asked the Secretary of State for Employment if he will make a statement on the presence of radon gas at South Crofty tin mine, Cornwall, on the investigations that have been carried out and on any interim findings and recommendations.
[pursuant to his reply, 27 March 1980, c. 532]: The Mines and Quarries Inspectorate is aware of the problem of concentrations of radon and its daughter products at South Crofty tin mine and has advised the mine management and workpeople on steps to reduce the concentrations. Much work has been done to improve the situation in the mine.Between 20 and 24 March 1980 a joint survey by the South Crofty mine ventilation officer and specialists from the Camborne School of Mines showed that about one-third of the measurements taken gave indications of levels which, if maintained throughout the year, would moderately exceed the upper exposure level recommended by the National Radiological Protection Board (NRPB) of 4 WLM—working level months—per year. The current Euratom directive on radiological protection specifies an upper exposure level equivalent to 40 WLM per year; this directive is under review. The Health and Safety Executive has recommended that the exposure levels should be kept as low as practicable and should not exceed those recommended by the NRPB (4 WLM per year). Work to improve the ventilation at the mine is proceeding to achieve this end.