The Hydrabolt is a hydraulically expansible rockbolt with superior bond strength for tensile loading applications. The hollow, tubular Hydrabolt is injected with high pressure water upon installation which then expands to adapt to the shape of a pre-drilled support hole.

The Hydrabolt has been designed to facilitate ease of installation and to provide the user with immediate support and a safe working environment. Unlike other designs, the Hydrabolt incorporates a check valve to prevent the fluid from being released once the inflating nozzle is removed. This system provides a better bond as the inflated tube adapts to the shape, size and irregularities of the hole and distributes the clamping force evenly throughout the length of the hole. As the installed Hydrabolt is sealed, the internal corrosion is self-inhibiting.

The patented design of the Hydrabolt valve provides a visual method of verifying the correct installation of the tubular rockbolts. The integral load indicator indicates that the Hydrabolt has been correctly installed by popping forward once the Hydrabolt has been installed with the correct internal pressure; secondly the colour of the load indicator identifies which length of Hydrabolt has been installed. The load indicator also confirms whether a Hydrabolt or X‑Pandabolt has been installed.

All of New Concept Mining’s Inflatable Bolts can be offered with Thermal Zinc Diffusion for improved corrosion protection if required.



New improved Hydrabolt indicator

Hydrabolts can now be fitted with a new button and indicator where the load indicator protrudes from the button after correct pressurisation. This allows better visibility of the indicator when checking for correct installation. This system is compatible with the new Self-auditing Jackpot.

Click here for more information on Poka Yokes (mistake proofing) in the mining industry.


Hydrabolt inflation animation
Hydrabolt load indicator


Benefits of the bolt

  • Quick and easy to install
  • Wide expansion range
  • Patented non-return valve which limits "spring-back" giving increased pull-out resistance
  • Pressurising done remotely
  • Not affected by blasting vibrations
  • No resin or grout required
  • No parts to lose in transport
  • Not susceptible to rock strength
  • Load distributed evenly over entire length of hole
  • Provides immediate support


Three models of the Hydrabolt are currently available and can be manufactured in lengths ranging from 0.9 to 3.0 meters in increments of 0.3 meters. Non-standard lengths can be accommodated upon request.

Model Nominal diameter (mm) Hole size range (mm) Nominal load capacity (kN) Typical bond length (mm)
Hydrabolt NT Ø26 Ø32–36 78 250
Hydrabolt Normal Ø26 Ø32–36 98 300
Hydrabolt Ø29 Ø29 Ø34–40 98 300