Rock slope surface monitoring technologies with focus on ground-based synthetic aperture radar

The stability of rock slopes in open pit mines is crucial to the safe and efficient operation of a surface mine. When not planned for, rock slope failures can cause injuries, equipment damage or loss, delayed production schedule, and even loss of economic ore. Slope monitoring has emerged as a viable engineering tool to help mine operators better understand rock slope behaviour and response to mining activities and environmental conditions during the life of the mine. This paper presents a state-of-the-art review of slope monitoring technologies with focus on the most recent development of Ground-Based interferometric Synthetic Aperture Radar (GB-SAR). Discrete slope surface monitoring systems such as laser prism surveys and surface extensometers provide very accurate and precise point measurements. The data obtained from strategically placed discrete monitoring systems is generally sufficient to accurately describe simple, local failures. For large scale, complex failures however, monitoring systems that produce full-face scans such as radar are necessary. For the purpose of providing near real-time slope displacement data, the most suitable method is ground-based radar interferometry. High resolution, combined with large area coverage, thanks to the possibility of installing the radar at long distances from the slope, and short scan time, make GB-SAR one of the most effective slope monitoring technologies available today. In this paper, it is shown that the GB-SAR systemis able to timely detect and provide alarms on large scale slope movements for both gentle and steep slopes, as well as local scale movements at bench-scale which is equally important to the safety of mine operators at the work face.