Assessment of Blast-Induced Ground Vibrations in Kangal Coal Mine Of EÜAŞ
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Assessment of Blast-Induced Ground Vibrations in Kangal Coal Mine Of EÜAŞ
E. ARPAZ1, K. GÖRGÜLÜ2, Y.S. DURUTURK2, Ö. UYSAL*3,
A. DEMİRCİ2, M.K. DİLMAÇ4, A. KOÇASLAN2
1
Kocaeli University, Kocaeli Vocational School, Kocaeli, Turkey
2
Cumhuriyet University, Faculty of Engineering, Department of Mining Engineering, Sivas, Turkey
3
Dumlupınar University, Faculty of Engineering, Department of Mining Engineering, Kütahya, Turkey
4
Atatürk University, Oltu Faculty Of Earth Sciences, Department of Mining Engineering, Erzurum, Turkey
ABSTRACT
Several large-scale mines and quarries are being planned at the present times, in order to supply the demand to
raw materials both from the economical and technical point of view. That the machineries installed in these
mines and quarries produce in high capacity utilization ratio and large amount of explosives are necessary to be
consumed unless the material is mined without blasting.
Within the context of this research work several site operations have been carried out in order to model the blast-
induced ground vibrations in open pit coal mine in Kangal. To this end 10 blasting activities for overburden
removal have been carried out and the related parameters have been measured with 7 devices. During the
operating, 69 vibrations have been recorded.
The data obtained from these measurements have been assessed on the basis of particle velocity components and
the site coefficients for every component have been determined.
Key Words: Blast, Ground vibration, Blast induced vibration, Blast vibration prediction
1. INTRODUCTION
The blasting operation is an irreplaceable necessity for many engineering works such as mining, construction,
quarrying, dam and tunnel construction. On the other hand, some problems such as ground vibrations, air cannon
and flying rocks come up as a result of the blasting operation. These factors become an important problem
especially for the operations performed near the residential areas. In recent years, the fair or unfair complaints
about the blasting operation have become one of the most important problems of the technical staff (Felice,
1993; Özdemir et al., 2004; Tuncer et al., 2003; Uysal et al., 2004). For this reason, it is necessary to consider the
solutions of the possible environmental problems in addition to technical and economic factors such as
fragmentation degree, size distribution and cost while determining the blasting conditions. The measurement and
estimation of the blast-induced parameters are of great importance in order to prevent the environmental
problems (Arpaz, 2000).54
In this study, the peak value of the blast-induced ground vibrations (PPVT, PPVV, PPVL, PVS and PPV), which
was measured by a series of the field surveys in Electricity Generation Company (EÜAŞ) Kangal Coal Mine
Enterprise was assessed by using the distance (spacing) and amounts of charge per delay and the field constants
that will be able to be used in controlled blast techniques were determined.
2. WORKING FIELDS
The study was conducted in Electricity Generation Company Kangal Coal Mine Enterprise. The enterprise is
located at approximately 100 km southeast of Sivas, 25 km south of county of Kangal, in the vicinity of
Kalburçayı. In the close vicinity of the enterprise, there is a thermal power plant that Electricity Generation
Company Directorate General (EÜAŞ) established in close vicinity of the county of Kangal.
The blasts are shots for loosening the upper layer of the coal. The formation consists of a rough detrital level
consisting of gravels at the bottom, and continuing with sandstone and clay stone respectively and a carbonous
pile with 30-60 m thickness that starts with silt and clay and continues upwardly with coal, clay and marn
lithology. Bore holes are in 14 m length and 250 mm diameter in average. The thickness of burden and the
spacing between bore holes can range between 8.55 and 13.7 m. ANFO is used as explosive, power gel dynamite
is used for priming and nonel capsule is used for firing.
3. FIELD SURVEYS AND ASSESSMENTS
Within the context of the field surveys, the blast-induced vibrations in EÜAŞ Kangal Coal Mine Enterprise were
observed. For this purpose, 10 shots performed during the stripping activities between the dates 31 March-6 June
2011 were measured by 7 blast seismographs and 69 values of data belonging the blast vibrations were recorded
triaxially (longitudinal, latitudinal and vertical) (Table 1). The frequency range of the peak particle velocity to be
used for the controlled blasting techniques was analyzed and their distribution was determined (Table 2, Fig 2).
The values of the scaled distance (SD) and peak particle velocity (PPV) accepted by many researchers were
taken into account when the obtained data were being assessed. The scaled distance is a value that takes the
distance between the blasting point and measuring point and maximum amount of the explosives per delay into
account, and it is calculated with the following formula.
R
SD = (1)
W
Here;
SD : Scaled Distance (m)
R : Distance between the blasting point and measuring point (m)
W : Maximum amount of explosives per delay (kg)
The following equation developed by United States Bureau of Mines (USBM) and used commonly was used to
predict peak particle velocity (PPV) (Dowding, 1985).55
PPV = k * ( SD) − β (2)
Here;
PPV : Peak particle velocity (mm/s)
K and β : Coefficient for the blast design and field geology.
The obtained data were assessed within the framework of the Regulation Regarding Evaluation and
Management of Environmental Noise which was finalized in 2010 and is in effect now in Turkey. The chart
regarding the evaluation is seen in Fig 1.
Fig 1. Turkish Republic Regulation Regarding Evaluation and Management of Environmental Noise
Table 1. Results of the measurements
Charge Particle Velocity
Event Distance
per delay Transverse Vertical Longitudinal Resultant Maximum
No (R)(m)
(W) (kg) (PPVT) (PPVV) (PPVL) (PVS) (PPV)
mm/s mm/s mm/s mm/s mm/s
1 270 140 23.5 22.2 27.6 29.9 27.6
2 270 271 17.4 18.7 17.4 19.3 18.7
9 225 232 17.7 14.5 13.5 18 17.7
10 200 330 5.46 9.91 7.24 10.8 9.9156
Table 2. Frequency distributions
Frequency range PPV
Number %
1-4 11 16
4-10 33 48
10-30 10 14
30-100 15 22
Fig 2. Frequency distributions
When the distribution is analyzed, it is seen that the frequency of the peak particle velocity intensifies between 4
and 10 Hz. For this reason, it is seen that the value of 19 mm/s for this enterprise, which is in the range of 4-10
Hz stated in the regulation can be taken as an allowable particle velocity value.
The obtained data were evaluated on the basis of the peak particle velocity and the field constants were
determined (Fig 3).
−1.27
R
PPV50% = 724.63 * r 2 = 0.70 (3)
W
−1.27
R
PPV95% = 1391.77 * (4)
W 57 Fig 3. The change of the particle velocity components against scaled distance The field constants obtained from the assessments belongs to 50% regression line and the use of the prediction interval (95%) equation in the controlled blast designs will carry the designs to a safer point. For this reason, the use of the prediction interval (95%) equation in designs was deemed suitable. A chart was prepared for use in practical calculations by using the obtained equation and that shows the changes of the estimated peak particle velocity values depending on distance-explosive amount per delay (Fig 4). Fig 4. The estimated peak particle velocity against distance and maximum amount of charge per delay
58 4. RESULTS AND SUGGESTIONS The blast-induced ground vibrations are one of the important subjects for complaints in sectors such as mining and construction which require rock excavation by blasting. For this reason, to get these problems under control is one of the fundamental aims in the applications of the controlled blast techniques. For this purpose, the vibration data values of at least 30 shots are generally obtained and the field constants for 95% prediction interval are determined by using peak particle velocity values. Then, the amount of explosive per delay is limited according to the distance between the building to be affected and shooting point by using these field constants. In this study, it was aimed at getting the ground vibrations under control with the controlled blasting techniques in EÜAŞ (Electricity Generation Company) Kangal Coal Mine Enterprise. For this purpose, the magnitudes (PPVT, PPVV, PPVL, PVS and PPV) of the blast-induced ground vibrations obtained from a series of the field surveys were measured. The obtained peak particle velocities (PPV) were evaluated by using the amount of charge per delay and distance (scaled distance), and the field constants to be used in the controlled blasting techniques were determined. In addition, the frequency values, one of the important damage criteria, were analyzed by considering the legal regulations in Turkey. As a result of this analysis, intensity between 4-10 Hz range for peak particle velocity was observed. Accordingly, the allowable peak particle velocity was determined to be 19 mm/s. In the light of all these evaluations, a practical chart that can be used in the enterprise to get the blast-induced ground vibrations under control was prepared. 5. ACKNOWLEDGEMENTS This study was supported by TÜBİTAK (The Scientific and Technological Research Council of Turkey) with the project numbered 110M294. Authors separately thank employees of EÜAŞ (Electricity Generation Company) and Demir Export.
59
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