Tome Architecture and management of a geological repository - Andra

4 - General architecture of the repository in a granite mediumThe final lining is poured (formed concrete) every two to four cycles, some tens of metres above thebottom of the shaft.The use of smooth blasting techniques using pre-cutting and/or post-cutting, minimises granite wherethe future seals will be sited.Shaft-sinking requires equipment made up of two sub-assemblies: moving equipment lowered throughthe shaft and static equipment located on the surface.The moving equipment is made up of a metal structure, the shaft-sinking platform. Work in the shaft iscarried out from the shaft-sinking platform. This platform, suspended by cables, is lowered down intothe shaft as work progresses.Figure 4.2.3Shaft-sinking platform (Konradsberg - Heilbronn salt mine - Germany)The static equipment is made up of a head-frame and a set of winches for the shaft-sinking platformmovements. Once shaft construction is completed, this equipment - specifically installed for shaftconstruction - is replaced by the permanent operating equipment.Shaft-sinking combining the "raise-boring" and shaft-sinking techniques.A "raise-boring" and shaft-sinking combined solution could be envisaged for sinking the third and/orfourth shaft.A "pilot borehole" roughly 30 cm in diameter is bored from the surface to an existing drift. The pilothole is reamed from the bottom to the surface (raise-boring method) to create a 2 to 3 m diameter“chimney” (in all cases maximum diameter less than 5 m). The reaming broken muck is recovered atthe underground station and transported to surface via an existing shaft or the ramp. The chimney isthen widened to the required final shaft diameter by sinking from the surface down to the drift. Thebroken muck is recovered at the chimney bottom and transported to surface ejected via another shaftor the ramp.Dossier 2005 Granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY65/228