Institut za rudarstvo i metalurgiju Bor

low water permeable, hydrothermally altered
and mineralized rocks with cracks.
The cracking aquifers, that are solely fed
on the account of water from atmospheric
precipitations, are present in these rocks.
According to the surveys, the groundwater
levels in the deposits in the area of
Cerovo are connected to the fractured aquifers,
hydrometeorological conditions,
terrain morphology and degree of rock
mass cracking. The surveys have found
that the groundwater levels are at 3-10 m
below ground surface.
The deposit parts above the local erosionbase
are characterized by relatively
small amounts of groundwater. Greater inflow
of ground water is expected at open
pits under the elevation of local erosion base
when there is infiltration of surface water.
THE EFFECT OF LOWERING THE
GROUND WATER AT OPEN PITS
ON FLORA IN THE VICINITY
According to the structure, the aquifers
on Cerovo are of fractured type because they
are found in cracks and fractures of solid
impermeable rocks. Water permeability of
those tocks depends primarily on nature and
extent of cracks through which the movement
of groundwater is according to the law
of linear gravitational filtration. The movement
of underground water can be directed
towards the Earth surface, if they are present
in aquifers under the hydrostatic pressure,
particularly expressed in sections of various
cracks. These pressures can be connected to
the emanation of gases and temperature
higher than 100 ° C, which is characteristic
for active or relatively extinct volcanic areas.
The aquifer of fractured type is characterized
by discontinuous aquifer zone or
zone of saturation with free ground water.
They are fed by infiltration of precipitation
in surface aquifers, surface and ground contact
with the surface of the basin as the local
erosion base. The amount of water in aquifer
primarily depends on the area of spreading,
feeding zone and discharge zone, collecting
area and thickness of aquifers.
The aquifers with free level are formed
on the waterproof rocks in loose, usually
quaternary and neogenetic sediments, but
also in cracked and classified geological
environments. They have wide distribution
in the nature. Smaller accumulations
of ground water could occur in the zones
of aeration in lenses or inter-layers of impermeable
rocks when the floating and
false aquifer is formed.
The zone above the free level of aquifer
up to the surface including the mining
belt, is called the over-aquifer or aeration
zone. The thickness of this zone depends
on relief and climatic conditions. Trees are
supplied with water and nutrients through
roots in this zone. In the area of aeration,
some kinds of water and movement of
water could occur, as follows:
• In a form of vapor from rocks of
higher humidity in the direction of
rocks of less humidity,
• Hygroscopic (in a from of vapor at
t>100 0 C) and membranous water
(adsorption force of particles with
thick membrane in the direction of
particles with a light membrane),
• Gravity free water in the zone of
aeration (infiltration of surface water
and atmospheric deposits under the
influence of capillary and gravity
forces),
• Gravity water in the zone of saturation-infiltration
(through the pores,
cracks and caverns).
The exploitation of copper ore deposit
in the area Cerovo leads to the formation
of depressions (funnels), thus lowering the
level of ground water around open pits.
Ground water under the depression curve
at the open pit is static and does not move,
while the water on boundary of depression
funnel and aeration zone is moved.
Horizontal distance, between the intersections
of open pit slopes and point
where depression curve is connected to
the static level of groundwater, is called
the radius of funnel effect on the level of
No 1,2010. 124
MINING ENGINEERING