RobinGriffiths
Well-known member
Cwm Nantcol
I remember seeing the inclined rock terrace with the intriguing black spoil heaps and invititing looking holes above whilst driving to start a walk up Rhiniog Fach and Y Lethr. This was 25 years ago. I thought once I'd knocked off The Nuttals, I'd have a bit more time for bimbling around obscure mines like these. This was indeed true, but I didn't get to walk up that terrace until today.
It turned out to be a pleasant visit. A good mine trackway leads off the footpath that then becomes steeper, following the dip of the bedding up the side of the hillside, with adits to the right, and dark spoilheaps to the left. Below this is a thick, solid bed of coarse sandstone forming a lofty ridge above the wide valley floor below.
There are perhaps a dozen adits, some blocked or collapsed, but there's about 6 that can be followed some way into the hillside, on occassion linking to that above or below. Generally backfilled to the left. The rock is very dark, fine grained and brittle with no obvious signs of mineralisation apart from its general, dark manganesey-ness. In a couple of places though, there are some manganese and calcite speleothems. Higher up the hillside, the manganese bed breaks surface, and the workings can be traced as two parallel shallow trenches.
The spoil heaps consists of the general mangenesey stuff, but there are some crystalline quartz samples, some pyrite, and some samples containing nice 5mm crystals of red hematite.
Indispensable reference of course is Dave Linton's http://www.hendrecoed.org.uk/Merioneth-Manganese/ website
I remember seeing the inclined rock terrace with the intriguing black spoil heaps and invititing looking holes above whilst driving to start a walk up Rhiniog Fach and Y Lethr. This was 25 years ago. I thought once I'd knocked off The Nuttals, I'd have a bit more time for bimbling around obscure mines like these. This was indeed true, but I didn't get to walk up that terrace until today.
It turned out to be a pleasant visit. A good mine trackway leads off the footpath that then becomes steeper, following the dip of the bedding up the side of the hillside, with adits to the right, and dark spoilheaps to the left. Below this is a thick, solid bed of coarse sandstone forming a lofty ridge above the wide valley floor below.
There are perhaps a dozen adits, some blocked or collapsed, but there's about 6 that can be followed some way into the hillside, on occassion linking to that above or below. Generally backfilled to the left. The rock is very dark, fine grained and brittle with no obvious signs of mineralisation apart from its general, dark manganesey-ness. In a couple of places though, there are some manganese and calcite speleothems. Higher up the hillside, the manganese bed breaks surface, and the workings can be traced as two parallel shallow trenches.
The spoil heaps consists of the general mangenesey stuff, but there are some crystalline quartz samples, some pyrite, and some samples containing nice 5mm crystals of red hematite.
Indispensable reference of course is Dave Linton's http://www.hendrecoed.org.uk/Merioneth-Manganese/ website
