19-May-2023

Ruislip Mudbath

High Speed 2 – Tunnel Consent, Risk to Shardeloes Lake

(To DfT, from Andrew Cordiner - 26/3/23)

We draw your attention to the current situation occurring at Ruislip Rugby Club where multiple fissures are opening up bringing tunnel grout to the surface. We remind you that the assessment of the evidence presented to the Judge stated that it was necessary to use the banned substance Tamcem CP to ensure quick setting of the grout in turbulent water conditions. Consequently the risk to the underlying water body was deemed low because HS2/Align engineers argued that the grout would set sufficiently quickly such that migration would be no more than 10m.

In light of the events occurring at Ruislip whereby grout has migrated far more than 10 m and is now registering all along the line with new fissures opening each day, it is clear that the arguments HS2 made before the judge misrepresented the case and that Environment Agency, HS2 Ltd and Align have misled the Courts and Parliament in their assessment of the risks. Furthermore, this also raises a question of whether HS2 Ltd / Align have or will generate subsidence and undermine support for above ground structures.

Given the proximity of the Tunnel Boring Machine to Shardeloes Lake and the Misbourne Chalk Stream and in light of the events at Ruislip, the precautionary principle dictates that HS2 Ltd must discontinue Tunnel Activities that could jeopardise the water body until an investigation into the events at Ruislip take place and engineers can conclude that the risks to Shardeloes and the Misbourne is and remains as assessed at “low risk”.

I write in the first instance to the Department for Transport since it is the department ultimately responsible should a major water body be impacted when the DFT did not adopt the precautionary principle and issue instructions to HS2 Ltd and Align to discontinue works until a formal investigation is undertaken.

Lack of Adequate Monitoring by the Environment Agency of HS2 Tunnelling Activity.

(from Paul Jennings)
Here is a sequence of correspondence with the Environment Agency over the monitoring of HS2 tunnelling activity. Despite reassurances throughout the consultation phase of HS2 by the Environment Agency that they would adequately monitor this activity is is clear from this correspondence they have not and have recklessly put the aquifer and our environment at obvious risk.

1 Our original Request to the Environment Agency for data relating to HS2 Tunnelling Activity

Discharge at Ruislip Rugby Club from HS2 tunnels February and March 2023

Dear Sirs.

This confirms our worst fears about HS2 tunnelling. Can you please supply all the volume data relating to the use of water, cement, bentonite, and chemicals in the HS2 tunnelling activity. There should at least be an hourly log of all materials used in the tunnelling activity. Please supply this ASAP.

This the second time (there was a subsequent third event at Ruislip Rugby Club) this happened in this area in recent weeks. I would expect you would be shutting down the HS2 operation until you know what is happening

2 Environment Agency Response.

HNL 303573 JH - RE: Discharge at Ruislip Rugby from HS2 tunnels.

19th April 2023

EIR Regulation 3(2) states that information is held if it is in our possession and has been produced or received by us, or it is held by another person on our behalf at the time the request is received.

Information not held - Volume data relating to the use of water, cement, bentonite, and chemicals in the HS2 tunnelling activity.

(Please note the Environment Agency did not respond to the second part of our request “I would expect you would be shutting down the HS2 operation until you know what is happening.”)

3 Our response to the Environment Agency

20th April 2023

So if you don’t have the information how are you monitoring HS2 tunnelling activity? To monitor any subsurface drilling or tunnelling activity this is vital information. During the consultation process we were given assurances from the Environment Agency they would be adequately monitoring HS2 tunnelling. It is now obvious that the Environment Agency have significantly let us down.

There are now 4 events, that we know of, where tunnelling and excavation fluids and chemicals have been lost into the aquifer. The first was at Chalfont St Peter where 3000 cubic meters of bentonite slurry were lost. More recently on three occasions tunnelling fluids have come to surface at Ruislip Rugby Club.

Please explain why you don’t have this vital information and as a matter of urgency explain how you are monitoring HS2 tunnelling and excavation activity. The data I have requested is required on a real time basis in order for you to protect the aquifer.