Radionuclide and mineralogical studies of kimberlite slime and soil samples obtained from the jwaneng diamond mine area, Botswana

Abstract

The -ray spectroscopic and x-ray powder diffraction (XRPD) techniques were applied to study concentrations of three naturally occurring radionuclides: 40K, 238U and 232Th and mineral contents in various types of soils and kimberlite slime samples obtained from Jwaneng diamond mine area, Southeastern Botswana. The distribution of the radioactive elements was observed to be uneven due to varying mineralogical compositions of samples. Quartz was the predominant mineral phase in all the samples. Whereas phlogopite, kaolinite, illite, calcite and smectite occurred in minor quantities, lizardite, talc and halloysite were in trace amounts. The annual dose level for the Jwaneng mine was calculated and found to be 0.012 mSv/yr. This baseline is still below the limits given as 50 mSv/yr and 1 mSv/yr recommended by boththe US National Council on Radiation Protection and Measurement (NCRP) and the International Commission on Radiological Protection (ICRP) for workers and members of the public respectively. However, inhalation of mineral dust particles by both workers and inhabitants of the area may constitute health hazards leading to silicosis and related illnesses. Preventive occupational health measures in the mine are continually advised to remain implemented.


(Botswana Journal of Technology: 2002 11(2): 39-45)