Table 3

 Dust concentration and prevalence of PTB by current job title

Current job titleMean respirable dust (mean respirable quartz)nPTB on historyPTB on history or radiograph
(both in mg/m3)n (%)n (%)
Driller0.48 (0.075)9425 (27%)43 (46%)
Winch operator0.48 (0.065)7318 (25%)28 (38%)
Team leader0.35 (0.054)539 (17%)21 (40%)
Underground assistant0.34 (0.048)11115 (14%)31 (28%)
Crew supervisor0.27 (0.038)537 (13%)16 (30%)
Loco operator0.25 (0.038)6111 (18%)18 (30%)
All six jobs0.37 (0.055)44585 (19%)157 (35%)