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Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK

The main Dolgellau gold belt swings about 15 miles in a narrow arc just to the north of Dolgellau, and flanks the southern, southeastern and eastern edges of the major structure, the Harlech Dome. It runs from the coast at Barmouth, west of Dolgellau, to the north-east of Ganllwyd, north of Dolgellau. In addition, three outlying mines, Prince Edward and Cwmprysor/Arenig, and Castell Carn Dochan, are isolated some 6 miles further north and east respectively of the most northerly group of mines in the main gold belt. The gold was worked from a series of NE-SW quartz veins, in places up to 6m wide.

At least a total 24 mines and 63 lesser mines are recorded to have worked for gold in the district, although some as a secondary product of lead or copper mines. Although most of the mines in the area produced a little gold, many were largely unsuccessful.

Two mines, Clogau (78,507 ounces between 1862-1911) and Gwynfynydd (40,054 ounces between 1862-1916), produced most of the area's recorded gold. A further two mines, Castell Carn Dochan (1913 ounces between 1864-98) and Cefn Coch (1392 ounces between 1862-1912), produced much of the rest!

The realisation of gold in the Dolgellau area during the 1840s resulted in a considerable but largely abortive goldrush during 1854-55. A lapse in activity led to a subsequent and more intense goldrush about 1860, but by 1870, most mines were derelict.

In 1887, the last and greatest goldrush began. Output peaked about 1900 after which a slow but steady decine began, mining being largely finished by the time of first world war.

Although little work has been done since this time, in more recent years both Clogau and Gwynfynydd mines have been exploited by companies taking advantage of the high premium payable for Welsh gold in the jewellery market.

The output for the district is uncertain and is probably significantly under recorded. It is thought that substantial quantities of ore was mined before 1860, but no reliable figures are available. Between 1861 and 1896 the recorded output was 279,027 tons of ore producing 126, 340 ounces of gold (a further 5,366 ounces of gold were also produced during this period, but without tonnage figures).

Ore output peaked in 1902 although the 29,953 tons of ore produced only 4,181 ounces of gold. However, the peak output of gold was in 1904 when 19,655 ounces of gold was produced from 23,203 tons of quartz ore.

Output after the first world war was very sporadic (although almost 3000 ounces of gold are recorded having been produced in 1935).

Welsh gold has traditionally been used to provide material for royal wedding rings, gold from the Dolgellau mines, Prince Edward Mine and Marina Mine, together with the mid-wales mine, Roman Deep at Dolaucothi, being used to make Princess Marina's wedding ring in 1935 (gold from the bar produced was also subsequently used for other royal rings).

refs:
Goldmining in Western Merioneth, T. A. Morrison (undated)
The Gold Mines of Merioneth, G.W. Hall (undated)

Modern working has been, as noted above, largely driven to meet the demands of the the jewellery market. None of the mines are currently working although one small company, Cambrian Goldfields Ltd., is again prospecting for, and creating jewellery with, Welsh Gold.

Fine examples of gold from the Dolgellau gold belt are held in the colection of the National Museum of Wales in Cardiff.




Mineral list contains entries from the region specified including sub-localities


Mineral List:
  • Acanthite ?
    Ag
     
    2
    S
    Description: The National Museum of Wales database "The Minerology of Wales" (http://www.nmgw.ac.uk/en/791/)has raised doubts regarding the identifications of acanthite and sylvanite at this location.
    Reference: [The National Museum of Wales database "The Minerology of Wales"]
  • Aleksite
    PbBi
     
    2
    Te
     
    2
    S
     
    2
    Reference: [BMS Database]
  • Altaite
    PbTe
    Reference: [BMS Database]
  • Anatase
    TiO
     
    2
    Reference: []
  • Anglesite
    PbSO
     
    4
    Reference: [No reference listed]
  • Ankerite
    Ca(Fe
    2+
     
    ,Mg,Mn
    2+
     
    )(CO
     
    3
    )
     
    2
    Reference: []
  • Aragonite
    CaCO
     
    3
    Reference: [BMS Database]
  • Arsenopyrite
    FeAsS - (Fe
     
    0.90
    Co
     
    0.10
    )AsS
    Reference: [BMS Database]
    Site Photo
    Castell Carn Dochan, Llanuwchilyn, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Bismuth
    Bi
    Reference: [BMS Database]
  • Bismuthinite
    Bi
     
    2
    S
     
    3
    Reference: [BMS Database]
    Site Photo
    Castell Carn Dochan, Llanuwchilyn, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Bornite
    Cu
     
    5
    FeS
     
    4
    Reference: [BMS Database]
  • Boulangerite
    Pb
     
    5
    Sb
     
    4
    S
     
    11
    Reference: [BMS Database]
  • Bournonite
    PbCuSbS
     
    3
    Reference: [BMS Database]
  • Brochantite
    Cu
     
    4
    [(OH)
     
    6
    |SO
     
    4
    ]
    Reference: [BMS Database]
  • Calcite
    CaCO
     
    3
    Reference: [Ian Jones collection]
    Site Photo
    Gwynfynydd Mine (Gwyn Mine; Morgan Mine; Mount Morgan Mine; British Gold Fields), Ganllwyd, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Ian Jones
  • Chalcoalumite
    CuAl
     
    4
    [(OH)
     
    12
    |SO
     
    4
    ] · 3H
     
    2
    O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Chalcocite
    Cu
     
    2
    S
    Reference: [BMS Database]
  • Chalcophyllite
    Cu
     
    18
    Al
     
    2
    [(OH)
     
    9
    |SO
     
    4
    |AsO
     
    4
    ]
     
    3
    · 33H
     
    2
    O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Chalcopyrite
    CuFeS
     
    2
    Reference: [BMS Database]
  • 'Chlorite Group'
    Reference: [BMS Database]
  • Chrysocolla
    (Cu,Al)
     
    2
    H
     
    2
    Si
     
    2
    O
     
    5
    (OH)
     
    4
    ·nH
     
    2
    O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Clinozoisite
    {Ca
     
    2
    }{Al
     
    3
    }[O|OH|SiO
     
    4
    |Si
     
    2
    O
     
    7
    ]
    Reference: [Gilbey, J.W., 1968. The mineralogy, paragenesis and structure of the ores of the Dolgellau Gold Belt, Merionethshire, and associated wall rock alteration. Unpublished Ph.D thesis, University of London, UK.]
  • Cobaltite
    CoAsS
    Reference: [BMS Database]
  • Copper
    Cu
    Reference: [recorded in the National Museum of Wales database]
  • Covellite
    CuS
    Reference: [BMS Database]
  • Cuprite
    Cu
     
    2
    O
    Reference: [BMS Database]
  • Devilline
    CaCu
     
    4
    (SO
     
    4
    )
     
    2
    (OH)
     
    6
    ·3H
     
    2
    O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Dolomite
    CaMg(CO
     
    3
    )
     
    2
    Reference: [National Museum of Wales datebase]
  • Erythrite
    Co
     
    3
    (AsO
     
    4
    )
     
    2
    ·8H
     
    2
    O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Galena
    PbS
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  • Gibbsite
    Al(OH)
     
    3
    Reference: [BMS Database]
  • Goethite
    α-Fe
    3+
     
    O(OH)
    Reference: [No reference listed]
  • Gold
    Au
    Reference: [BMS Database]
    Site Photo
    Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
     
  • Gold
    var: Electrum
    (Au, Ag)
    Reference: [Mineralogical Magazine 1884 6 : 108-108]
  • Gypsum
    Ca[SO
     
    4
    ] · 2H
     
    2
    O
    Reference: [BMS Database]
    Site Photo
    Castell Carn Dochan, Llanuwchilyn, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Halotrichite
    FeAl
     
    2
    (SO
     
    4
    )
     
    4
    ·22H
     
    2
    O
    Reference: [No reference listed]
  • Hedleyite
    Bi
     
    7
    Te
     
    3
    Description: Hedleyite occurs as tiny inclusions in galena on a specimen (K3) in the Kingsbury Collection held at the Natural History Museum, London (Naden, 1988). This, the Uk's first occurrence, is the only known specimen from Clogau Mine. No other examples have come to light despite extensive studies (National Museum of Wales database). Whilst confirmed analytically, the occurrence should be treated with caution due Kingsbury's known creative specimen provenancing practices (Ryback et al., 1998).
    Reference: [BMS Database]
  • Hemimorphite
    Zn
     
    4
    [(OH)
     
    2
    |Si
     
    2
    O
     
    7
    ] · H
     
    2
    O
    Reference: [No reference listed]
  • Hessite
    Ag
     
    2
    Te
    Reference: [BMS Database]
  • Hydrozincite
    Zn
     
    5
    [(OH)
     
    3
    |CO
     
    3
    ]
     
    2
    Reference: [No reference listed]
  • Langite
    Cu
     
    4
    [(OH)
     
    6
    |SO
     
    4
    ] · 2H
     
    2
    O
    Reference: [BMS Database]
  • Lead ?
    Pb
    Description: Readwin reported native lead with gold from the Dolgellau Gold-belt. Neither occurrence has since been confirmed.
    Reference: [Natiom]
  • Mackinawite
    (Fe,Ni)
     
    9
    S
     
    8
    Reference: [BMS Database]
  • Malachite
    Cu
     
    2
    [(OH)
     
    2
    |CO
     
    3
    ]
    Reference: [BMS Database]
  • Marcasite
    FeS
     
    2
    Reference: [No reference listed]
  • Matildite
    AgBiS
     
    2
    Reference: [BMS Database]
  • 'Mica Group'
    Reference: [BMS Database]
  • Molybdenite
    MoS
     
    2
    Reference: [BMS Database]
  • Monohydrocalcite
    CaCO
     
    3
    ·H
     
    2
    O
    Reference: [BMS Database]
  • Nagyágite
    Pb
     
    5
    Au(Te,Sb)
     
    4
    S
     
    5-8
    Reference: [BMS Database]
  • Pentlandite
    (Fe,Ni)
     
    9
    S
     
    8
    Reference: [BMS Database]
  • Pickeringite
    MgAl
     
    2
    (SO
     
    4
    )
     
    4
    ·22H
     
    2
    O
    Reference: [No reference listed]
  • Pilsenite
    Bi
     
    4
    Te
     
    3
    Reference: [BMS Database]
  • Pyrargyrite
    Ag
     
    3
    SbS
     
    3
    Reference: [national Museum of Wales database]
  • Pyrite
    FeS
     
    2
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  • Pyrrhotite
    Fe
     
    7
    S
     
    8
    , (-4M), also given as Fe
     
    1-x
    S (x = 0 - 0.2)
    Reference: [BMS Database]
  • Quartz
    SiO
     
    2
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  • Rhodonite
    MnSiO
     
    3
    Reference: [BMS Database]
  • Scorodite
    Fe
    3+
     
    AsO
     
    4
    ·2H
     
    2
    O
    Reference: [BMS Database]
  • 'Sericite'
    Reference: [UKJMM 21:37]
  • Sphalerite
    (Zn,Fe
    2+
     
    )S
    Reference: [ref: Goldmining in Western Merioneth, T. A. Morrison (undated)]
  • Sylvanite ?
    (Au,Ag)
     
    2
    Te
     
    4
    Description: The National Museum of Wales database "The Minerology of Wales" (http://www.nmgw.ac.uk/en/791/)has raised doubts regarding the identifications of acanthite and sylvanite at this location.
    Reference: [The National Museum of Wales database "The Minerology of Wales"]
  • Tellurobismuthite
    Bi
     
    2
    Te
     
    3
    Reference: [BMS Database]
  • Tetradymite
    Bi
     
    2
    Te
     
    2
    S
    Reference: [BMS Database]
  • Tetrahedrite
    (Cu,Fe,Ag,Zn)
     
    12
    Sb
     
    4
    S
     
    13
    Reference: [BMS Database]
  • Thaumasite
    Ca
     
    3
    [CO
     
    3
    |SO
     
    4
    |Si(OH)
     
    6
    ] · 12H
     
    2
    O
    Reference: [BMS Database]
  • Tyrolite
    Ca
     
    2
    Cu
     
    9
    [(OH)
     
    4
    |(H
     
    2
    O)
     
    11
    |CO
     
    3
    |(AsO
     
    4
    )
     
    4
    ] · 0-1H
     
    2
    O
    Reference: [BMS Database]
    Site Photo
    Trial level, Vigra Mine, Bontddu, Dolgellau Gold Belt, Gwynedd (Merionethshire), Wales, UK
    © Steve Rust
  • Wroewolfeite
    Cu
     
    4
    [(OH)
     
    6
    |SO
     
    4
    ] · 2H
     
    2
    O
    Reference: [BMS Database]


    68 entries listed. 64 valid minerals.

    Localities in this Region:
    UK
     
    • Wales
      • Gwynedd (Merionethshire)
        • Dolgellau Gold Belt
          • Barmouth
          • Llanfachreth
          • Llanuwchilyn

    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!
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    Copyright © Jolyon Ralph and Ida Chau 1993-2009. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 8th Nov 2009 01:59:03