Development of roofbolting in Australian coal mining

Roof bolting technology in Australian coal mines has advanced quite considerably during the 40 years plus since the introduction. The main area where the majority of improvements have taken place is in the stiffness of the support. This has been achieved by the introduction of chemical anchors and full encapsulation of bolts, higher grades of steel with more efficient deformations and the introduction of cable bolts and resin grouted strand bolts. Another important development occurred in the area of direct application of confinement to the rock mass by installing bolts in pre-failed rock conditions and application of high pretensioning to the support. All the changes introduced to the roof bolting technology which resulted in better rock reinforcement are analysed and the directions for further future development are discussed.