The challenge
A single radar can't see in 3D
Slope-deformation radar monitors are now widely used in open-cut coal mining, to monitor highwall and low-wall deformations.
Since the introduction of this technology, there’s been better management of risk associated with slope failure, protecting both workers and equipment. However, a well-recognised problem is that radar monitors only measure deformation that is facing towards the detector (line-of-sight bias).
This bias can lead to misinterpretation of deformation size, rate and failure mechanism, and therefore miscalculation of failure volume, which can significantly impact safety and productivity.
Current methods to compensate for the bias make potentially inaccurate assumptions about the deformation vector relative to the wall/slope orientation.
Using multiple slope monitors to observe the same region of highwall or low wall can address this problem.
However, due to the expense associated with deploying multiple monitors for the one zone, this is rarely done.
Often, only a single monitor is available at a given site.
Our response
Computer vision + radar = more information
We integrated a computer-vision system with an existing slope monitor and made high-precision tracking of the field of view possible.
By combining assumptions on the deformation characteristics, the true deformation vector was then able to be estimated.
The system used the existing radar measurements, a camera and software, making it much more cost-effective than buying or renting multi-radar monitoring systems.
This approach also ensured much more accurate monitoring than was previously possible with a single radar unit.
This method clearly detected 3D deformation vectors, which were consistent with both an understanding of the failure mechanism as well as previous measurements undertaken using a dual-radar system.
The results
Superior slope monitoring
We undertook an Australian Coal Industry Research Program (ACARP) supported project to field test and quantify the performance of a prototype system which could deliver a low-cost solution to slope-deformation monitoring in open-cut mines.
We successfully demonstrated the innovative fusion of vision and radar data could achieve at least millimetre precision at a range of around 500m and anticipate much greater ranges can be supported with high-quality optics and suitable conditions.