Restoration in 200 years
Posted On March 6, 2019
The Brett Aggregate planning permission in January 2017 was passed – subject to S106 legal agreement – by HCC. Restoration phase would last 2 years and then passed to Ellenbrook Fields Country Park. (SLR 403.01009.00132 June 2015):
The reality of open plan quarrying is that restoration may not happen in this way. It is more likely to be like this:
View of a similar quarry, the site would be closed to the public for many years.
It is extremely unlikely that the Brett Quarry would go back into public domain.
- Bromate bromide contamination is very close to the site workings. A recent map shows 1/3 of quarry site already contaminated.
- Lagoons will be there for the full duration – 32 years – very deep and dangerous.
- The site is open plan with dumper trucks crossing site
- Rights of way will be withdrawn across site.
- The progression of the bromate, bromide plume is still spreading. Borehole data outside the quarry site is showing small but increasing contamination.
It is expected that within the quarry’s lifetime the whole area will be contaminated.
The operator plans to excavate down to the lower mineral horizon (LMH) to 16 M. This is to get a total yield of 8M tons over the lifetime of the quarry.
Brett Aggregates have updated their planning application to reduce cross contamination of the UMH & LMH groundwater. This is called Groundwater & Water Management Plan (PL/0755/16), it puts a clay seal across workings, and comprehensive monitoring of conditions. The plan must be in accordance with policy 16 of the Hertfordshire Waste Core Strategy 2012 and NPPF para 143.
The old Hatfield Quarry
In the case of Hatfield Quarry, which is now Cemex, the excavation reached the LMH and bromate was recorded at 1500µg/l. Cross contamination may have occurred between the LMH and upper (UMH) contaminating groundwater.
If a quarry has worked with contamination in the groundwater, it will be closed and monitored. These sites became no-go areas and will not be put back into the public domain.
Today, the old quarry sites are now covered over and sectioned off to allow telemetry monitoring of groundwater condition. This action is necessary to restrict access by the public who may interfere with solar panels and borehole equipment:
Solar panels & boreholes monitoring the old workings
Remedial Plan 1
For the last 10 years Bishops Rise pumping station in Hatfield has been scavenging (pumping out) bromate from the plume. This remedial plan has not been a complete success and a 2nd Remedial plan will be put into operation.
The Environmental Agency dealing with this contamination have requested professional and interested parties to submit their remedial plans.
Public access has been heavily restricted to the old Hatfield quarry, which began operations in 1944, the site shown in yellow is quicksand and waterlogged.
The whole area will be fenced off, with signage to deter trespassers
A paper, 371 pages deals with this incident:
“The hydrogeology of bromate contamination in the Hertfordshire Chalk: double-porosity effects on catchment-scale evolution” for the Doctor of Engineering of University College London. Ciara Maria Fitzpatrick.
A second paper covers 458 pages:
The Hydrogeology of Bromate Contamination in the Hertfordshire Chalk: Incorporating Karst in Predictive Models.
Simon James. Cook Department of Earth Sciences UCL
It is predicted that without remedial action the contamination may be with us for 200 years.