GFRP-HIPREX Bolts - Minova Global

GFRP-Hollow Bar Bolts (HIPREX)


The high torsion GFRP hollow bar injection bolts are fitted with an expansion packer and integrated non-return valve. Two additional valves are fitted to both ends of the tube, the top valve to burst when the packer is inflated, the bottom valve to prevent backflow after injection. 

When starting the injection process the check valve will be opened and the medium will run through the hollow bar filling it and inflating the packer. The non-return valve opens but ensures that the medium will not flow backwards if the hydraulic pressure is reduced. After filling the bolt and packer to a certain pressure the disc will burst and allow rock injection. 

After the injection is complete the non‑return valve will close and prevent backflow of the resin. After the resin has cured the hollow bar will be fixed in the hole with a high bond strength. 

The GFRP system allows cutting during heading or mining of ore. Rapid heading will not be delayed. High corrosion resistance allows permanent application with high durability and the light weight makes handling easy, even in confined underground conditions.


  • High hydraulic burst pressure > 240 bars 
  • High corrosion resistance 
  • Permanent application 
  • Cuttability 
  • Continuous threaded bar 
  • High tensile strength 
  • High end loading 
  • Flexibility 
  • Low weight 
  • Easy handling 
  • Anti-static

Industry Sectors

Coal Mining

Hard Rock Mining


Common Uses



Technical Data Sheet

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