Rock Bursting in Virgin Development; development of a standardized process to evaluate the potential conditions of new mining areas prior to development
Mr Lloyd Howell (Glencore), Mr Brad Simser (Glencore), Mr Stephen H.Falconer (Chief Mine Geologist - Glencore)
In rare instances, violent rock bursting has occurred in “virgin” development such as ramps or connection drives. A common factor for bursting in virgin development is geological structure such as dykes or faults. If the structure is storing locked up energy such as an asperity on a fault, then a tunnel intersecting it might trigger a sudden release.
Some of the risk can be reduced by keeping people away from the face or exposed to unsupported ground. The key is knowledge of major structures that might intersect planned development and understanding the nature of the structure.
In April of 2014, Glencore, Sudbury Integrated Nickel Operations, Nickel Rim South Mine began development of a 2.3km long exploration development drift at a depth of roughly 2,000 m, in order to establish a drill platform for a potential new ore zone. To evaluate the ground conditions, a series of ‘pilot’ holes were drilled sub parallel to identify significant structures.
An innovative method to quickly orient and evaluate the core in a timely manner was established using Acoustical (ATV) and Optical Televiewer (OTV) surveys in the relatively shallow dipping ‘pilot’ holes. Further analysis of the ATV and OTV data showed the potential to project intermediate structures to the planned drift and also to evaluate the ground conditions locally ahead of the face.