GROUND SUPPORT & ROCK REINFORCEMENT
A render of the new MacLean BP3 with Agilis system
Rock sure
Paul Moore looks at ground support & rock reinforcement developments , from new rock bolt technology to resins , foams and grouts
It isn ’ t often you see a real underground mining technology innovation – but the new MacLean BP3 , featuring the Agilis mixing system , is one of them . It addresses the long standing problem of how to produce high quality and consistent wet shotcrete at the face without having to use trans-mixer trucks . The project has been a collaboration between RufDiamond , the Agilis mixing and delivery system designer , Bay- Lynx , the fabricator , and MacLean Engineering , which supplied the state of the art carrier to integrate with Agilis .
Agilis allows for an exact shotcrete mix design and volume ( engineered shotcrete mix to be batched ) every time to eliminate overages and shortages , with zero risks of emergency offloads and no waiting for ready-mix trucks or rejecting a “ hot ” load because it took too long to arrive onsite . It offers a 30 cubic metres per hour output , with no batch plant required but with consistent fresh maximum strength shotcrete and continuous pour capability . It also requires minimal washout ( only the auger ) with faster cleanup and less environmental waste . By nature , it reduces traffic both on surface and underground plus less staffing & equipment required to achieve equal production rates . The attached interview details the project via a Q & A with the main stakeholders .
Epiroc ’ s new anti-spin cable bolt
Moving on to new bolt designs , developed by New Concept Mining ( NCM ) in South Africa , now part of Epiroc , the new Anti-Spin Cable is an anchor utilising a self-activating expansion shell
The new Anti-Spin Cable is an anchor utilising a self-activating expansion shell to allow instant pre-tensioning immediately upon installation prior to grouting to allow instant pre-tensioning immediately upon installation prior to grouting . The Anti-Spin Cable is installed using a semi-mechanised process to insert and then tension the cable to 25 to 35 kN . A unique anti-spin mechanism allows tensioning to be achieved without torque and energy being applied into the cable , which would otherwise reduce applied pre-load . A load indicator in the grout seat confirms that the correct pre-load had been achieved at installation . The integrated grouting mechanism ensures the Anti-Spin Cable is fully encapsulated to maximise load transfer and corrosion protection . The anti-spin mechanism itself mitigates cable rotation during tensioning ; while a grout seat includes an integrated load indicator and spherical seat . A self-activating mechanical end anchor reduces activation stroke during tensioning and is rated to full cable capacity . Finally , a corrugated grouting sleeve is the conduit for the grout to flow to the back of the hole , with a mechanical interlock between the grout and sleeve .
The main benefits are immediate support , plus the fact the bolts are post-grouted and pretensionable with load indicator . The anti-spin mechanism prevents cable twisting and there are no grout or breather tubes that could be accidentally pinched . Plus it offers mechanised pre-tensioning ( without a cropper and tensioner ).
Smart rock bolt technology
ThingWave ' s smart rock bolt technology enables wireless condition monitoring of rock and cable bolts . With the breakthrough technology , ThingWave ’ s offers geotechnicians and mine engineers the ability to monitor changes of deformation of tunnels , drives , and galleries in
International Mining | AUGUST 2022