Many people will probably have seen the strange shell-like formations that have grown on rusting iron objects in mines.

The trip to Cwmorthin at the weekend was specifically to look for these and here are some of the results:

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Although this has been discussed in the past, we never seemed to reach a definitive answer, but...

A trip to one of the slate mines on the Moelwyns a few months back sparked the interest of a geologist we took along and the subject has now developed into a university project, with the possibility that it may warrant further study in the future.

With that in mind, I'd be grateful for any reports of where these 'shells' have been found :flowers:

The details needed are pretty minimal - mine name at the very least and possibly also rough location in the mine. Photographs would be a bonus, just for confirmation.

I'll update the post below as and when.

Any help would be much appreciated! :thumbup:

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Locations that mine 'shells' have been found:


North Wales

Cwmorthin Slate Mine - several locations, Floor 4 OV in particular

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Some on the pipes in Moel Fferna... EWJ pointed them out a couple of weeks ago.

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derbyshie-
holme bank chert mine
jug holes
ashford black marble mine

wilts
monks park

have some pics and will look them out
always called it popcorn rust before tho 😉

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Found these on old bits of Iron, when digging old mine dumps in Cornwall for Mineral specimens, So may not just be underground!!.
Off topic but used to find amazing ferns of metallic copper growing from the Iron tracks down Mount Wellington mine Cornwall. Touch them and they disintigrated!!

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Found them in many derbyshire spa mines including Long Rake. 🙂

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hbcm

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northants iron mine

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Found in most of the North Cardiganshire mines.

and often found in Devon & Cornwall

See rusty 'bubbles' all over the place, anywhere there's iron underground really, but not sure I've seen such perfect shell like forms as in this photo taken by Vanoord.
[photo]Cwmorthin-Floor-4-05-01-2008-Image-59927[/photo]

Lot's in Nenthead, pretty much anywhere, where it's damp and wet and you have some iron.

Those shell's on the rail, they do look like real sea shells, but coated in iron - pretty amazing.

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We know them as Rust Mussels in Cornwall.
Hope he doesn't need to collect any samples...?

We also get copper deposits too.
This sample, collected shortly before the mine flooded, measures 140 mm long (just shy of six inches in old money) and was found coating a piece of wire rope in a pool of water on 3 level east Mount Wellington (1987)
The close up shows bunches of crystals making up the whole structure. The sample weighs in at a tad short of 3 ounces.
The last picture shows the mould marks of the wire rope it was on.
The crystals were very shiny and bright when first found

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P.S. Why won't the first image open when clicked on ? This also happened with the Grambler pics in the general chat section.......
:confused:

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🔗Cwmorthin-Slate-Mine-User-Album-Image-58754[linkphoto]Cwmorthin-Slate-Mine-User-Album-Image-58754[/linkphoto][/link]

Here is a close up of rust shells growing on pipework somewhere on the Back Vein Incline, Cwmorthin. Out of interest, are they ever seen in large numbers above ground? I was careful not to touch them, so have no idea how robust they are, or if they are hollow or solid. I would certainly like to find out more about them, as they came as quite an unexpected surprise. I tried looking up more information online, but oddly not much luck so far. Surprised they are apparently little documented.


'The Doors of Durin, Lord of Moria. Speak friend and enter!'

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have seen broken ones and they are hollow
dnt no if full of water when complete tho

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Usually part full of water to my (limited) experience of breaking them - chiefly through climbing ironwork and unavoidably breaking some. They tend to be brittle but surprisingly robust.

Many thanks for the comments. I have a trip to Cwmorthin planned for mid-May and hope to get some more photos of rust shells.



'The Doors of Durin, Lord of Moria. Speak friend and enter!'

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Hope he doesn't need to collect any samples...?

'He' is actually a She ;-)

Interesting that they exist in mines all over the country.

@mikebee62
Did you really see them above ground, out in the open? Shell-like formations rather than just rust or rust bubbles?

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It was mentioned in a previous post that rust shells are abundant on 4th floor old vein of Cwmorthin in particular. Is there any known reason why they would be more abundant in a certain area of a mine, and be less abundant or absent from another area of that mine? Would it perhaps be dependent on the amount of water present, as I strongly suspect is the basic reason, or a more complicated situation altogether, eg the the manner in which the water was actually making contact with the iron :- a flow of water over the iron structure, a fine spray falling on it, or water inside a hollow structure leaking out? It would be interesting to map the relative abundance of this phenomena in different regions of the same mine. Cwmorthin being large and varied, I think would be perfect for this kind of investigation.

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Floor 4 is a bit odd (for Cwmorthin) in that it hasn't seen anyone in there for around 100 years - the connection from below has only been recently re-made; and the connection from the outside has been long lost.

Thus, there's been no human traffic to destroy the rust shells that have been growing on the rails, somewhere that feet would have destroyed them long ago had anyone been in there. (There was somewhere else I had in mind other than Cwm Floor 4 for the trip, but that required a lot more walking. Again, it's long-abandoned).

It's not so much that the conditions are right from a chemical point of view, it's the lack of disturbance that has benefitted them.

Generally, the shells seem to be more frequent in places that are undisturbed; and also where it's damper.

As Davel has said elsewhere, I suspect that the composition of the iron is an (perhaps the) important factor.

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Agreed, the combination of low (or better still, no) foot-fall is key to there survival and the presence of moisture (not total submersion) is a part of their environmental requirements. The theory that rusting wrought iron is the only medium for their growth is beginning to form but obviously the older the mine, the less likely you are to find modern steel structures. If anyone were to spot them attached to anything other than ironwork then we would be very interested to hear about it and see some photos.

For the purposes of research and only if it doesn't cause you too much trouble. Should anyone notice these 'shell like' formations, or anything similar, in a mine outside the North Wales slate area, it would be greatly appreciated if you could take a couple of photo's of the shell and it's surroundings and upload them here, just a quick note to say where it was would also be very helpful.

I think it's safe to say these formations are worth preserving but due to their brittle nature, tread carefully :thumbup:

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