ABSTRACT
A B S T R A C T : The paper presents measurement results of speed of roof rock separation for three
selected headings protected with various types of support, i.e. individual roof bolting, combined
system of prop support and roof bolting, and prop support. The measurements were carried out for
a period of dozen to several dozens of months. Separations were recorded with the use of low and
high multilevel telltales as well as extensometers. Speed of separations was determined in relation
to the time of measurement. Recording separations for a long period of time allowed for an esti-
mation of stability of the analysed workings as well as for relating movement of roof layers to va-
rious types of support applied in their construction.
