Tome Architecture and management of a geological repository - Andra
Tome Architecture and management of a geological repository - Andra
Tome Architecture and management of a geological repository - Andra
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4 - General architecture <strong>of</strong> the <strong>repository</strong> in a granite medium• Summary assessment <strong>of</strong> the dump footprintThe broken rock storage dump represents a volume <strong>of</strong> several million cubic metres; this volume (<strong>and</strong>even more) is frequently found in open-cast mining. As backfilling date is not fixed in advance, thesurface area for a dump capable <strong>of</strong> accommodating all the broken rock has been estimated.As there is no study site, only the general dump <strong>management</strong> principles can be given, that willsubsequently be adapted to the site topography. On the basis <strong>of</strong> a 10 meters high dump, the arearequired could vary from roughly one hundred hectares for scenario S1a to about 250 ha for scenariosS1b, S1c <strong>and</strong> S2.• General dump design <strong>and</strong> operation principlesThe dump project should be studied according to the site for its best integration with the l<strong>and</strong>scape <strong>and</strong>the hydrographic network.Sens de progression de la verse3. Végétalisation de la verse 1. Préparation de la surface(décapage de la terre2. Mise en verse des déblaisvégétale et drainage)(compactage et surfaçage)Figure 4.1.4Phased dump operating principleOn a rather flat site (without any specific topography), a dump is generally operated in sections.Scraping <strong>and</strong> surfacing operations, constructing the drainage network, placing the broken rock <strong>and</strong>capping follow on from each other <strong>and</strong> progress with the development <strong>of</strong> the dump.Apart from the geometric aspects, the dump is mainly designed to ensure the stability <strong>of</strong> the brokenrock <strong>and</strong> prevent rainwater from percolating into the emplaced materials.Preparatory earthworks, scraping <strong>of</strong>f the soil, shaping dump sections, building ditches <strong>and</strong> slopes, <strong>and</strong>storm <strong>and</strong> settlement basins are necessary.Lastly, the topsoil from the scraping <strong>of</strong> the various zones where the surface installations <strong>and</strong> dump arebuilt is assembled <strong>and</strong> stored near the dump. It is used as <strong>and</strong> when necessary to cover the dumpbefore vegetalisation.• Recovering broken muck from the dump for backfilling operationsBroken rocks can also be retrieved for backfilling operations by section, similar to the way in whichdumping was first organised.The backfill materials recovered from a dump must be conditioned before their re-use. Conditioningmay involve crushing <strong>and</strong> screening the retrieved materials <strong>and</strong> possibly mixing with added swellingclay.Dossier 2005 Granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY56/228
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