Traditionally convergence measurement is performed by
measuring tape or laser rangefinder. More sophisticated solution is to create a convergence station where measurements
are performed not only between points within one profile, but
also between different profiles. Neither of these methods, it is not as comprehensive as convergence measurements by
using a laser scanner. Convergence monitoring was focussed
on part of the tailgate impacted mainly by additional stress
from an unmined left pillar in overburden seam No. 3 (see
Fig. 1). Cases where the scanned area is in the immediate vicinity of the coal face, have not been found from any available
sources.