Tracking of surface deformations is typically achieved using periodic measurements of both vertical and horizontal deformations using conventional, Ground Positioning Satellite (GPS), and or photographic techniques. Within the last decade, satellite based methods have also found limited applications over some underground coal mines and commercial applications for open pit mines. In this paper, the authors will review the subsidence monitoring over one of the Colorado operations utilizing precise GPS measurements. This case study will address geologic setting, vertical and horizontal displacements, the influence of topography and gate pillar designs on surface subsidence and fracturing, upon longwall extraction of the Upper D Seam. In addition, we will review the potential use of satellite based, remote sensing methods. InSAR technologies are finding new interest in the U.S. mining industry for (1) investigating the utility of InSAR in discriminating different types of seismic events including underground explosions, natural earthquakes and mine collapses (2) tracking surface subsidence for satisfying permitting requirements and (3) potential use in the area of mine safety. The combination of satellite InSAR imaging and GPS measurements is suggested for enhancing the quality of ground movement analysis including assessment of horizontal deformations and effects on surface resources. Satellite data availability, and the improvements in interpretation and processing tools, are very promising.
U.S. regulations require prediction and tracking surface subsidence resulting from underground mining primarily for environmental requirements. This is typically achieved using periodic measurements of both vertical and horizontal deformations using conventional, Ground Positioning Satellite (GPS), and or photographic techniques. Within the last decade, Satellite based methods have also found limited applications over some underground coal mines and particularly for open pit mines. In this paper, following a review of common subsidence measuring techniques, we will first review the subsidence monitoring over one of the Colorado operations utilizing precise GPS measurements.