From what Aggregate Industries claims - in its crazy scheme to import 100,000 tonnes of sand and gravel all the way from Hillhead into Blackhill for processing, each round trip almost 53 miles - the waste material from Houndaller is pretty important to the restoration of Blackhill, crucial in fact:
The silt (contained in the unprocessed material) being brought in from Houndaller Quarry would ensure that the steep sided former quarry void in the south-eastern lagoon would be filled and more sympathetically restored, in accordance with the consented restoration and aftercare scheme. 6.15
It’s a bold claim. But it doesn’t stop there. To justify the exceptional circumstances that the NPPF requires for major development in an AONB, to justify all the 44-tonne HGVs traipsing back and forth across Woodbury Common and the East Devon Pebblebed Heaths SAC SPA:
...the additional silt that would be generated from processing Hillhead (Houndaller) mineral would supplement the filling of the lagoons at Blackhill to meet the approved restoration contours of the site upon cessation of mineral processing operations, allowing a heathland restoration commensurate with the SSSI, SAC, SPA designations of the surrounding common.
Should materials not be permitted to be imported to the site, this could potentially result in the processing plant at Blackhill Quarry otherwise remaining under-utilised for the remainder of the planning permission and the permitted restoration not being able to be completed.
Even in Amec's "Technical note: Blackhill Nutrient Investigation":
Importing this material is required in order to achieve approved ground contours and restoration. 1
More bold claims. Are any true?
If we assume - using AI’s figures - a maximum of 20% wastage, then from 100,000 tonnes this would amount to some 20,000 tonnes or about 10,000m3. AI has already said, in its application to quarry Straitgate Farm, that the area in question, Lagoon 3 (Area 6), has a void capacity of 218,000m3 and that "infilling of this lagoon would achieve the approved restoration contours" 8.12.
The waste material from Houndaller would therefore fill less than 5% of this void. It would make no significant difference to the restoration of Blackhill, particularly given the steep sides elsewhere in the quarry - see below. The statements in 6.15 and elsewhere are therefore false; yet more fabrications, fibs, inventions, deceptions; the material would NOT ensure the filling of any steep sided former quarry void; the material would NOT ensure the completion of any permitted restoration.
More to the point, the waste material from Houndaller may actually be damaging to Blackhill's restoration; phosphorus levels for the Hillhead material range from 63mg/kg to 173mg/kg, pH values from 5.89 to 7.13. The approved restoration scheme for Blackhill says:
...all soils will be tested for pH and nutrient content to ensure that they are suitable for heathland restoration i.e. phosphorous is less than 10mg/kg and that the pH is between 3 and 5 3.6.1
Moreover, the restoration scheme does not rely on importation of material from either Houndaller or Straitgate. For Area 6, quite the contrary in fact:
It is expected that the majority of the available void will be used during the remaining life of the processing plant (i.e. to the end of 2016). The final height of the silt is not yet known but may be higher than originally thought. 4.8.2
On completion of silting operations at the end of 2016, the eastern wall will be clear felled and the timber removed from the site and soils will be stripped and stored for use in the restoration of the area. The eastern wall will then be removed to a depth of 3 metres above the surface of the drying silt. The material from the wall will be used with other indigenous material to form a capping to the silt body, approximately 1 metre in depth, and to batter the side slopes. The soils will be thinly spread over the whole area. 4.8.3
Perhaps AI should explain how, in little more than 2 years, it managed to go from a final height of silt that "may be higher than originally thought" to a shortfall of 218,000m3, particularly given that Venn Ottery has yielded more material than originally expected. In any case, a DCC officer has already explained that if material from elsewhere was not available to meet any shortfall, the already agreed earthworks would produce a perfectly acceptable landform.
AI was granted planning permission to continue processing at Blackhill in 2011, with Condition 7:
The restoration shall be carried out in accordance with the approved scheme, or such alternative schemes as may be subsequently approved in writing by the MPA.
It's a condition, not a suggestion.
