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�����$� PHWKRGRORJ\� IRU� LPSDFW� DVVHVVPHQW� DQG�DFRXVWLF�PRQLWRULQJ�RI�TXDUU\�DFWLYLWLHV� F. Asdrubali, G. Baldinelli 'HSDUWPHQW�RI�,QGXVWULDO�(QJLQHHULQJ��3HUXJLD�8QLYHUVLW\��,WDO\�� $EVWUDFW� The work presents a methodology to assess the acoustic impact around extractive areas, the validation of which was made through the study of a quarry situated in Perugia (Italy). A preliminary analysis was conducted to locate sensible areas, to characterize all the various noise sources in the quarry and to determine their contribution to the global acoustic climate. Afterwards, a simulation model for the noise sources in the quarry was implemented: through noise measurements, its reliability was verified. A detailed study on the quarry was therefore carried out, simulating different exercise conditions, corresponding to different noise sources at work in the quarry or to different morphologies during all the quarry life. The model allowed to point out the specific contribution of each source to the global noise, to create different noise maps, to assess the effectiveness of the acoustic mitigations. The reliability of the model was also assessed by a one-year noise monitoring of the area of the quarry. ��,QWURGXFWLRQ� It is well known that quarries and quarry-related activities produce a series of impacts on the environment of remarkable entity, such as changes of the site shape, loss of vegetation, dust particle emission, noise and vibrations. If the quarry is located in an urban area, or in any case close to dwellings, noise and vibration can be perceived by the local community as the most serious impact on the environment, affecting both working activities and night sleep. Assessing the acoustic environment in the area of a quarry can be rather complex: all the activity phases need to be analyzed, from exploitation to the

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morphological re-establishment of the area; a thorough and detailed knowledge of all the various noise sources (jackhammers, buckets, rock crushers, trucks) is necessary; there are changes due to different seasonal activities and to the different site shapes. The paper presents a methodology to assess acoustic impact and monitoring of extractive activities, which was validated in the case of the quarry of Olmo, in the town of Perugia, Italy. The methodology is based both on simulations and acoustic measurements; its accuracy has been verified thanks to a one-year monitoring of the quarry. ���0HWKRGRORJ\�SURSRVHG� The proposed methodology is made of four different steps: a) a preliminary study of the productive stage, aimed to choose the sensitive receptors and to acoustically characterize the noise sources in the area; b) the selection and calibration of the calculation model able to simulate outdoor noise propagation; c) the estimation of noise and the setting up of acoustic maps for the most significant scenarios during the life of the quarry; d) the comparison of the results attained from the model with those supplied by noise monitoring campaigns carried out near the sensitive receptors. The calculation model can also provide useful information as regards mitigation and their efficiency to reduce noise in the quarry area. ����3UHOLPLQDU\�VWXG\� The aim of the preliminary study is to verify the acoustic impact that the quarry has upon the surrounding areas, so to direct and program the following activities (noise mapping and monitoring). In particular, the preliminary study can allow to: - single out the sensitive receptors; - characterize the noise sources in detail; - assess the noise levels along the plant’s perimeter and near the sensitive

receptors present in the area; - detect background noise in the area; - identify the contribution of the sources inside the quarry upon the noise

emitted outside; - provide indications for carrying out acoustic monitoring near the sensitive

receptors. ����6HOHFWLRQ�DQG�YDOLGDWLRQ�RI�FDOFXODWLRQ�PRGHOV� As far as outodoor noise propagation, many models such as ISO 9613-2 [1], [2], BS 5228 [3] or Schall 03 can be satisfactorily used in the case of quarries, eventually adapted in analyzing the problem under investigation.

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ISO 9613-2 assumes noise sources as punctiform; the method contains a series of algorithms to calculate various effects, such as reductions due to divergence, to atmospheric absorption, soil absorption, reflection from the soil and reduction due to obstacles that act as barriers. The Schall 03 model is proposed by the German State Railways as calculation model for sound reduction and propagation of noise produced by railway traffic; in its structure it is similar to the one contained in ISO 9613-2, since it takes into account variations in level produced by barriers, buildings, dense vegetation and the reflection and reverberation due to walls and reflective surfaces. There are also a lot of commercial software and programs which can be suitable to simulate noise propagation. The chosen model has to be first of all adapted to the peculiar characteristics under examination and its reliability has to be verified through suitable measurements. In particular, a few noise measurements can be carried out, under known conditions, close to some sensitive receptors and the measurements results can be compared with the results given by the model. ����1RLVH�HVWLPDWH�DQG�FRQVWUXFWLRQ�RI�DFRXVWLF�PDSV� After validating he calculation model, the simulation phase can be carried out. The simulations have to concern several scenarios, which correspond to just as many operational conditions of the quarry; the simulations allow to: - reduce the number of acoustic measurements carried out in the quarry; - underline the specific contribution of the different sources upon the total noise

of the area under examination; - simulate all the different configurations of the quarry during its cultivation; - evaluate noise close to sensitive receptors and compare it with limitations

imposed by the law; - identify possible acoustic mitigation interventions�and assess their efficacy. �����$FRXVWLF�PRQLWRULQJ�The last phase of the study is the acoustic monitoring of a certain number of sensitive receptors, which is extremely important to check if law limits are exceeded and, at the same time, to verify the accuracy of noise levels predicted by the models. It is important that the monitoring covers the whole exploitation period of the quarry; it has to be repeated in different periods of the year, to include different exploitation phases of the quarry and also to assess fluctuations in the background noise. ��7KH�FDVH�VWXG\�RI�WKH�2OPR�TXDUU\� ����'HVFULSWLRQ�RI�WKH�TXDUU\� The “Olmo” quarry is located in the city of Perugia (Umbria, Italy).

4

The quarry has been in service since 1940; the geology of the area is characterized by some formations of the carbon sedimentary series of Umbria and Marche. Top end esplanade represents the remaining part of the former quarry plane. Quarry bottom esplanade is the location of the rock crusher system and sieve; top end esplanade represents the object of the remaining cultivation; two service routes connect the various areas of the quarry.

�������� �� ���� � � �� ������� � �� �

� � ��� �

�

��� ������� ��� � � ���� ��� ��� �

� ��� � � ! �"#� � � ���

"%$ "'&

Figure 1: Birdseye view of the Olmo quarry������3URGXFWLRQ�F\FOH� The production cycle of the digging activity is aimed at producing calcareous inert material. The final product is obtained by the following work stages: a) excavating and rock crushing, performed thanks to an excavator equipped

with jackhammer; b) loading and transporting: an excavator is used equipped with a self- digging

bucket to unload calcareous material onto trucks; regarding transportation of inert material to the plant or outside the quarry, 2 Fiat dumpers are used with 12 cubic meter loading capacity.

c) rock crushing system, performed through a plant located in the quarry bottom esplanade, which also makes the selection of inert material, mainly made up of a loading hopper, a primary crusher, a primary sieve, a hammer mill and a secondary sieve.

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Figure 2: Jackhammer in excavation

phase Figure 3: Birdseye view of the

crushing plant ����1RLVH�VRXUFHV�According to the production cycle described above, the main noise sources inside the Olmo quarry are: the crushing plant and sieve, the jackhammer, the bucket and passing heavy trucks. In order to attain detailed characterization of the different sources a series of phonometric measurements was taken for each one so to calculate the noise power in dB (A) by considering the direction of the emission. The crushing plant was acoustically analyzed at each single source. The phonometer was placed near the machines. The assumption of the semi-sphere propagation of noise was made; to calculate the source power Lw from the level Lp measured in a point with r distance, the following equation was used:

8log20 ++= U// () � � � � (1)

The assumption was made to assimilate all the machines of the plant into one source, whose calculate emitting power is equal to 113,1 dB(A). The noise measurements taken to acoustically characterize the jackhammer are reported as an example in Table 1; an average noise power of 115,3 dBA was therefore assumed for all simulations. As far as the the bucket, an average noise power of 105,0 dBA was calculated from the measuremtes and assumed for all�simulations.

Table 1: Summary of the measurements to characterize the jackhammer �

Phonometer position Distance Leq(dBA) Noise power

dB(A) Side 8.5 m 88.3 114,9 Front 8.5 m 91.7 118,3 Back 8.5 m 82.3 108,9

Average noise power 115.3

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The contribution of passing trucks to global noise was estimated using SEL. This is used to assess the disturbance caused to the community by short-term noise events, occurring repeatedly throughout the day or in any case within a defined time span, as in the case of the working hours in the quarry.

( ) GW��ORJ��6(/*+

,+

,.-/+01,.- ∫= � � � ���(2)

Where LA(T) is the instantaneous pondered sound level A and the integration extremes, T1 and T2 show the time span within which LA(t) does not fall lower than 10 dB of the maximum level reached in the event. The Leq continuous equivalent level relative to T time, is attained by the following equation:

∑=

=

2

3

43 56 7Q76(/$/HT

1

10/10

)(101

log10),( � � � (3)

ni is the number of how many times the trucks pass by. A semi-cylindrical model was assumed to simulate noise propagation from the road. ����&DOFXODWLRQ�PRGHO�FDOLEUDWLRQ��Schall 03 model was chosen for the acoustic mapping of the quarry area; a few measurements were taken for its validation. The comparison between the calculated noise level and the measured one was made for different working conditions and at different locations that coincided with the�sensitive receptors; a maximum difference of 1.5 dBA was found (table 3). �Table 3. Comparison among the results attained by the SCHALL 03 model and

the phono-metrical measurements.

Condition Leq m (dBA)

Leq c (dBA)

∆L (dBA)

Background noise + crushing plant 47,2) 46,9 -0,3 Background noise + jackhammer bottom esplanade 48,2 49,5 1,3 Background noise + jackhammer on top esplanade 63,9 62,5 -1,4 Background noise + crushing plant + jackhammer on top esplanade 65,0 65,2 0,2

m= measured; c = calculated ���� 6LPXODWLRQV Several simulations were carried out and each one allowed to find the contribution of one or more sources compared to the others. Two illustrations correspond to each simulation; one represents the iso-level curves of noise, the other reports the sections, which allowed determining the geometrical data of

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input for the model; fig. 4 and 5 report as an example the acoustic map due to the sole crushing plant. ����0LWLJDWLRQ�LQWHUYHQWLRQ� In the study case of the quarry of “Olmo” here described, the following noise control interventions were performed: - procedures to follow during the cultivation phase; - deviation of the road segment; - creation of natural barriers; - use of sound proof and absorption panels. ������3URFHGXUHV�GXULQJ�WKH�FXOWLYDWLRQ�Simulations illustrated that R3 and R4 receptors are not affected by the contribution of the jackhammer if it is working in a lower position. The jackhammer can be in fact sound protected from the slope underneath (a 6 m tall rock wall); this procedure, regarding the methodology of exploitation of the quarry is already a mitigation intervention on its own. ������1DWXUDO�EDUULHUV�Two natural barriers were set up near receptor R3: these are soil mounds 2.5m tall and 13-14m long; these barriers were integrated with sound proof and absorption panels to make up a barrier for noise generated by heavy trucks passing by. The acoustic monitoring carried out showed a decrease in R3 receptor of 6 dB (A) after the installation of the barrier.

1

Figure 4: Acoustic map when only the crushing

plant is operating.

8

1

��

Figure 5: Cross section of the calculation grid. �������'HYLDWLRQ�IURP�WKH�URXWH�During the exploitation of the quarry a new road was opened; the trucks were therefore removed from the vicinity of R3 receptor therefore eliminating problems pertaining to this source (fig. 6). The deviation of the road led to a further reduction of 2 dBA in R3. Table 4 summarizes the main results attained through the mitigation interventions and the acoustic improvements for R3 receptor.

1

3

2

5

4

6

8

79

9

R3

Figure 6: Acoustic impact of the new road.

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Procedures during the cultivation

Sound proof and absorption panels and

Natural barriers

Deviation from the route

Ante operam 68,6 dB(A) 66,5 dB(A) 60,6 dB(A) Post operam 66,5 dB(A) 60,6 dB(A) 58,7 dB(A)

Table 4. Reduction in dB(A) attained in receptor R3 thanks to the mitigation interventions. ����0RQLWRULQJ� In order to periodically control the acoustic emissions of the quarry, monitoring campaigns were performed near the sensitive receptors called R3 and R4. Monitoring was carried out by following these criteria: - there were 4 measurement campaigns, one for each receptor, one per season; - each measurement campaign lasted 5 straight days of which 3 workdays, one

Saturday, and one Sunday. This way, the seasonal fluctuations were singled out both of the background noise and the environmental one, in function also of the excavation activities. All the measurements taken have also allowed to: - further check the results found by applying the mathematical model used; - check if the mitigation interventions performed receptor were useful. The results of the monitoring are reported in table 5

Table 5. Results of the acoustic monitoring �

Point LAeq spring

dB(A) LAeq winter

dB(A) LAeq autumn

dB(A) LAeq summer

dB(A)

R3 58,7 60,6 66,5 68,6 R4 53,5 57,5 55,1 57,8

���&RQFOXVLRQV� The aim of this work was to find and elaborate a valid methodology to evaluate acoustic impact and for acoustic monitoring of excavation operations; the methodology proposed was verified in the case of the ”Olmo” quarry in Perugia, Italy. The typology of the productive activity, the particular nature of noise sources, the presence of an urban center near the quarry make this study case particularly interesting from a technical-scientific point of view. The study of this particular productive activity aimed at predicting the noise level in the area surrounding the quarry during the various operative conditions. A preliminary study was initially carried out to find the sensitive receptors, to assess the acoustic characteristics of the noise sources and to determine the contribution of each one inside the quarry area.

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The main noise sources found were: crusher system and sieve, the jackhammer, the self-dumping bucket to load and unload and the trucks used to transport the inert material outside the quarry premises; each section was the object of acoustic characterization. The next phase was the acoustic simulation for which the German SCHALL 03 calculation code was used for sources plotted as punctiform; a classical method with semi-cylindrical propagation was chosen for simulating noise produced by trucks. Both models were adapted to the characteristics of the study case and their reliability was verified through appropriate measurements; the gap between the results found through the mathematical model and the measurements were always less than 1-1.5 dB(A) in all the conditions considered. The simulations concerned several scenarios, which corresponded to the different operative conditions of the quarry and allowed to: - show the specific contribution of the different sources to the total noise of

the area; - find the possible mitigation interventions and assess their efficacy. Along with the modeling phase, acoustic monitoring was carried out near the sensitive receptors in order to periodically check the acoustic emissions of the quarry. Phonometrical measurement campaigns began in the summer of 2001 and ended in the spring of 2002. The comparison of all the data acquired during monitoring and those found through simulations further confirm the reliability of the methodology proposed. ��5HIHUHQFHV���[1] ISO 9613/1994 $FRXVWLFV�� $WWHQXDWLRQ� RI� VRXQG� GXULQJ� SURSDJDWLRQ�

RXWGRRUV���3DUW����FDOFXODWLRQ�RI�WKH�DEVRUSWLRQ�RI�VRXQG�E\�WKH�DWPRVSKHUH. [2] ISO 9613/1994 $FRXVWLFV�� $WWHQXDWLRQ� RI� VRXQG� GXULQJ� SURSDJDWLRQ�

RXWGRRUV���3DUW����JHQHUDO�PHWKRG�RI�FDOFXODWLRQ� [3] British Standard BS 5228, 1RLVH�DQG�YLEUDWLRQ�FRQWURO�RQ�FRQVWUXFWLRQ�DQG�

RSHQ� VLWHV��3DUW����&RGH� RI�SUDFWLFH� IRU� EDVLF� LQIRUPDWLRQ� DQG�SURFHGXUHV�IRU�QRLVH�DQG�YLEUDWLRQ�FRQWURO.

[4] UNI 9884 Acustica, &DUDWWHUL]]D]LRQH� DFXVWLFD� GHO� WHUULWRULR� PHGLDQWH� OD�GHVFUL]LRQH�GHO�UXPRUH�DPELHQWDOH.

[5] Ferrovie Statali Tedesche - Ufficio Centrale delle Ferrovie Statali, 6&+$//���, Munich, luglio 1990