A few years ago, I succeeded in making a copper nugget from carbonate rich chrysocolla, the yield was pretty damn poor, but it was a bit of real cornish copper.

I've read that various beaches have been milled and "following a storm, tin can be concentrated naturally".

I'm really interested in these deposits and trying to get myself enough tin oxide to have a go at it.

I've walked around and observed very dark patches and I've had a go at vanning, but the stuff doesn't seem to separate too well. I gather that the dark patches could in fact be tourmaline and the tin oxide may be a different colour (I'm sure I've read this somewhere).

I'm very interested in refining this idea further and would like to hear the wisdom of you lot.

S

Beach tin is normally brown in colour. Tolgus Tin Streams survived for many years streaming beach sand.
I would suggest Perranporth beach after a period of North wind, it seems to accumulate below Droskyn Head.
We've had this discussion before and what you found then was coal.

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Cassiterite on the vanning shovel is usually quite pale, except when it is very coarse, slight grinding of coarse material will become lighter in colour. The sort of black sands that you can find on many beaches in Cornwall, although they contain tin they don't often contain free tin, the material needs to be ground then you should be able to see a separation but it's often quite fine. To smelt on a small scale you need good clean material >60% Sn and the closer to 70 the better.

I'd heard about Droskyn point as well.

I wonder how best to separate it.

Thinking out of the box, it would be possible to do a thermite reaction with tin and any impurities would either boil off, or form a slag, including silica.

I rigged up a furnace using a couple of massive terracotta plant pots I'd dried out in a bonfire, then filled with barbecue charcoal (lit) to about 1/4 full, then a mixture of finally divided coal and ore. (which I'd previously roasted in a wok - made the house smell of sulphur dioxide!!!! ) the whole thing was covered with a bit of stainless gauze, an inverted plantpot and blown with an industrial vacuum cleaner (on blow). Sadly, most of my ore was blown out of the top pot. The yield was about 4%.

I imagine, getting enough tin oxide would be very tedious indeed.

The other option was to do some vanning in likely adits.

Edit:- Interesting point Geoff. I wonder if coarse black tin with impurities (silica/tourmaline) would undergo gravity separation following being thermited.

http://www.amazingrust.com/experiments/how_to/Thermite.html 

Have a read of the above. It's doable in theory.

I tried the copper one, but it was impure and upon ignition, it "exploded" :lol:

If you go to Droskyn in the right conditions it should take no time at all, but nothing worthwhile is ever easy.

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I think I asked the question regarding the black stuff on Porthmeor Beach (St Ives) - which I think is below the portal (blocked) of quite a major adit. I think a lot of that is perhaps tourmaline. It's black, separates (not sure by gravity - perhaps particle shape) and that's about it!

I'd steer clear of thermite for many reasons, if it smelts and there are other metallic impurities it will all end up in the tin, along with any unused aluminium, a very bad idea if there's any arsenic present.

If you want to try industrial chemistry there are better routes, chloride fuming will deal with quite low Sn and make a clean separation from other elements as long as you've got your temperature under control. I did this some years ago on a bit of a scale and could produce tin metal by electrolysis.


Seriously though much better to get a clean concentrate, smelt in a crucible with anthracite, you live in Cornwall and even after 4000 + years of people digging it up there's still plenty to be had 😉

I think I asked the question regarding the black stuff on Porthmeor Beach (St Ives) - which I think is below the portal (blocked) of quite a major adit. I think a lot of that is perhaps tourmaline. It's black, separates (not sure by gravity - perhaps particle shape) and that's about it!

What you found on Porthmeor is as I said before, coal, it's quite simple if you rub it between your hands they will become black, if you collect enough of it you could heat your home. ::)

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Stuey, it seems the main difficulty you have to overcome is being able to identify cassiterite. Both coarse material in rock and fine on the shovel or in a pan. You need to obtain some and have a play around with it.

St Agnes beach is possible , I have found some very nice specimens of wood tin on the beach, but it takes some finding, People in the past also concentrated, tin in the Polberro adit using planks of wood to act as a riffle, I have very successfully concentrated tin using a gold pan, I work with glass fibre so made a mould and a white pan, worked very well. 😉

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Next time I'm down at Perranporth, I'll see if I can obtain some.

I gather that pools are often surrounded by a black cresent with a honey coloured cresent around/over it. I read that the black was high in tourmaline and the honey coloured stuff was cassiterite. I assume that the reason Perranporth was noted for this was that the separation was particularly marked, with a uniform(ish) grain size and distribution.

I'll have a go at it and see how I get on.

Oddly enough, I have a weighing machine with vibrating planes which might offer a separation method! I'll have a go at that too.

Next time I'm down at Perranporth, I'll see if I can obtain some.

I gather that pools are often surrounded by a black cresent with a honey coloured cresent around/over it. I read that the black was high in tourmaline and the honey coloured stuff was cassiterite. I assume that the reason Perranporth was noted for this was that the separation was particularly marked, with a uniform(ish) grain size and distribution.

I'll have a go at it and see how I get on.

Oddly enough, I have a weighing machine with vibrating planes which might offer a separation method! I'll have a go at that too.

You seem to be answering your own question

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I also seem to recall that the blue hills tin streams used to process beach sand, Maybe St Agnes or around that area!!

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I also seem to recall that the blue hills tin streams used to process beach sand, Maybe St Agnes or around that area!!

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I also seem to recall that the blue hills tin streams used to process beach sand, Maybe St Agnes or around that area!!

The tinning rights on the beach and surrounding area are spoken for and closeley guarded, take my tip and stay well clear of

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Stuff.

You seem to be answering your own question

I was particularly interested in talking with people who had actually done this and offering suggestions. I'm not thinking about opening a commercial operation, just making a nugget from first principles. As far as I'm concerned, people with mineral rights issues can have a chat if concerned, I'm not about to start dredging!

Hi Stuey, I concentrated tin using a gold pan from a large bag full of rock and loose cassiterite crystals collected from underground at Whiteworks mine, amazing you just scrapped them off the walls!!!, Anway we smelted some in my mates coal fire using a carbon crucible and a mixture of crushed anthracite, cassiterite crystals and fluorite as a flux, we found the mix in an old assaying book. It worked when we used a hoover to blow air into the fire!!!, used a bag of coal but got enough tin to make a small ingot. I still have it!!!nearly 30 years later, It can be done!! 😉

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Stuff.

You seem to be answering your own question

I was particularly interested in talking with people who had actually done this and offering suggestions. I'm not thinking about opening a commercial operation, just making a nugget from first principles. As far as I'm concerned, people with mineral rights issues can have a chat if concerned, I'm not about to start dredging!

All I am saying is there are plenty of places to go, why needlessly upset some one. If you still want to go there then do so, it won't affect me in any way but don't say you havn't been warned,

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I wouldn't go deliberately upsetting someone, although it may sometimes appear otherwise. 😉

Shame about Whiteworks mine, I had an amazing cassiterite sample out of their, I gave it to the School of Mines museum, when I was there, It was on display at Pool but not sure what happened to the Museum let alone my Cassiterite sample? :ohmygod:

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