Rockfall scaling ranges from simple scaling of loose rock mass with hand-held tools such as “Gwala” to more advanced processes such as the sensitive blasting with low energy rock-breaking cartridges.
Rockfalls presents major hazards in excavations for highways and railways in mountainous terrain. A rockfall event is generally initiated by climatic and biological event that causes a change in the forces acting on a rock. In a mining environment, rockfall usually occur due to blasting induced vibration. Rockfall in general range from minor falls to larger falls which affects the safety of people and may also cause damage to infrastructure. Rockfall may also include substantial slope failures that cause serious damage to critical public and private infrastructure.
A rockfall protection system refers to the structural elements used for the mitigation of the potential hazards resulting from un-controlled falls off ground. Rockfall hazards mitigation systems aim at minimising the potential effects of rockfall events through the design and installation of rockfall protection systems. Rockfall protection systems are engineered to be durable, effective and to save lives.
However, there are cases where the structural elements used for rockfall hazards mitigation systems are inadequate. In these cases the fractured rock-mass must be dislodged from the high-wall instead of being restrained by means of structural elements. This is often achieved through a process commonly known as rockfall barring. Rockfall scaling ranges from a simple removal of small and loose rocks to a more advanced process that involve drilling and blasting with with rock-breaking cartridges and other specialised explosives materials, this is commonly referred to as trim blasting. Hoff Geotechnik is a world leader on rockfall hazards mitigation and protection systems through sensitive blasting techniques (triming).
It should be noted that in almost all the cases where rockfall scaling is needed the physical site access is highly restricted and specialised systems for access of people and machinery is utilised. Hoff Geotechnik has assembled and trained a team of specialist technicians to drill long boreholes which are charged with rock-breaking cartridges to trim-out unstable rock-mass using specialised explosives. Hoff Geotechnik has developed extensive technical expertise and proprietary systems to safely carry-out these activities in any type of physical condition including snowy and hot regions.
Our range of rockfall scaling or purging systems include:
- Sensitive blasting with low energy explosives
- Hand-barring with gwala and other proprietary equipment
- Barring/purging with gas-bags
- Barring/purging with neumatic jacks
Prepared by
Ernest Rankhododo (MSc. Eng.)
