Measurements of dust concentration were made with the
use of CIP-10 gravimetric dust meters. They allow measuring
the weight of total dust as well as the weight of its respirable
fraction. Dust meters suck the air at a rate of 10 dm3/min and
force its circulation through dust meter filters collecting dust
from air. The dust meters were always suspended on the
longwall shearer close to the cutting drum. The measurement
was taken only during the cutting of solid coal.