Pneumoconiosis Field Research: Environmental conditions at Cynheidre Colliery 1977-1980. Compositional results

This addendum lists the results of the analyses of the airborne dust samples taken at Cynheidre Colliery 1977-1980, which were not available in time for the Technical Memorandum TM/81/16.The ash and quartz concentrations, which have fallen over the period, have mean overall values of 1.10 mg/m3 and 0.15 mg/m3 respectively. The other measured constituents of the dust also show a tendency to decrease although the annual mean coalface respirable dust concentration rose from 2.2 in 1976/77 to 3.2 mg/m3 in 1980/81.