Chapter 7: Noise and Vibration - Rio Tinto Simandou

Simandou SEIA Volume II Rail Chapter 7: Noise and Vibration

7-1

7 Noise and Vibration 7.1 Introduction This chapter presents an assessment of the impacts of the Simandou Railway on the acoustic environment. It considers the effects on people (1) and property of noise and vibration during construction and operation of the railway including the impacts of blasting during construction of tunnels. Potential sources of noise and vibration during construction will include clearing and grubbing of the railway corridor, earthmoving, trackbed formation, tracklaying, erection of bridges, construction traffic and tunnel blasting. The principal source during operation will be train operations with minor emissions from fixed facilities such as the railhead yard. Vibration from sources other than blasting has been considered but is judged unlikely to cause adverse impacts as vibration from construction equipment and trains typically only causes significant impacts at distances up to 50 m. Following clearance, there will be no buildings within the construction corridor of 60 m either side of the railway centreline, and as such significant impacts from vibration are not predicted to occur during either construction or operation (tunnel blasting is considered separately). The remainder of the chapter is structured as follows: Section 7.2 describes the assessment methodology; Section 7.3 presents the baseline conditions; Section 7.4 presents the assessment of impacts from the railway prior to mitigation; Section 7.5 describes the planned approach to mitigation and the resulting residual impacts; and Section 7.6 provides a summary of the assessment. Supporting information is provided in the following annexes: Annex 7A - Noise and Vibration Glossary;

Annex 7B - Noise and Vibration Impact Assessment Criteria and Methodology: this annex provides

background to the development of the criteria used for evaluation of impacts including a review of current guidance and legislation, codes and policies used to identify project specific noise and vibration criteria for the Simandou Project and description of the methods used to predict noise and vibration levels; and

Annex 7C - Noise Design Assumptions and Source Data: this annex presents Project data including

design parameters and assumptions relevant to noise emissions, from which source terms have been developed for the purpose of the assessment.

As some of the terminology used in noise assessment is technical in nature a brief introduction to some key terminology is provided below. More details are provided in Annex 7A: Noise and Vibration Glossary.

An Introduction to Noise Terminology dBA: Environmental noise levels such as noise generated by industry, construction and road traffic are

commonly expressed in dBA or A-weighted decibels, Decibels are units of sound measured on a logarithmic scale. This means that a step of 10 dB represents a ten-fold increase in intensity or sound energy. The A-Weighting scale is a standard weighting of the audible frequencies designed to reflect the response of the human ear to noise. To the typical human ear an increase of 10 dBA actually sounds slightly more than twice as loud.

LAeqT: Time varying noise sources are often described in terms of statistical noise descriptors. LAeq (the

(1) The responses of animals (eg mammals and birds) to noise and vibration can differ from those of people and the effects of noise on species is therefore discussed in Chapter 11: Biodiversity.


7-2

equivalent continuous A-weighted sound pressure level) is a value that, simply expressed represents the average sound level over a period of time. The period of time (T) may be daytime hours (say 12 hours from 0600 to 1800), night time hours (12 hours from 1800 to 0600), all day (24 hours), or any other relevant period.

LA90T: this is an alternative statistical descriptor calculated as the sound level exceeded for 90% of the time. For a noise environment with a fairly steady background noise level on which occasional noisy events are superimposed (such as occasional passage of trains through a rural area) it simply expressed, represents the background noise level. Other percentile values are used to present different aspects of the noise environment such as LA95T and LA10T.

LAmax: this is the maximum sound pressure level recorded during a measurement period.

7.2 Approach 7.2.1 Study Area The assessment study area is defined as the area within which people could be adversely affected by noise and vibration from construction or operation of the railway. Initial scoping identified that noise from construction and operation could be perceptible up to 1 000 m away. This is therefore defined as the study area for the noise assessment. The general distribution of settlements located within this area has been identified from 2003 aerial photography in each of the nine sections of the railway as shown in Figure 7.1. A total of approximately 490 settlements are located within this area, excluding those currently within the 120 m construction corridor that will be relocated as a result of occupation of land for the Project (see Chapter 18: Land Use and Land-Based Livelihoods for further information on land acquisition, resettlement and compensation). These settlements range from single houses to large villages. There are no larger towns located within 1 000 m of the railway. It must be noted that the identification of settlements along the full alignment has been done from remote data only and the actual numbers and locations may have changed since these data were gathered. However, as the final details of the alignment is still to be confirmed it is not considered appropriate at this stage to identify individual settlements that could be affected. The data are therefore used to provide an indication of the likely scale of impact on settlements using the available information. This is considered to provide an adequate representation of the expected degree of impact at this stage in the development of the scheme. More detailed studies will be undertaken once the horizontal and vertical alignment of the railway is finalised, to predict actual noise levels in individual settlements and to design location specific mitigation as required. 7.2.2 Legal and Other Requirements There are no national standards or guidelines for noise and vibration or blasting in Guinea. In the absence of national standards the assessment has therefore made reference to a range of guidelines including the World Health Organization Guidelines for Community Noise. A review of noise and vibration regulations, standards and guidance from other countries has also been conducted to inform the development of evaluation criteria. Details are provided in Annex 7B: Noise and Vibration Impact Assessment Criteria and Methodology. The following Rio Tinto Environment Standard has also been taken into consideration: E6 – Noise and Vibration Control.


7-3

7.2.3 Prediction of Impacts 7.2.3.1 Construction Noise Bruel & Kjaer’s Predictor V8.01, noise modelling software has been used to calculate noise emissions from construction activities utilising the methods identified within British Standard BS5228 (1). Further details of the methodology are provided in Annex 7B: Noise and Vibration Impact Assessment Criteria and Methodology. As the nature and duration of construction activities will vary along the route and during the construction timeframes, a number of scenarios have been assessed as set out in Table 7.1. Table 7.1 Construction Scenarios and Expected Duration

Scenario Duration Operating Period

Clearing, earthworks and grading Short Term (<1 month) Daytime

Laying of ballast and track, tamping Short Term (<1 month) Daytime

Bridge construction Medium Term (1 – 6 months) Daytime

Blasting of tunnels and cuttings Long Term (> 6 months) 24 hrs / day

Construction traffic serving the various areas of construction activity will create intermittent noise on public roads. The impact of construction traffic was assessed using the Calculation of Road Traffic Noise methodology recommended by the United Kingdom Department of Transport in the Design Manual for Roads and Bridges (DMRB) (2). Existing levels of traffic on the roads used by construction vehicles are expected to be low or very low in most cases, given that there are few major settlements and little existing industry in the region, however exact numbers of existing vehicles are not known. 7.2.3.2 Blasting Impacts Airblast and ground vibration levels from blasting during tunnelling have been predicted using the methodology outlined in the ICI Blasting Guide. Further details are provided in Annex 7B: Noise and Vibration Impact Assessment Criteria and Methodology. 7.2.3.3 Operational Noise Noise from railway operations has been predicted using SoundPLAN noise modelling software utilising the Nord (3) calculation method to calculate average (LAeq) and maximum (LAmax) noise levels. These data are used to estimate the numbers of settlements that will be affected by different levels of noise from trains. The model takes into account the number of trains, the mix of wagons and locomotives, and the speed of trains. Further details are provided in Annex 7B: Noise and Vibration Impact Assessment Criteria and Methodology. The modelling does not take into account details of the vertical alignment of the railway or the surrounding topography as these are not available at the present time. This is considered to provide a conservative approach as, where the railway will operate in a cutting, the noise levels in the surrounding area will be lower than predicted. Where the railway is elevated (by more than about 2 m above ground level), noise levels will be slightly higher than those predicted but the increase would typically be less than 2 dB. The modelling was conducted based on the following parameters for the railway:

(1) BS5228:2009 Noise and Vibration Control on Construction and Open Sites

(2) Available at www.dft.gov.uk/standards/dmrb (3) NORD (1996) - Railway Traffic Noise - Nordic Prediction Method. Tema Nord: 1996:524, Nordic Council of Ministers.


7-4

the railway will carry approximately nine loaded and nine empty trains per twenty four hour period (eighteen movements) and approximately 32 500 tonnes of product per train;

each train will consist of up to 240 wagons with up to six locomotives with a total length of 2 823 m,

configured with two locomotives at the front, middle and rear of the train and two rakes of 120 wagons in between (2 - 120 - 2 - 120 - 2);

the maximum train speed is 100 km/h; and each locomotive will have a 4 400 horsepower diesel engine, six axles (21.6 tonnes per axle) and a

length of 22.3 m. Noise source levels are based on actual measurements from a similar Rio Tinto operation which reflects realistic in-service track and vehicle conditions rather than new track. 7.2.4 Evaluation of Impacts 7.2.4.1 Overview As discussed in Section 7.2.2 there are no Guinean standards or guidance for noise and vibration and reference is therefore made to international sources. All receptors are considered to be of equal sensitivity and receptor sensitivity is not therefore considered in the analysis. 7.2.4.2 Evaluation of Construction Noise Impacts A review of international standards and guidelines for construction noise is presented in Annex 7B: Noise and Vibration Impact Assessment Criteria and Methodology. These sources establish noise limits for construction noise at the façade of residential buildings ranging from 35-55 dBA at night to 65-75 dBA during the daytime. IFC General EHS Guidelines also provide guidance on acceptable noise levels based on WHO standards and these are set out in Table 7.2. Table 7.2 IFC / World Bank Noise Level Guidelines

Receptor

Maximum Allowable Ambient Noise Levels, LAeq,1hr, dBA Free field

Daytime Night-time

07:00 – 22:00 22:00 – 07:00

Residential, institutional, educational 55 45

Industrial, commercial 70 70

Source: IFC General EHS Guidelines Table 1.7.1

Based on these standards and guidelines, criteria for evaluating the significance of construction noise impacts are set out in Table 7.3. Different thresholds are set for day time and night time, and according to the duration of the impacts on the basis that short term noise (<1 month) will cause less impact than medium (1-6 months) or long term (>6 months) noise. Additionally, a threshold for critical noise impacts is established at an LAmax of 85dBA as this is a well-established level at which hearing damage can start to occur.

KISSIDOUGOUFORÉCARIAH

BE YL A

GUÉCKÉDOU

K É R O U A N É

CO YAH

F A R A N A HK I N D I A

K A N K A N

D A B O L ADALABAP I T ATÉLIM ÉLÉ K O U R O U S S A

D U B R É K A

MA C EN TA

M A M O U

S i e r r aS i e r r aL e o n eL e o n e

L i b e r i aL i b e r i a

Heremakono

BalziaCentre

BanankoroKouankan

Moribadou

ManfranBanankoro

Moribaya

Mamouroudou

BoussouraHeremakono

Baténafadji 1

DouakoBeindou

Banankoro

Banankoro

SibiribaroMamouroudou

Mamouroudou

Komodou

Soromayah

Niala

PassayaVillage

Heremakono

Sérédou

VasérédouWatankaCentre

Dandaya

Babila-Centre

Douako-Centre

Kérouané

Faranah

Banankoro

Binikala Moribadou

BanankoroAlbadariah

SangardoDamaro

Nionsomoridou

KounsankoroBenty

Farmoréah

DandayaTassendi

Souguéta

MolotaCentre

Kolente

Friguiagbé

Tassendi

SanouyaYomayaLimban

Sikhourou

MambiaCentre

Kindia

Marella

BangouyaCentre

Soya

KégnékoCentre

Madina-Oula

Forécariah

Mamou

OuréKaba

Kounkouré

Moussayah

Soyah

Boussoura

Macenta

Tokounou

Douako

Mamouroudou

DantiliyaBanankoro Sonkonia

Heremakono

Mamouroudou

Hérémakono

Guéckédou

N.1

N.10

N.29

9°0'0"W

9°0'0"W

10°0'0"W

10°0'0"W

11°0'0"W

11°0'0"W

12°0'0"W

12°0'0"W

13°0'0"W

13°0'0"W

10°0

'0"N

10°0

'0"N

9°0'0"

N

9°0'0"

N

100000

100000

200000

200000

300000

300000

400000

400000

500000

500000

1000

000

1000

000

1100

000

1100

000

Client: Taille: Titre:Légende:Section de voie ferrée numéro / Rail Section Number

1 2 3 4 5 6 7 8 9

Agglomération dans 1000m / Settlement within 1000mAgglomération / Settlement

Chef lieu de préfecture / Prefecture Chief TownChef lieu de sous-préfecture / Sub-Prefecture Chief TownAutre agglomération importante / Other Significant SettlementRoute principale / Primary RoadLimite de la préfecture / Prefecture BoundaryFrontière entre états / National Boundary

File:

0131

299S

iman

douG

IS_IG

_CK\

Maps

\ERM\

Noise

\Rail

\May

2012

_revis

ions\r

w_rec

eptor

s_wit

hin_1

km.m

xd

Date: 02/07/2012

Vérifié par: RL

Projet: 0131299Dessiné par: WB

Approuvé par: KR Echelle: Comme barre d'échelle

Figure 7.1Zones habitées situé à 1 km de la ligne médiane de chemin de fer / Settlements Within 1km of the Railway Centreline

0 50

kilomètres

Projection: WGS 1984 UTM Zone 29N

A4

G u i n e aG u i n e a

M a l iM a l i

S i e r r aS i e r r aL e o n eL e o n e

G u i n e a - B i s s a uG u i n e a - B i s s a u

S e n e g a lS e n e g a l

L i b e r i aL i b e r i a


7-6

Table 7.3 Evaluation Criteria for Construction Noise at Dwellings (façade levels)

Operating Period

Daytime Noise Level, LAeq dBA Night time Noise Level, LAeq dBA All

Periods LAmax

Impact Rating

Not Significant

Minor Moderate Major Not

SignificantMinor Moderate Major Critical

Short term exposure

< 1 month <70 70-75 >75-80 >80 <55 55-60 >60-65 >65

> 85 Medium term exposure

1- 6 months <65 65-70 >70-75 >75 <45 45-55 >55-60 >60

Long term exposure

> 6 months <55 55-60 >60-65 >65 <45 45-50 50-55 >55

7.2.4.3 Evaluation of Blasting Impacts International standards and guidelines for airblast and vibration have also been reviewed to establish criteria for assessment of impacts from blasting. Details are presented in Annex 7B: Noise and Vibration Impact Assessment Criteria and Methodology. The resulting criteria are set out in Table 7.4. No distinction is made between minor and moderate impacts because of the nature of impacts from blasting and the response of receptors. Table 7.4 Criteria for Evaluation of Impacts from Blasting

Period Airblast dB(Z) 95 percentile Vibration PPV mm/s 95 percentile

Significance Not

Significant Minor /

Moderate Major Critical

Not Significant

Minor / Moderate

Major Critical

Daytime <115 >115-125 > 125-140 > 140 <2 >2-5 > 5-10 > 10

Night time <105 >105-115 >115-140 > 140 <1 >1-2 >2-5 > 5

7.2.4.4 Evaluation of Operational Noise Impacts With respect to operational noise impacts, the World Health Organization Guidelines for Community Noise provide the following generic guidance concerning nuisance effects from noise. To protect the majority of people from being seriously annoyed during the daytime, the sound pressure

level on balconies, terraces and outdoor living areas should not exceed 55 dB LAeq for a steady, continuous noise. To protect the majority of people from being moderately annoyed during the daytime, the outdoor sound pressure level should not exceed 50 dB LAeq.

At night, sound pressure levels at the outside façades of living spaces should not exceed 45 dB LAeq and 60 dB LAmax, so that people may sleep with bedroom windows open. These values are obtained by assuming that the noise reduction from outside to inside with windows partly open is 15 dB.

A review of railway noise standards and guidelines from other countries has also been undertaken and is discussed in Annex 7B: Noise and Vibration Impact Assessment Criteria and Methodology. These sources establish limits for railway noise at the façade or residential buildings ranging from 45 to 65 dBA at night and from 55 to 70 dBA during the day.


7-7

These sources have been used to determine the criteria for evaluation of noise impacts from the operating railway set out in Table 7.5. As with construction, an LAmax of 85 dBA is established for critical impacts. Table 7.5 Evaluation Criteria for Railway Operational Noise at Dwellings (façade levels)

Operating Period

Daytime Noise Level, dBA

LAeq, Period

Night time Noise Level, dBA

LAeq, Period All

Periods

Impact Rating Not

Significant Minor Moderate Major

Not Significant

Minor Moderate Major Critical

Operational Railway

<55 55-60 >60-65 >65 <50 50-55 >55-60 >60 > 85

Because the railway is an intermittent source with trains passing only on average every 80 minutes, the criteria are based on the noise contribution from the railway and do not account for the baseline which is assumed to be a generally quiet rural noise climate. 7.3 Baseline The baseline noise environment along the railway is generally assumed to be a quiet rural noise climate but this was confirmed by monitoring undertaken at ten locations along the railway corridor identified in Table 7.6. Measurement locations were chosen on the outskirts of settlements to capture the baseline noise level without it being unduly affected by localised sources such as people, vehicles or animals. Monitoring was undertaken on a continuous basis over a 24 hour period during February 2008 (the dry season) with an integrating precision sound level meter of type 1 per ICE 651 standard (1979). The meteorological conditions were typical of the dry season, with a high ambient air temperature and low humidity in day time and high at night. The wind was not sufficient to have any impact on the noise measurements. The baseline data were analysed to calculate hourly LAeq and LA95 parameters. It will be noted that the baseline survey data were analysed to provide the LA95 rather than the more usual LA90 background noise parameter. As the monitoring and analysis was complete by the time of this assessment, it was not possible to reanalyse the data to provide LA90 but a standard correction of 1 dB was applied to convert LA95 to LA90.

The results are summarised in Table 7.6. The ambient noise environment is generally quiet and typical of rural locations. Reported noise sources included people, wild birds, insects, livestock and trucks, and in some locations blacksmithing, music and background traffic. In the majority of cases noise levels were higher during the daytime than at night as a result of human activities during the day, however, at one location, Soyah, the night time noise level was higher than daytime, due to insect noise and birds. This is considered to be generally unrepresentative of the characteristics of the wider railway corridor.


7-8

Table 7.6 Noise Monitoring Locations

Location Coordinates UTM 29N Hourly Level in Calm Period, dBA

Easting Northing Day (7h00-22h00) Day (7h00-22h00)

LAeq, 1hr LA95,1hr LAeq, 1hr LA95,1hr

Simandou to Mamou

Korela 503869 954961 41 30 37 26

Moribiendou 505786 970638 45 34 32 26

Wassako 495898 1021097 41 30 30 26

Kédjandou 493066 1022067 44 34 36 25

Gamara 320621 1093483 43 37 40 38

Gbanhouria 315832 1097893 39 31 33 29

Mamou

Soyah 174329 1139010 36 31 49 41

Margabanta 174557 1138028 39 30 33 22

Mamou to Coast

Doto 733032 1045866 44 33 36 29

Moussayah 735714 1047007 44 38 37 33

Source: Social and Environmental Baseline studies 2008

7.4 Assessment of Impacts 7.4.1 Overview This section presents the results of an assessment of impacts from: noise during construction (Section 7.4.2); blasting during construction (Section 7.4.3); and noise during operation (Section 7.4.3). It should be noted that the process of initial route optimisation included the application of a range of avoidance criteria that have reduced the number of settlements potentially affected by noise from the railway during both construction and operation. Further details are set out in Chapter 3: Alternatives. 7.4.2 Noise Impacts during Construction

7.4.2.1 Overview This section addresses the impacts of construction on noise levels from: short and medium construction activities involving work over weeks and months; longer term construction activities during tunnelling; and construction traffic. 7.4.2.2 Short and Medium Term Construction Works This section assesses the likely noise levels and the total number of potential impacts at all settlements within 1 000 m of the railway over the construction period. Modelling has focussed on the noisiest works which are expected to occur during the earthworks and track laying phases. Impacts are assessed against criteria for daytime noise as normal construction work will be undertaken only during the daytime working hours.


7-9

Figure 7.2 shows the distances from the railway centreline at which significant impacts are predicted to occur during short (< 1 month) and medium term (1-6 months) construction activities. The numbers of identified settlements within the distances for short term impacts in each section of the railway are presented in Table 7.7. Similar estimates are not provided for medium or long term construction activities as these will be much more restricted in their distribution. Table 7.7 Numbers of Settlements Potentially Exposed to Significant Noise Impacts during Short

Term Construction Activities (Daytime)

Rail Section Minor Impacts

(150-200 m) Moderate (85-150 m)

Major (30-85 m)

Critical (0-30 m)

1 6 3 0 0

2 0 0 0 0

3 3 0 0 0

4 9 1 0 0

5 7 1 0 0

6 0 0 0 0

7 0 0 0 0

8 0 0 0 0

9 0 1 0 0

Total 25 6 0 0

These data suggest that up to of the order of about 31 settlements could be affected by significant short term noise impacts with 80 % experiencing minor impacts, and the remaining 20 % experiencing moderate impacts, and none being close enough to experience major or critical impacts. The sections where most impacts are expected are in Sections 4, 5 and 1. These have the highest concentration of population alongside the rail corridor as illustrated in Figure 7.1. These impacts will occur over only a few days or weeks as construction passes by settlements. Where larger structures such as river and road bridges are being constructed this will take several months and settlements near these locations will experience significant impacts at greater distances because of the longer duration, as illustrated in Figure 7.2. Examination of the area around the fixed facilities at the railhead yard and the indicative location for the midpoint servicing facility indicates that there are no settlements within distances of these locations that could experience significant impacts from construction noise. At this time it is not possible to identify settlements near other structures but they will be identified during further studies to be undertaken prior to start of construction and appropriate mitigation will be planned as described in Section 7.5.2.

50m

50m100m

200m

300m

400m

500m

600m

700m

800m

1000m

900m

1000m

900m

800m

700m

600m

500m

400m

200m

300m

100m30m - 85m

85m - 150m

150m - 250m

> 250m

30m - 170m

170m - 300m

300m - 500m

> 500m

Taille: Titre:

Dessiné par: WB Approuvé par: KR

Projet: 0131299

File:

0131

299S

iman

douG

IS_IG

_CK\M

aps\E

RM\N

oise\R

ail\M

ay20

12_re

vision

s\rw_

signif

icanc

eofim

pacts

_con

struc

tion.m

xd

A4Impacts critiques / Critical impacts

Impacts majeures / Major impacts

Impacts modérés / Moderate impacts

Impacts mineurs / Minor impacts

Pas significative / Not Significant

Figure 7.2Importance des impacts présentés en fonction de la distance au ligne médiane de la voie ferrée (Construction) / Significance of Impacts Presented as Distance from the Rail Centreline (Construction)

Date: 04/07/2012 Vérifié par: RL

Ligne médiane du tracé de la voie ferrée /

Centreline of rail alignment

Journ

ée / D

aytim

e

Légende Client:

Construction de 120m du corridor de la voie

ferrée / 120m rail construction corridor

Journ

ée / D

aytim

e

Construction ferroviaire (Journée à court terme) / Railway Construction (Daytime Short-Term)

Construction d'infrastructure (Journée à moyen terme) / Infrastructure Construction (Daytime Medium-Term)


7-11

7.4.2.3 Longer Term Tunnel Construction Works This section assesses the likely noise levels and potential impacts at the settlements within the vicinity of the tunnel construction areas. To meet the Project schedule tunnelling operations are planned to continue for 24 hours, unlike other railway construction activities which will take place principally during the day and the construction sites will continue in use for a large part of the three year construction period. The noisiest activities will be drilling and blasting combined with general construction activity at tunnel portals. Long term night time impacts are therefore relevant for settlements close to the tunnel portals. Predictions of noise levels from these activities indicate that: critical impacts would occur at any settlements within 30 m of the centreline; major impacts would occur in day time within 30 to 250 m and at night within 30 to 425 m; moderate impacts would occur in day time within 250 to 425 m and at night within 427 to 700 m; and minor impacts would occur in day time within 425 to 700 m and at night within 700 to 1 100 m. Examination of settlements around the current tunnel portal locations indicates that there is one settlement close enough to experience major impact from tunnelling noise, one will experience moderate impact and two will experience minor impacts. These are all near the eastern portals of the Mamou tunnels in Section 3. There are no settlements near the short tunnel north of the Simandou Mine in Section 9. 7.4.2.4 Construction Traffic Noise Outside the construction work areas there may be further impacts arising from construction traffic. It is estimated that there will be an average of about 23 trucks per hour leaving the Marine Offloading Facility and Conakry Container Port and travelling eastward to deliver materials along the rail corridor, and a similar number returning empty to the coast. The actual number will vary during the construction period with flow peaking after about 12 months, and will decrease with distance from the coast as materials are delivered along the corridor. In addition there will be an average of approximately six ballast truck movements per hour in each rail section delivering rock and ballast from local quarries. Towards the end of construction, ore is also likely to be transported by truck from the mine to the coast prior to start of railway operations. This initial ore transportation is expected to require an additional ten trucks per day in each direction, adding twenty trips per day to the construction traffic along the national road network. Taking all these figures into account it is estimated that heavy vehicle flows could reach 600 trucks per day or more in the busiest locations. Construction traffic will use the N4 and N1 highways as far as Faranah, then the N2 to N’Zérékoré and Beyla, and will connect from these roads to logistical supply centres and the construction workfronts using existing local roads and some new roads constructed for the Project. Towns and villages on these roads could therefore be affected by noise from this traffic. The United Kingdom Calculation of Road Traffic Noise method has been used to calculate noise levels from construction traffic assuming a peak hourly flow of approximately 60 vehicles and an average speed of 50 km per hour. It is estimated that under these worst case circumstances which are likely to occur towards the western end of the route, a noise level of approximately 60-65 dB LAeq, 1hr would be produced at a distance of 10 m from the road. This level of noise will be sufficient to cause significant impacts for some people living along roads used by Project traffic. The severity of impact will depend on the proximity of homes and other noise sensitive locations (schools, places of worship etc) to the roads being used and on existing levels of road traffic noise. On main roads impacts will lower due to existing traffic noise, with the result that impacts in settlements along national roads are likely to be not significant. More noise impact is expected to occur in small towns and villages along minor roads used by trucks once they have left the larger roads. The locations of affected settlements cannot be identified at this time as access routes and traffic numbers are yet to be determined, but in settlements where substantial flows of Project traffic occur and where homes and other buildings are close to the roadside, moderate significant


7-12

impacts are likely during the daytime. Construction traffic will operate mainly during daylight working hours, so significant impacts from sleep disturbance due to traffic noise at night are not expected to occur as a regular occurrence. 7.4.3 Blasting Impacts during Tunnel Construction 7.4.3.1 Overview The railway tunnels will be excavated by drilling and blasting. Blasting has the potential to cause adverse impacts on people and structures from airblast and ground vibration. As actual blast parameters are not yet determined and are dependent on further geotechnical investigations, an assessment of likely blast types was undertaken to determine the potential for significant impacts from airblast and ground vibration using the methodology outlined in Section 7.2.3. Impacts were predicted at various distances from the tunnel alignments using four potential charge weights or Maximum Instantaneous Charge (MIC) of 20 kg, 50 kg, 100 kg and 200 kg to provide an indication of the potential for adverse blasting impacts. The results of the calculations are presented in graphical format in Figure 7.3 for airblast and Figure 7.4 for ground vibration. Figure 7.3 Airblast Calculation


7-13

Figure 7.4 Ground Vibration Calculation

Using the impact thresholds defined in Table 7.4 and impact distances determined from Figure 7.3 for airblast and Figure 7.4 for ground vibration, Table 7.8 presents the number of settlements with the potential to be affected by blasting emissions for the range of MICs assessed associated with tunnelling. Airblast will be emitted from the tunnel portals and significant impacts could occur at settlements within relevant distances of the tunnel portals. Ground vibration will affect any settlements within the relevant distances of the tunnel centreline. Table 7.8 Numbers of Settlements Potentially Exposed to Significant Impacts during Railway

Tunnel Blasting

Number of Settlements potentially affected by

Airblast Number of Settlements potentially affected

by Ground Vibration

MIC, kg Minor/

Moderate Major Critical

Minor/ Moderate

Major Critical

Residential Daytime

> 115 dBZ > 125 dBZ > 140 dBZ > 2 mm/s >5 mm/s > 10 mm/s

20 2 0 0 4 1 0

50 2 1 0 3 2 1

100 2 2 0 5 3 2

200 3 2 0 5 3 5

Residential Night time

> 105 dBZ > 115 dBZ > 140 dBZ >1 mm/s >2 mm/s > 5 mm/s

20 3 2 0 1 4 1

50 3 3 0 5 3 3

100 7 4 0 3 5 5

200 8 5 0 3 5 8


7-14

As tunnelling will be a 24 hour operation the night time criteria are relevant to evaluation of impacts. Blasting activity will progress through the tunnels and these impacts are expected to occur over a relatively short period (likely to be a few weeks) whilst blasting is taking place near each settlement. The data suggest that up to thirteen settlements could be adversely affected by significant night time impacts from airblast and sixteen due to ground vibration if the highest MIC of 200 kg is used. Of these, eight could experience critical vibration impacts as a result of being within about 400 of the tunnel centreline, with five experiencing major impacts from airblast and vibration and the others minor to moderate impacts. All of these impacts are associated with the Mamou tunnels in Section 3. Villages near both portals of the western tunnel and villages near the eastern portal of the eastern tunnel would be affected by airblast, and the majority of vibration impacts would occur along the western tunnel. 7.4.4 Noise Impacts during Operation This section assesses the likely noise levels and potential impacts at settlements near the railway during operations. Noise levels along the railway have been predicted using the modelling approach described in Section 7.2.3, taking into account the proposed noise specification for Simandou trains detailed in Annex 7C: Noise Design Assumptions and Source Data, and taking into account variation in speed along the route. The profile of predicted noise levels along the route is illustrated in Figure 7.5. Figure 7.6 shows the distances from the railway centreline at which significant impacts are predicted to occur during the day time and at night. The numbers of identified settlements within these distances are presented in Table 7.9. Table 7.9 Numbers of Settlements Potentially Exposed to Significant Noise Impacts during Railway

Operations

Section Day Night

Minor Moderate Major Critical Minor Moderate Major Critical

1 24 12 2 0 34 24 14 0

2 30 2 0 0 38 30 2 0

3 6 4 0 0 6 6 4 0

4 27 9 1 0 34 27 10 0

5 23 8 3 0 30 23 11 0

6 0 0 0 0 2 0 0 0

7 0 0 0 0 1 0 0 0

8 3 2 0 0 3 3 2 0

9 3 2 1 0 8 3 3 0

Total 116 39 7 0 156 116 46 0

These data suggest that more than 300 settlements could be affected by significant noise impacts. Of these about half will experience minor impacts, about one third moderate impacts, and about 15% being close enough to experience major impacts. No settlements are close enough for critical noise impacts to occur during operation. The sections where the most significant impacts are likely to occur are in Sections 4, 2, 1 and 5. These have the highest concentration of population alongside the rail corridor as illustrated in Figure 7.1. There will be only small numbers of settlements affected by moderate or major impacts in Sections 3, 8 and 9, and only minor night time impacts in Sections 6 and 7 where the railway crosses the sparsely populated plateau area in Kankan and Kérouané prefectures.


7-15

Figure 7.5 Railway Operations Noise Predictions

50m

50m100m

200m

300m

400m

500m

600m

700m

800m

1000m

900m

1000m

900m

800m

700m

600m

500m

400m

200m

300m

100m30m - 200m

200m - 350m

350m - 700m

> 700m

30m - 100m100m - 200m

200m - 350m

> 350m

Taille: Titre:

Dessiné par: WB Approuvé par: KR

Projet: 0131299

File:

0131

299S

iman

douG

IS_IG

_CK\

Maps

\ERM

\Nois

e\Rail

\May

2012

_revis

ions\r

w_sig

nifica

nceo

fimpa

cts_o

perat

ion.m

xd

A4Impacts critiques / Critical impacts

Impacts majeures / Major impacts

Impacts modérés / Moderate impacts

Impacts mineurs / Minor impacts

Pas significative / Not Significant

Figure 7.6Importance des impacts présentés en fonction de la distance au ligne médiane de la voie ferrée (Opération) / Significance of Impacts Presented as Distance from the Rail Centreline (Operation)

Date: 12/05/2012 Vérifié par: RL

Ligne médiane du tracé de la voie ferrée /

Centreline of rail alignment

Journ

ée / D

aytim

eNu

it / N

ight ti

me

Légende Client:

Construction de 120m du corridor de la voie

ferrée / 120m rail construction corridor


7-17

7.5 Mitigation Measures and Residual Impacts 7.5.1 Overview Measures to mitigate significant impacts are discussed under the three headings of: construction noise; blasting; and operational noise. 7.5.2 Mitigation of Construction Noise Impacts The assessment indicates that a small number of settlements located within about 150 m of construction work could experience moderate impacts from construction noise, with others up to about 200 m away experiencing minor impacts. These impacts will be mitigated by adopting good site practices throughout construction work and where necessary adopting specific additional measures during noisy activities close to settlements, or when essential work has to be carried out outside daytime working hours. The Project will adopt the following good practices to minimise noise during construction: noise performance will be considered in the selection of construction equipment and vehicles in

accordance with Rio Tinto’s Buy Quiet Policy;

mobile plant (eg compressors, generators) and other noisy construction plant such as concrete batching will be located as far from the nearest potential sensitive receptors (people and wildlife) as possible, plant will be oriented to direct noise emissions away from sensitive locations as far as possible, and on-site structures and terrain will be used to screen sensitive locations and provide noise suppression wherever practicable;

noisy construction work will be carried during daylight hours as far as is practicable; where construction work outside daylight hours is unavoidable the residents of nearby villages will be

notified in advance;

piling and pile driving will only be undertaken during daylight hours; equipment and vehicles will be regularly maintained in accordance with manufacturers’ specifications;

vehicles will be required to follow designated routes and strict speed limits will be applied to all vehicles

moving around the construction area and on public roads; In planning routes for construction traffic, consideration will be given to the potential for significant noise impacts where access routes are in close proximity to settlements or environmentally sensitive areas;

where major impacts from traffic noise cannot be avoided, consideration will be given to the need to provide temporary bypasses around sensitive receptors;

all Project drivers will receive training in good driving practices to minimise impacts from noise; and

the noise level of audible warning devices will be kept to the minimum necessary for the health and

safety of employees.

Noise levels will be monitored during construction. If moderate or more significant impacts are found to occur, consideration will be given to options for additional mitigation. In the event that major or critical impacts occur over an extended period, the affected households will be consulted and if agreed may be temporarily relocated for the duration of noisy works.


7-18

The potential for significant adverse noise impacts will be considered during planning of construction works and access roads close to settlements and noise levels will be monitored in settlements within 150 m during construction. If moderate or more significant impacts are predicted during planning, or are found to occur during monitoring, consideration will be given to additional measures to mitigate these impacts. In the event of major or critical impacts occurring over an extended period, the affected households will be consulted and if agreed may be temporarily relocated for the duration of noisy works. With these measures noise impacts during railway construction should be no more than minor. 7.5.3 Mitigation of Blasting Impacts Airblast and vibration levels from tunnel blasting will be mitigated to ensure that no major or critical impacts occur in nearby settlements by. The Project will adopt the following good practices to minimise the potential for adverse impacts from blasting during construction of the rail tunnels and operation of the mine: blasting will be undertaken following a planned schedule and the local community will be informed of this

in advance;

blast designs and procedures will be developed to keep noise and blasting to a minimum without compromising blast requirements and will consider appropriate drilling grid, charge size, charging plan, blasting ratio, charge stemming and delay interval;

delayed / micro-delayed or electronic detonators will be used; and

levels of airblast and vibration caused by blasting will be monitored and the results will be used to inform future blast design.

If significant airblast or ground vibration impacts cannot be avoided by reducing the MIC or other technical measures, consideration will be given to the need for temporary relocation of residents for the duration of blasting activity. This will be planned and implemented in full consultation with the affected people. With these measures there should be minor or no significant impacts from blasting. 7.5.4 Mitigation of Operational Noise Impacts The assessment has identified the potential for minor, moderate and major noise impacts during railway operation at a large number of nearby settlements during the daytime and at night. This takes into account compliance of Simandou trains with the noise standards set out by the US Department of Transportation Federal Railroad Administration and Rio Tinto as set out in Annex 7C: Noise Design Assumptions and Source Data. As explained in Chapter 2: Project Description, the final railway alignment is still to be determined and this assessment is based on the indicative alignment available at this stage. It is not therefore possible to determine exactly what mitigation will be required at this time but further studies will be carried out during finalisation of the railway alignment to determine noise levels in settlements near the railway and detailed mitigation measures will be designed to keep this impacts as low as is reasonably practicable. These may include: use of noise barriers (berms or fences) located between the noise source and the receptor; and

relocating noise sources so that there is no direct line of sight between the source and receptors.

Where critical or major impacts on homes cannot be avoided consideration will be given to the option of relocating the affected community. This will be explored in consultation with the affected people and will be planned and implemented in accordance with the Project Framework for Land Acquisition, Resettlement and Compensation (the PARC Framework). Further details are provided in Chapter 18: Land Use and Land-Based Livelihoods.


7-19

In addition the following measures will be taken to avoid increases in railway noise during maintenance activities and from deterioration in equipment, including: consideration of noise impacts on sensitive receptors when planning for track maintenance including

track grinding, ballast cleaning and sleeper and rail replacement;

informing people living nearby when noisy maintenance activities such as track grinding are scheduled;

regular maintenance of locomotives and wagons to maintain noise levels at design specifications; and

regular maintenance of wheels and tracks, including rail welds, to reduce the roughness of running surfaces.

With these measures the impacts from railway operations should be of no more than minor significance. 7.6 Summary of Findings This chapter presents an assessment of the impacts from the Simandou Railway on the acoustic environment. It includes consideration of the effects of noise and vibration from construction, including blasting and rock excavation, and on noise and vibration from operations on people living near the railway. The following types of impacts are assessed: noise during construction; blasting during construction; and noise during operation. Noise during construction is assessed for short term (<1 month) impacts relating to earthworks, site preparation and track laying, medium term (1-6 months) for supporting infrastructure items such as the railhead and maintenance facilities, and bridges, longer term (> 6 months) for tunnel construction, and in relation to construction traffic. A summary of the impacts, mitigation measures and resultant residual impacts is presented in Table 7.10. Where night time activities are taking place (tunnel construction and operation), the night time noise impacts are presented as these represent the worst case scenario.


7-20

Table 7.10 Summary of Residual Impacts and Mitigation

Impact Impact before mitigation Mitigation Measures Residual impact

Impacts on settlements from noise from construction activity and traffic

1 settlement near a tunnel portal will experience major long term noise impacts at night during tunnel construction.

Mobile plant (eg compressors, generators) and other noisy construction plant such as concrete batching will be located as far from the nearest potential sensitive receptors (people and wildlife) as possible, plant will be oriented to direct noise emissions away from sensitive locations as far as possible, and on-site structures and terrain will be used to screen sensitive locations wherever practicable.

Noisy construction work will be carried during daylight hours as far as is practicable. Where construction work outside daylight hours is unavoidable the residents of nearby villages will be

notified in advance. Piling and pile driving will only be undertaken during daylight hours (except for port operations). Equipment and vehicles will be regularly maintained in accordance with manufacturers specifications. Vehicles will be required to follow designated routes and strict speed limits will be applied to all vehicles

moving around the construction area and on public roads. In planning routes for construction traffic, consideration will be given to the potential for significant noise

impacts where access routes are in close proximity to settlements or environmentally sensitive areas. Where major noise impacts from traffic cannot be avoided, consideration will be given to providing

temporary bypasses around noise sensitive receptors. All Project drivers will receive training in good driving practices to minimise impacts from noise. The noise level of audible warning devices will be kept to the minimum necessary for the health and

safety of employees. Noise performance will be considered in the selection of construction equipment and vehicles in

accordance with Rio Tinto’s Buy Quiet Policy. The potential for significant adverse noise impacts will be considered during planning of construction works and access roads close to settlements and noise levels will be monitored in settlements within 150 m during construction. If moderate or more significant impacts are predicted during planning, or are found to occur during monitoring, consideration will be given to additional measures to mitigate these impacts. In the event of major or critical impacts occurring over an extended period, the affected households will be consulted and if agreed may be temporarily relocated for the duration of noisy works.

Minor or Not Significant

1 settlement near a tunnel portal will experience moderate long term impacts at night during tunnel construction and 6 settlements moderate short term impacts as railway construction passes.

Potential for moderate impacts on settlements located along minor roads used by high flows of construction traffic.

2 settlements near tunnel portals will experience minor long term impacts at night during tunnel construction and 25 settlements minor short term impacts as railway construction passes.


7-21

Impact Impact before mitigation Mitigation Measures Residual impact

Impacts on settlements of airblast noise and ground vibration from tunnel blasting

With maximum charge size, there could be:

critical impacts at up to 8 settlements from ground vibration.

Blasting will be undertaken following a planned schedule and the local community will be informed of this in advance.

Blast designs and procedures will be developed to keep noise and blasting to a minimum without compromising blast requirements and will consider appropriate drilling grid, charge size, charging plan, blasting ratio, charge stemming and delay interval.

Blasting will be undertaken using delayed / micro-delayed or electronic detonators. Levels of airblast and vibration caused by blasting will be monitored and the results used to assist in

design of future blasting to avoid significant impacts.


major impacts at 5 settlements from airblast and ground vibration.

minor-moderate impacts at 8 settlements from airblast and 3 from ground vibration.

Impacts on settlements from train noise during railway operation

Major impacts from night time rail operations at 46 settlements (7 during the day).

During detailed design further studies will be carried out to identify where mitigation is required including: use of noise barriers (berms or fences) located between the noise source and the receptor; relocating noise sources so that there is no direct line of sight between the source and receptors; and where critical or major impacts on homes cannot be avoided consideration will be given to the option of

relocating the affected community. This will be explored in consultation with the affected people and will be planned and implemented in accordance with the Project Framework for Land Acquisition, Resettlement and Compensation (the PARC Framework). Further details are provided in Chapter 18: Land Use and Land-Based Livelihoods.

The following measures will be taken to avoid increases in railway noise during maintenance activities and from deterioration in equipment: consideration of noise impacts during planning for track maintenance including track grinding, ballast

cleaning and sleeper and rail replacement informing people living nearby when noisy maintenance activities such as track grinding are scheduled regular maintenance of locomotives and wagons to maintain noise levels at design specifications regular maintenance of wheels and tracks, including rail welds, to reduce the roughness of running

surfaces


Moderate impacts from night time rail operations at 116 settlements (39 during the day).

Minor impacts from night time rail operations at 156 settlements (116 during the day).

Documents

Chapter 7: Noise and Vibration - Rio Tinto Simandou