Measurement of radon concentration forassessment of the radiological hazard in theChakwal coalmines of the Salt Range, Pakistan

Abstract

Radon and its progeny are prevalent everywhere on the lithosphere especiallyin the mining environment. Coal exists in the Salt Range that passes throughPakistan. The aim of the present study was to measure radon concentrationand assess the associated radiological hazard in the coalmines developed inthat portion of the Salt Range which passes through the district of Chakwalin Pakistan. Among the various coalmines in the coalfield, five were selectedfor radon survey. A passive integrated technique consisting of SSNTDs (solidstate nuclear track detectors) was employed for the measurement of radonconcentration in these coalmines.Box type dosimeters containing CN-85detectors were placed for three months at six locations in every selectedcoalmine. After removing the dosimeters, the CN-85 detectors were etchedin alkaline solution to enlarge the alpha tracks in the detectors and countedunder an optical microscope. The track densities were converted to radonconcentration. The average concentration of radon in the coalmines varied inthe range 50–114 Bq m−3. Radon exhalation rates from the samples of coaland shale collected from the coalmines were determined to be respectively934 (830–1010) and 1302 (1020–1580) mBq m−2h−1. The radiation dose andcorresponding health risk for the mine workers were also estimated