Table 3 Dust concentration and prevalence of PTB by current job title.
| Current job title | Mean respirable dust (mean respirable quartz) | n | PTB on history | PTB on history or radiograph |
|---|---|---|---|---|
| (both in mg/m3) | n (%) | n (%) | ||
| Driller | 0.48 (0.075) | 94 | 25 (27%) | 43 (46%) |
| Winch operator | 0.48 (0.065) | 73 | 18 (25%) | 28 (38%) |
| Team leader | 0.35 (0.054) | 53 | 9 (17%) | 21 (40%) |
| Underground assistant | 0.34 (0.048) | 111 | 15 (14%) | 31 (28%) |
| Crew supervisor | 0.27 (0.038) | 53 | 7 (13%) | 16 (30%) |
| Loco operator | 0.25 (0.038) | 61 | 11 (18%) | 18 (30%) |
| All six jobs | 0.37 (0.055) | 445 | 85 (19%) | 157 (35%) |