A good news story from DCC

Following our earlier post, DCC's Minerals Officer has notified us of a press release closer to home from Devon Wildlife Trust, showing that, despite the National Trust's unsuccessful proposals for quarries in Shropshire, restoration of a former quarry can indeed be successful. So, for balance:

Devon Wildlife Trust have acquired the recently-restored Meeth Quarry near Hatherleigh for management as a nature reserve. The mineral operator, Imerys, had restored the site in accordance with their planning permission prior to putting it on the market, with the restoration having biodiversity as its main aim as illustrated by the approved plans.

Fly ash - adding it to cement and china clay waste could save the Pebble Beds

Fintan264

The Devon Stone Federation advised DCC, Local Aggregate Assessment (LAA, 5.15), that as an alternative to the "qualities of the Pebble Beds resource" china clay waste has a number of issues including "increased water demand and proportion of cement required in concrete". However, as posted earlier, this did not stop china clay waste being used in the construction of the Olympic Park or One Coleman Street in London.

What the Devon Stone Federation, whose five quarrying members include AI, failed to mention was that any extra cement required can be offset cost effectively with 'fly ash'. Fly ash was not referred to in DCC's otherwise comprehensive LAA, yet it "has been in common use as a cementitious component in concrete in the UK for several decades". The construction of One Coleman Street used "30-40% fly ash in place of Portland cement" to reduce its environmental impact.

Fly ash is a residue from coal-fired power stations. Worldwide, more than 65% of fly ash produced from power stations is disposed of in landfills and ash ponds. However, "as a very fine, inert and lightweight material, fly ash is ideal when used in the concrete mix as a substitute for cement". "As well as reducing the amount of water required in the mixture, fly ash can limit demand for natural resources. Studies conducted by the UKQAA and partnership bodies have shown that fly ash can be included in the concrete mix at rates of up to 80% of the cement content, significantly reducing the need for both natural aggregates and water, while reducing the concrete’s carbon footprint. While [each tonne of] cement creates approximately one tonne of carbon in the manufacturing process and contains 913kg/tonne of embodied carbon, fly ash contains 4kg/tonne".

Cement production worldwide "produces more than 5% of mankind's carbon dioxide emissions" - more than the entire aviation industry; using fly ash at Coleman Street alone saved 500 tonnes of CO2. AI itself does not produce cement, it sources it from UK producers and a Holcim plant overseas. AI does however supply fly ash, and it is used in 25% of Holcim's cement output.

So, DCC should recognise (at least for concrete applications, which is where two thirds of sand and gravel end up) that with the help of cement additives there are sustainable, environmental, economic and viable alternatives to the Pebble Beds piled up all across Cornwall and Devon, that should be used before plundering more virgin resource. It may not be in the Devon Stone Federation's interests to promote the use of waste china clay aggregates, but surely it must be in the interest of the county, its people and the environment, and this should be reflected in Devon's mineral policies.

Would a 4000 signature petition help?

The National Trust had wanted to buy Lea Quarry North at Wenlock Edge, a SSSI in Shropshire, from Aggregate Industries to "provide diverse opportunities for people, heritage, biodiversity, tourism and the economy". It was sold instead to Edge Renewables, who "chip wood from sustainably managed forests for renewable energy biomass incinerators". The National Trust opposed the retrospective planning application from Edge Renewables, as did Natural England, Shropshire Hills AONB and over 4000 others by way of petition. However, planning officers recommended approval and yesterday councillors voted to grant permission to the renewable energy business. The petition made no difference at all.

2012 - "the lowest year for aggregates and concrete sales since 1965"

That's according to the Mineral Products Association, the trade association representing 90% of aggregates production in the UK. The MPA sales survey results showed a fall of 9% in aggregates, cement and ready mixed concrete markets in 2012. Road construction fell by 44% in the first nine months of 2012 compared with the same period of 2011. How foolhardy then, following the lowest aggregates sales since 1965 - ironically the year that all our problems started when English China Clays bought Straitgate Farm, that AI is still pushing ahead for a brand new sand and gravel quarry.

Grading analysis results from Straitgate

Grading analysis results have been supplied by Aggregate Industries following its recent activity at Straitgate Farm. The test pits had an average of 9.3% silt, 28.0% sand and 62.7% gravel. The six boreholes across the site had an average of 14.6% silt, 32.5% sand and 52.9% gravel.

Any questions relating to the grading results can be directed to AI's Head of Geological Services. Contact us for his details.

Secondary vs. Primary

The left pile: secondary aggregate - a by-product from china clay (kaolin) operations dumped for over 250 years as waste in huge amounts across Cornwall and Devon; the right pile: primary aggregate - a finite virgin resource sitting under Straitgate Farm. Two different materials we are told; different properties - physically, chemically, economically.

Whilst DCC in its Local Aggregate Assessment said "Devon has the capacity to support increased production of secondary... aggregates", it also said that "limited spatial occurrence" and "technical requirements" may constrain their use.

In evidence to the Competition Commission, however, Aggregate Industries said that whilst "in Cornwall and Devon alone there was about 600 million tonnes of secondary aggregates already available with about 40 million tonnes more being generated a year", its customers were "increasingly able, willing and prepared to use secondary and recycled aggregates". AI added "secondary and recycled aggregates now accounted for between 25 and 30 per cent of the current market and were a substitute for primary aggregates in the vast majority of cases. AI used secondary aggregates in its own production of [ready mix concrete] and other products."

The aggregates levy, currently £2 per tonne, was introduced by the government in 2002 not only to "address the environmental costs associated with quarrying" but also to support "the use of alternative materials such as recycled materials and certain waste products". Encouraging local use of secondary aggregate would have the advantage of extending reserves of sand and gravel whilst also reducing the 'mountains' of tipped waste across Cornwall and Devon. Is Devon's Mineral Planning Authority doing enough to achieve this?

Admittedly, not all china clay waste is suitable - nine tonnes of waste are generated for every tonne of china clay produced - but for the right quality of granite fraction (stent) there has been a "long history of satisfactory use in ready mixed concrete over much of Cornwall and Devon". In addition "An assessment of the specifications and standards available demonstrates that there are a significant number of applications available for the use of China Clay waste derived aggregates. While many secondary materials are used in low value applications such as fill, China Clay waste derived aggregates are suitable for a number of higher value applications including use in concrete and bitumen bound products."

Furthermore, it's now finding applications elsewhere. In 2006 the construction of One Coleman Street, a prestigious commercial building in London, was "the first major use of china clay stent coarse aggregate outside the locality of its production in the South-West" and "demonstrated the feasibility of using 100% secondary coarse aggregates in a large scale project remote from the source of aggregate". The stent aggregate concrete "cost a little more" due to the "transportation and testing costs" but this was partially offset by the stent being "exempt from the UK aggregates levy" and "if used more often for future projects there would be less need for extensive testing". The project won the 2007 Concrete Centre Award for Sustainability. AI will know about it since it supplied the aggregate. It will also know about the construction of the Olympic Park, where it supplied "secondary aggregates arising from the production of China Clay".

So, if the economics can work supplying London, why not Devon?

With existing supply agreements coming to an end, "IMERYS Minerals Ltd are actively developing the growth of their secondary aggregates (china clay waste) products from Cornwall and are currently seeking partners to realise the full potential of the materials in the markets they serve". With its new Minerals Plan, maybe DCC should work with Cornwall to facilitate and encourage this. And how about Devon's own levy too, on primary aggregate extracted from the Budleigh Salterton Pebble Beds?!

Construction industry ‘faces 10 more years of pain’

Construction output in the three months to November was "down 9.8%" on the same period in 2011. Furthermore the BBC reports on an industry lobby group that "doesn't anticipate the industry returning to its former levels until at least 2022". Something DCC should bear in mind when forecasting aggregate shortfalls for the years ahead.

Can Straitgate produce a ROI of 8% for Holcim?

Naturally, the question of financial return is central to whether Aggregate Industries and parent Holcim ultimately take Straitgate forward to a planning application. We have argued before that the commercial viability of a quarry here can only be marginal at best, and is a factor not yet assessed by DCC despite the NPPF saying "Pursuing sustainable development requires careful attention to viability and costs in plan-making and decision-taking. Plans should be deliverable." Holcim is now however working to a new financial benchmark.

A summary of the initial hearing held with AI on 16 May 2012 for the Competition Commission makes clear that "Holcim had recently publicly announced a new cost-cutting plan in order to improve the group’s profitability. Holcim needed to achieve an overall return on investment (after tax) of 8 per cent, while AI’s operations were only currently achieving a 2.7 per cent return (before tax)."

Yet "there had also been significant increases in the production costs, particularly for fuel and energy, for these products. Increased taxation such as the aggregates levy and carbon taxes had also raised costs." In December Holcim announced it was "to accelerate a restructuring program and write off 410 million Swiss francs of fixed assets in Europe". 

Investigations by AI and its consultants will uncover more about Straitgate's commercial potential, but here's a list of some of the other costs that AI will need to consider, over and above operating costs, before breaking the ground at Straitgate Farm once again:

Cost of preliminary work: surveys, consultants, boreholes, test pits, material testing

Cost of planning permissions and appeals; legal costs; professional fees

Cost of public relations: exhibitions, local liaison

Cost of site infrastructure: weighbridge, offices, etc.

Cost of access modifications: road modifications, land purchase required for access

Cost of a 15 mile round trip for each load of as-dug material transported to Blackhill, if permitted. If not

Cost of moving and constructing new plant at Rockbeare if permitted

Cost of acceptable standoffs from homes thereby reducing the recoverable resource

Cost of protecting the setting of the listed Straitgate Farmhouse thereby reducing the resource

Cost of restricting excavation to 1m above highest water table as enforced elsewhere

Cost of downstream flooding mitigation - in perpetuity

Cost of preserving stream flows to wetland habitats in Ancient Woodland - in perpetuity

Cost of protecting private water supplies

Cost of restoration (if it were to ever get that far)

Cost of a community fund for local projects in compensation to local people

Less of course what AI can sell the site for afterwards, which could be significant if industrial development were to be permitted, or not, as in the case of Foxenhole where 38 acres sold for £300k last year - no more than the going rate for farmland.

Would Holcim accept a lower return in order to maintain local sales control? Would a Swiss-based multinational care? In the end the limited resource and the cost burdens may well undermine the commercial rationale for proceeding, particularly if Holcim's 8% target is to be met. 

DCC is overstating the 'recoverable' resource at Straitgate by more than 50%

We have long argued that the resource figure for Straitgate with which DCC went out to Public Consultation, up to 3.6 million tonnes (Mt) giving an expected lifetime for the site of about 10 years, was inaccurate and misleading. English China Clays' "Report on the reserves of Pebble Beds at Straitgate Farm", December 1990, and appendix, substantiates this claim.

DCC would have long had a copy of this report. We however have only just seen it, kindly supplied by Aggregate Industries (see note below). The report analyses results from 24 boreholes drilled across the site in 1990. Only limited geological information existed beforehand, and subsequent resource calculations are based upon this data. 

From the report it is clear that 2.311Mt is the maximum resource figure at Straitgate that DCC should have consulted upon, as this is the net tonnage recoverable above the water table from "sub area A" (section 5.3). There was no reason for DCC to ever think Straitgate could be quarried below the water table, particularly considering airport safeguarding, and in fact at Blackhill "to protect the hydrology of the area it [was] proposed to cease excavation at 1 metre above the maximum level of the water table". Would the hydrology and the receptors around Straitgate Farm deserve any less protection?

And even 2.3Mt is based on a number of assumptions, some of which are now unrealistic:

A "working margin of 5 metres behind the tree screen and 15 metres around Straitgate Farmhouse and access" [BGS recommends 250m stand-offs]; A "working margin of 15 metres" from the A30 [unrealistic]; "Water levels are based on July readings" [the water table is up to 1.4m higher in winter]; "No allowances have been made for face angles or haul roads".

Reducing the depth of deposit by say 1m for the seasonal movement in the water table could cut the resource by c.0.4Mt. Restricting excavation to "1 metre above the maximum level of the water table" as at Blackhill loses another c.0.4Mt. Sensible stand-offs from properties, another c.0.2Mt. So even 2.3Mt can quickly become c.1.3Mt. Of that, gravel (the component of value) makes up about 70%.

And remember, DCC was originally talking about 8Mt at Straitgate, even though it had been known for many years that the eastern half of the site was "geologically more complex". Here, the Pebble Beds are not only covered with a deep outcrop of sandstone, but a large portion of them is also underwater.

So if we are going to talk about destroying a farm and violating the East Devon landscape, creating something like the photograph above, let's consult on the correct figures so that local people know exactly what's involved and are able to make an informed response. We should then consider how little economically recoverable sand and gravel there actually is at Straitgate Farm, and debate whether that's a price worth paying for the loss of so much.

Note: In relation to ECC's report, AI wishes to point out that "it covers the first detailed borehole exploration and resource analysis in 1990 and that the estimates quoted therein do not reflect modern planning conditions or economic expectations - a finite, modern resource calculation will be undertaken following receipt of all expert opinions into hydro-geology, landscape, noise, ecology etc etc probably this time next year (ie as most studies need a full set of seasons to be valid)."

AI's conundrum

Labels have now been assigned to categorise previous posts on this blog, and are sorted in the sidebar by frequency. Unsurprisingly the labels Exeter Airport and birdstrike are near the top.

Aggregate Industries is busily performing tests on its gravel, but what is it doing to reassure Exeter Airport that, if it quarries Straitgate, it isn't going to leave behind a large body of water directly beneath its flight path, attracting birds and increasing the risk of birdstrikes? After the wettest year on record for England, it's hard to imagine how a quarried void at Straitgate could not fill up with water, or how gulls or other birds would not be attracted to such water, as at "Seagull Pond" at Blackhill Quarry.

Gulls at Blackhill Quarry

So it may be that AI cannot provide the airport with that reassurance. After all, in order to replace the groundwater storage being removed at Straitgate, the Environment Agency (EA) would want provision made to store water run-off to prevent flooding downstream. This was the condition made by the Devon River Authority at the time of the 1967 planning application: a 49 acre lake and overflow weirs for "balancing flood flows".

The conundrum for AI is that if it were to dig a hole at Straitgate, the EA would want a body of water, the Airport would not, and the company would have difficulty stopping one forming anyway. Therefore for AI to proceed any further, it needs to know how it would overcome this seemingly insoluble predicament and give the answer to DCC, whose Minerals Plan could be found unsound if it continued to insist on Straitgate Farm being a Preferred Site when there's clearly such a big question mark hanging over its deliverability.

From the Airport's perspective, whilst last year was the safest year on record for air travel, it is understandable that it is protective of its airspace. Birdstrike incidents are recorded for each airport in the UK and the data is publicly available. DCC has been warned that "Under the Air Navigation Law, it is a criminal offence to endanger an aircraft or its occupants by any means". Birdstrike incidents can sometimes have terrible consequences.