ATLAS Copco has developed a new type of rock bolt that can adapt to rock deformation or displacement underground, while maintaining a constant load capacity.
Following in the footsteps of Swellex rock bolts and MAI self-drilling anchors, the Roofex deep mine rock bolt fulfils the need for effective bolting in difficult underground applications such as tunnelling in squeezing ground or deep mining in poor quality rock.
The new bolt is a high quality steel bar inside a smooth plastic sheathing which is fixed inside the borehole with cement or resin grout.
The bolt also has a patented energy absorber which functions as a sliding element over the high quality steel bar.
This allows the bolt to extend outwards under load while still ensuring that the load capacity remains constant.
In this way, the bolt can absorb sudden displacements such as rock burst or seismic events.
This makes the Roofex especially suitable for developing new, deep underground excavations in poor quality rock or in areas where rock burst or seismic events are frequent.
The bolt can be pro-duced in standard lengths typically used in mining and tunnelling, and the dis-placement capacity can be pre-selected during manufacturing.