Wookey Hole Caves, Somerset.
The client, Wookey Hole Show Caves, were planning to drill and blast a new tunnel from an existing cave to Chamber 20, a cave that previously was only accessible by divers. There was a small risk that the vibration from the works could dislodge a 10 tonne block in the roof of the currently accessible cave.
Geobrugg engineers designed e solution using their ROCCO 12/3.1350 ring net to catch a 10 tonne block if it were to become detached during the blasting of the new tunnel. The biggest problem RARR Ltd faced was getting the net installed, this had never been installed in this orientation before, let alone in a cave under the Mendip hills, this was a world first. To carry out the project all tools, equipment, anchors and all components of the catch net had to be carried into the cave system by hand. A roped access system was installed to allow access to the entire perimeter of the work area at 2Om height, all the anchors were hand drilled into the Dolomitic Conglomerate Rock and all components of the net were hauled by hand the largest being 120kg in weight. The project was completed on time and in budget and saved £250,000 on scaffolding needs.