Only last week, we reminded readers how in 2017 we posted that AI’s last two quarries in East Devon produced significantly less than expected – and there's every chance Straitgate would too. It’s worth repeating some of that post:
We all know that forecasting what a quarry might yield is an inexact business, even if the mineral companies would have us believe otherwise...
Take Straitgate. Once upon a time, it was thought that the site could yield some 20 million tonnes. In 2012, DCC went out to public consultation telling people that there were 3.6 million tonnes. In 2017, Aggregate Industries will struggle to make the case for 1.2 million tonnes.
When AI eventually came clean on exactly how it hoped to win those 1.2 million tonnes - without retaining a 1 metre unquarried buffer to protect water supplies - the company reminded us that "Calculations have been undertaken by Chartered Geologists".
So let’s look at AI’s other two quarries in the area to see how well its chartered geologists did there.
In 2011, AI reassessed its sand and gravel reserves in Devon and found that it had lost 2 million tonnes; equivalent to a couple of Straitgates...
The 2 million tonnes were lost at nearby at Marshbroadmoor and Venn Ottery. Both have similar geology to Straitgate, both yielded considerably less than initially expected.
It's important to know how much resource a site is likely to yield. For Straitgate:
... the size of the mineral benefit must be weighed against the destruction of an East Devon farm, the loss of thousands of metres of hedgerows, trees and dormice habitat, the risk to drinking water supplies to more than a hundred people, the risk of birdstrike by creating water bodies 195m directly beneath an international flight path, and the pollution and carbon emissions from a 2.5 million mile haulage plan.
We also posted in 2017 that Quarrying and processing restarts at Hillhead, that:
Aggregate Industries has 4.23 million tonnes of sand and gravel available at Houndaller – with planning permission – enough to last the company 12 years or more.
Hillhead is the location to which Aggregate Industries has relocated its processing plant; it is the location that had not only 4 million tonnes of permitted reserves but also a further 8 million tonnes of resource nearby; it is the location where Aggregate Industries would transport any winnings from Straitgate – a 46 mile round trip for each load, some 2.5 million miles in all.
Aggregate Industries referred to Houndaller’s "mineral reserve figure of 4.23 million tonnes", not only in this application, but also in the Supporting Statement for the Straitgate Farm application in 2017:
The Hillhead Quarry mineral deposit comprises 4.2 million tonnes of sand rich sand and gravel with planning permission in an area known as Houndaller. 3.6.3
The quantity of material at Houndaller was deemed a relevant fact to be considered when determining the Straitgate application. Likewise, any significant changes to this figure should also be deemed relevant.
Houndaller was referred to in the September 2018 Monitoring Report for Hillhead:
4.9 Houndaller contains an estimated reserve of 4.2 million tonnes of sand and gravel and extraction resumed on this part of the site on 16 September 2016.
However, just 12 months later, in the September 2019 Monitoring Report for Hillhead:
4.10 Houndaller contains an estimated reserve of 2.2 million tonnes of sand and gravel. Extraction resumed on this part of the site on 16 September 2016.
Surely, Aggregate Industries hadn’t lost 2 million tonnes of reserve in just one year? We assumed it must be a typo. However, Devon County Council subsequently advised:
The information presented in the Monitoring Report is provided by the operator. Houndaller has been active for a while and a certain proportion will be due to extraction. Some of the reserves may have initially been overestimated, however you would need to ask the operator for that information.
So, ask the operator we did. Perhaps we touched a nerve. Aggregate Industries has now responded, more so perhaps – given the number of courtesy copies – in reply to Devon County Council than to us:
For reasons of commercial confidentiality it is an accepted principle that individual quarry reserve/sales figures where a Quarry Operator can be identified remains confidential and excluded from Site Monitoring Reports which are published on MPA websites. This principle will be enforced for AIUK sites going forward, notwithstanding that quarry managers may refer to this detail during monitoring visits.
There are however particular circumstances where the company may wish from time to time, at its discretion, to refer to such figures; Quarry Liaison Meetings and Planning Applications being examples.
Turning now to the disclosure of mineral reserves at Houndaller (Hillhead) Quarry; the estimated reserve figure of 4.2 million tonnes quoted in the Monitoring Report following the Monitoring Visit on the 20th September 2018 was a historical figure on the company's mineral reserves schedule that had been quoted since mineral extraction ceased in 2007 to reopening Hillhead in 2017. The 4.2Mt reserves figure was therefore correct, as per our mineral reserves schedule at the time of DCC's September 2018 Monitoring Visit, however, prior to the end of 2018 a re-evaluation of reserves at Houndaller was concluded in the light of recent quarry extraction data and the most recent borehole information. The company's reserves schedule for Houndaller was subsequently revised to 2.9 million tonnes as at 1st January 2019.
The Quarry Manager who hosted the Monitoring Visit on the 19th September 2019 made a topographic error that was recorded in the Monitoring Report; the reserve figure should have read 2.9 million tonnes and not 2.2 million tonnes.
To be quite clear, we will not be entering into any further correspondence with third parties on matters relating to commercially sensitive reserves and sales figures in the future.
So, for future reference: Don’t go writing to Aggregate Industries if you notice a couple of million of tonnes of sand and gravel have gone missing.
How much has Aggregate Industries actually lost in this case? Let’s be generous and say the company has been getting through about 300k tonnes pa.; historically, sales at Blackhill were at this sort of level. Over the two years of 2017 and 2018 this might have amounted to 600k tonnes, thereby reducing reserves from 4.2 to 3.6 million tonnes. Aggregate Industries now reports that at the end of 2018, Houndaller actually had 2.9 million tonnes, which would indicate that the company, in its "re-evaluation of reserves", has lost in the region of 700k tonnes. This equates to more than two years' supply, and nearly the amount available at Straitgate Farm. How careless.
So, given Aggregate Industries' record of over-estimating mineral resources – at three local quarries now – how on earth can Aggregate Industries be sure that there’s even a million tonnes at Straitgate, particularly given that its consultants – before reports were whitewashed – considered that for this site "there is also likely to be other unmapped local faulting"?
