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Community Update on the Magheracloone Subsidence Incident – 19.12.2019

Posted on 19.12.2019 - updated on: 16.04.2024

Gyproc update to the Residents Forum on December 10th

 

  • A routine survey on 10th December noted surface cracks adjacent to the borehole area and to the west of the 2018 subsidence. It presents no risk to the public infrastructure. The relevant authorities have been notified. The area is on Gyproc lands and is 220m from the R179 and 330m from the nearest dwelling.

  • Monitoring of the LP4900 using the extensometers has been in place since August 21st 2019. The system is working well and will continue into the future. The results to date show that the mine workings under the road remain stable. The highest reading noted so far was 0.35mm. Note, action is only required if movement is over 10mm. A report by SRK on the level monitoring carried out over the past year will be made available to the residents’ forum representatives.

  • There have been 38 Drone surveys now carried out since the original subsidence event in September 2018 and these will also continue into the future.

  • Remedial works of the grounds of the original subsidence have been completed with all surface cracks and crownholes filled and made safe. The fencing put in place to reduce the risk of persons accessing the grounds will be removed in the coming weeks.

  • Works recommended during the investigation of the December 2018 crownhole to improve surface drainage over the old mines have also been completed to minimise surface water entering the old mine workings.

  • There have been 5 boreholes completed as part of the study of the R179 road, laser scans of those areas will start in the coming weeks and will be completed in early 2020. It is expected that this study will be completed by March, then zones for the installation of extensometers will be confirmed. It is hoped to have them installed by the end of April. The objective is to have the same monitoring system in place on the R179 as exists now on the LP4900.

  • De-watering the old Drumgossatt mine has currently paused due to a fault identified in the in well pipe – equipment required to correct this fault has been ordered from the USA and once the fault is corrected, de-watering will recommence.

  • Water release from the Drummond mine continues to the River Bursk and the rain over the last few months has had its normal effect. There have been no breaches to the discharge licence in Nov/Dec and one very minor breach in October.

Update December 18th

 

  • Further drone surveys on the area noted on the 10th December have recorded no change in conditions since it was first identified on the 10th. The area has been fenced off and signposted as dangerous ground. There is a depression of the ground in the area and it is close to the area of the crownhole of August 7th. It will continue to be monitored.   

 

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