GEO Brasil - UNEP

state of the subsoil
the state of environment in Brazil
small size enterprises due to illegality, lack of control and
inspection and other random factors, such as end of
commercial activity, which can lead to incorrect figures In
1995, mining was responsible for 753 thousand direct jobs
and 3,2 million indirect jobs In the last 20 years, a reduction
in the employment capacity of the sector and a migration
to the services sector has been observed (Barreto 2001)
According to BRASIL, 1993 (apud Barreto, 2001), there were
400 thousand illegal miners in the country at the beginning
of the 1990s 61 percent of these miners were working in the
Amazon region (Pará and Mato Grosso), 20 percent in the
Midwest, 8 percent in the Southeast, 7 percent in Northeast
and 4 percent in the South The majority (72 percent) were
employed in gold mines, 11 percent in precious stones
mines, 10 percent in diamond mines, 1 percent in cassiterite
mines and 6 percent other
minerals
The mineral extractive industry has
grown considerably recently, with
a mean annual growth rate of 82
percent, observed in the period of
1996-2000 In 2000, it accounted for
85 percent of the GDP (Barreto
2001) The oil sector had an annual
growth rate of 283 percent in the
period between 1997 and 2000,
accounting for 54 percent of the GDP in 2000 (Machado
2002) Thus, the mineral/energy sector is responsible for a
significant part (139 percent) of the Brazilian GDP
Horizonte and Salvador, landslides are frequent, causing
human, material and financial losses
Subsidence (collapse) problems occur in carstic areas with
natural underground caves and in areas of underground
mining, as for example in the carboniferous region of the
south of Brazil Uncontrolled exploration in carbonatic areas
leads to excessive decrease in groundwater level and change
to the hydrologic regime
Mining activities in urban and semi urban areas are also
responsible for subsoil degradation Today, we can easily
observe vast degraded areas neighbouring large urban
centres This is a result of clay, sand, gravel and pebble
extraction activities
Erosion processes can be encouraged if a carefully designed
plan, containing an environmental
renewal element, is not followed
during open-air mining activities
Normally, the openings used for
scouring and/or removing the layer
to be mined can cause severe
damage to the surface of the
ground
The main environmental impacts
of mineral production during
research, mining, processing,
storing or transportation stages are described in Table 1
(Souza 2001)
2 Subsoil Degradation
The misuse of the subsoil can lead to several problems
These result from uncontrolled urban development, mining
activities, environmental liabilities, agriculture, cattle, lack
of technology, pollution of water resources, uncontrolled
use of underground water and the need for improved
legislation, among others
A wide variety of human actions are also responsible for
geotechnical problems (subsidence, landslides and erosion)
that result in soil and subsoil degradation In the coast,
there are problems related to shoreline erosion In hilly urban
areas, such as São Paulo, Rio de Janeiro, Vitória, Belo
21 Environmental Impact of Mining Activities
Charcoal – the water pollution caused by acid draining is
probably the most significant impact of coal mining and
processing activities This is the result of the infiltration of
rainwater that reacts with the waste generated from mining
and processing activities, reaching superficial and/or
underground water sources
Gold Mining - the occurrence of arsenium, a toxic element,
in the auriferous Quadrilátero Ferrífero region in the state of
Minas Gerais (Figure 2, area 40), is worth noting as far as
the environmental impacts of mining are concerned In Nova
Lima and Passagem de Mariana, arsenium oxide plants were
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