UK Grid Reference: SH617183
Latitude: 52°44'39"N
Longitude: 4°2'56"W
Manganese-bearing shales overlain by coarse-grained greywacke, at the base of a grey siltstone layer (Hafotty formation). The mine was worked prior to 1928, producing 44,000 tons of manganese ore.
The ore-bed is thinly laminated and superficially stained with a purplish brown residue from the weathering of the manganese minerals. It consists mainly of spessartine with some rhodochrosite, quartz albite and chlorite. It may have formed as a gel at the water/sediment interface in a shallow marine basin, initially as rhodochrosite, but was regionally metamorphosed to spessartine.
Ref.: P.M. Allen, A.A. Jackson: Geological Excursions in the Harlech Dome, BGS, 1985
One of five continuous manganese mines that worked the outcrop for three miles north of Barmouth, and the largest of the Merioneth manganese mines according to recorded output.
Ref.:
The manganese Mines of North Wales, G. C. Down, British Mining No. 14 (A monograph of the Northern Mines Research Group)1980.
Mineral List
6 entries listed. 4 valid minerals.
The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please
register so you can add to our database. This locality information is for reference purposes only. You should never attempt to
visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders
for access and that you are aware of all safety precautions necessary.
Mineral and Locality Search
