Institut za rudarstvo i metalurgiju Bor

underground water in the first waterbearing
horizon on the surface.If the level
of groundwater, under the influence of
mining areas of open pit, falls, the imperfect
wells will dry (enter only with one
part into water-bearing layer) deepened to
the aquifer water and the zone will of
aeration will become thicker. The movement
of hygroscopic and membranous
water will move in it from top to bottom
and thus drying the soil and mining water.
Lack of water in the surface layer causes a
change of environmental factors for survival
the certain types of flora in the environment
of open pits in the area Cerovo.
The additional disadvantage is also that
the surfaces of open pit funnel pit and
overburden dump because of exposure to
the south and increased insolation - degraded
and deforested areas (too much
light and heat), and lack of atmospheric
precipitation during the vegetation period
(characteristic of the Bor region) to supply
the mining zone with ground water and
lack of water in the soil and ground layer
of air overheating, lag in growth of plants,
and sensitive species are completely disappeared.
Storey flora due to lack of moisture
to dry, and leaves of trees (beech forest)
instead of dark green color, due to
lack of water, takes a yellowish color.
In order to evaluate the belt around the
open pits that will be affected, the scope of
influence the mined areas on environment
is determined using the known formulae
from literature that rely on knowledge the
zone of well action, and radius of action.
Determination of trajectory the impact
zone of open pits on the level of groundwater
in the area of Cerovo
Trajectory curve of free groundwater
level, established after formation of depression
funnels (mined areas of open
pits), is determined in situ by measurements.
However, open pits are in the stage
of design (except the open pit C1 that
needs to be expanded) and trajectory impact
on lowering the level of ground water
of open pits at the Cerovo is estimated
using a formula that was derived according
to professor M. Miljkovic.
To check the range of depression funnel
influence on drainage the underground
water in the vicinity of open pits and possible
impact on flora, it was started from
the fact:
• The final slopes of open pits in
Cerovo cut one or more aquifer horizons,
each separated by impermeable
layers of rocks.
• At the intersection of water bearing
rocks and slopes of open pits, water
freely flows into formed depression
where lowering of ground water levels
appears from the intersecting
point to the waterproof layer.
• Free ground water level within the
waterproof rocks, with removal from
intersecting point, has a position in a
form of depression funnel of drainage
the water bearing rocks.
• The rectangular coordinate system is
set to zero in intersection point of
impermeable rocks and flat of open
pit slopes using the following formula:
K
X = 2 × ln S (m), where:
P
K – filtration coefficient (according to
the estimation of 15 m / day);
X – range of depression impact (m);
P – porosity of rocks (according to the
estimation P = 0.40);
H – height of water column for peak elevation
of 245 m (depth water bearing
horizon to the intersecting point
of open pit slopes with waterproof
rocks H= S for PK CPD; H = 435
m); for PK C1, H=270 m
S – height of water level reduction
(S = H - h),
h – height of benches that can be
flooded is 15 m (bottom of the
open pit), Figure 1.
The average vertical distance from the
bottom of open pit to the estimated level
No 1,2010. 125
MINING ENGINEERING