Small scale mining is when a group of people come
together with an idea to search for an area rich in minerals to mine it (Hilson,
2001). Small-scale mining brings several benefits to some countries mainly in
the form of employment and revenue but simultaneously impacts negatively on the
natural environment. Small-scale
mining is usually common in areas that are rich in gold, bauxite and diamonds.
However, Ntibrey (2015) found out that most small-scale miners popularly engage
in gold mining. Gold is one of the world’s most cherished and expensive minerals
found in the natural environment and hence people use any means to extract it.
This has become a major environmental issue in areas which are rich with these
minerals especially Ghana and some parts of Africa and Asia (Hilson, 2002).
It is estimated that globally more than 12-15 million
miners including 4 million women and over 1 million children are involved in
small scale gold mining (International Labour organization (ILO), 2013).
According to Tschakert and Singha (2007) about 84% of the total labour force in
the mining sector operates without an official license.
The extraction of
gold releases cyanide, arsenic trioxide and Sulphur dioxide into the
environment (Hilson, 2001). The small scale illegal miners also add heavy metals
like mercury in their operations. According to Malm (1998) the use of cyanide
and mercury in the process of gold mining has become a major concern for many environmental
scientists and economists because these substance returns to the environment
later as harmful pollutants.
The aim of this
paper is to discuss some environmental impacts and policies in the small-scale
mining industry by reviewing some literatures.
DIRECT IMPACT OF MINING ON THE ENVIRONMENT AND IT’S
INDIRECT EFFECT ON AGRICULTURE
Surface mining is the process of removing the
vegetation of a place using heavy equipment to mine the mineral. The land
degradation occurs when this process creates pits and deep holes in the mine
sites (Ntiamoah, 2000). One
major environmental impact of small scale mining is land degradation (Hilson,
2002). This is mainly due to the method used in the operation. According to (Aryee
et al., 2003; Hilson, 2002) the method involves ploughing trenches, upturning
of vegetation and clearing of huge expanses of forest, these activities leaves
the land bare which can leads to land erosion. The potential mine sites are
mostly stripped bare of the vegetation and topsoil (Kessey et al., 2013).
The cutting down
of trees for mining leads to
deforestation. Iddrisu and Tsikata (2015) explains how deforestation
can lead to the loss of top soil through wind and increased water erosion. They
argued that, the forest has the potential to hold more water and the trees can
prevent sediments runoffs. So, when it rains, the rainwater can stay on the
leaves and evaporates into the atmosphere, the leaves decrease the impact of raindrops on the soil which causes
less soil erosion. The roots of the trees also help to absorb water from
the soil and makes the soil drier to absorb more rainwater. The roots in the
forest also hold the soil in place, reducing the movement of sediment which can
reduce the capacity of the river downstream from breaking its banks. Ricardo
and Hersilia (2004) suggests that deforestation in the forest causes a rapid runoff
of rainwater and increasing flooding during rainy seasons due to the inability
of the soil to hold the water. This flooding has destroyed most crops in farms
posing a serious risk on food insecurity.
A 2015 report by the Global Forest Resource Assessment
(GFRA) suggests that, the annual rate of deforestation in Ghana between the year
1995 and 2015 is assumed to be at a rate of 136 384.86 ha. According to Schueler
et al. (2011) Surface mining alone account for 57% deforestation in Ghana and about
45% of farmlands has been lost within mining concessions
Another impact of small scale
mining activities is the destruction of lakes and streams. Water is essential
for life (drinking, washing, cooking and crop irrigation). Illegal small-scale mining has been identified as a
major factor affecting the availability of quality water through the discharge
of mercury and other substances into streams and rivers, this has led to the
coloration of such waters. Other studies (Aryee et al., 2015; Maponga & Ngonma,
2003) suggests that, the reckless use of the mercury has contributed extremely
to the pollution of rivers and streams within these areas thus rending them
unusable for domestic and aquatic life. Again,
most small-scale miners usually operate along the banks of rivers thus
destroying the river banks and making them prone to overflows after heavy rains
(Aryee et al., 2015).
Hilson (2002) argues that the
physical, chemical and biological make up of rivers that serves as habitat for
some aquatic organisms such as fish has been disrupted by the illegal small-scale
miners. This is due to the diversion that has been made on the streams to make
way for the mining activities. Sediments are eroded into the water when it
rains thus disrupting the reproductive life cycle of these aquatic organisms.
Eventually, some of these species are lost through extinction to a new habitat.
This further affects fish production annually
The toxic chemicals which ends up in the water bodies
has affected the quality and quantity of rivers for crop irrigation (Aryee et
al., 2015). According to Hilson (2002) many farmers relies on this water bodies
for irrigation during the dry season for high yields, but the quality of this
water ends up affecting the crop production. Lombe (2003) argues that most food
crops have been contaminated with heavy metals.
Agricultural farm lands have largely been destroyed through
mining and has thereby reduced the availability of farm lands for agricultural
activities and subsequently increasing shortages of food and other agricultural
produce (Global Forest Resource Assessment (GFRA), 2015).