Lloyd George Acoustics PO Box 717 Hillarys WA 6923 T: 0439 987 455 F:9300 4199 E: [email protected]W: www.lgacoustics.com.au Environmental Noise Assessment IMD Battler Gold Project Reference: 15093322-01 draft.docx Prepared for: Bioscope Environmental Member Firm of Association of Australian Acoustical Consultants
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Environmental Noise Assessment · Reference: 15093322-01 draft.docx Page 1 1 INTRODUCTION The Battler gold mine is located approximately 14 kilometres (km) south-southeast of Southern
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As part of the environmental impact assessment for the Southern Cross Gold, Parker Range
Battler Deposit, the existing ambient noise levels at two locations close to the proposed
project area were measured.
The purpose of these measurements is to provide baseline noise levels in the surrounding
area of the proposal. Once the noise levels of the mining operations are predicted, these
will be compared to the baseline noise level results to:
allow the impact of noise level increases over low ambient noise levels to be
assessed/determined;
allow the likelihood of noise exceedances resulting from the combination of the
ambient noise with that of the proposal to be assessed/determined; and
enable assessment of the likely audibility of any tonal, modulation or impulsive
components in the noise from the proposal to be assessed/determined.
Measurements and analysis were conducted in accordance with the Environmental Protection Authority: Guidance for the Assessment of Environmental Factors - Draft Guidance No. 8: Guidance for Environmental Noise (Guidance No. 8).
Appendix A contains a description of some of the terminology used throughout this report.
2 MEASUREMENT PROCEDURE
Ambient noise measurements were carried out between the 15 and 28 April 2011. These
dates did not include any activity related to the proposal.
The measurements were conducted outdoors with the microphone at least 3 metres from
any reflecting surface other than the ground, and at a height of at least 1.2 metres above the
ground.
The noise levels were logged continuously over a period of two weeks, which included two
weekends, using sample periods of 15 minutes' duration. Measurements were conducted in
accordance with Clause 5 of Australian Standard 1055.1-1990 (Standards Australia, 1990).
The measurement locations, detailed below and shown graphically in Figure 2.1, were
chosen to represent the various conditions (road/bush) within the project area.
1900-2200 hours Monday to Saturday and 0900-2200 hours on Sundays and public
holidays = LA90 32 dB
2200-0700 hours Monday to Saturday and 2200-0900 hours on Sundays and public
holidays = LA90 22 dB
0700-1900 hours Monday to Saturday = LA90 24 dB
Location 2 East of proposed extraction area
1900-2200 hours Monday to Saturday and 0900-2200 hours on Sundays and public
holidays = LA90 29 dB
2200-0700 hours Monday to Saturday and 2200-0900 hours on Sundays and public
holidays = LA90 22 dB
The weather observations made by the Bureau of Meteorology Southern Cross station for
the measurement period is provided below in Table 3.1.
Table 3.1 Weather Observations from the BOM Southern Cross Office
Date Day
Temps Rain
9:00 AM 3:00 PM
Min Max Temp RH Dir Spd Temp RH Dir Spd
°C °C mm °C % km/h °C % km/h
15 Fr 11.9 27.2 0 19.4 52 NE 24 26.5 28 NE 17
16 Sa 13.1 29.6 0 19.6 51 NNE 33 28.9 24 N 15
17 Su 11.8 32.1 0 22.4 32 N 22 31.3 16 WSW 11
18 Mo 17.6 26 0 19.6 71 SSE 28 25 46 SSE 28
19 Tu 14.5 24 3.6 15.2 97 SE 19 23.2 56 ESE 13
20 We 12.7 26.1 0 15.3 89 E 17 25.4 42 E 11
21 Th 13.9 27.3 0 18.8 56 E 22 26.5 37 ESE 19
22 Fr 14.5 30.8 0 20.5 43 NE 28 30 26 NNE 22
23 Sa 12.9 34.4 0 23.1 37 N 9 33.6 11 NW 26
24 Su 12.1 32.4 0 23.3 36 NNW 11 31.5 23 WNW 24
25 Mo 14.2 29.8 0 20.3 64 SSW 2 29.5 32 NNW 15
26 Tu 16 27.7 2.6 17.5 86 NW 13 27.1 35 NNE 24
27 We 16.2 24.2 5.8 18.3 89 NW 20 22.9 42 WNW 31
28 Th 10.9 19.8 0 14.7 54 SW 19 19.1 31 W 17
Lloyd George Acoustics
Reference: 11021791-01 Page 6
4 DISCUSSION
It can be seen that the noise levels vary throughout the day and are influenced by such
things as wind in trees, local noise sources (noise from general activities), birds and road
traffic. As expected the short-term measurements (LA1 and LA10) are influenced by local
noise sources much more than the background (LA90) levels.
The most important measurements for this assessment are the background levels (LA90) and
these can be seen to vary by approximately 20 to 25 dB during a 24-hour period. The
lowest background levels (the “L90” of the LA90 noise levels) occur during the night-time
period of 2200-0700 and are fairly consistent at both locations at approximately LA90 22 dB.
Daytime levels range from LA90 21 to 32 dB and evening from LA90 20 to 37 dB. The higher
background levels during the evening is likely to be the result of bird noise.
These results indicate that background noise levels in the area are relatively low, which is
consistent with the rural setting. As such, if noise originating from the Battler site exhibits
tonal characteristics, which is common for the type of operation proposed, these
characteristics would be readily discernible at the nearest noise sensitive receptors
(residences at the Unkovich farm).
To ensure compliance with the Environmental Protection (Noise) Regulations 1997, the
following noise limits would apply:
0700-1900 hours Monday to Saturday = LA10 40 dB1
1900-2200 hours Monday to Saturday and 0900-2200 hours on Sundays and public
holidays = LA10 35 dB
;
2
2200-0700 hours Monday to Saturday and 2200-0900 hours on Sundays and public
holidays = LA10 30 dB
; and
3
Once anticipated noise associated with the proposed mining operation has been
predicted, the management measures required to ensure achievement of these limits at
the nearby residences will need to be established.
.
1 Under the Regulations, a day-time level of LA10 45 dB is allowed, however a 5 dB penalty may be
applied if the noise is found to exhibit tonal noise characteristics (see Appendix A).
2 Under the Regulations, an evening level of LA10 40 dB is allowed, however a 5 dB penalty may be
applied if the noise is found to exhibit tonal noise characteristics (see Appendix A).
3 Under the Regulations, a night-time level of LA10 35 dB is allowed, however a 5 dB penalty may be
applied if the noise is found to exhibit tonal noise characteristics (see Appendix A).
Lloyd George Acoustics
APPENDIX A
Terminology
Lloyd George Acoustics
Reference: 11021791-01 Page A1
The following is an explanation of the terminology used throughout this report.
Decibel (dB)
The decibel is the unit that describes the sound pressure and sound power levels of a noise
source. It is a logarithmic scale referenced to the threshold of hearing.
A-Weighting
An A-weighted noise level has been filtered in such a way as to represent the way in which
the human ear perceives sound. This weighting reflects the fact that the human ear is not as
sensitive to lower frequencies as it is to higher frequencies. An A-weighted sound level is
described as LA dB.
Sound Pressure Level (Lp) The sound pressure level of a noise source is dependent upon its surroundings, being influenced by distance, ground absorption, topography, meteorological conditions etc and is what the human ear actually hears. Using the electric heater analogy above, the heat will vary depending upon where the heater is located, just as the sound pressure level will vary depending on the surroundings. Noise modelling predicts the sound pressure level from the sound power levels taking into account ground absorption, barrier effects, distance etc.
LASlow This is the noise level in decibels, obtained using the A frequency weighting and the S time weighting as specified in AS1259.1-1990. Unless assessing modulation, all measurements use the slow time weighting characteristic.
LAmax An LAmax level is the maximum A-weighted noise level during a particular measurement.
LA1
An LA1 level is the A-weighted noise level which is exceeded for one percent of the
measurement period and is considered to represent the average of the maximum noise
levels measured.
LA10 An LA10 level is the A-weighted noise level which is exceeded for 10 percent of the measurement period and is considered to represent the “intrusive” noise level.
LAeq The equivalent steady state A-weighted sound level (“equal energy”) in decibels which, in a specified time period, contains the same acoustic energy as the time-varying level during the same period. It is considered to represent the “average” noise level.
LA90 An LA90 level is the A-weighted noise level which is exceeded for 90 percent of the measurement period and is considered to represent the “background” noise level.
Lloyd George Acoustics
Reference: 11021791-01 Page A2
Background Noise Background noise or residual noise is the noise level from sources other than the source of concern. When measuring environmental noise, residual sound is often a problem. One reason is that regulations often require that the noise from different types of sources be dealt with separately. This separation, e.g. of traffic noise from industrial noise, is often difficult to accomplish in practice. Another reason is that the measurements are normally carried out outdoors. Wind-induced noise, directly on the microphone and indirectly on trees, buildings, etc., may also affect the result. The character of these noise sources can make it difficult or even impossible to carry out any corrections.
Ambient Noise Means the level of noise from all sources, including background noise from near and far and the source of interest.
Specific Noise Relates to the component of the ambient noise that is of interest. This can be referred to as the noise of concern or the noise of interest.
Tonal Noise A tonal noise source can be described as a source that has a distinctive noise emission in one or more frequencies. An example would be whining or droning. The quantitative definition of tonality is:
the presence in the noise emission of tonal characteristics where the difference between —
(a) the A-weighted sound pressure level in any one-third octave band; and
(b) the arithmetic average of the A-weighted sound pressure levels in the 2 adjacent one-third octave bands,
is greater than 3 dB when the sound pressure levels are determined as LAeq,T levels where the time period T is greater than 10% of the representative assessment period, or greater than 8 dB at any time when the sound pressure levels are determined as LA Slow levels.
This is relatively common in most noise sources.
Lloyd George Acoustics
Reference: 11021791-01 Page A3
Chart of Noise Level Descriptors
Typical Noise Levels
Lloyd George Acoustics
Appendix C
Terminology
Lloyd George Acoustics
The following is an explanation of the terminology used throughout this report.
Decibel (dB)
The decibel is the unit that describes the sound pressure and sound power levels of a noise source. It
is a logarithmic scale referenced to the threshold of hearing.
A-Weighting
An A-weighted noise level has been filtered in such a way as to represent the way in which the human
ear perceives sound. This weighting reflects the fact that the human ear is not as sensitive to lower
frequencies as it is to higher frequencies. An A-weighted sound level is described as LA dB.
Sound Power Level (Lw)
Under normal conditions, a given sound source will radiate the same amount of energy, irrespective of
its surroundings, being the sound power level. This is similar to a 1kW electric heater always radiating
1kW of heat. The sound power level of a noise source cannot be directly measured using a sound level
meter but is calculated based on measured sound pressure levels at known distances. Noise modelling
incorporates source sound power levels as part of the input data.
Sound Pressure Level (Lp)
The sound pressure level of a noise source is dependent upon its surroundings, being influenced by
distance, ground absorption, topography, meteorological conditions etc and is what the human ear
actually hears. Using the electric heater analogy above, the heat will vary depending upon where the
heater is located, just as the sound pressure level will vary depending on the surroundings. Noise
modelling predicts the sound pressure level from the sound power levels taking into account ground
absorption, barrier effects, distance etc.
LASlow
This is the noise level in decibels, obtained using the A frequency weighting and the S time weighting
as specified in AS1259.1-1990. Unless assessing modulation, all measurements use the slow time
weighting characteristic.
LAFast
This is the noise level in decibels, obtained using the A frequency weighting and the F time weighting
as specified in AS1259.1-1990. This is used when assessing the presence of modulation only.
LAPeak
This is the maximum reading in decibels using the A frequency weighting and P time weighting
AS1259.1-1990.
LAmax
An LAmax level is the maximum A-weighted noise level during a particular measurement.
LA1
An LA1 level is the A-weighted noise level which is exceeded for one percent of the measurement
period and is considered to represent the average of the maximum noise levels measured.
LA10
An LA10 level is the A-weighted noise level which is exceeded for 10 percent of the measurement
period and is considered to represent the “intrusive” noise level.
Lloyd George Acoustics
LAeq
The equivalent steady state A-weighted sound level (“equal energy”) in decibels which, in a specified
time period, contains the same acoustic energy as the time-varying level during the same period. It is
considered to represent the “average” noise level.
LA90
An LA90 level is the A-weighted noise level which is exceeded for 90 percent of the measurement
period and is considered to represent the “background” noise level.
One-Third-Octave Band
Means a band of frequencies spanning one-third of an octave and having a centre frequency between
25 Hz and 20 000 Hz inclusive.
LAmax assigned level
Means an assigned level which, measured as a LA Slow value, is not to be exceeded at any time.
LA1 assigned level
Means an assigned level which, measured as a LA Slow value, is not to be exceeded for more than 1% of
the representative assessment period.
LA10 assigned level
Means an assigned level which, measured as a LA Slow value, is not to be exceeded for more than 10% of
the representative assessment period.
Tonal Noise
A tonal noise source can be described as a source that has a distinctive noise emission in one or more
frequencies. An example would be whining or droning. The quantitative definition of tonality is:
the presence in the noise emission of tonal characteristics where the difference between -
(a) the A-weighted sound pressure level in any one-third octave band; and
(b) the arithmetic average of the A-weighted sound pressure levels in the 2 adjacent one-third
octave bands,
is greater than 3 dB when the sound pressure levels are determined as LAeq,T levels where the time
period T is greater than 10% of the representative assessment period, or greater than 8 dB at any time
when the sound pressure levels are determined as LA Slow levels.
This is relatively common in most noise sources.
Modulating Noise
A modulating source is regular, cyclic and audible and is present for at least 10% of the measurement
period. The quantitative definition of modulation is:
a variation in the emission of noise that —
(a) is more than 3 dB LA Fast or is more than 3 dB LA Fast in any one-third octave band;
(b) is present for at least 10% of the representative.
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Impulsive Noise
An impulsive noise source has a short-term banging, clunking or explosive sound. The quantitative
definition of impulsiveness is:
a variation in the emission of a noise where the difference between LA peak and LA Max slow is more than 15
dB when determined for a single representative event;
Major Road
Is a road with an estimated average daily traffic count of more than 15,000 vehicles.
Secondary / Minor Road
Is a road with an estimated average daily traffic count of between 6,000 and 15,000 vehicles.
Influencing Factor (IF)
100m within roadmajor each for 6
450m within roadmajor each for 2
100m within roadsecondary each for 2
dB) 6 of (maximumFactor Traffic
noise thereceiving premises theof radius 450m a
within land commercial of percentage the%TypeB
noise thereceiving premises theof radius a100m
within land commercial of percentage theB Type %
noise thereceiving premises theof radius 450m a
within land industrial of percentage the%TypeA
noise thereceiving premises theof radius a100m
withinland industrial of percentage theA Type %
:
B Type %B Type %20
1A Type %A Type %
10
1
450
100
450
100
450100450100
where
Representative Assessment Period
Means a period of time not less than 15 minutes, and not exceeding four hours, determined by an
inspector or authorised person to be appropriate for the assessment of a noise emission, having
regard to the type and nature of the noise emission.
Background Noise
Background noise or residual noise is the noise level from sources other than the source of concern.
When measuring environmental noise, residual sound is often a problem. One reason is that
regulations often require that the noise from different types of sources be dealt with separately. This
separation, e.g. of traffic noise from industrial noise, is often difficult to accomplish in practice.
Another reason is that the measurements are normally carried out outdoors. Wind-induced noise,
directly on the microphone and indirectly on trees, buildings, etc., may also affect the result. The
character of these noise sources can make it difficult or even impossible to carry out any corrections.
Ambient Noise
Means the level of noise from all sources, including background noise from near and far and the
source of interest.
Specific Noise
Relates to the component of the ambient noise that is of interest. This can be referred to as the noise
of concern or the noise of interest.
Lloyd George Acoustics
Peak Component Particle Velocity (PCPV)
The maximum instantaneous velocity in mm/s of a particle at a point during a given time interval and
in one of the three orthogonal directions (x, y or z) measured as a peak response. Peak velocity is
normally used for the assessment of structural damage from vibration.
Peak Particle Velocity (PPV)
The maximum instantaneous velocity in mm/s of a particle at a point during a given time interval and
is the vector sum of the PCPV for the x, y and z directions measured as a peak response. Peak velocity
is normally used for the assessment of structural damage from vibration.
RMS Component Particle Velocity (PCPV)
The maximum instantaneous velocity in mm/s of a particle at a point during a given time interval and
in one of the three orthogonal directions (x, y or z) measured as a root mean square (rms) response.
RMS velocity is normally used for the assessment of human annoyance from vibration.
Peak Particle Velocity (PPV)
The maximum instantaneous velocity in mm/s of a particle at a point during a given time interval and
is the vector sum of the PCPV for the x, y and z directions measured as a root mean square (rms)
response. RMS velocity is normally used for the assessment of human annoyance from vibration.