John
Thanks for the message.
>The Harlech Dome manganese mines worked carbonate-silicate manganese ores,
>which formed a statiform bed best developed around the southern/western
>flanks of the Rhinogau, chiefly from above Bontddu, around west to Barmouth
>and northwards beyond Harlech.
>
>Although the footwall-rocks have a bit of cubic pyrite, it never
>constituted a signifcant component of the mineralisation.
That was my understanding, Allen & Jackson, _Geology of the Country
Round Harlech_, give a thickness of 50mm for that bed.
>Chief pyrite localities where it was recovered for "sulphur" ie. sulphuric
>acid & byproducts were:
>
>Cae Coch near Llanwrst - a huuuu-uuuge massive volcanogenic pyrite deposit,
>now chiefly famous for the extraordinary acid-water loving microbiology
>that thrives underground - the so-called acid streamers that some of us
>trolls refer to as "snot-gobblies". David Jenkins of Bangor did the
>groundbreaking work on this site. Estimated to be 100 cubic M of biomass in
>there living off the oxidising pyrite!!
I've seen them in Parys mine where they were referred to as snotites.
As I said in my reply to the group, I'd forgotten about the Conwy
valley sulphur mines/wells.
>Dave - give me the locality names and I'll try to look into it in more
>detail for you.
According to Gwynedd Archaeological Trust's Sites and Monuments
Record, two of the Harlech Dome manganese mines have sulphur mines
associated with them. They are:
Llety'r Wialch, Penamnen, SH604333
which is described as "Sulphur/Manganese mine"
Harlech Sulphur Mine, SH605280
which has the same grid reference as Coed manganese mine.
I haven't found an on-line source for the Merioneth mining
statistics, so I've not been able to check if there's any recorded
pyrites output for Llety'r Wialch. According to Down, _Manganese
Mines of North Wales_, pyrites were recorded as being mined at Coed
1872-1875 but, as I said before, I hadn't associate pyrites with
sulphur. Perhaps there were significant pyrites deposits at these two
locations.
If you do know anything about these two locations I'd be grateful. My
particular interest is the industrial archeology of the manganese
mines and my web site
http://www.btinternet.com/~birchlands/Merioneth-Manganese/ is an
attempt to document them.
Regards
Dave
--
Dave Linton
Tel: (01341) 280901 (UK) +44 1341 280901 (international)
Fax: 0870 124 9761 (UK)
http://www.btinternet.com/~birchlands/dlinton/
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