Measurement of displacement for open pit to underground mining transition using digital photogrammetry

The newest digital photogrammetric technology is applied to investigate the deformation characteristics of rock mass when it changes from open pit to underground mining. First, the calculation formulas of pixel deformation and instrumental error were derived. Based on this, the calculation of digital camera calibration were obtained and used to calibrate the physical model for rock mass undergoing the changing mining process. Finally, the deformation characteristics of rock mass were revealed based on a geotechnical engineering of Daye iron mine and the monitored results of digital photogrammetry were compared with the dial indicators. It was found that the surface deformations measured by digital photogrammetric technique are similar to the results using dial indicators. The maximum error between these two was less than 0.02 mm. These tests demonstrate the efficacy of digital photogrammetry as a powerful technique for deformation measurement in the geotechnical model tests.