Dismantling and decommissioning of the Andújar Uranium Mill (AUM)

Disused installation of the Andújar Uranium Mill

In 1986 Enresa undertook the preliminary tasks, the start-up and the performance of the dismantling and decommissioning plan for the Andújar uranium mill (Jaén).

Aimed at restoring the site and integrating it into the surroundings, the Enresa project was approved by the Ministry of Industry and Energy in 1991. The basic criteria for performance were as follows:

• To prevent risks for persons and the environment.
• To prevent the dispersal of contaminants.
• To control radon gas flows.
• To guarantee the long-term stability of the structures.
• To minimise maintenance requirements.

Preparation of the site and preliminary tasks

Studies were carried out on the geology of the area and environmental impact and radiological and environmental surveillance programmes were performed. A pool was constructed for the treatment of the waters prior to their release to the river, the machinery decontamination pit was extended and the electrical installation was adapted for performance of the works.

Dismantling

The installations and equipment existing on the site were decontaminated and chopped and then stored in metallic containers or cages. These cages were subsequently transferred to the previously stabilised tailings dyke for sealing with concrete.

Demolition

Andújar Uranium Mill: before and after dismantling.

The different buildings and other constructions at the mill were knocked down and demolished and placed on top of the concreted metallic cages. Compacting of all these structures was performed with tailings.

Remodelling and stabilisation of the tailings dyke

The configuration of the dyke was remodelled by modifying its profile and relocating the tailings and by compacting the contaminants arising from cleaning of the terrain of the site and spreading them across the dyke crown. All the products arising from dismantling and demolition were incorporated in this stabilised dyke. This guarantees the long-term safety of the site.

Placing of covering layers

Multiple protective layers were extended over the stabilised dyke: radon and seepage barrier, layer of gravel, bio-intrusion barrier, filter, topsoil, erosion protection barrier, topsoil and vegetation.

Environmental restoration

More than a thousand trees and shrubs were planted in the area and native plant species were planted on the dyke, thus achieving the integration into the landscape of the site.

Implementation of a surveillance and maintenance plan

On completion of the rehabilitation works, a surveillance and control system was implemented at the site to ensure compliance with the project objectives. The plan contemplates assessment of the quality of surface and groundwaters, the level of radon, possible changes in the coverage of the dyke, intrusions, etc.

Public participation

There were constant communications by Enresa to the local authorities and to the general public interested in the project during the works and after.