Wednesday, 29 June 2011

The Joy of (Gwaith) Setts...


Usually referred to as a disused granite quarry,  Manod Bach Quarry (Gwaith Setts), actually extracted dolerite from the late 1800's up until 1972. Not that there isn't some nice granite about here, but the really good stuff is over on Manod Mawr, overlaying the fine slate beds of Graig Ddu.
Dolerite is an igneous rock, intruded into the sedimentary mudstone and grit stratas here by plutonic action some 500 million years ago. It's very hard, close grained and intractible, which makes it ideal for use as cobbles.


A determined search will reveal plenty of other minerals to be found here, including some lovely Quartz crystals, Galena (lead),  Pyrite and a few more esoteric ones like Brookite and Anatase.
The remains of several inclines run up to the quarry face, which is itself passed by the first of the Graig Ddu inclines on it's way up to Manod Mawr; a popular walk with locals. The old GWR railway station and yard was once below the quarry, from where much of the produce was distributed. Ironically, close to the old station site today is a depot  for a  road haulage firm, Hughes of Manod.



Further south of the quarry, on a higher level, is an old drumhouse with views over to Cwmorthin and the Moelwyns. But the most noticeable thing here at Gwaith Setts are the  towering slate tips of Diffwys and Votty. They loom over the site, the Diffwys 6 floor mill chimney sticking up over the skyline. No matter where you go in Blaenau Ffestiniog, even in a Dolerite quarry, you can't get away from the slate.









2 comments:

geotopoi said...

Interesting stuff. Looks like you get grand views there.

Iain Robinson said...

Thanks, Graham.

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