Responding to a request from Anglo Platinum, 3D Laser Mapping released their first laser-based geotechnical monitoring system ‘SiteMonitor4D’ in 2004.
Designed to monitor and quantify changes to the rock face, SiteMonitor4D will automatically alert mine safety managers via email or SMS when issues arise. Such near real-time warnings enable critical safety-monitoring decisions to be made quickly and efficiently
Since 2004, the range and resolution of commercial laser scanners have improved significantly which means we have the possibility to improve the failure prediction in the SiteMonitor software. 3D Laser Mapping began an innovative research project with Durham University in 2013 exploring the benefits of using rockfall analysis as a predictor of failure.
Based on the results of a project where laser scan data was collected for 100,000 square metres of coastal cliffs over an 8 year period. The resolution of the scan data was 0.01m and the volume of all the rockfalls (small and large) were quantified by volume. The smallest detectable rockfall was 0.00001 cubic metre of rock.
This project showed that the mean monthly rockfall activity (total volume of rock falling out of the face) is directly correlated to the size of the final failure. In addition, it can be seen that in the month before a significant failure, the total rockfall volume for that month increases significantly.
The reason for this correlation can be explained in geological terms. Rockfalls are caused by differential strain and deformation of the rock mass. This can coincide with the evolution of a brittle fracture. If a fracture starts to develop that daylights on the rock face, then the increasing stress at this point will cause rockfalls. As the fracture develops, the strain deformation at the rockfall will increase causing rockfalls. Eventually this increases exponentially, leading to larger rockfalls and subsequent failure of the rock face.
Currently, most monitoring and failure prediction in the mining industry is undertaken by radar systems which focus on the detecting small scale movements of the whole rock face. This is appropriate in some circumstances but the monitoring method should be decided by the geotechnical environment. Using rockfall as a predicitor may be more appropriate in some environments and this will be a useful tool for the geotechnical engineer.
Rockfall analysis is available as part of the SiteMonitor 4D software suite and is already deployed in the mining industry.
Using SiteMonitor4D with the new Rockfall Analysis feature allows you to have a clear view of the stability and changes of mass within a slope, allowing you to plot the monthly rockfall activity against time. (See slide 19 of ‘SiteMonitor4D Slideshare) This advanced visibility allows you to take action before a critical situation, allowing for increased safety.
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Notes to Editors:
3D Laser Mapping is a world leading provider of laser scanning technology. We offer solutions that capture 3D data and then process this data to deliver information for making decisions.
Headquartered in Bingham, near Nottingham in the UK, the company employs over 35 highly trained, specialist staff. We achieve global reach through our branch offices in South Africa, USA and Australia as well as our network of international distributors.
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3D Laser Mapping is proud to serve our hundreds of customers which include mining companies, governments, academic institutions and blue-chip owners & operators of assets such as highways, power lines, railways and buildings to name but a few.