Longwall Mining Subsidence Surveying: An Engineering Technology Comparison.
Proc 5th Int'l Fig Symp Deformation Measurements & 5th Can Symp Univ NB 1988 :298-307
This U.S. Bureau of Mines investigation evaluates and compares conventional and high-technology geodetic surveying systems using a survey grid installed over stable ground with physical characteristics typical of current longwall mine subsidence study sites. The positions of 145 monuments along the grid were measured during a 1-month period by electronic distance meter-theodolite- levels (edm-theodolite), an automatic recording infrared laser tachymeter, a satellite-based global positioning system, aerial photography (photogrammetry), and a prototype inertial surveyor. Statistical analysis indicates that the average three-dimensional displacements from the base (edm-theodolite) for both the tachymeter and photogrammetry were within 0.25 Ft (0.076 M).
Proc 5th Int'l (Fig) Symp. Deformation Measurements & 5th Can Symp; Univ NB, 1988, PP. 298-307