Menu Start About GMA Quality & Environment Products Rock safety system Thorbolt® Accessories Thorbolt® Injection system Packers Inflatable packers Compressible packers Injection tubes Machine shoes Other References Agents News Download Find us Contact Us System Thorbolt® involves bolting and grouting in one step…. Grouting means that grouting compound is pumped into the rock to seal cracks… .. Machine shoes, to reduce vibrations in and around machines… Accessories for tunnels and rock works… © 2017 GMA Ground Machinary Applications AB. All rights reserved.