Bryn Eglwys quarry: Difference between revisions
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Three parallel [[Stratum|veins]] of [[Ordovician]]<ref name=AJR>{{cite book |last=Richards |first=Alun John |title=The Slate Regions of North and Mid Wales, and their Railways |publisher=Carreg Gwalch |year=1999 |isbn=0863815529}}</ref> slate run through mid Wales, from the region north of [[Dinas Mawddwy]] through [[Corris]] and south west towards [[Tywyn]]. These veins are the southern edge of the [[Harlech Dome]] [[anticline]] which surfaces in the north at [[Blaenau Ffestiniog]].<ref name=AJR/> Where the veins cross the site of Bryn Eglwys, they are inclined at an angle of about 30 degrees from the horizontal, sloping downwards to the south-west. The widest of these veins is the 600 ft thick "Broad Vein" that lies to the north of site and consists of layers of hard, grey [[shale]] with patches of slate. The Broad Vein slate is hard and durable, but does not split into thin sections, so is generally unsuitable for use as [[Roofing slate#Uses of slate|roofing slates]]. <ref name=Century>{{cite book |title=Talyllyn Century |last=Rolt |first=L.T.C. |publisher=David & Charles |year=1965}}</ref> |
Three parallel [[Stratum|veins]] of [[Ordovician]]<ref name=AJR>{{cite book |last=Richards |first=Alun John |title=The Slate Regions of North and Mid Wales, and their Railways |publisher=Carreg Gwalch |year=1999 |isbn=0863815529}}</ref> slate run through mid Wales, from the region north of [[Dinas Mawddwy]] through [[Corris]] and south west towards [[Tywyn]]. These veins are the southern edge of the [[Harlech Dome]] [[anticline]] which surfaces in the north at [[Blaenau Ffestiniog]].<ref name=AJR/> Where the veins cross the site of Bryn Eglwys, they are inclined at an angle of about 30 degrees from the horizontal, sloping downwards to the south-west. The widest of these veins is the 600 ft thick "Broad Vein" that lies to the north of site and consists of layers of hard, grey [[shale]] with patches of slate. The Broad Vein slate is hard and durable, but does not split into thin sections, so is generally unsuitable for use as [[Roofing slate#Uses of slate|roofing slates]]. <ref name=Century>{{cite book |title=Talyllyn Century |last=Rolt |first=L.T.C. |publisher=David & Charles |year=1965}}</ref> |
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The "Middle Vein" (sometimes known as the "Red Vein") lies about 100 yards south of the Broad Vein. It is about 60 ft thick but contains low quality, [[Friability|friable]] slate that contains a large number of [[fossil]]s |
The "Middle Vein" (sometimes known as the "Red Vein") lies about 100 yards south of the Broad Vein. It is about 60 ft thick but contains low quality, [[Friability|friable]] slate that contains a large number of [[fossil]]s, predominately [[graptolites]]. |
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<ref>Blackie, R.C. (1927): [http://jgslegacy.lyellcollection.org/cgi/reprint/83/1-5/711.pdf The Geology of the Country between Llanelidan and Bryneglwys]. ''Quarterly Journal of the Geological Society'', volume 83, pp. 711-736. doi:10.1144/GSL.JGS.1927.083.01-05.29</ref> |
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This vein was not worked commercially at Bryn Eglwys. <ref name=Century/> |
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The third vein is the "Narrow Vein" which lies about 100 yards south of the Middle Vein and is also about 60 ft thick. It contains the highest quality slate of the three veins and the most commercially valuable, being easy to split into roofing slates and slabs and both durable and strong. The vein is mostly a continuous bed of slate, containing only the occasional seam of [[quartz]]. However the quality of the rock varies over the depth of the vein, with the best material found nearest the surface. <ref name=Century/> |
The third vein is the "Narrow Vein" which lies about 100 yards south of the Middle Vein and is also about 60 ft thick. It contains the highest quality slate of the three veins and the most commercially valuable, being easy to split into roofing slates and slabs and both durable and strong. The vein is mostly a continuous bed of slate, containing only the occasional seam of [[quartz]]. However the quality of the rock varies over the depth of the vein, with the best material found nearest the surface. <ref name=Century/> |
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Revision as of 07:25, 13 July 2009
Bryn Eglwys was a remote slate quarry located near Abergynolwyn in Gwynedd mid-Wales.
History
The quarry was first worked on a small scale in the early 1840s. In 1864 William McConnel leased the quarry, forming the Aberdovey Slate Company Limited. McConnel planned to increase production at Bryn Eglwys. The limiting factor was the transportation of finished slates by pack horse to the wharves at Aberdovey. To overcome this, McConnel built the Talyllyn Railway, a narrow gauge line running from the quarry to Tywyn, where slate could be transhipped to the newly built Aberystwyth and Welsh Coast Railway.[1]
The railway ran to Nant Gwernol, a lonely spot about 430 feet below the main quarry level. From there the half mile long Galltymoelfre Tramway and a pair of inclines connected to the quarry.
Neither the quarry nor its associated railway were great commercial successes. By 1879 the company had run out of funds and both were auctioned off on 9 October of that year. After this and a subsequent auction failed to find a bidder, William McConnel personally bought both and an upturn in the slate market allowed the quarry to expand further.
McConnel died in 1902 and the quarry became the property of his son W.H. McConnel. However the leases on the land the quarry occupied were close to running out and Bryn Eglwys ceased production in 1909.
In 1911 the local Liberal Member of Parliament Henry Haydn Jones purchased the quarry, along with the Talyllyn Railway and the village of Abergynolwyn, forming the Abergynolwyn Slate & Slab Co. Ltd. New leases were signed with the landowners and the quarry resumed production.
The quarry remained in production until a serious collapse on December 26, 1946 - it had been unsafe for some time.
Geology
Three parallel veins of Ordovician[2] slate run through mid Wales, from the region north of Dinas Mawddwy through Corris and south west towards Tywyn. These veins are the southern edge of the Harlech Dome anticline which surfaces in the north at Blaenau Ffestiniog.[2] Where the veins cross the site of Bryn Eglwys, they are inclined at an angle of about 30 degrees from the horizontal, sloping downwards to the south-west. The widest of these veins is the 600 ft thick "Broad Vein" that lies to the north of site and consists of layers of hard, grey shale with patches of slate. The Broad Vein slate is hard and durable, but does not split into thin sections, so is generally unsuitable for use as roofing slates. [3]
The "Middle Vein" (sometimes known as the "Red Vein") lies about 100 yards south of the Broad Vein. It is about 60 ft thick but contains low quality, friable slate that contains a large number of fossils, predominately graptolites. [4] This vein was not worked commercially at Bryn Eglwys. [3]
The third vein is the "Narrow Vein" which lies about 100 yards south of the Middle Vein and is also about 60 ft thick. It contains the highest quality slate of the three veins and the most commercially valuable, being easy to split into roofing slates and slabs and both durable and strong. The vein is mostly a continuous bed of slate, containing only the occasional seam of quartz. However the quality of the rock varies over the depth of the vein, with the best material found nearest the surface. [3]
Description
References
- ^ Boyd, James I.C. (1988). The Talyllyn railway. Wild Swan Publications Ltd. ISBN 0906867460.
- ^ a b Richards, Alun John (1999). The Slate Regions of North and Mid Wales, and their Railways. Carreg Gwalch. ISBN 0863815529.
- ^ a b c Rolt, L.T.C. (1965). Talyllyn Century. David & Charles.
- ^ Blackie, R.C. (1927): The Geology of the Country between Llanelidan and Bryneglwys. Quarterly Journal of the Geological Society, volume 83, pp. 711-736. doi:10.1144/GSL.JGS.1927.083.01-05.29