Size distribution of airborne dust produced by the drilling process

The aim of this work was to investigate the size distribution of dust particles produced during the drilling process. It has already been proved that the degree of harmful effect of inhaled dust is closely related with dust particle size. The dust data needed to determine size distribution were obtained by sampling dusty atmospheres during the drilling process with a short-period thermal precipitator.

Drilling and dust sampling processes were carried out in a model gallery which simulated the working face. Rock samples used in drilling were brought from the various galleries of Kozlu mines, Zonguldak Colliery. The tests were carried on four types of sandstones, two types of shales and conglomerate, in total seven types of sedimentary rock. For each type of rock six dust samples were taken and evaluated.

It is concluded that the frequency distribution of airborne dust particles produced by each rock type is approximately lognormal. The geometric mean values of dust particles for sandstone, shales and conglomerate are found to be 0.89, 0.95 and 0.83 μm respectively. In other words, the mean value of dust particles produced during the drilling operation of different rocks are around 1 μm in diameter, which has the maximum probability to be retained in the lungs during respiration.