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Community Update on the Magheracloone Subsidence Incident – 22.01.2020

Posted on 22.01.2020 - updated on: 16.04.2024

22nd January 2020

Subsidence of material at pre-existing crown hole on Gyproc lands

  • 16m wide and 11m deep subsidence at pre-existing crown hole over old mine workings on Gyproc lands
  • Crown holes occur over old mine workings and no additional movement has been observed at the site

During a routine inspection on the morning of Saturday 18th January 2020, it was noted that a circular shaped subsidence hole measuring approximately 16m wide and 11m deep had appeared on the site of a pre-existing mining crown hole that had first occurred in August 2019.  The subsidence noted on Saturday, 18th January 2020 is not a new crown hole; it is the subsidence of material that was used to backfill the original August 2019 crown hole.  It is located approximately one-third of a kilometre from the nearest dwelling. The area is located entirely within Gyproc owned lands and is not close to any private homes, public infrastructure or bordering roads (it is located 280 metres north of the R179). 

Gyproc has, in line with best practice and its stringent mining licence regulations, fenced off the area, advised the relevant authorities and has investigated the matter further.  Gyproc is confident it poses no risk to the public and no additional land movement has been observed at the site since.

The site of this subsidence is at a pre-existing crown hole that appeared in August 2019 over old and known mine workings. Since becoming aware of this subsidence at the crown hole, Gyproc has continued to monitor and survey the area and can now provide updated information as of today, 22 January 2020.

What happened?

The infill material used to backfill the crown hole that appeared in August 2019 has moved and settled further into the crown hole and this has resulted in the surface hole appearing at the site.

How did it happen?

This is being investigated at present.  The view expressed by the mine engineering team who have reviewed the site suggests that the reason for the fresh subsidence at the site of this crown hole is likely due to the fact that the mine workings beneath the original crown hole in August 2019 contain water.  

The material that initially fell into the water in the August 2019 crown hole has most likely settled a short distance from the base of the crown hole.  Over time, this material has settled further, and this then created the space for crown hole infill material to move, creating the surface feature and subsidence that has now appeared.

What has Gyproc done since observing this fresh subsidence?

Gyproc has engaged mine engineering experts to review the risks and report on any actions to take.  We continue to monitor the area and survey the area and will continue to keep people informed.

The drone survey conducted on 21.02.20 does not indicate any additional surface movements at the site.

What is the current update on the Planning Application?

Gyproc has not yet confirmed an exact date for submitting a planning application for an open cast mine at Drumgossatt.  As shared with members of the local community recently, we do expect it to be in the first half of 2020 though not in the first quarter. We believe it is very important for the whole community to have the opportunity to consider any developments in advance, to be given all the relevant and correct information and we look forward to the opportunity to engage with the community proactively through information sharing events in advance of submitting any application. 


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