Rockfall protection systems in the mining environment are used as a means of protecting the mine’s assets which include employees and plant.
The word “system” correctly embraces the different structural components that should be considered when facing a rockfall problem.
Different types of systems are available, and a key distinction should be made between active and passive protection systems.
Passive systems do not affect the process of the rock detaching, but focus rather, on containing falling debris, thereby averting danger to the infrastructure and its users. These systems include:
- Drapery wire mesh;
- Rockfall protection barriers;
- Rockfall protection embankments.
Active systems act on the rock-detachment process and is used to prevent instability from occurring. These systems include:
- Pre-stressed wire anchors;
- Rock bolts;
- Grouted bars;
- Armored mesh anchored to the rock slope.
The performance of these systems are directly related to the durability of each component. Each component in the system is therefore carefully selected and needs to perform for a required time period while withstanding the expected stresses.
Maccaferri has invested enormous resources in research and development over the years which yielded many innovative solutions for the rockfall protection market (Mac.ROTM Systems) and also the development of our own software programs (MAC.RO Studio). Currently, Maccaferri Africa are involved in a range of mining projects which require both active and passive solutions to mitigate the risks faced at different mines.
Current running projects:
- Venetia Mine (De Beers Group) – Cut N23 Slope Stabilization
Venetia mine experienced numerous rockfall instabilities on cut face N23 in the recent past. These instabilities resulted in rocks detaching from the slope face, which either put their assets at risk or interfered with production. The mine subsequently made the decision to mitigate the problem in order to lower the risk of such incidents occurring. Maccaferri’s Steelgrid® HR 50 was used as the rockfall drapery solution on the 15 000 m² face and installed by Marshall Developments.
- Voorspoed Mine (De Beers Group) – SW 23 Slope Stabilization
Voorspoed mine had instability on cut face SW23 which led to some rockfall failure occurring on the slope. With the risk of damaging either mine assets or life, a rockfall drapery solution was proposed to prevent damages occurring. The solution which the mine chose was Maccaferri’s Steelgrid® HR50. Marshall Developments is currently installing the 6000m2 of drapery Steelgrid® HR50 mesh.
- Foskor Mine –Rockfall Protection (Rockfall Barrier and Rockfall Drapery)
Foskor Mine had space and energy limitations and therefore required two different solutions. For one of the sections where instabilities were of concern, a simple drapery solution was in order because of the amount of debris and block sizes expected to travel down the slope. The mine selected Maccaferri’s Steelgrid® HR50 rockfall drapery mesh for the 4500 m² area. With the other section of the mine where instabilities were also noticed, the space and energy requirements were completely different. For mitigation of this section a simple drapery approach was not the optimum solution. Therefore, for this section a Maccaferri dynamic rockfall barrier (RMS050 ICAT/2 PLUS) with an energy rating of 500 kJ, 150 m long and 3m high was chosen. The installation of the rockfall mitigation solutions are being done by Marshall developments. These instabilities are at the time of writing.
Rockfall Mitigation has reached the stage where engineered systems and design tools are readily available. Maccaferri is proud of being a household name when it comes to providing innovative solutions to our clients.