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Supplemental Information Request 2

Measuring Baseline Noise Levels

Original IR:

IR 11.3 – Measuring Baseline Sound Levels

References:

SID #13 – Baseline Technical Report – Noise – Marathon PGM-Cu Project

SID #17 – Impact Assessment Technical Report – Noise – Marathon PGM-Cu Project

Related Comments:

CEAR # 557 (Ontario Ministry of the Environment)

Rationale:

The EIS reports unusually high levels of background sound (40 dBA) at remote receptors,

and may inappropriately minimise the possible acoustic impacts of the Project.

The Ministry of the Environment commented that the background noise measurements

reported by SCI may have been made using inappropriate equipment and methods. The

sound level meters used by the consultant are not recommended by their manufacturer for

measurement of noise levels lower than 40.0 decibels. The manufacturer has confirmed

that these meters are not designed for this sort of measurement. The operating manual for

one of the meters states that the noise floor (generated within the meter itself) is

“approximately 35 dBA”, and that the minimum sound level with which the meter should be

used is 40 dBA.

According to detailed measurement logs, provided to the Ministry upon request, a number

of measurements were made with the 40 dB “threshold” setting engaged in the meter. Non-

zero thresholds are intended for measurements of occupational (close-up worker exposure)

noise, and not for environmental (distant community exposure) measurements.

Systemic errors in the measurement of existing background noise at remote receptors in

the baseline Noise Report (SID #13), arising from equipment limitations and/or other

measurement inaccuracies can lead to inappropriate noise criteria being established and

predicted impacts being minimised. The discrepancy between the reported measured

sound level and the modelled sound level from road traffic is of particular concern, as it

means that the effect of the Project might be misstated by quoting overly high background

levels.

Information Request:

Re-measure the baseline ambient noise for Points of Reception N1 to N5 using equipment

and methodologies acceptable to the Ministry of the Environment, or if it is not feasible to

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re-measure these Points of Reception, the predicted background levels of 18 dBA

generated by the traffic modelling should be used for Points of Reception N1 to N5 rather

than 40 dBA. Use these new baseline levels to re-assess the significance of noise impacts

from the Project.

SCI Response:

Re-measurement of Background Noise

Background noise was re-measured at four locations on the Project site between

September 21 and 30, 2013.

In consultation with the Ministry of the Environment (MOE), a noise pre-test plan was

prepared and submitted to the MOE for comment and approval prior to carrying out the field

work. The plan, entitled Background Noise Pre-Test Plan, Marathon PGM-Cu Project,

Marathon, Ontario, proposed the following program:

Re-measure background noise using Bruel & Kjaer (B&K) 2250 sound level meters

at three remote rural locations on site:

o N1 – on the east side of the property, near the Pic River,

o N3 – on the west side of the property, at the northern tip of Hare Lake, and

o N5 – on the north side of the property.

Eliminate N2 and N4 from the testing program and rely on traffic noise modelling

results instead.

Record hourly equivalent continuous A-weighted sound pressure levels (Leq) at each

location for a minimum of 48 hours.

Rely on traffic noise data for background noise at locations N2 and N4 near

Highway 17.

In addition to this program, MOE requested the following:

measure and report hourly L90,

measure noise at each location for a minimum of four days (two weekdays and two

weekend days), and

record simultaneous continuous audio.

The program was reviewed and approved by MOE prior to the completion of field work.

Methodology Between September 21 and 30, 2013, background noise levels were re-measured at the following three remote wilderness locations on the Project site, as summarized below. Refer to Figure 1 for sample locations.

Location N1 – on the east side of the property, near the Pic River,

Location N3 – on the west side of the property, at the northern tip of Hare Lake, and

Location N5 – on the north side of the property.

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Background noise levels were also measured at the north Hare Lake Cottage (Location N6) to better characterize noise levels received at the nearest Noise Sensitive Receptor (NSR). SCI owns this cottage. Four B&K 2250 sound level meters (SLMs) were used for the measurements. In accordance with the test plan, each SLM was protected in a weatherproof enclosure and an outdoor microphone was connected to an extension cable and fastened to a tripod. The microphone was equipped with an outdoor windscreen. Each SLM was powered by an external power supply (deep cycle marine battery).

Continuous audio recordings were made during the measurement period using the SLM. The readings were subsequently reviewed to identify noise sources contributing to the measured levels.

Daily wind statistics between the hours of 7:00 am and 4:00 pm, available from the Environment Canada Marathon Airport Weather Station, were examined for the measurement dates.

The measurements were completed in accordance with the following MOE guidance documents:

NPC-102 Instrumentation

NPC-103 Noise Measurement Procedures

NPC-233 Information to be Submitted for Approval of Stationary Sources of Sound Results A summary of the background sound level measurement results is provided in Table 1, below: Table 1: 2013 Background Sound Level Measurement Results

Location Measurement Period Lowest Leq

(dBA)

Lowest L90

(dBA)

Day Night Day Night

N1: Pic River Sept. 21 to 24, 2013 28.0 21.3 21.8 20.2

N3: Hare Lake Sept. 21 to 24, 2013 31.2 31.6 29.7 30.6

N5: North Property Sept. 26 to 30, 2013 25.7 25.2 23.5 23.2

N6: North Hare Lake Cottage Sept. 21 to 24, 2013 31.9 32.0 30.8 28.9

Notes: 1. dBA: sound pressure level in A-weighted decibels

2. Leq : One hour equivalent continuous A-weighted sound pressure level

3. L90 : One hour ninetieth percentile A-weighted sound pressure level

4. Daytime Hours: 7:00 am to 7:00 pm; Night Time Hours: 7:00 pm to 7:00 am

The 2013 background noise lowest hourly Leq were lower than those measured in 2009 at all three previously measured locations (N1, N3 and N5). The lowest hourly Leq for the Hare Lake area (N3 and N6) was 31.2 and 31.9 dBA during the day, and 31.6 and 32.0 dBA during the night, slightly higher than the Leq measured for the Pic River station (N1) and the north property station (N5). Over the four day

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measurement period, the hourly Leq for the four stations ranged from 25.7 to 50.3 dBA during the day and from 21.3 to 48.2 dBA during the night. The lowest hourly L90 for the Hare Lake area (N3 and N6) was 29.7 and 30.8 dBA during the day and 28.9 and 30.6 dBA during the night. The hourly L90 for Hare Lake ranged from 29.7 to 42.6 dBA during the day and 28.9 to 41.2 dBA during the night. The lowest hourly L90 for N1 and N5 was 21.8 and 23.5 dBA during the day, and 20.2 and 23.2 dBA during the night. The daytime hourly L90 for N1 and N5 ranged from 21.8 to 43.9 dBA and the night time hourly L90 ranged from 20.2 to 40.7 dBA. Figures 2 to 5 show the Leq and L90 at each measurement location along with the available wind speed data from the Marathon Airport Weather Station (7:00 am to 4:00 pm). The figures generally show that elevated noise levels were consistent with elevated wind speeds. The natural noise sources identified on the audio recording consisted of rustling vegetation, wind, and wildlife. Other existing audible noise sources at some locations included Highway 17 and the Canadian Pacific Railway rail line, located approximately 3 km west of Hare Lake. Assessment of Project Noise Impacts TGCL evaluated noise impacts from the Project in 2012, and the results were reported in SID#17. Subsequent to the publishing of SID#17, minor modifications to the mine configuration, such as expansion of the Process Solids Management Facility (PSMF) footprint to the west and south, were made. Noise impacts from these changes were re-modelled consistent with the methodology documented in SID#17. All references in this SIR response to noise impacts are based on the updated and current mine plan details, as documented in various IR and SIR responses. Noise impacts for the Project are defined as the highest predicted hourly Leq for any phase of mine life, and include noise spectral data in dBA. Background noise is represented for the Hwy 17 NSRs by the lowest traffic noise hourly Leq, including spectral data (as reported in SID#13 and SID#17) and for the north Hare Lake NSR by the lowest hourly Leq measured in September 2013. Background noise for the south Hare Lake NSR is represented conservatively by the lowest hourly Leq measured in September 2013 for north Hare Lake. A comparison of predicted noise impacts and the September 2013 background noise data is provided in Table 2 for daytime noise and in Table 3 for night time noise. The relevant MOE exclusionary noise limits are provided in each table for comparison. The four Hwy 17 NSRs are considered to be in a Class 2 area and the two Hare Lake NSRs are considered to be in a Class 3 area. The significance of the differences between background noise and predicted noise impact are made using a MOE qualitative noise increase rating scale from the MOE Noise Guidelines for Landfill Sites (1998), as summarized below:

Sound Level Increase (dB) Qualitative Rating

1-3 Insignificant

3-5 Noticeable

5-10 Significant

10 and over Very Significant

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Table 2: Predicted Operations Daytime Hourly Leq

Receptor Noise Type Height

(m)

MOE Criteria (dBA)

1

Hourly Leq

(dBA)

Sound Pressure Level (dBA) Octave Band

63 Hz

125 Hz

250 Hz

500 Hz

1000 Hz

2000 Hz

4000 Hz

8000 Hz

North Hare Lake Cottage Operations

1.5 45 37.6 22.0 28.1 30.7 33.1 31.4 23.2 -- --

Background 31.9 4.5 12.4 12.5 22.3 26.5 26.9 25.2 18.9

South Hare Lake Cottage Operations

1.5 45 33.9 21.5 27.1 28.8 29.0 22.7 5.3 -- --

Background 31.2 7.9 15.8 15.8 23.2 25.7 25.2 24.0 17.7

May’s Gifts Operations

1.5 50 46.8 26.4 32.9 35.9 39.8 43.3 40.1 23.0 --

Background 53.4 35.0 42.2 45.9 44.3 47.9 45.7 43.6 36.7

Peninsula Inn

Operations 1.5 50

43.1 26.0 32.3 35.7 38.8 37.5 30.8 13.7 --

Background 50.8 33.3 40.7 45.4 42.9 42.3 43.7 40.1 33.7

Operations 4.5 50

48.7 26.4 33.0 37.0 41.9 45.4 41.9 24.7 --

Background 52.5 33.9 40.9 42.6 46.5 47.3 45.0 40.9 34.6

Travelodge

Operations 1.5 50

42.0 28.0 34.5 36.4 35.8 33.4 31.3 26.7 18.6

Background 51.6 32.7 40.0 44.1 43.4 46.9 44.1 39.1 32.4

Operations 4.5 50

43.5 28.0 34.6 36.6 37.7 37.5 32.7 27.1 21.3

Background 53.9 32.5 39.7 42.5 47.8 50.0 46.3 40.4 33.7

Wayfare Inn

Operations 1.5 50

47.9 26.0 32.8 35.9 40.2 44.6 42.0 24.9 --

Background 50.4 32.2 39.3 41.9 40.3 45.6 44.2 39.9 32.8

Operations 4.5 50

49.1 26.1 32.9 37.1 43.4 45.6 41.9 24.7 --

Background 51.2 32.0 38.9 40.4 45.1 46.5 44.1 39.0 32.8

Notes: 1. MOE Exclusionary Limits for Daytime Noise, draft MOE document NPC-300.

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Table 3: Predicted Operations Night Time Hourly Leq

Receptor Noise Type Height

(m)

MOE Criteria

1

(dBA)

Hourly Leq

(dBA)

Sound Pressure Level (dBA) Octave Band

63 Hz

125 Hz

250 Hz

500 Hz

1000 Hz

2000 Hz

4000 Hz

8000 Hz

North Hare Lake Cottage Operations

1.5 40 35.1 21.7 27.4 29.5 30.4 26.1 16.2 -- --

Background 32.0 7.8 15.6 16.6 26.9 27.6 24.2 21.1 16.9

South Hare Lake Cottage Operations

1.5 40 33.2 21.4 26.8 28.3 28.1 20.2 -- -- --

Background 31.6 6.9 12.1 15.5 24.4 27.1 25.6 22.9 16.3

May’s Gifts Operations

1.5 45 42.6 25.8 31.8 34.7 37.3 37.5 33.2 16.0 --

Background 44.9 26.6 33.8 37.5 35.9 39.5 37.3 35.1 28.3

Peninsula Inn

Operations 1.5 45

40.9 25.6 31.6 34.5 36.9 33.9 24.2 6.7 --

Background 42.4 24.8 32.3 37.0 34.4 33.8 35.2 31.7 25.3

Operations 4.5 45

43.9 25.9 32.0 35.1 38.5 39.4 35.0 17.7 --

Background 44.1 25.5 32.4 34.2 38.1 38.9 36.6 32.4 26.2

Travelodge

Operations 1.5 45

41.9 28.0 34.5 36.4 35.5 33.1 31.2 26.7 18.5

Background 43.1 24.2 31.5 35.7 34.9 38.4 35.6 30.6 24

Operations 4.5 45

43.2 28.0 34.5 36.4 37.4 37.2 32.3 26.9 21.1

Background 45.4 24.1 31.2 34.1 39.3 41.5 37.8 32.0 25.3

Wayfare Inn

Operations 1.5 45

43.1 25.4 31.5 34.3 37.3 38.6 35.1 17.9 --

Background 42.0 23.7 30.8 33.5 31.8 37.1 35.7 31.5 24.4

Operations 4.5 45

43.9 25.5 31.6 34.8 38.9 39.4 34.9 17.7 --

Background 42.8 23.6 30.5 32.0 36.6 38.0 35.7 30.5 24.4

Notes: 1. MOE Exclusionary Limits for night time noise, draft MOE document NPC-300.

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The predicted Project daytime hourly Leq of 37.6 dBA for the north Hare Lake Cottage and 33.9 dBA for the south Hare Lake Cottage are higher than the lowest measured background hourly Leq of 31.9 dBA and 31.2 dBA, respectively. Both predicted daytime levels are lower than the MOE daytime exclusionary limit of 45 dBA. Based on the MOE guideline for qualitative effects, the increase over background at the north Hare Lake Cottage (owned by SCI) of 5.7 dB is considered significant (> 5 dB) while the increase at the south Hare Lake Cottage of 2.7 dB is considered insignificant (< 3 dB). The predicted night time hourly Leq of 35.1 dBA for the north Hare Lake Cottage and 33.2 dBA for the south Hare Lake Cottage are higher than the lowest measured background hourly Leq of 32.0 dBA and 31.6 dBA, respectively. Both predicted night time levels are lower than the MOE night time exclusionary limit of 40 dBA. Based on the MOE guidelines for qualitative effects, the increase over background noise at the north Hare Lake Cottage (owned by SCI) of 3.1 dB is considered noticeable while the increase at the south Hare Lake Cottage of 1.6 dB is considered insignificant (< 3 dB). The predicted Project noise at both Hare Lake Cottages is below MOE exclusionary criteria, which are based on perceptibility and annoyance that can influence the use and enjoyment of property and interfere with lifestyle or normal functioning (e.g. relaxing, speech intelligibility). Although the increase at the north Hare Lake Cottage would be qualitatively rated as “significant” using the MOE noise scale as described above, both day and night time predictions are below the MOE exclusionary criteria. It is also noted that the cottage is owned by SCI. The predicted noise impacts at the south Hare Lake Cottage are considered insignificant with respect to the lowest measured hourly background Leq. The measurement results show the natural background noise is often above the lowest measured hourly Leq. The predicted Project daytime hourly Leq for the four Hwy 17 NSRs ranged from 42.0 dBA to 49.1 dBA. The predicted results are lower than the modelled background noise levels of 50.4 to 53.9 dBA and also below the MOE Class 2 daytime exclusionary limit of 50 dBA. As a result, the predicted impact of daytime Project-related noise on the Hwy 17 NSR is considered to be insignificant.

The predicted night time hourly Leq for the four Hwy 17 NSRs ranged from 40.9 dBA to 43.9 dBA. For three of the four Hwy 17 NSRs (May’s Gifts, Peninsula Inn, Travelodge Hotel), the predicted Project night time hourly Leq were below the predicted night time background traffic noise. For one NSR (Wayfare Inn owned by SCI) the predicted Project night time hourly Leq of 43.1 dBA and 43.9 dBA are higher than the background traffic noise at the same location of 42.0 dBA and 42.8 dBA, while remaining below the MOE 45 dBA exclusionary limit. The difference in the noise levels is 1.1 dB and is considered insignificant since it is less than 3 dB, based on MOE qualitative effects.

Conclusions

Based on the assessment of predicted Project noise to the current background noise measurements for the project, the following conclusions are drawn:

The proposed Project will result in an insignificant increase in noise at the south Hare Lake cottage for both daytime (2.7 dB) and night time (1.6 dB) noise. Predicted

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Project noise at the south Hare Lake cottage will be below the MOE exclusionary daytime and night time limits of 45 and 40 dBA, respectively.

The proposed Project will result in an insignificant increase in noise at all four Highway 17 NSRs since the predicted Project noise levels at three NSRs (May’s Gifts, Peninsula Inn, Travelodge) will be lower than the predicted background noise levels and noise levels at one NSR (Wayfare Inn) will be 1.1 dB above the background levels. Project noise at the Wayfare Inn is below the MOE exclusionary night time limits of 45 dBA. SCI owns the Wayfare Inn and the Peninsula Inn.

Project noise levels at the north Hare Lake cottage are predicted to be rated as “significant” over background noise levels since they are predicated to be up to 5.7 dB higher than background. Predicted noise levels at this NSR will however be below the applicable MOE daytime and night time exclusionary limits of 45 and 40 dBA. It is also noted that this cottage is owned by SCI.

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SCALE

SCALE 1:60000m

Figure 2: Background Sound Level Measurement at Location N1Hourly Leq, L90 & Wind Speed Time History

Saturday September 21 to Tuesday September 24, 2013  

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Figure 3: Background Sound Level Measurement at Location N3 Hourly Leq, L90 & Wind Speed Time History

Saturday September 21 to Tuesday September 24, 2013  

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Figure 4: Background Sound Level Measurement at Location N5 Hourly Leq, L90 & Wind Speed Time History

Thursday September 26 to Monday September 30, 2013  

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Figure 5: Background Sound Level Measurement at Location N6 Hourly Leq, L90 & Wind Speed Time History

Saturday September 21 to Tuesday September 24, 2013  

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