Dust concentrations in coal drivages and bord and pillar workings

Results from dust sampling trials in coal drivages and bord and pillar workings are reported.Data from trials at two collieries during pillar formation work involving simultaneous mechanised getting and loading operations suggest that on average the dust concentration near the machine operator is 1.4 times the mean of concentrations near the machine and loader operators.Experiments in 16 coal drivages indicate that spatial variations in dust concentrations, in both exhaust and forced ventilation conditions, are determined by the local arrangement of ventilation systems and by geological constraints peculiar to each particular drivage. There is no evidence from the data that it is possible to generalise about systematic differences in concentrations depending on sampling position.The derivation of appropriate operational dust standards is discussed in the light of the results.