Monday, 5 October 2015

AI now 'admits' it's down to 900,000 tonnes of resource

Several months ago we calculated that Aggregate Industries had overstated the saleable resource by at least 500,000 tonnes, after its claims that the 1.66 million tonnes figure already factored in the 1m maintained above the maximum water table to satisfy the Environment Agency.

DCC therefore asked AI "to provide a simple, but evidenced assessment of the resource available". This is AI's response:


Applying this loss factor results in a saleable quantity of 1,659,780 tonnes of sand and gravel, 1,200,000 tonnes of which is from the Pebble Bed deposit. 8.76
AI's gross volume of 1,408,000m3 agrees with our calculations of 5.47m x 256,000m2 = 1,400,000m3, but the company is still claiming "a saleable quantity of 1,659,780 tonnes".

But now however, and contrary to what was previously said, it goes on to admit:
Since elsewhere in the Regulation 22 response it now accepts that:
the "saleable quantity of 1,659,780 tonnes" cannot therefore be "saleable" at all, and the resource available, excluding anything from the overburden, is now 900,000 tonnes - by AI's reckoning.

But AI has even made a hash of this calculation. Elsewhere AI accepts that:
... 256,000m3, being the volume required to restore a 1m soil thickness over the base of the mineral working. 5.9
but it's simple arithmetic to work out that the 300,000 tonnes AI has deducted for the 1m should in fact be:
256,000m3 x 80% (allowing 20% wastage) x 2 tonnes/m3 = 410,000 saleable tonnes
In which case the resource is 1,200,000 - 410,000 = 790,000 tonnes, before overburden.

For that overburden, AI has unrealistically assumed the same wastage of 20% as it has for the Pebble Beds. We were previously advised by AI’s Head of Geological Services that the overburden:
...can only be quantified on a month by month basis in a working scenario as it can depend as much on the weather as the skill of the excavator driver whether blending is possible. It is therefore not a tonnage I can quote in a formal Competent Person Report, however I would anticipate nominal tonnages and if pushed to guess would say approx, 200,000 saleable tonnes...
In total, therefore, AI has no more than 990,000 tonnes, including any speculative overburden.

This is the quantity - less than 3 years worth - that must now be weighed against the harm and the destruction of an East Devon farm.

This is the quantity that should have been in the draft Devon's Minerals Plan that is now out for consultation. DCC was warned, but chose to believe AI instead. But then DCC has made the same mistake before. Back in 2013 we wrote "DCC is overstating the 'recoverable' resource at Straitgate by more than 50%":
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.