<title>Slope stability radar for monitoring mine walls</title>

Abstract

Determining slope stability in a mining operation is an important task. This is especially true when the mine workings are close to a potentially unstable slope. A common technique to determine slope stability is to monitor the small precursory movements, which occur prior to collapse. The "slope stability radar" has been developed to remotely scan a rock slope to continuously monitor the spatial deformation of the face. Using differential radar interferometry, the system can detect deformation movements of a rough wall with sub-millimeter accuracy, and with high spatial and temporal resolution. The effects of atmospheric variations and spurious signals can be reduced via signal processing means. The advantage of radar over other monitoring techniques is that it provides full area coverage without the need for mounted reflectors or equipment on the wall. In addition, the radar waves adequately penetrate through rain, dust and smoke to give reliable measurements, twenty-four hours a day. The system has been trialed at three open-cut coal mines in Australia, which demonstrated the potential for real-time monitoring of slope stability during active mining operations.

Experimental results of a ground-based interferometric SAR

“…Recently, a new type of SAR system, the ground based interferometry SAR (GB-InSAR), has demonstrated its effectiveness in applications as detecting displacement of large structures, monitoring landslides mine highwall stability, and rapid topographic mapping, etc [1]- [4]. The most critical performance requirement for the GB-SAR system is the deformation measurement accuracy achieving up to millimeter, and even sub-millimeter.…”

“…This brings specific characteristics and problems to both the radar system and the signal processing technique. Firstly, stepped frequency continuous wave (SFCW) instead of other wave is preferred in GB-InSAR [1][2][3][4][5]. Secondly, the atmospheric effect cannot be neglected, despite of the much shorter distance of observation compared with satellite radar [6][7][8][9].…”

A review of terrestrial radar interferometry for measuring surface change in the geosciences

“…those related to campaign timing and look directions) that are known from satellite SAR interferometry (Rudolf et al, 1999;Reeves et al, 2001;Aguasca et al, 2004;Werner et al, 2008). This adaptation also allowed the correction of limitations in the technique (e.g.…”

“…This adaptation also allowed the correction of limitations in the technique (e.g. those related to campaign timing and look directions) that are known from satellite SAR interferometry (Rudolf et al, 1999;Reeves et al, 2001;Aguasca et al, 2004;Werner et al, 2008). While satellite-based radar interferometry provides large spatial coverage and high precision for detecting surface change, orbit-related limitations prevent successful operations in some cases.…”

Monitoring systems for warning impending failures in slopes and open pit mines

“…In general, these systems are capable of continuous monitoring movement with high accuracy (0.1-0.2 mm) over medium to large areas in real time without the need for mounted reflectors or equipment on the slope. Furthermore, the measurement is minimally affected by rain, dust, or smoke (Reeves et al 2001;McHugh et al 2006;Hutchison and Widelski 2007). The most common devices and methods of Subsurface displacement measurement are inclinometers, extensometers, acoustic emission, and time-domain reflectometry.…”