21.   When finely ground coal dust is injected into the mixture it burns more quickly and with less pollution.

22.   Campaigners claim deposits of coal dust released into the atmosphere are a health hazard.

23.   Campaigners claim deposits of coal dust released into the atmosphere are a health hazard and a nuisance.

24.   But nothing comes smoothly, and as the band nearly reaches its goal Danny succumbs to a festering lung problem brought on by years of breathing coal dust.

25.   Coal dust dances in the flatland winds.

26.   In Beijing and other Chinese metropolises ordinary people have been driven to riot by pollution ranging from incessant noise to choking clouds of coal dust.

27.   It is a town of hidden shafts and abandoned pits, a treacherously hollowed-out place where the class struggle takes place amid swirling clouds of coal dust.

28.   Now he stands beside the wreckage wearing an incredulous expression, his cheeks streaked with oil and coal dust and silvery beads of sweat.

29.   On Sundays the church was crowded with scrubbed parishioners, the men with their eyes still ringed black with coal dust.

30.   Opportunities abound, yet coal miners would rather choke on coal dust than change their location or occupation.