CL:AIRE has Published Asbestos in Soil and Construction & Demolition Guidance

CL:AIRE has published the Joint Industry Working Group Asbestos in Soil and Construction & Demolition (C&D) Materials guidance titled “Control of Asbestos Regulations 2012: Interpretation for Managing and Working with Asbestos in Soil and Construction & Demolition materials: Industry Guidance (shortened name CAR-SOILTM)”.

This authoritative document has been prepared with the support of the Health and Safety Executive and presents the definitive explanation of how the legal requirements of the Control of Asbestos Regulations 2012 (CAR 2012 or the Regulations) have been interpreted to apply to work with asbestos contaminated soil and construction & demolition materials.

The guidance is underpinned by the fundamental requirements expressed in the Regulations, in relation to the protection of employees from risks related to exposure to asbestos, but is set within a carefully considered framework designed specifically for soil and C&D materials contaminated with asbestos.

In order to be more directly applicable to the risks associated from work on soil and C&D materials contaminated with asbestos, the Regulations have been interpreted in order to allow practical guidance to be produced that is fit for purpose whilst allowing compliance to be demonstrated with the overarching requirements set out in the Regulations.

To  download a copy of the guidance document, go to CL:AIREs website:


Durham Wildlife Trust

We have been supporting Durham Wildlife Trust with the site characterisation of multiple land parcels within the Valley Burn surface water course corridor in County Durham.  The work was undertaken to identify potential constraints from contaminated land with regards to planned ecological improvement works to the burn; the improvement works included aspects such as re-meandering of the burn, the creation of new ponds and general habitat improvement works.

Our work commenced with the production of a bespoke desk study report for each land parcel, and from that work sites were either screened out of the need to do any further work as all risks were understood, or, sites were prioritised for further assessment comprising intrusive ground investigation, or, just a watching brief as the works progressed.

It was important for the Trust to understand if the planned ecological improvement works could lead to contamination pathways being created by disturbing the ground and remobilising historic contamination.  This could result in negative impact on the quality of the burn, and also impact on human health with regards to site redevelopment workers and future site users.  The Trust rely on volunteers for some aspects on projects such as planting new habitats and understanding the sites history prior to getting hands mucky was very important.

It is always surprising what a site history reveals, whilst several sites had always just been greenfield without past development, several areas had suffered significant industrial use historically, including one land parcel comprising part of a former huge iron works tip.  The site had been reclaimed in the 1980s and looking at it now it just appeared to be a natural part of the burn corridor.

Another land parcel within the floor of a steep wooded valley appeared natural but on investigation was found to have over a metre Made Ground within it, luckily this was found to be reworked natural deposits that was entirely free of contamination, its origin was not certain but it was possibly placed years ago to improve boggy ground, as an old drift mine is present in the area (the sandstone boulder in the pic below likely to be from the mine), or, it was possibly just a convenient place for a free/easy tip when houses were being constructed in the local area which was a common practice prior to the stringent environmental regualations that are in force today.

Our reports on the project were used by the Trust to inform their works and decision making, along with the Environment Agency.

Some photos from one of the investigations are provided below for interest, including an old beer bottle removed from deep within the fill.

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Look what we dug up in a trial pit

Whilst out on site trial pitting with an excavator last week we dug a perfectly preserved beer bottle out of the ground from about 1.5m bgl, intact with lid and a trace of beer within it.  The bottle was buried within clay deposits that must have been re-worked at some time in the past.

An initial search on google (and our favourite local pub The Museum Vaults, ex Vaux PH; in the name of research only!) identifies that the bottle probably dates from the late 1800s, early 1900s, but we cannot work out why it has Middlesbrough on it, if anyone has a clue drop us a line!

Here are some pictures of the bottle we dug out of the ground in Spennymoor, and some pictures of the original brewery and drays that were once a regular sight on local roads.

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Mine Spoil

Mine spoil was found to be exposed in the bank side of a burn on a site that we are working on in County Durham.

There are several mine entries located within the site (shafts and adits), they worked a coal seam that outcrops within a steep wooded valley that follows the burn.  A review of historical plans going back to the 1800s revealed an interesting site history, with tramways and aerial ropeways removing the coal from the valley.

Mining legacy still has the potential to impact development sites across the UK, and was particularly widespread in this part of the North East up until the closure of the coal field in the 1980s, some pictures from the site show the coal waste from the mining within the bank of the burn, including layers of red shale.

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Gateshead District Heating Scheme

We are supporting Gateshead Council, Clancy Docwra and d3 Associates with the delivery of the new Gateshead District Heating Scheme.

This is an ambitious project to create a sustainable energy source for civic buildings in Gateshead, and commercial partners who are buying into the scheme.

Phase 1 of the project involves the construction of approximately 3km of pipeline through the centre of Gateshead, across the A167 and down to the southern quayside area of the River Tyne.

The pipeline will connect to various buildings including the Civic Centre, The Baltic, The Sage and The Hilton Hotel.

An energy building to supply the pipeline with hot water is being constructed on Quarryfield Road.

DBS are undertaking an intrusive investigation of the pipeline route to provide information on ground and groundwater conditions, to obtain samples for lab testing to identify suitable disposal routes for all trench arising’s, and to identify potential risks to human health and property receptors from contamination.

Our appointed drilling subcontractor on the scheme is Geocore of Cleveland.

To inform the work, we prepared a detailed “Sampling and Analysis Plan” for agreement between all parties prior to commencement, due to the nature of the pipeline route through the centre of historical Gateshead there are a wide variety of potential pollutant linkages based on past site use and location. Our work built upon various Phase 1 reports prepared by the council to move the project forward.

The work is being undertaken under planning controls, our final risk assessment reports will support the discharge of relevant planning conditions.

Further information on the scheme can be found on Gateshead Councils website using the following link:



EA Withdraw Soil Guideline Value (SGV) for Nickel

The Environment Agency (EA) has withdrawn the Soil Guideline Value (SGV) for nickel following discussions with Public Health England (PHE) about new information, as reported by CL:AIRE.  The SGV report, the toxicity (TOX) report, and the supporting information document for nickel will remain available for historical reference on the EA archives.

The SGV for nickel was published in 2009.   In February 2015, the European Food Safety Authority (EFSA) published their scientific opinion on the public health risk from the presence of nickel in food and drinking water.  The full report is available here:

EFSA recommend an oral TDI for nickel that is considerably lower than the oral HCV used in the derivation of the SGV.   The EA is withdrawing their reports in light of this new expert opinion.   The EA will not be updating them as it no longer undertakes work to derive new SGV or TOX reports, but it will continue to recommend that relevant public health bodies are consulted on any new industry-led guideline value projects.

New CIRIA Guidance Published C735 & C748

CIRIA C735 and C748.

CIRIA have just released new guidance documents on the installation and verification of ground gas protection measures for new buildings, and the use of membranes as VOC barriers, the documents are as follows:

  • Good practice on the testing and verification of protection systems for buildings against hazardous ground gases – CIRIA C735; and
  • Guidance on the use of plastic membranes as VOC vapour barriers – CIRIA C748.

The first guidance on the installation of gas protection systems for buildings was published in the early 1990s. Since then the frequency of installation and variety of systems has increased considerably. However, there is evidence that the installation of many of these systems has failed to meet an acceptable standard.

The publications provide best practice guidance for the designer, installer, verifier and regulator on the verification and integrity testing of gas protection systems, and options for vapour barriers. For verification the guidance sets out a flexible, risk based and practicable framework that can be adapted to provide site specific advice on the need for and scope of verification activities (including any integrity testing).

Recommendations are presented for the promotion of the best practice described in this publication and for recognition of the important role that local authority (LA) regulators play in its increased acceptance and application throughout the industry.



Understanding a Coal Mining Ground Investigation

Before retiring recently, Tim King of The Coal Authority produced an excellent paper on the hazards of coal mining legacy and designing and interpreting a suitable ground investigation to assess the risks fully.

The paper includes excellent photographs from UK Coals surface mining projects that allows the reader to visualise the hazards in the subsurface, and how key features could easily be missed or misinterpreted during ground investigation that could have significant implications to future built development at surface with regards to ground stability.

We thought the paper was so good, we are reproducing it in full here, with kind permission from Tim and The Coal Authority.

Understanding a coal mining ground investigation, Tim King, Senior Project Manager – The Coal Authority.

“When a ground investigation (GI) is undertaken to determine the extent of coal extraction of shallow seams the results are often confusing. When people talk about shallow workings, broken ground, voids, etc, I imagine that everyone has their own visual image as to what that entails.

Exposure of coal seams during surface mining operations gives a real insight into how coal was worked in the past. Information gained from a GI inevitably leads to second guessing how the seam was worked.

Cored boreholes give the best data but open boreholes are more cost-effective particularly on big development sites. Understanding the drillers’ logs is essential in painting the best picture as to what ground conditions exist beneath a site.

Below are some images taken during opencast operations.  What are they telling us?


Tim Picture 1

A fairly level coal seam of a good thickness overlain by blocky sandstone under a stiff boulder clay.

If we take a closer look what do we see now?

Tim Picture 2

Pillars of coal with collapsed material or broken ground between them. The broken ground appears to consist of collapsed sandstones/mudstones that sit directly above the coal. They demonstrate no competency having collapsed soon after support was withdrawn.

Imagine a grid of boreholes designed to capture the extent of coal extraction. It is quite feasible that a grid interval is adopted that coincides with the pillar interval, subsequent results indicating that coal is present in all boreholes suggesting that coal has not been worked. In reality that is not the case. This shows the importance of staggering the grid to obtain more accurate information.

Let’s take an even closer look to see if the photograph is telling us more.

Tim Picture 3

Here, collapse has occurred filling the void but the overlying strata has sagged rather than collapsed. Evidence of bed separation perhaps?

If an open hole borehole was drilled between the pillars the driller would probably record ‘broken ground and loss of flush’ as the drill bit encountered the separations in the stratified layers and the unconsolidated collapsed material.

If an open hole borehole was drilled over the pillar what would we expect? Would we expect intact strata? I would say yes. However look again at the second photograph, see how the strata immediately above the pillars is drawn into the collapse. The driller may again record ‘broken ground and loss of flush’.

In the next photograph our grid of boreholes would encounter solid coal until it hit a stowed roadway with a coal roof. How difficult would that be to interpret?

Tim Picture 4

The photograph below shows the line of an arched roadway driven in coal. Again unless you struck a steel arch I think that no one would identify that!

Tim Picture 5

The next photograph shows a shaft that has been uncovered. If it was an unrecorded shaft then drilling directly above it would be extremely dangerous, not knowing if it was filled throughout its depth or filled above a manmade staging.

Tim Picture 6

The next photograph demonstrates the irregular size and shape of pillars.

Look at the remnant coal stump. How has that survived without being crushed?

Tim Picture 7

The answer is it has gained support from the collapsed material that filled the voids. The other question that has no sensible answer is why was it left and not taken out at the time.

These are some of the conundrums that drillers, engineers and geologists are faced with. We rely on their knowledge and skill to interpret often confusing data”.


Tim King, Senior Projects Manager (now retired), Public Safety and Subsidence, Coal Authority

Photos and Article: reproduced with kind permission of UK Coal and The Coal Authority