62 Robam-Väizene-Anepaio-Kolats-Valgma 2008

5 th International Symposium
„Topical Problems in the Field of Electrical and Power Engineering”,
Doctoral School of Energy and Geotechnology
Kuressaare, Estonia, January 14 – 19, 2008
Measuring mining influence in the form of students practice in
opposition to the emotional environmental impact assessment
Karin Robam, Vivika Väizene, Ain Anepaio, Margit Kolats, Ingo Valgma
Department of Mining, Tallinn University of Technology
karin.robam@ttu.ee
Abstract
Environmental impact assessment of mining
influence is a procedure that involves an analysis
of vibration, noise and drainage water effects on
the environment and effects that attends if
drainage water has been pumped out of mines.
Data for environmental impact assessment,
geotechnological research and teaching comes
mainly from fieldwork measurements, laboratory
analysis and modelling. Measuring is useless
without laboratory analysing and modelling or
processing of the data with modern software. In
addition to analysing and taking into account the
comments new results and conclusions have to be
produced. The purpose of the analysis is to find out
and appraise the positive or negative impact of
mining influence.
Keywords
Fieldwork, environmental impact of mining,
geotechnology, experiments, testing, modelling,
visualisation.
Introduction
Environmental impact assessment base on available
data, which is gathered from fieldwork or laboratory.
In this article is handled environmental impact
assessment through noise, ground vibration, water
velocity, flow and discharge from the mines.
Data is gathered from measurements in the course of
science club fieldworks. The science club of mining
and geology was started in the spring semester of
2006, where the excursions to the phosphorite
grounds in Maardu and to the limestone deposit in
Harku took place to assess the effects of mining
(http://mi.ttu.ee/teadusklubi) [2].
Students are included in fieldworks to make studies
more attractive and interesting. During the
fieldworks students adjust better to the speciality and
it expands the knowledge about using modern
equipment, which increases the quality of student’s
work.
Measuring water velocity, flow and
discharge from the mines
The purpose of measuring water velocity, flow and
discharge from the mines is analysing water quality,
level, and movement that are related to mining [3].
Water velocity is measured by using universal
current meter (Figure 1). Universal current meter
serves to determine the current velocities in water
courses, canals, channels and rivers. It allows to
measure stream flow velocity for using rods or as
cable-suspended meter equipment from 0.025 m/sec
up to 10 m/ and water depth up to three meters. For
each propeller turning one impulse is given [4].
Figure 1 Measuring water velocity (left) with universal Current Meter F1 (right)
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That portion of the channel cross section in which
flow occurs is called active portion and a cross
section where the flow velocity is nonexistent is
called off-channel storage or dead storage. The area
of a channel has to divide into shares according to
profile of channel width. Firstly have to measure the
distance from shore and water depth at various
points across the stream flow to construct a channel
profile. The current velocity meter may be used to
determine a vertical axis of water velocity at several
points across a stream channel.
As a result of surveying distance from the bank,
water depth, current meter depth to water level and
number of propeller rotations are measured and
scheme of the flow is constructed (Figure 2). The
stream flow for the profile is the sum of the average
velocities of each subsection of stream flow times its
cross-sectional area.
0
Streambed width, m
0 0,5 1 1,5 2 2,5 3 3,5 4 4,5
-0,05
Streambed depth, m
-0,1
-0,15
-0,2
-0,25
-0,3
-0,35
Water surface
Universal current meter depth to water level
Streambed
Stream vertical axis
Figure 2 Streambed cross section
Test pumping for evaluating hydraulic
conductivity of the rocks
Submersible pump MP1 (Figure 4) is used for test
pumping. It is specially designed for the purging and
sampling groundwater in boreholes with an internal
diameter of at least 50 mm and the dynamic water
level must not exceed 80 metres. Pumping water out
of boreholes is used to determine the coefficient of
hydraulic conductivity. Pump has to be performed in
several wells where water level will be surveyed. As
the result of pumping water level decreases around
the borehole and depression cone will be developed.
As pumping continues, a cone of depression with its
centre at the pumped well spreads out from well in
all directions. The dimensions of the cone of
depression depend upon the rate of recharge, the
water-bearing properties and extend of the aquifer,
the rate and duration pumping.
If borehole passes through sort of unvaried soil level
the coefficient of hydraulic conductivity (Figure 3)
is calculated with the next formula:
k
2,303Q
1
= log [5]
2 2
π(h 1 + h 2)
r2
r
Figure 3 Determining the coefficient of hydraulic
conductivity
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Figure 4 Testpumping in the abandoned spoils of a strip mine
Monitoring ground and air vibration
Vibration can cause negative effects to the human
health and to the reliability of mining machines.
That is why it is important to keep vibration level
under limited value and control it by carrying out
measuring with vibration monitors. In order to get
most accurate results device should be attached
directly to the object under study. For measuring
vibrations of soil and rock ground under the
vibration monitor should be cleaned and monitor
itself fixed with bolts (Figure 6).
Log shows the results as 4 channels: 3 geophone
channels, 1 microphone channel [6].
According to the graphic of results of vibration
analysis (Figure 5) it is possible to assess vibration
influence.
Figure 6 Positioning monitor towards vibration
source
Figure 5 Results of vibration analysis near
Surface miner milling cutter
Noise measurement
Noise measurement are performed with device TES
1352A. It is used for measuring machine influence
on the environment also noise influence on sanitary
conditions in populated areas and is necessary for
valuating working conditions on mechanical
processing.
Noise is advised to measure from certain distance
like 1m, 5m, 10m etc. Measuring results are store on
the machine memory what can be drawn into the
computer with program called Sound Meter and
processed in appropriate software (Figure 7).
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110
105
Sound level (dB, A)
100
95
90
85
Sound intensity
80
9:59:02 10:01:55 10:04:48 10:07:41 10:10:34 10:13:26 10:16:19
Time
Figure 7 Measuring noise of a hydraulic hammer (left), Noise chart of a surface miner milling (right)
Acknowledgements
Field works and this paper is related to the Estonian
Science Foundation study- Grant No. 6558.
References:
Figure 8 Measuring mining benches, angles and
elevations for understanding the technology
Conclusions
Modern testing equipment and software allows to
produce and evaluate environmental impact of
mining.
Due to measuring water velocity, flow and discharge
from the mines, test pumping for evaluating
hydraulic conductivity of the rocks, monitoring
ground and air vibration it is possible to analyse
mining impact to environment.
The most easy and useful way is to perform the
measurement in the form of science club that has
been successfully started in Mining department of
Tallinn University of Technology.
1. Karu, V. Science club of Mining and
Geology. EU legislation as it affects mining. INFRA
22944 TAIEX workshop. 2006.
2. Karu, V; Pärnasalu, R; Õnnis, A. Science
Club of Mining and Geology as it Affects Higher
Education. Doctoral school of energy and
geotechnology. Tallinn University of Technology
2007
3. Reinsalu Enno, Lind Helena, Valgma Ingo,
Technogenic water body in closed oil shale mines,
Oil Shale, Estonian Academy Publishers, Tallinn,
2006, -
4. Equpiment for water pumping Eijkelkamp.
http://www.eijkelkamp.com [30.10.2007]
5. Jaaniso, V. Soil Mechanics and
Engineering Geology
http://www.tud.ttu.ee/material/epi/Valdo_Jaaniso/Ge
otehnika%20alused/PinmehA.doc [30.10.2007]
6. Vibration monitor
http://www.abem.se/products/vibraloc/Vibraloc.pdf
[31.10.2007]
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