Assessment of occupational radiation exposure in underground artisanal gold mines in Tongo, Upper East Region of Ghana.

Assessments of radon and gamma radiation levels were carried out in underground artisanal gold mines in Tongo. This is one of the numerous artisanal gold mining communities in Ghana. Solid State Nuclear Track Detectors (SSNTDs) were used to estimate the mean (222)Rn concentration and dose rates during the Harmattan season (November 2010 to February 2011). The values for the (222)Rn concentration at each monitoring site ranged from 14 ± 4 Bq m(-3) to 270 ± 9 Bq m(-3), with a mean value of 98 Bq m(-3). These measurements are well below the lower action level of 500 Bq m(-3) recommended by ICRP for workplaces. The activity concentrations of (40)K, (232)Th and (238)U were determined using gamma-ray spectroscopy method. The effective dose estimates of 0.11 ± 0.02 mSv y(-1) to 0.68 ± 0.04 mSv y(-1) were below the allowable limit of 20 mSv per annum for occupational exposure control recommended by the ICRP. The total annual effective dose varied from 0.22 ± 0.04 mSv y(-1) to 1.92 ± 0.08 mSv y(-1).

Radiation exposure control from the application of nuclear gauges in the mining industry in Ghana.

The use of nuclear gauges for process control and elemental analysis in the mining industry in Ghana, West Africa, is wide spread and on the increase in recent times. The Ghana Radiation Protection Board regulates nuclear gauges through a system of notification and authorization by registration or licensing, inspection, and enforcement. Safety assessments for authorization and enforcement have been established to ensure the safety and security of radiation sources as well as protection of workers and the general public. Appropriate training of mine staff is part of the efforts to develop the necessary awareness about the safety and security of radiation sources. The knowledge and skills acquired will ensure the required protection and safety at the workplaces. Doses received by workers monitored over a period between 1998 and 2007 are well below the annual dose limit of 20 mSv recommended by the International Commission on Radiological Protection.