Characteristic Colliery A Colliery B
Use of respiratory protection equipment Slightly > national average Significantly < national average
Dust Levels Not excessive over last 10 years but some increase last 10-years Dusty
Places of Work   Most of those affected had worked in geological faults & cutting through stone may have led to increased quartz exposure
Mining methods   Recent introduction machinery to cut through rock previously removed by explosives requiring removal of miners when firing, & lower exposures.
Working hours Cases worked longer than non-cases & standard work week. Work week time doubled in extreme cases & 7 days/wk, 12 hr shifts common. Considered most significant factor leading to increased CWP incidence in collieries A & B.  
Table 2: Main findings from focused investigation on Collieries A and B [17].