04-07-2013, 02:01 PM
Environmental effect of mineral exploitation in Nigeria
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ABSTRACT
The three stages of mineral development, viz exploration, mining and processing, have caused different
types of environmental damages, which include ecological disturbance, destruction of natural flora and
fauna, pollution of air, land and water, instability of soil and rock masses, landscape degradation and
radiation hazards. The environmental damage has in turn resulted in waste of arable land, as well as
economic crops and trees.Since much of the damage is inevitable, if the minerals must be developed,
both the government and the mineral industry must be involved in taking precautionary and remedial
measures that can minimize the ill-effects of mineral development. Emphasis should shift from waste
disposal to waste minimization through sorting, recycling of reagents and water. While the government
should provide the regulatory legislation with appropriate sanctions, the mineral-producing companies
are expected to carry out mandatory precautions, remedies or compensation for the damage done.
INTRODUCTION
Exploitation of mineral resources has assumed prime
importance in several developing countries including
Nigeria. Nigeria is endowed with abundant mineral
resources, which have contributed immensely to the
national wealth with associated socio-economic benefits.
Mineral resources are an important source of wealth for a
nation but before they are harnessed, they have to pass
through the stages of exploration, mining and processing
(Adekoya, 2003; Ajakaiye, 1985). Different types of
environmental damage and hazards inevitably accompany
the three stages of mineral development. It is the
purpose of this paper to present in a nutshell the negative
effect on the environment of the activities involved in
harnessing the minerals in Nigeria. An attempt will also
be made to examine the possible precautions and remedies
that can be applied in order to mitigate the effect of
adverse environmental impact of mining activities.
Air, land and water pollution
Varying degrees of pollution of air, water and land occur
in the course of mineral development depending on the
stage and scale of activities attained. While only minor
pollution occurs during mineral exploration, more intense
air and water pollution emanates from the exploitation
stages, particularly if carried out on a large scale. In
Nigeria, the greatest pollution effect comes from a largescale
exploitation of petroleum, limestone and rocks used
in the construction works (Unesco-Mab, 1995).
In the oil-producing areas of the country oil spillage of
differing intensity resulting from burst pipelines, tanks,
tankers, drilling operations, etc. is a common phenomenon.
It causes water and land pollution with grave conesquences
on both aquatic and terrestrial life. For example,
fishes living in surface waters are killed as a result of
which fishermen in such areas have lost their means of
livelihood. Groundwater pollution has made it impossible
for the indigenes of the affected Niger Delta areas to
obtain potable water. Well water is almost invariably
covered with a thin oil film.
Ecological disturbance
Another adverse effect of mineral extraction and processing
activities, which may not be immediately felt, is the
disturbance of the ecosystem with possible adverse
consequences on the floral and faunal community in
general. For example, the deforestation of an area during
the mine development may cause the elimination of some
plants and the exodus of some animals that feed on such
036 Int. J. Phys. Sci.
plants or depend on them for cover, from the affected
area. Similarly, the noise generated in the course of blasting,
quarrying and crushing can also frighten away part
of the fauna in a mining locality.
Oil spillage produces a devastating ecological disturbance
in the oil-producing states as well as in areas
where leakage occur due to natural breakage of oil pipe
line or illegal bunkering (Aigbedion, 2005). The plants,
animals, soils and water are affected. As mentioned
earlier, the vegetation may suffer degradation and eventual
death. Some of the animals, especially fish and other
aquatic life, as well as small terrestrial animals particularly
those that feed on fish or lower plants, may die for
lack of food or from contamination with the oil spillage,
which normally spread rapidly. The soil gets soaked in oil
and water is covered with oil. Consequently the ecosystem
suffers not only disequilibria but also pronounced
degradation with dire consequences on the food chain
(Adepelumi et al., 2006).
Degradation of natural landscape
A common negative effect of mining minerals from the
earth’s surface is the destruction of its natural landscape,
creating open space in the ground and generating heaps
of rock wastes that cannot be easily disposed off. These
phenomena are amply demonstrated in several parts of
Nigeria, where commercial mining or quarrying had occurred
in the past or is currently taking place.
In the Younger Granite Province, especially the Jos
Plateau, tin and columbite mining has resulted in the
destruction in places of the scenic landscape which is
replaced by unsightly large irregular holes and heaps of
debris produced by the opencast method of mining
(Brooks, 1974). The alteration of the landscape almost
invariably creates a problem of erosion in the mining
localities with the result that most of the opencast pits are
filled with water. A similar situation exists in all the
limestone and marble quarries in differing proportions at
Ewekoro, Sagamu, Nkalagu, Gboko, Ashaka, Kalambaina,
Okpilla, Jakura, etc. In many localities, particularly
near centres of heavy construction works (road and
building), large granite and gneiss inselbergs with their
delightful scenic view are now being pulled down to produce
rock aggregates e.g. at Abuja, Abeokuta, Ibadan,
Ilorin, Minna, Kaduna, Kano, Bauchi, etc.
Conclusion
Extraction and processing of mineral resources is the
backbone of the national economy in many developed
and developing countries of the world. However, the
great danger poised by mineral exploitation such as
abandoned sites, biodiversity damage, use of hazardous
use of chemicals with potential health risk to mine workers
and neighborhood communities deserved urgent
attention. Emphasis should shift from waste disposal to
waste minimization through sorting; recycling of regents
and water. Safe disposal of unavoidable waste in stable
and aesthetically acceptable structure must be enforced
through legislation