RADIOACTIVITY LEVELS AROUND THE JOS TIN MINES AND MILLS
RADIOACTIVITY LEVELS AROUND THE JOS TIN MINES AND MILLS
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Date
1995-10
Authors
RABIU, NASIRU
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Abstract
Cassiterite, the most common tin bearing mineral is associated with a
number of mineral impurities such as monazites, zircon, thorite and
xenotime which contain radioactive U and Th that may constitute
radiological hazard. The interest of this work is therefore to determine
the level of radiological hazards associated with the activities of tin
mining and milling. To this end, 55 samples of soil, minerals, plants
and water collected around the Jos tin mines and mills were analysed for
gross radioactivity using G-M tube and liquid scintillation counter in
the case of water samples. The gross activity of the soils and plant
range from 0.1 - 6.0 Bq/g and that of the water sample range from 0.1 -
0.3 cps. The highest activity was recorded in the monazite waste (95.9
Bq/g) and zircon (77.4 Bq/q) samples. Nine of the soils and minerals
samples that were found to have appreciable activity were subsequently
analysed using 3" x 3" Nal(Tl) detector coupled to a computer and the U
and Th concentrations were determined. The U and Th concentrations range
from 61 - 2042 ppm and 104 ppm to 2.7% respectively. The dose
contribution from the U and Th were then calculated. The doses obtained
were found to be within the maximum permissible dose of 5 rem/yr (50
mSv/yr) for radiation workers except in two cases where doses of 37
rem/yr (370 mSv/yr) and 79 rem/yr (790 mSv/yr) were obtained. But, all
were found to be higher than the maximum permissible dose of 0.5 rem/yr
(5 mSv/yr) for the general population. This makes monitoring around the
tin mines and mills mandatory. However, this will only be possible when
the necessary laws on radiation protection are made by the Government.
Description
Thesis submitted to the Postgraduate School,
Ahmadu Bello University, Zaria,
in partial fulfillment of the award for the degree of
Master of Science in Physics.
Department of Physics
Ahmadu Bello University
Zaria
October, 1993
Keywords
RADIOACTIVITY,, JOS TIN MINES,, MILLS