Whether the DoW CoP can or cannot be used to backfill quarries is a question that must be considered on the specifics of any proposed backfill operation.
As outlined in the Definition of Waste Code of Practice Training, generally, for activities involving the backfill of quarries, it is unlikely the DoW CoP will be the right mechanism to deposit materials to restore the land to original pre-extraction levels (especially in large volumes). This will generally be determined in the first instance by the planning permission originally granted, i.e. many planning permissions for mineral extraction and related activities are applied using minerals and waste planning local plans. These often stipulate where mineral workings are available and restoration of these sites should use waste materials to backfill voids under a relevant landfill permit.
Where large voids will require significant high volumes of potentially mixed wastes, and the long-term impacts of infill should be monitored due to the hydrogeological setting, it is right that an environmental permit, with its protective engineering requirements and monitoring should be employed to cover backfill activities.
The permitting approach also enables commercial arrangements to be brought into play to cover some of these engineering and monitoring costs. Planning requirements and consultation responses to the planning application process will often make it clear that a landfill for waste is to be the suitable management route for quarry backfill activities. In such cases, an Environmental Permit for Recovery or Disposal is required from the relevant regulator. Therefore the parameters of a granted planning permission for the mineral site and subsequent backfill activity are key, as well as consideration of planning consultation responses from the relevant regulator.
However, there may be some backfill activities in old mineral workings that are able to use the DoW CoP for limited materials placement activities, such as the following:
· where the overall void is not being infilled but cut and fill activities are being used to re-landscape the quarry floor profile to create relevant future use settings.
· hard development such as warehousing, business estates, shopping centres and similar construction projects.
· low-level restoration to form habitat creation schemes such as scrapes, lakes, ponds, and wetlands, or for different mosaic soil conditions for biodiversity net gain for instance.
· the creation of sandy banks for bird nesting sites perhaps to enhance existing cliff faces, or to create more safe, stable landforms.
· engineering works to stabilise dangerous cliffs, with toe base deposits to support unstable slopes.
These engineering activities should be carried out under a relevant planning permission for the stated purpose, and may be within the scope of the DoW CoP, providing all the other requirements of the Code are met in full.
The activity must not be a fee-earning deposit activity carried out to enable disposal of waste materials from other sites, that are discarding surplus materials, even if those materials are inert soils and stones.
So, for quarry backfill projects, it is critical that the relevant planning permission frame is understood. The scale of activity must be appropriate, and the relevant consultees must have given approval before any project uses a DoW CoP approach to undertake limited backfill activities in a quarry site setting. Where DoW CoP can be used in principle, all the requirements of the Code must be met in full, and the project managed to achieve the stated aims under the granted planning consent for limited backfill activity.
Published 27 Jun 2024
