No gas readings have been detected on the Blackline alarms are all reading 0.00% LEL No Gas. There is no gas migration into houses.
The results of the BGS and MRSL monitoring around the whole site outside the footprint of No 7 Cleat Hill are within normal background levels.
There is still some variation in results at the geothermal borehole but all recordings are within the previous range.
No gas readings have been detected on the Blackline alarms are all reading 0.00% LEL No Gas. There is no gas migration into houses.
The results of the BGS and MRSL monitoring around the whole site outside the footprint of No 7 Cleat Hill are within normal background levels.
There is still some variation in results at the geothermal borehole but all recordings are within the previous range.
No gas readings have been detected on the Blackline alarms are all reading 0.00% LEL No Gas. There is no gas migration into houses.
The results of the BGS and MRSL monitoring around the whole site outside the footprint of No 7 Cleat Hill are within normal background levels and do not indicate any migration of gas from the geothermal borehole towards any of the houses.
There is some variation in results, dependent on rainfall, temperature and atmospheric pressure changes and this is normal.
The MRSL monitoring at the geothermal borehole indicates that there is still gas flow from the ground, but it is limited to the immediate area of the boreholes (within 5m) and it emits from three, very localised, points in the ground.
It is easily dispersed in the air and cannot be detected at 50mm above the ground surface. This shows the gas is not under any significant pressure.
MRSL continue to monitor additional areas, such as number 7 Cleat Hill and the surrounding areas; no gas has been detected in these areas.
BGS results show that the previous increase in flux measured at the borehole has now reduced back down, the last result being 35ppm/s. All other results are within normal variations.
All data has been reviewed by the Technical Cell who agree that there is no change to the safety of the residents.
The next scheduled meeting is Tuesday 1 April, however the group can be called at any time in the week if needed.
No gas readings have been detected on the Blackline alarms are all reading 0.00% LEL No Gas. There is no gas migration into houses.
The results of the BGS and MRSL monitoring around the whole site outside the footprint of No 7 Cleat Hill are within normal background levels and do not indicate any migration of gas from the geothermal borehole towards any of the houses.
There is some variation in results, dependent on rainfall, temperature and atmospheric pressure changes and this is normal.
The MRSL monitoring at the geothermal borehole indicates that there is still gas flow from the ground, but it is limited to the immediate area of the borehole (within 5m) and it emits from three, very localised, points in the ground.
It is easily dispersed in the air and cannot be detected at 50mm above the ground surface. This shows the gas is not under any significant pressure.
There has been some increase in the flow (or flux) rate recorded by BGS at a single point near to the geothermal borehole (within 5 m). It has increased on three consecutive visits up to 3.3m3/day.
On the third increase MRSL were asked to complete additional monitoring at the borehole and at the location of the former No 7 Cleat Hill. If there is an increase in leakage from the deep gas reservoir then No 7 is the location where it will be first detected.
There was no gas detected anywhere at that location. MRSL also completed some additional check monitoring that indicates the BGS results are valid.
Whilst these increases might seem concerning the current rates are still a fraction of the flow that was occurring before the well was sealed and caused the gas to migrate large distances.
The situation has been reviewed by the Technical Cell who all agree that there is no change to the safety of the residents.
We will be undertaking a trial of alternative monitoring equipment / lidar technology by QLM.
QLM’s product is a new type of lidar technology that can remotely monitor methane emissions up to 200 meters away, using cloud-based access. It can create images showing methane leaks and measure the amount of gas being released.
The lidar system looks similar to a CCTV camera and needs to be mounted on a mast or pole. Like CCTV, it can be controlled remotely and moves left, right, up, and down using a motorised base.
At the visit on Tuesday 4 February, QLM will have a mobile mast system towed behind a car. This will allow QLM to set up the lidar system at Cleat Hill to scan the borehole (from the road) and the demolished house (from a safe distance).
Whilst the device operates like a camera it does not record footage that could identify people or property, there is an example of the equipment and footage below.
You can read gas readings from the British Geological Survey to 22 November (PDF).