Radioactivity in Surface Soils Around the Proposed Sites for Titanium Mining Project in Kenya

M K Osoro,M J Mangala,I V S Rathore,A O Mustapha

doi:10.4236/jep.2011.24053

M K Osoro, M J Mangala + Show 2 more

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https://doi.org/10.4236/jep.2011.24053

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Abstract

Radioactivity measurements were carried out around Maumba and Nguluku villages, two of the proposed sites for titanium mining in the coastal area of Kenya. Samples of surface soils were analyzed using a HPGe gamma spectrometer. The average activity concentrations for 226 Ra, 232 Th and 40 K are 20.9  7.6, 27.6  9.1 and 69.5  16.5 Bqkg –1 , respectively. The absorbed dose rates in air, calculated on the basis of the measured activity concentrations, range from 9.8 to 50.0 nGyh –1 , with an average of 29.2 nGyh –1 . These values are below the global population-weighted mean, and they should be considered when planning appropriate monitoring and surveillance programmes during the mining operation, as well as the reclamation and restoration programmes after mining.

Highlights

The ambient natural background radiation is usually of little or no radiological concern, and it varies from one location to another depending partly on the local geology
Mining results in large volumes of materials containing natural radionuclides – the so called naturally occurring radioactive materials (NORM). This is not restricted to uranium and thorium ores, it is true for other raw materials like heavy mineral sands, phosphate rocks, etc
According to the mining company, the proposed operations will involve clearing the vegetation, removing and stockpiling the topsoil for further use in rehabilitation process, excavation of the dunes using bucket wheel excavators or scrapers and, transportation of the ore-bearing sand to the wet plant where the heavy minerals will be separated from sand

Summary

Introduction

The ambient natural background radiation is usually of little or no radiological concern, and it varies from one location to another depending partly on the local geology. Mining results in large volumes of materials containing natural radionuclides – the so called naturally occurring radioactive materials (NORM). This is not restricted to uranium and thorium ores, it is true for other raw materials like heavy mineral sands, phosphate rocks, etc. Tiomin Resources Inc., the Canadian mining company, discovered vast deposits of titanium in the coastal area Kenya [3]. According to the mining company, the proposed operations will involve clearing the vegetation, removing and stockpiling the topsoil for further use in rehabilitation process, excavation of the dunes using bucket wheel excavators or scrapers and, transportation of the ore-bearing sand to the wet plant where the heavy minerals will be separated from sand. It is estimated that mining activities in each of the two sites will take seven years

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