{"id":12138,"date":"2020-02-04T14:14:12","date_gmt":"2020-02-04T14:14:12","guid":{"rendered":"https:\/\/www.bgs.ac.uk\/?post_type=case_study&#038;p=12138"},"modified":"2021-09-20T14:03:56","modified_gmt":"2021-09-20T14:03:56","slug":"banc-dolhelfa-mid-wales-landslide-case-study","status":"publish","type":"case_study","link":"https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/","title":{"rendered":"Banc Dolhelfa, Mid Wales"},"content":{"rendered":"\t\t\t<section class=\"hero-section hero-section-with-social\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info-wrap\">\n\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info\">\n\t\t\t\t\t\t\t\t\t<h1>Banc Dolhelfa, Mid Wales <\/h1>\n\t\t\t\t\t\t\t\t\t<p>Landslide case study<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n\t\t\t<div class=\"social-wrap social-wrap-inline-them\">\n\t\t\t\t<div class=\"sea-background-f\">\n\t\t\t\t\t<span>Share this article<\/span><a target=\"_blank\"  href=\"https:\/\/www.facebook.com\/sharer\/sharer.php?u=https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\"><span class=\"icon-facebook\"><span class=\"hidden\">Facebook<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/twitter.com\/intent\/tweet?text=Banc%20Dolhelfa,%20Mid%20Wales&#038;url=https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\"><span class=\"icon-twitter\"><span class=\"hidden\">Twitter<\/span><\/span><\/a><a   onclick=\"javascript:void( (function() {var e=document.createElement('script' );e.setAttribute('type','text\/javascript' );e.setAttribute('charset','UTF-8' );e.setAttribute('src','\/\/assets.pinterest.com\/js\/pinmarklet.js?r='+Math.random()*99999999);document.body.appendChild(e)})());\"  href=\"javascript:void(0);\"><span class=\"icon-pinterest\"><span class=\"hidden\">Pinterest<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/wa.me?text=https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\"><span class=\"icon-whatsapp\"><span class=\"hidden\">WhatsApp<\/span><\/span><\/a><a   href=\"mailto:?subject=Banc%20Dolhelfa,%20Mid%20Wales&#038;body=%20(https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/)\"><span class=\"icon-mail\"><span class=\"hidden\">Email<\/span><\/span><\/a><a href=\"#\" data-copy=\"https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\" class=\"copy-url-on-click\"><span class=\"icon-link\"><span class=\"hidden\">Copy Link<\/span><\/span><\/a><\/div><\/div>\t\t\t\t\t\t\t<\/section>\n\t\t\t\n\n\n<section class=\"wp-block-bgs-blocks-content-container content-section\"><div class=\"container\"><div class=\"row\"><div class=\"col-12\">\n<p>The <a href=\"http:\/\/www.midwalesgeology.org.uk\/\" target=\"_blank\" rel=\"noreferrer noopener\">Mid Wales Geology Club<\/a> (project leader: Colin Humphrey), in association with the <a href=\"http:\/\/www.geologywales.co.uk\/central-wales-rigs\/\" target=\"_blank\" rel=\"noreferrer noopener\">Central Wales RIGS Group<\/a> (chairman: Prof Bill Fitches), carried out a walkover survey of the  landslide in Banc Dolhelfa in April 2010.&nbsp; <\/p>\n\n\n\n<p>The summary information for this landslide case study has been taken entirely from <a href=\"https:\/\/www.midwalesgeology.org.uk\/the-landslide-at-banc-dolhelfa\/\" target=\"_blank\" rel=\"noreferrer noopener\">Welsh  RIGS report 578<\/a> and is not the work of BGS.<\/p>\n\n\n\t\t\t\t<div  class=\"owl-carousel carousel-primary-color carousel owl-theme thumbs-carousel-js\">\n\t\t\t\t\t<div class=\"item\"><figure  class=\"img-wrap\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/DiGMap50_000.jpg\" class=\"attachment-medium size-medium\" alt=\"Aerial photograph of the Banc Dolhefa landslide. Red hashing denotes extent of BGS-mapped landslide deposit.\" \/><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Aerial photograph of the Banc Dolhefa landslide. Red hashing denotes extent of BGS-mapped landslide deposit. BGS \u00a9 UKRI.<\/p>\n<\/div>\n\t\t\t\t\t\n\t\t\t\t<\/figcaption><\/figure><\/div><div class=\"item\"><figure  class=\"img-wrap\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/Banc_Dolhefa_feature_P877690.jpg\" class=\"attachment-medium size-medium\" alt=\"The Banc Dolhefa landslide. (Photograph courtesy of C. Humphrey Mid Wales Geology Club).\" \/><figcaption class=\"caption sm-line\">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>The Banc Dolhefa landslide. (Photograph courtesy of C Humphrey, Mid Wales Geology Club.)<\/p>\n<\/div>\n\t\t\t\t\t\n\t\t\t\t<\/figcaption><\/figure><\/div><div class=\"item\"><figure  class=\"img-wrap\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/P877701.jpg\" class=\"attachment-medium size-medium\" alt=\"The Banc Dolhefa landslide taken from the toe of the landslide. (Photograph courtesy of C. Humphrey, Mid Wales Geology Club).\" \/><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>The Banc Dolhefa landslide taken from the toe of the landslide. (Photograph courtesy of C Humphrey, Mid Wales Geology Club.)<\/p>\n<\/div>\n\t\t\t\t\t\n\t\t\t\t<\/figcaption><\/figure><\/div><div class=\"item\"><figure  class=\"img-wrap\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/GeologyMap_001.jpg\" class=\"attachment-medium size-medium\" alt=\"Geology map of the Banc Dolhelfa landslide. Red hashed area is the landslide deposit. Green dot is the location of National Landslide Database record for this event. \u00a9 Crown Copyright.\" \/><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Geology map of the Banc Dolhelfa landslide. Red hashed area is the landslide deposit. Green dot is the location of National Landslide Database record for this event. \u00a9 Crown Copyright. <\/p>\n<\/div>\n\t\t\t\t\t\n\t\t\t\t<\/figcaption><\/figure><\/div>\t\t\t\t<\/div>\n\t\t\t\t\n\n\n<h2 class=\"wp-block-heading\">The landslide<\/h2>\n\n\n\n<p>The Banc Dolhefa landslide (<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/national-landslide-database\/\">BGS National Landslide Database<\/a> ID 11853\/1) is about 5&nbsp;km south of Llangurig in Mid Wales and is one of the largest bedrock slides in Mid Wales. The landslide is 650&nbsp;m long and 150\u2013200&nbsp;m wide, calculated to have displaced around one third of a million cubic metres of rock. It is currently inactive, but a falling block was reported in 1850.<\/p>\n\n\n\n<p>This is a complex landslide, predominantly <a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide#translational\">translational<\/a> in nature, with evidence of planar rock and debris sliding on the south side of the depletion zone and block failure by falling on the north side. <\/p>\n\n\n\n<p>Failed rock on both sides broke into a debris flow in the accumulation zone.&nbsp; Evidently the south side slid on bedding  planes partly concordant with the topographic slope and the back and north side failed on subvertical joints, leaving a steep escarpment. Subsequent progressive failure and retreat of the escarpment has occurred by slumping and rock fall.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Superficial deposits landslides<\/h2>\n\n\n\n<p>Most landslides in the area are in superficial deposits, but here the Silurian bedrock itself has failed. The trigger for the original failure is thought to be post-glacial movement on the visible fault parallel to the upper south edge. Subsequently, there has been some further collapse and retreat of parts of the northern escarpment. Scree deposits show that weathering and rock displacement has continued from the upper part of the slide in recent times.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Geology <\/h2>\n\n\n\n<p>The geology associated with this landslide is the <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=GLR\">Glanyrafon Formation<\/a>, which comprises interbedded mudstones and sandstones that are approximately 430 million years old. The lower slopes of the landslide are covered with Devensian-aged till. There is a steeply dipping, east\u2013north-east-striking fault very close to the southern flank of the landslide, passing beneath it at depth.\u00a0The <a href=\"https:\/\/webapps.bgs.ac.uk\/lexicon\/lexicon.cfm?pub=PTR\">Pysgotwr Grits Formation<\/a> is to the north and not incorporated into the landslide. <\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"LandslideDepositNote\">Note on the mapped landslide extent<\/h3>\n\n\n\n<p>The red hashed area is the landslide deposit as published by BGS, although the more recent detailed work in the <a href=\"https:\/\/www.midwalesgeology.org.uk\/the-landslide-at-banc-dolhelfa\/\" target=\"_blank\" rel=\"noreferrer noopener\">RIGS report <\/a>shows the deposit to be larger and more rectangular, with the south flank running parallel to the fault and the slide mass extending to the River Wye at the toe.<\/p>\n\n\n\n<p>As with all BGS landslide maps, only the deposit is shown and the backscarp of this landslide can be seen above the deposit where the underlying Ordnance Survey map highlights a scarp slope where the Pystgotwr Grit Formation crops out.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Visiting the site<\/h2>\n\n\n\n<p>Banc Dolhefa is an excellent, clearly visible example of a complex landslide in bedrock and is of amateur and undergraduate geological and geomorphological interest. On-site, there are features that offer an opportunity for wide-ranging technical discussion of failure mechanisms. <\/p>\n\n\n\n<p>An alternative to visiting the site itself is, for small groups, to view it from across the Wye valley, especially from SN 914 748, although parking is unsuitable for large vehicles. No rights of way exist over or near the landslide; many parts are dangerously steep and there is also a risk of rock fall.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Reference<\/h2>\n\n\n\n<p>Humphrey, C.\u00a02012.\u00a0<a href=\"https:\/\/www.midwalesgeology.org.uk\/the-landslide-at-banc-dolhelfa\/\" target=\"_blank\" rel=\"noreferrer noopener\">The Landslide at Banc Dolhelfa, near Llangurig, Powys.<\/a> <em>Open University Geological Society Journal<\/em>, Vol. 33:2, 33\u201340.<\/p>\n<\/div><\/div><\/div><\/section>\n\n\n<section class=\"cta-section  sea-background-e \">\n\t<div class=\"container\">\n\t\t<div class=\"row md-row\">\n\t\t\t<div class=\"col-12\">\n\t\t\t\t<h2>Contact the Landslide Response Team<\/h2>\t\t\t\t<div>Tel: 0115 936 3143     Email: landslides@bgs.ac.uk   <\/div>\t\t\t\t<div class=\"btn-wrap\"><a href=\"mailto:landslides@bgs.ac.uk\"  class=\"button primary-background   \">Contact us<\/a><\/div>\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n<\/section>\n\t\n\n\t\t\t\t\t<section   id=\"latest-content-951-block_5efc3d3507b5f\" class=\"grid-section  primary-background   \" >\n\t\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row header-of-section\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t<h2>You may also be interested in<\/h2>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row grid-wrap\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-case-studies\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/pennington_feature_P761259-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"fall at Pennington Point. (Photo: \u00a9 Eve Mathews)\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/pennington_feature_P761259.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-case-studies\/\">Landslide case studies<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>The landslides team at the BGS has studied numerous landslides. This work informs our geological maps, memoirs and sheet explanations and provides data for our National Landslide Database, which underpins much of our research.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-case-studies\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Debris flow on A83\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\">Understanding landslides<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>What is a landslide? Why do landslides happen? How to classify a landslide. Landslides in the UK and around the world. <\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/holbeck_hall_feature-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Holbeck Hall Landslide\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/holbeck_hall_feature.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/\">How to classify a landslide<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>Landslides are classified by their type of movement. The four main types of movement are falls, topples, slides and flows. <\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Storegga_landslide_website_feature-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Storegga landslide\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Storegga_landslide_website_feature.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/\">Landslides in the UK and around the world<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>Landslides in the UK, around the world and under the sea.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/section>\n\t\t\t\t","protected":false},"excerpt":{"rendered":"","protected":false},"featured_media":24547,"parent":0,"menu_order":2,"template":"","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"on","_relevanssi_pin_keywords":"banc dolhefa","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"72123,51064,33594,34185,70595,57984","_relevanssi_noindex_reason":"","footnotes":""},"tags":[145],"region":[8],"topic":[],"purpose":[],"area":[],"challenge":[],"challenge_topic":[],"filter_group":[],"subject":[783],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Banc Dolhelfa, Mid Wales - British Geological Survey<\/title>\n<meta name=\"description\" content=\"The Banc Dolhefa landslide is about 5 km south of Llangurig in Mid Wales and is one of the largest bedrock slides in Mid Wales.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Banc Dolhelfa, Mid Wales - British Geological Survey\" \/>\n<meta property=\"og:description\" content=\"The Banc Dolhefa landslide is about 5 km south of Llangurig in Mid Wales and is one of the largest bedrock slides in Mid Wales.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\" \/>\n<meta property=\"og:site_name\" content=\"British Geological Survey\" \/>\n<meta property=\"article:modified_time\" content=\"2021-09-20T14:03:56+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/Banc_Dolhefa_feature_P877690.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"640\" \/>\n\t<meta property=\"og:image:height\" content=\"430\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"3 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\",\"url\":\"https:\/\/www.bgs.ac.uk\/case-studies\/banc-dolhelfa-mid-wales-landslide-case-study\/\",\"name\":\"Banc Dolhelfa, Mid Wales - 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