Architecture and management of a geological repository - Andra

8 – Surface installationsThis industrial zone is developed progressively based on the changing needs of the underground work.For example, the backfill preparation installations may only be built once the decision to close hasbeen taken.The surface installations for site management and administration are grouped around the personneltransfer shaft. These are basically office buildings, a central emergency building and a "living" spacefor the personnel working on the site (cloakrooms, showers, canteens, etc.).8.4 Broken rock storage dumpBroken rocks from the excavation sites are stored in a dump built at the edge of the working zone.These broken rocks are re-used as much as possible to make up the repository closing backfill, to aheight of around 40%. The remainder of the broken rocks stays on the surface 131 .• Brief assessment of the surface areaThe broken rock storage dump represents a volume of several million cubic metres; this volume (andeven more) is frequently found in open-cast mines. As the date for backfilling is not fixed in advance,the surface area for a dump capable of holding all the broken rock has been estimated.As there is no defined dump site, only the general dump management principles can be given, that willsubsequently be adapted to the site topography. A compromise will have to be found between thedump height and its surface area, as a dump can be more flexible to manage if it’s height is lower. Atthis stage in the studies, a low-lying dump has been considered, around ten metres high. The dumpsurface area could therefore be in the region of between 100 and 300 hectares.• General dump design and operation principlesThe dump project should be studied for its greatest integration with the landscape and thehydrographic network.Scraping off the topsoil and using it torevegetable the dump3 Landscaped andrevegetated dump2 Placement ofbroken rock1 Preparationof surfaceDirection of progress of the dumpFigure 8.4.1Dump operating principle per sectionA dump is generally operated in sections. The scraping and surfacing operations, constructing thedrainage network, placing the broken rock and covering the soils follow on from each other andprogress with the development of the dump.131 The difference compared with 100% is explained by the volume occupied by the disposal packages and the engineered structure liners,and by the "swell factor" effect of the backfillDOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM326/495