

[Jim Webster]

I think it's one of the issues that solid work that actually provides reliable evidence for 'what everybody knows' rarely makes the headlines or causes surprises 

I remember reading a comment, perhaps forty years ago, that one problem with (from memory German) academic research was that everybody tried to make their PhD more radical than the others so at least people would read it

[Nick Harbud]

I thought the problem wth German research was plagiarism of previous work...

[Imperial Dave]

Ouch...

[DBS]

A very interesting paper.  I was not at all surprised by their conclusions regarding the range of West Country tin distribution in the Bronze Age, but I had not previously understood that the ores there had enjoyed such ease of early access from streams; given all the tin mines, I had always lazily assumed that mining was the only option.

[Nick Harbud]

Mineral extraction, especially its development resulting from improved technology, is a fascinating topic.  I remember some years ago reading about a new chemicals plant that had been commissioned in Australia.  It produced some 360,000 tonnes of ammonium nitrate per year, dedicated to the production of ANFO to be used in local iron ore mining operations.  The scale of this operation is truly awesome!

[Jim Webster]

Mineral extraction, especially its development resulting from improved technology, is a fascinating topic.  I remember some years ago reading about a new chemicals plant that had been commissioned in Australia.  It produced some 360,000 tonnes of ammonium nitrate per year, dedicated to the production of ANFO to be used in local iron ore mining operations.  The scale of this operation is truly awesome!

I remember reading that in some mines in South Africa, the explosive was mixed in ordinary cement mixers literally at the face that was to be used at.
In Northern Ireland, the sale of pure Ammonium Nitrate fertiliser was (and I think still is) banned and instead Calcium Ammonium Nitrate or Nitrochalk is used.
It's 27% plant available nitrogen as opposed to 34.5%
And yes you can get the ammonium nitrate out of Nitrochalk, it involves 'distillation' and is a process you leave to geographically distant minions.
And back in the 1968 I almost got into trouble at school for selling ammonium nitrate to lads in my class who were trying to make bangers

[Nick Harbud]

I think your school pals might have great difficulty in getting ordinary ammonium nitrate to explode due to it being very hygroscopic, that is, it will absorb atmospheric moisture to an extent that renders it inert.  Notwithstanding, ammonium nitrate that is not stored correctly can spontaneously explode, as witnessed in Beirut during 2020.

Many explosives that involve ammonium naitrate mixtures have to be mixed and used soon after manufacture, and ANFO works in places like South Africa or Australia where is not normally much moisture down the holes into which the explosive is poured.

And just to make all remaining hair stand up on everyone's heads, one should consider the use of amatol (a mixture of ammonium nitrate and toluene) as the main explosive for mines on the western front in WW1. 

For example, in 1917 the British dug 21 mines beneath Messines Ridge.  Only 19 were successfully fired on the night of the battle.  One of the remaining mines exploded during a thunder storm in 1955.  One is still there, precise whereabouts unknown.

In another case, there were several mines dug under German positions on Vimy Ridge that were not fired due to the successful battle in 1917.  During the 1980s, these mines were explored by a retired Colonel Royal Engineers who discovered many of them not only had their main charges in place, but also had priming charges that had become rather unstable over the years.  Large parts of the Ridge were hurriedly taped off from visitors.

 

[Jim Webster]

Don't worry I've spent a lifetime keeping ammonium nitrate dry 
The lads did manage to make it go bang. So successfully that somebody reported them to the head master at the school.
He was outraged and rather than summoning me, phoned my parents. Luckily, my mother, who was a teacher, who would understand, was out. My father answered the phone and his comment was along the lines of 'as long as he's getting more than we paid for it'.
At this point the head master realised that selling ammonium nitrate wasn't illegal. Indeed it wasn't even against school rules 

It has to be said that had this happened a mere year or two later, there could have been far more fuss and the involvement of the 'authorities'.

The big problem with Ammonium nitrate is that when it burns, and you put the fire out, traces of it on steelwork can then just spontaneously catch fire again. You have to just demolish what's left.

Whilst it does absorb water, for agricultural purposes it comes in a plastic bag, which is in a woven plastic bag that takes the weight etc.
During the first gulf war, because most Ammonium nitrate is produced using natural gas as the energy source, I bought my spring Ammonium nitrate in the autumn, put each half ton bag in a big bale bag, and then stored it outside with no ill effects until March 

In the UK we are encouraged to store it outside. Beirut explains exactly why this is a good idea.

[Imperial Dave]

 

[Erpingham]

Fascinating though it is, we don't seem to have much evidence of the use of ammonium nitrate explosives in the Bronze Age.  Indeed, the suggestion is that tin didn't need to be mined for - there was so much alluvial tin lying around in Devon and Cornwall, just waiting for someone to find a use for it. 

It is perhaps surprising there doesn't seem to be much evidence of tin smelting from the period.  The sorts of quantities of tin exports over centuries talked of in the paper ought to have left some traces.

[Jim Webster]

Fascinating though it is, we don't seem to have much evidence of the use of ammonium nitrate explosives in the Bronze Age.  Indeed, the suggestion is that tin didn't need to be mined for - there was so much alluvial tin lying around in Devon and Cornwall, just waiting for someone to find a use for it. 

It is perhaps surprising there doesn't seem to be much evidence of tin smelting from the period.  The sorts of quantities of tin exports over centuries talked of in the paper ought to have left some traces.

That's the bit that struck me as well. When it says "Small farming communities across Cornwall and Devon would have dug, washed, crushed and smelted the abundant tin ore from the alluvial deposits in the region. The heavy sand to gravel-sized tin ore is in a layer buried under soft layers of barren silt, sand and gravel."
Given it was done within the community you would have expected some evidence. After all we have evidence of other metal working on later archaeological sites. Slag seems to last forever