As a mine grows and more areas are opened up, in-situ stresses in the rock mass will adapt to the changing conditions and are often concentrated around excavated areas. This phenomenon can lead to a progressive deformation of backs, ribs or sills in underground mine- an effect often referred to as excavation convergence.
While slight movements, including convergence, can occur naturally in mines, significant amounts of convergence can indicate a situation developing that has the potential to threaten the safety of mine personnel, damage equipment, and disrupt operations – leading to productivity losses or much worse.
For many underground mines, ongoing convergence monitoring is vital to ensure that the mine remains safe and optimally productive. The data yielded from this practice is used by engineers to proactively spot potential risks while they are still manageable, and then make the decisions necessary to deal with the situation.
Traditionally, convergence monitoring has been performed using manual measurements using distometers or even simple measuring tape. Some larger and more modern mines complement these manual measurements using technology such as instrumented rock or cable bolts, stationary LiDAR scanners, or a combination of these devices.
While all this equipment does yield results and may continue to be used where the situation warrants it, mining engineers also now have another, highly efficient option: mobile convergence monitoring achieved by using a mobile LiDAR (laser) scanner.
Unlike installed instrumented bolts and range-finding devices that only measure and produce data at a specific point, as well as static scanning that takes a long time and requires equipment to continually be disassembled, moved, and reassembled, mobile convergence monitoring allows for whole areas to be scanned easily, quickly, and accurately. This allows mine engineers to have a wealth of rapidly obtained information at their fingertips, helping them make better decisions faster. This solution has enabled some of the largest mines in the world to collect convergence monitoring data for entire extraction levels in a fraction of the time of traditional methods, and with greatly reduced human exposure.
The uGPS Rapid Mapper™ mobile 3D underground laser scanner is rugged, easy to maintain and use, and purpose-built for use in underground mines, making it the ideal device with which to perform mobile convergence monitoring.