Noise Specialist Study for the Proposed Expansion Project at the Dundee Precious Metals Tsumeb Smelter

Transcription

1 Noise Specialist Study for the Proposed Expansion Project at the Dundee Precious Metals Tsumeb Smelter Project done for SLR Environmental Consulting (Namibia) (Pty) Ltd Report compiled by: Nicolette von Reiche Report No: 16SLR01-02 Draft Date: January 2017 Address: 480 Smuts Drive, Halfway Gardens Postal: P O Box 5260, Halfway House, 1685 Tel: +27 (0) Fax: +27 (0)

2 Report Details Report Title Client Report Number Report Version SLR Environmental Consulting (Namibia) (Pty) Ltd 16SLR01-02 Draft Date January 2017 Prepared by Notice Declaration Copyright Warning Document Record Nicolette von Reiche, BEng Hons (Mech.) (University of Pretoria) Airshed Planning Professionals (Pty) Ltd is a consulting company located in Midrand, South Africa, specialising in all aspects of air quality, ranging from nearby neighbourhood concerns to regional air pollution impacts as well as noise impact assessments. The company originated in 1990 as Environmental Management Services, which amalgamated with its sister company, Matrix Environmental Consultants, in Airshed is an independent consulting firm with no interest in the project other than to fulfil the contract between the client and the consultant for delivery of specialised services as stipulated in the terms of reference. Unless otherwise noted, the copyright in all text and other matter (including the manner of presentation) is the exclusive property of Airshed Planning Professionals (Pty) Ltd. It is a criminal offence to reproduce and/or use, without written consent, any matter, technical procedure and/or technique contained in this document. Version Date Reviewed by Comments Draft 12 January 2016 Client review Report Number: 16SLR01-02 Draft i

3 Glossary and Abbreviations Airshed ASG BOD A DPM EC EHS ESIA GLCC Hz IEC IFC ISO LAeq (T) LAIeq (T) LReq,d LReq,n Airshed Planning Professionals (Pty) Ltd Atmospheric Studies Group Basis of Design Descriptor that is used to indicate 10 times a logarithmic ratio of quantities that have the same units, in this case sound pressure. Descriptor that is used to indicate 10 times a logarithmic ratio of quantities that have the same units, in this case sound pressure that has been A-weighted to simulate human hearing. Dundee Precious Metals European Commission Environmental, Health, and Safety (IFC) Environmental and Social Impact Assessment Global Land Cover Characterisation Frequency in Hertz International Electro Technical Commission International Finance Corporation International Standards Organisation The A-weighted equivalent sound pressure level, where T indicates the time over which the noise is averaged (calculated or measured) (in A) The impulse corrected A-weighted equivalent sound pressure level, where T indicates the time over which the noise is averaged (calculated or measured) (in A) The LAeq rated for impulsive sound and tonality in accordance with SANS for the day-time period, i.e. from 06:00 to 22:00. The LAeq rated for impulsive sound and tonality in accordance with SANS for the night-time period, i.e. from 22:00 to 06:00. LR,dn The LAeq rated for impulsive sound and tonality in accordance with SANS for the period of a day and night, i.e. 24 hours, and wherein the LReq,n has been weighted with 10 in order to account for the additional disturbance caused by noise during the night. LA90 LAFmax LAFmin LP LPA LPZ LW mamsl NLG PFS p pref RHF SABS The A-weighted 90% statistical noise level, i.e. the noise level that is exceeded during 90% of the measurement period. It is a very useful descriptor which provides an indication of what the LAeq could have been in the absence of noisy single events and is considered representative of background noise levels (LA90) (in A) The A-weighted maximum sound pressure level recorded during the measurement period The A-weighted minimum sound pressure level recorded during the measurement period Sound pressure level (in ) A-weighted sound pressure level (in A) Un-weighted sound pressure level (in ) Sound Power Level (in ) Meters above mean sea level Noise level guideline Pre-feasibility study Pressure in Pa Reference pressure, 20 µpa Rotary Holding Furnace South African Bureau of Standards Report Number: 16SLR01-02 Draft ii

4 SANS SLM SLR SoW SRTM t/a TSL USGS WG-AEN WHO South African National Standards Sound Level Meter SLR Environmental Consulting (Namibia) (Pty) Ltd Scope of Work Shuttle Radar Topography Mission Tonnes per annum Top submerged lance (furnace) United States Geological Survey Working Group for the Assessment of Environmental Noise World Health Organisation Report Number: 16SLR01-02 Draft iii

5 Executive Summary Dundee Precious Metals (DPM) owns and operates the Tsumeb smelter complex which processes high sulphur, high arsenic and low copper grade concentrates to produce blister copper. As at the end of 2015, the smelter processes tonnes of concentrate per annum (t/a). DPM proposes several upgrades to the smelter to increase processing capacity to t/a. These include: Upgrades to Ausmelt to improve availability, including the installation of a continuous discharge weir to stabilise the bath level in the furnace. The installation of a rotary holding furnace (RHF). The implementation of slow cooling methods of slags from the RHF and converters. The upgrade of the slag mill to increase capacity and improve copper recovery. The installation of a third 13 ft by 30 ft Pierce-Smith Converter similar to those currently installed. Airshed Planning Professionals (Pty) Ltd (Airshed) was appointed SLR Environmental Consulting (Namibia) (Pty) Ltd (SLR) to provide independent and competent services for the compilation of the environmental noise specialist study as part of the Environmental and Social Impact Assessment (ESIA) process for the proposed smelter expansion project. The main objective of the noise specialist study was to determine the potential impact on the acoustic environment and noise sensitive receptors (NSRs) due to proposed upgrades to the Tsumeb smelter. To meet the above objective, the following tasks were included in the Scope of Work (SoW): 1. A review of available technical project information. 2. A review of the legal requirements and applicable environmental noise guidelines. 3. A study of the receiving (baseline) acoustic environment, including: a. The identification of NSRs from available maps and field observations; b. A study of environmental noise attenuation potential by referring to available weather records, land use and topography data sources; and c. Determining representative background/baseline noise levels through the analysis of sampled environmental noise levels obtained from surveys conducted in September and October An impact assessment, including: a. The establishment of a source inventory for current activities and the expansion project. b. Noise propagation simulations to determine environmental noise levels. c. The screening of simulated noise levels against environmental noise criteria. 5. The identification and recommendation of suitable mitigation measures and monitoring requirements. 6. Determining impact significance. 7. A specialist noise impact assessment report. This assessment considered the following two operational phase scenarios: The base scenario is representative of current activities and a concentrate processing rate of t/a. The project scenario includes proposed plant upgrades and an increase in concentrate processing rate of t/a. In the assessment of sampled and simulated noise, reference was made to the International Finance Corporation (IFC) noise level guidelines (NLGs) for residential, institutional and educational receptors (55 A during the day and 45 A during the night) since these are applicable to nearby receivers. The IFC s 3 A increase criterion was used to determine the potential for noise impact. Report Number: 16SLR01-02 Draft iv

6 The baseline acoustic environment was described in terms of the location of receivers, the ability of the environment to attenuate noise over long distances, as well as existing background and baseline noise levels. The following was found: The closest noise sensitive receivers include the town of Tsumeb and its suburbs to the south and south-west as well as farmsteads. Atmospheric conditions are more conducive to noise attenuation during the day. On average, noise impacts are expected to be most notable to the north-west and south of the facility. Natural terrain features to the south of the site provide some acoustic shielding to residents of Tsumeb and its suburbs. Current operational activities at the smelter complex are only faintly audible at the farmstead to the northwest of the complex. Community activities, traffic, domesticated animals, birds and insects are the main contributors to the acoustic climate of the area. Representative background noise levels were determined as being 44.8 A during the day and 39.4 A during the night. These levels were applied in the estimation of the extent to which noise levels increase as a result of the base and project scenarios. Sound power levels were determined from similar operations and area wide calculations. The source inventory, local meteorological conditions and information on local land use were used to populate the noise propagation model (CadnaA, ISO 9613). The propagation of noise was calculated over an area of 6 km east-west by 6 km north-south. The area was divided into a grid matrix with a 10 m resolution and NSRs were included as discrete receptors. The following was found: Simulations indicated that neither the base, nor the project scenario will result in exceedances of NLG at noise sensitive receptors. The increases in noise levels above the background of 44.8 A during the day and 39.4 during the night are also less than 3 A at all noise sensitive receptors. Presently, residents on the farm of Mr. Potgieter and close to the Tsumeb Private hospital are able to hear DMP Tsumeb smelter activities under calm wind conditions and especially at night. The increases in noise levels are however less than 3 A and not sufficiently higher to result in annoyance. The overall increase in noise levels from the base scenario to levels as a result of the project scenario, is less than 1 A. Since, for a person with average hearing acuity an increase of less than 3 A in the general ambient noise level is not detectable, it is unlikely that noise sensitive receptors will be affected by the expansion project from an environmental noise perspective. The impact of the no. 2 oxygen plant during its start-up cycle was identified as an existing, albeit non-routine, source of noise that need to be addressed as part of improving the current acoustic performance of the smelter complex. The silencer on the outlet need to be replaced or maintained as a matter of priority. The significance of environmental noise impacts was determined using the methodology adopted by SLR for the ESIA. The significance of the base/current scenario, which is also representative of the no-go option, was found to be low. The expansion project will not change the significance of noise impacts. It should be noted that the significance of impacts during the start-up of the no. 2 oxygen plant is considered medium. With the implantation of mitigation measures, the significance will be reduced to low. Basic good practice noise management and mitigation measures will ensure NLGs are not violated at NSR s around the DPM Tsumeb smelter complex. Report Number: 16SLR01-02 Draft v

7 Table of Contents 1 INTRODUCTION Objective Scope of Work Description of Activities from a Noise Perspective and Selection of Assessment Scenarios Background to Environmental Noise and the Assessment Thereof Approach and Methodology Limitations and Assumptions LEGAL REQUIREMENTS AND NOISE LEVEL GUIDELINES IFC Guidelines on Environmental Noise SANS (2008) DESCRIPTION OF THE RECEIVING ENVIRONMENT Noise Receivers Environmental Noise Propagation and Attenuation potential Sampled Background and Baseline Noise Levels IMPACT ASSESSMENT Noise Sources and Sound Power Levels Noise Propagation and Simulated Noise Levels MANAGEMENT, MITIGATION, AND RECOMMENDATIONS Good Engineering and Operational Practices No. 2 Oxygen Plant Exhaust Noise Emissions Monitoring IMPACT SIGNIFICANCE REFERENCES ANNEX A: CALIBRATION CERTIFICATES ANNEX B DETAILED SURVEY RESULTS Site 1 15 September 2016 day-time DPM Tsumeb off-line Site 2 15 September 2016 day-time DPM Tsumeb off-line Site 3 15 September 2016 day-time DPM Tsumeb off-line Site 4 15 September 2016 day-time DPM Tsumeb off-line Site 5 15 September 2016 day-time DPM Tsumeb off-line Oxygen plant during start-up 15 September 2016 day-time Site 1 15 September 2016 night-time DPM Tsumeb off-line Site 2 15 September 2016 night-time DPM Tsumeb off-line Site 3 15 September 2016 night-time DPM Tsumeb off-line Site 4 15 September 2016 night-time DPM Tsumeb off-line Site 5 15 September 2016 night-time DPM Tsumeb off-line Site 1 5 October 2016 day-time DPM Tsumeb online Site 2 5 October 2016 day-time DPM Tsumeb online Site 3 5 October 2016 day-time DPM Tsumeb online Site 4 5 October 2016 day-time DPM Tsumeb online Site 5 5 October 2016 day-time DPM Tsumeb online Site 1 5 October 2016 night-time DPM Tsumeb online Report Number: 16SLR01-02 Draft vi

8 9.18 Site 2 6 October 2016 night-time DPM Tsumeb online Site 3 6 October 2016 night-time DPM Tsumeb online Site 4 6 October 2016 night-time DPM Tsumeb online Site 5 6 October 2016 night-time DPM Tsumeb online List of Tables Table 1: IFC noise level guidelines... 9 Table 2: Typical rating levels for outdoor noise, SANS (2008)... 9 Table 3: SLM details Table 4: Survey site descriptions and acoustic observations Table 5: Source noise inventory (Base scenario) Table 6: Source noise inventory (Project scenario) Table 7: Octave band LW s Table 8: Noise propagation simulation results at nearby receivers Table 9: Noise propagation simulation results at nearby receivers during the start-up cycle of the no. 2 oxygen plant Table 10: Impact significance of the base (current) scenario Table 11: Impact significance of the project scenario List of Figures Figure 1: A-weighting curve... 4 Figure 2: Location of noise sensitive receptors, noise survey sites and terrain elevations of the study area Figure 3: Wind roses (Plant Hill data, January 2013 to October 2016) Figure 4: Day-time noise survey results Figure 5: Night-time noise survey results Figure 6: No. 2 oxygen plant exhaust Figure 7:3 rd octave frequency spectra of measurement conducted 27 m from the exhaust of the no. 2 oxygen plant Figure 8: Base scenario, simulated day-time noise level (LAeq) Figure 9: Base scenario, simulated increase in day-time noise level ( LAeq) above the background Figure 10: Base scenario, simulated night-time noise level (LAeq) Figure 11: Base scenario, simulated increase in night-time noise level ( LAeq) above the background Figure 12: Project scenario, simulated day-time noise level (LAeq) Figure 13: Project scenario, simulated increase in day-time noise level ( LAeq) above the background Figure 14: Project scenario, simulated night-time noise level (LAeq) Figure 15: Project scenario, simulated increase in night-time noise level ( LAeq) above the background Report Number: 16SLR01-02 Draft vii

9 1 Introduction Dundee Precious Metals (DPM) owns and operates the Tsumeb smelter complex which processes high sulphur, high arsenic and low copper grade concentrates to produce blister copper. As at the end of 2015, the smelter processes tonnes of concentrate per annum (t/a). DPM proposes several upgrades to the smelter to increase processing capacity to t/a. Airshed Planning Professionals (Pty) Ltd (Airshed) was appointed SLR Environmental Consulting (Namibia) (Pty) Ltd (SLR) to provide independent and competent services for the compilation of the environmental noise specialist study as part of the Environmental and Social Impact Assessment (ESIA) process for the proposed smelter expansion project. 1.1 Objective The main objective of the noise study was to determine the potential impact on the acoustic climate and receivers given activities proposed as part of the expansion project, in addition to current noise impacts. 1.2 Scope of Work To meet the above objective, the following tasks were included in the Scope of Work (SoW): 1. A review of available technical project information (Section 1.3). 2. A review of the legal requirements and applicable environmental noise guidelines (Section 2). 3. A study of the receiving (baseline) acoustic environment (Section 3), including: a. The identification of NSRs from available maps and field observations; b. A study of environmental noise attenuation potential by referring to available weather records, land use and topography data sources; and c. Determining representative background/baseline noise levels through the analysis of sampled environmental noise levels obtained from surveys conducted in September and October An impact assessment (Section 4), including: a. The establishment of a source inventory for current activities and the expansion project. b. Noise propagation simulations to determine environmental noise levels. c. The screening of simulated noise levels against environmental noise criteria. 5. The identification and recommendation of suitable mitigation measures and monitoring requirements (Section 4.2.2). 6. Determining impact significance (Section 6) 7. A specialist noise impact assessment report. 1.3 Description of Activities from a Noise Perspective and Selection of Assessment Scenarios A detailed history of the Tsumeb smelter and design of proposed upgrades can be found in the Basis of Design (BOD) and Pre-Feasibility Study (PFS) reports completed by Worley-Parsons for DPM in 2015 (report ref GE-BOD and PM-REP-0001). The summary below is included to provide context and background. The original smelter at Tsumeb included a lead smelter consisting of a sinter plant and two blast furnaces, and a copper smelter with a reverberatory furnace and two Pierce-Smith converters. Production commenced in 1962 with t/a lead and t/a copper production capacities. In 1976, a third Pierce-Smith converter was commissioned. In 2008, the Report Number: 16SLR01-02 Draft 1

10 Ausmelt furnace, a Top Submerged Lance Furnace (TSL) originally constructed for lead processing, was re-commissioned as part of the copper smelting process. DPM acquired the plant in 2010 with the objective to treat high sulphur, high arsenic, and low copper grade concentrates. Following its acquisition, DPM implemented a series of upgrades which included: The commissioning of a second oxygen plant in 2012; Improvement of off-gas cleaning systems from 2012 to 2013; The decommissioning of the reverberatory furnace in 2013; The commissioning of a tonnes per day (t/d) acid plant in 2015; The addition of two new and larger (13 ft by 30 ft) Pierce-Smith converters at the end of 2015; and A new effluent treatment plant. Arsenic trioxide was also produced as a by-product from smelter dusts at an arsenic plant. Arsenic trioxide by-product was sold to the insecticide and wood treatment industries. The arsenic plant was however decommissioned at the end of Dusts containing arsenic, previously treated at the arsenic plant, is now disposed of at the hazardous waste disposal site commissioned by DPM in The upgrades listed above increased the smelter s copper concentrate processing capacity to t/a. To further eliminate the production bottleneck at the Ausmelt section because of limited matte holding capacity for converter feed, DPM proposes the following upgrades to increase processing capacity to t/a: Upgrades to Ausmelt to improve availability, including the installation of a continuous discharge weir to stabilise the bath level in the furnace. The installation of a rotary holding furnace (RHF). The implementation of slow cooling methods of slags from the RHF and converters. The upgrade of the slag mill to increase capacity and improve copper recovery. The installation of a third 13 ft by 30 ft Pierce-Smith Converter similar to the ones currently installed. There are currently numerous sources of noise on-site. These include vehicular traffic, diesel mobile equipment, rail transport, mineral sizing (crushing, screening and milling), feeder systems, conveying systems, materials handling, motor driven equipment (fans, compressors, pumps), furnaces, converters, information and warning sirens/hooters. Noise is generally mechanical in nature but there are also several sources of aerodynamic noise. Examples of aerodynamic noise include airflow through the oxygen plant, through air pollution control equipment and converters. Upgrades proposed as part of the expansion will add additional sources of noise. The installation of the new RHF, its feed, fuel and mechanical systems as well as off-gas extraction, cleaning and venting systems will result in localised noise level increases. The increase in overall processing and production rates will also affect noise levels because of more frequent vehicle trips, increased material handling rates etc. This assessment considered the following two operational phase scenarios: The base scenario is representative of current activities and a concentrate processing rate of t/a. The project scenario includes proposed plant upgrades and an increase in concentrate processing rate of t/a. Report Number: 16SLR01-02 Draft 2

11 1.4 Background to Environmental Noise and the Assessment Thereof Before more details regarding the approach and methodology adopted in the assessment is given, the reader is provided with some background, definitions and conventions used in the measurement, calculation, and assessment of environmental noise. Noise is generally defined as unwanted sound transmitted through a compressible medium such as air. Sound in turn, is defined as any pressure variation that the ear can detect. Human response to noise is complex and highly variable as it is subjective rather than objective. Noise is reported in decibels (). is the descriptor that is used to indicate 10 times a logarithmic ratio of quantities that have the same units, in this case sound pressure. The relationship between sound pressure and sound pressure level is illustrated in this equation. Where: Lp is the sound pressure level in ; p is the actual sound pressure in Pa; and =20 log pref is the reference sound pressure (pref in air is 20 µ Pa) Perception of Sound Sound has already been defined as any pressure variation that can be detected by the human ear. The number of pressure variations per second is referred to as the frequency of sound and is measured in hertz (Hz). The hearing of a young, healthy person ranges between 20 Hz and Hz. In terms of LP, audible sound ranges from the threshold of hearing at 0 to the pain threshold of 130 and above. Even though an increase in sound pressure level of 6 represents a doubling in sound pressure, an increase of 8 to 10 is required before the sound subjectively appears to be significantly louder. Similarly, the smallest perceptible change is about 1 (Brüel & Kjær Sound & Vibration Measurement A/S, 2000) Frequency Weighting Since human hearing is not equally sensitive to all frequencies, a filter has been developed to simulate human hearing. The A-weighting filter simulates the human hearing characteristic, which is less sensitive to sounds at low frequencies than at high frequencies (Figure 1). A is the descriptor that is used to indicate 10 times a logarithmic ratio of quantities that have the same units (in this case sound pressure) that has been A-weighted. Report Number: 16SLR01-02 Draft 3

12 10.0 A-weighting Curve DB FREQUENCY (HZ) Figure 1: A-weighting curve Adding Sound Pressure Levels Since sound pressure levels are logarithmic values, the sound pressure levels as a result of two or more sources cannot just simply be added together. To obtain the combined sound pressure level of a combination of sources such as those at an industrial plant, individual sound pressure levels must be converted to their linear values and added using: _ =10 log This implies that if the difference between the sound pressure levels of two sources is nil the combined sound pressure level is 3 more than the sound pressure level of one source alone. Similarly, if the difference between the sound pressure levels of two sources is more than 10, the contribution of the quietest source can be disregarded (Brüel & Kjær Sound & Vibration Measurement A/S, 2000) Environmental Noise Propagation Many factors affect the propagation of noise from source to receiver. The most important of these are: The type of source and its sound power (LW); The distance between the source and the receiver; Atmospheric conditions (wind speed and direction, temperature and temperature gradient, humidity etc.); Obstacles such as barriers or buildings between the source and receiver; Ground absorption; and Reflections Report Number: 16SLR01-02 Draft 4

13 To arrive at a representative result from either measurement or calculation, all these factors must be taken into account (Brüel & Kjær Sound & Vibration Measurement A/S, 2000) Environmental Noise Indices In assessing environmental noise either by measurement or calculation, reference is generally made to the following indices: LAeq (T) The A-weighted equivalent sound pressure level, where T indicates the time over which the noise is averaged (calculated or measured). The International Finance Corporation (IFC) provides guidance with respect to LAeq (1 hour), the A-weighted equivalent sound pressure level, averaged over 1 hour. LA90 The A-weighted 90% statistical noise level, i.e. the noise level that is exceeded during 90% of the measurement period. It is a very useful descriptor which provides an indication of what the LAeq could have been in the absence of noisy single events and is considered representative of background noise levels. LAFmax The maximum A-weighted noise level measured with the fast time weighting. It s the highest level of noise that occurred during a sampling period. LAFmin The minimum A-weighted noise level measured with the fast time weighting. It s the lowest level of noise that occurred during a sampling period. 1.5 Approach and Methodology The assessment included a study of the legal requirements pertaining to noise impacts, a study of the physical environment of the area surrounding the project and the analyses of existing noise levels in the area. The impact assessment focused on the estimation of sound power levels (LW s) (noise emissions ) and sound pressure levels (LP s) (noise impacts) associated with the operational phase. The findings of the assessment components informed recommendations of management measures, including mitigation and monitoring. Individual aspects of the noise impact assessment methodology are discussed in more detail below Information Review A review of information available for activities proposed as part of the Tsumeb smelter expansion was conducted. The following were considered in the review: The Tsumeb Smelter Expansion Basis of Design (Worley-Parsons, 2015) The Tsumeb Smelter Expansion Pre-Feasibility Study (Worley-Parsons, 2015) The Tsumeb Smelter Expansion Pre-Feasibility Study Process Design Criteria (Worley-Parsons, 2015) The DPM Emission Testing report for the Tsumeb Smelter (Skyside, 2016) Environmental and Social Impact Assessment (ESIA) for the New Sulphuric Acid Plant, Tsumeb, Namibia (Golder Associates, 2013) Academic articles and on-line resources; and Data supplied by DPM and SLR via personal communication Review of Assessment Criteria To the author s knowledge, environmental noise level guidelines or standards have not yet been set for Namibia. Reference is therefore made to guidelines published by the International Finance Corporation (IFC) in their General Environmental, Health and Safety (EHS) Guidelines of Report Number: 16SLR01-02 Draft 5

14 1.5.3 Study of the Receiving Environment Receivers generally include private residences, community buildings such as schools, hospitals and any publicly accessible areas outside the industrial facility. Receivers included in the assessment were identified from available maps, satellite imagery and field observations. The ability of the environment to attenuate noise as it travels through the air was studied by considering local meteorology, land use and terrain. Atmospheric attenuation potential was described based on data recorded at the Pant Hill ambient monitoring station which is situated on the southern boundary of the smelter complex. Readily available terrain and land cover data was obtained from the Atmospheric Studies Group (ASG) via the United States Geological Survey (USGS) web site. A study was made of Shuttle Radar Topography Mission (STRM) (90m, 3 arc-sec) data and Global Land Cover Characterisation (GLCC) data for Africa. The extent of noise impacts as a result of an intruding noise depends largely on existing noise levels in an area. Higher ambient noise levels will result in less noticeable noise impacts and a smaller impact area. The opposite also holds true. Increases in noise will be more noticeable in areas with low ambient noise levels. Data from noise survey conducted by Airshed and with the assistance of SLR was studied to determine representative background/baseline noise levels for use in the assessment Source Inventory The source noise inventory was informed by: Process specific LW s from similar operations as contained in the database of Airshed and François Malherbe Acoustic Consulting. General area wide noise emissions from heavy and light industrial as well as commercial areas Noise Propagation Simulations The propagation of noise from proposed activities was simulated with the DataKustic CadnaA software. Use was made of the International Organisation for Standardization s (ISO) 9613 module for outdoor noise propagation from industrial noise sources. ISO 9613 specifies an engineering method for calculating the attenuation of sound during propagation outdoors to predict the levels of environmental noise at a distance from a variety of sources. The method predicts the equivalent continuous Α- weighted sound pressure level under meteorological conditions favourable to propagation from sources of known sound emission. These conditions are for downwind propagation or, equivalently, propagation under a well-developed moderate ground based temperature inversion, such as commonly occurs at night. The method also predicts an average A-weighted sound pressure level. The average A-weighted sound pressure level encompasses levels for a wide variety of meteorological conditions. The method specified in ISO 9613 consists specifically of octave-band algorithms (with nominal mid-band frequencies from 63 Hz to 8 khz) for calculating the attenuation of sound which originates from a point sound source, or an assembly of point sources. The source (or sources) may be moving or stationary. Specific terms are provided in the algorithms for the following physical effects. A basic representation of the model is given: Report Number: 16SLR01-02 Draft 6

15 =,,,,, Where; LP is the sound pressure level at the receiver LW is the sound power level of the source K1 is the correction for geometrical divergence K2 is the correction for atmospheric absorption K3 is the correction for the effect of ground surface K4 is the correction for reflection from surfaces K5 is the correction for screening by obstacles This method is applicable in practice to a great variety of noise sources and environments. It is applicable, directly or indirectly, to most situations concerning road or rail traffic, industrial noise sources, construction activities, and many other ground-based noise sources. It does however not apply to blast waves from mining. To apply the method of ISO 9613, several parameters need to be known with respect to the geometry of the source and of the environment, the ground surface characteristics, and the source strength in terms of octave-band sound power levels for directions relevant to the propagation. If the dimensions of a noise source are small compared with the distance to the listener, it is called a point source. All sources of noise at the proposed plant were quantified as point sources or areas represented by point sources. The sound energy from a point source spreads out spherically, so that the sound pressure level is the same for all points at the same distance from the source, and decreases by 6 per doubling of distance. This holds true until ground and air attenuation noticeably affect the level. The impact of an intruding industrial/mining noise on the environment will therefore rarely extend over more than 5 km from the source and is therefore always considered local in extent. The propagation of noise was calculated over an area of 6 km east-west by 6 km north-south with the DPM Tsumeb smelter complex located centrally. The area was divided into a grid matrix with a 10 m resolution and receivers were included as discrete receptors. The model calculates LP s at each grid and discrete receptor point at a height of 1.5 m above ground level Presentation of Results Noise impacts were calculated in terms of: Day and night-time noise levels as a result of the base and project scenarios in comparison with guidelines; and The effective increase ambient day and night noise levels over the background. Results are presented in isopleth form. An isopleth is a line on a map connecting points at which a given variable (in this case LP) has a specified constant value. This is analogous to contour lines on a map showing terrain elevation. In the assessment of environmental noise, isopleths present lines of constant noise level as a function of distance. Simulated noise levels were assessed according to guidelines published in by the IFC. To assess annoyance at nearby places of residence, reference was made to guidelines published by the South African Bureau of Standards (SABS) in South African National Standards (SANS) of Report Number: 16SLR01-02 Draft 7

16 1.5.7 Recommendations of Management and Mitigation The findings of the noise specialist study informed the recommendation of suitable noise management and mitigation measures. 1.6 Limitations and Assumptions The quantification of sources of noise was restricted to activities associated with the DPM Tsumeb smelter complex. Routine noise impacts from operations were estimated and simulated. In the absence of detailed plant equipment, both stationary and mobile, use was made of general noise factors and data available for similar operations. Construction and closure phase impacts were not quantified or assessed but are expected to be similar in magnitude to operational phase impacts. Its significance would however be reduced given the short-term nature of these phases. Report Number: 16SLR01-02 Draft 8

17 2 Legal Requirements and Noise Level Guidelines 2.1 IFC Guidelines on Environmental Noise The IFC General Environmental Health and Safety Guidelines on noise address impacts of noise beyond the property boundary of the facility under consideration and provides noise level guidelines. The IFC states that noise impacts should not exceed the levels presented in Table 1, or result in a maximum increase above background levels of 3 A at the nearest receptor location off-site (IFC, 2007). For a person with average hearing acuity an increase of less than 3 A in the general ambient noise level is not detectable. = 3 A is, therefore, a useful significance indicator for a noise impact. It is further important to note that the IFC noise level guidelines for residential, institutional, and educational receptors correspond with the SANS guidelines for urban districts (Table 2). Table 1: IFC noise level guidelines Area One Hour LAeq (A) 07:00 to 22:00 One Hour LAeq (A) 22:00 to 07:00 Industrial receptors Residential, institutional, and educational receptors SANS (2008) SANS (2008) successfully addresses the way environmental noise measurements are to be taken and assessed in South Africa, and is fully aligned with the WHO guidelines for Community Noise (WHO, 1999). The values given in Table 2 are typical rating levels that should not be exceeded outdoors in the different districts specified. Outdoor ambient noise exceeding these levels will be annoying to the community. Table 2: Typical rating levels for outdoor noise, SANS (2008) Type of district Equivalent Continuous Rating Level (LReq,T) for Outdoor Noise Day/night LR,dn (c) (A) Day-time LReq,d (a) (A) Night-time LReq,n (b) (A) Rural districts Suburban districts with little road traffic Urban districts Urban districts with one or more of the following; business premises; and main roads Central business districts Industrial districts Notes (a) LReq,d =The LAeq rated for impulsive sound and tonality in accordance with SANS for the day-time period, i.e. from 06:00 to 22:00. (b) LReq,n =The LAeq rated for impulsive sound and tonality in accordance with SANS for the night-time period, i.e. from 22:00 to 06:00. Report Number: 16SLR01-02 Draft 9

18 (c) LR,dn =The LAeq rated for impulsive sound and tonality in accordance with SANS for the period of a day and night, i.e. 24 hours, and wherein the LReq,n has been weighted with 10 in order to account for the additional disturbance caused by noise during the night. SANS also provides a useful guideline for estimating community response to an increase in the general ambient noise level caused by intruding noise. If is the increase in noise level, the following criteria are of relevance: 0 : There will be no community reaction; 0 < 10 : There will be little reaction with sporadic complaints ; 5 < 15 : There will be a medium reaction with widespread complaints. = 10 is subjectively perceived as a doubling in the loudness of the noise; 10 < 20 : There will be a strong reaction with threats of community action ; and 15 < : There will be a very strong reaction with vigorous community action. The categories of community response overlap because the response of a community does not occur as a stepwise function, but rather as a gradual change. Report Number: 16SLR01-02 Draft 10

19 3 Description of the Receiving Environment This chapter provides details of the receiving acoustic environment which is described in terms of: Local receivers; The local environmental noise propagation and attenuation potential; and Sampled background and baseline noise levels. 3.1 Noise Receivers Noise receivers generally include places of residence and areas where members of the public may be affected by noise generated by industrial/mining activities. Those that could potentially be affected by noise from the project are presented in Figure 2 and include town of Tsumeb and its suburbs to the south and south-west (no. 1, 2 and 3) and scattered farmsteads (no. 4 and 5). These are areas considered sensitive to changes in ambient noise. 3.2 Environmental Noise Propagation and Attenuation potential Atmospheric Absorption and Meteorology Atmospheric absorption and meteorological conditions have already been mentioned with regards to their role in the propagation on noise from a source to receiver (Section 1.4.4). The main meteorological parameters affecting the propagation of noise include wind speed, wind direction, temperature, and relative humidity. These along with other parameters such as relative humidity, air pressure, solar radiation and cloud cover affect the stability of the atmosphere and the ability of the atmosphere to absorb sound energy. Reference is made to Plant Hill data for the period January 2013 to October Wind speed increases with altitude. This results in the bending of the path of sound to focus it on the downwind side and creating a shadow on the upwind side of the source. Depending on the wind speed, the downwind level may increase by a few but the upwind level can drop by more than 20 (Brüel & Kjær Sound & Vibration Measurement A/S, 2000). It should be noted that at wind speeds of more than 5m/s ambient noise levels are mostly dominated by wind generated noise. The diurnal wind field is presented in Figure 3. Note that in terms the IFC guidelines for day- and night-time noise, day-time is defined as being from 07:00 to 22:00 and night-time from 22:00 to 07:00. Wind roses represent wind frequencies for the 16 cardinal wind directions. Frequencies are indicated by the length of the shaft when compared to the circles drawn to represent a frequency of occurrence. Wind speed classes are assigned to illustrate the frequencies with high and low winds occurring for each wind vector. The frequencies of calms, defined as periods for which wind speeds are below 1m/s, are also indicated. On average, noise impacts are expected to be most notable to the north-west and south of the facility. Report Number: 16SLR01-02 Draft 11

20 Figure 2: Location of noise sensitive receptors, noise survey sites and terrain elevations of the study area (a) Day-time wind field (06:00 to 22:00) (b) Night-time wind field (22:00 to 06:00) Figure 3: Wind roses (Plant Hill data, January 2013 to October 2016) Report Number: 16SLR01-02 Draft 12

21 Temperature gradients in the atmosphere create effects that are uniform in all directions from a source. On a sunny day with no wind, temperature decreases with altitude and creates a shadowing effect for sounds. On a clear night, temperatures may increase with altitude thereby focusing sound on the ground surface. Noise impacts are therefore generally more notable during the night. An average temperature of 25.8 C and humidity of 28.8% were applied in simulations Terrain, Ground Absorption, and Reflection Noise reduction caused by a barrier (i.e. natural terrain, installed acoustic barrier, building) feature depends on two factors namely the path difference of the sound waves as it travels over the barrier compared with direct transmission to the receiver and the frequency content of the noise (Brüel & Kjær Sound & Vibration Measurement A/S, 2000). There is n ridge along the southern boundary of the smelter complex that provides acoustic shielding to residents south of the plant (Figure 2). Sound reflected by the ground interferes with the directly propagated sound. The effect of the ground is different for acoustically hard (e.g., concrete or water), soft (e.g., grass, trees, or vegetation) and mixed surfaces. Ground attenuation is often calculated in frequency bands to consider the frequency content of the noise source and the type of ground between the source and the receiver (Brüel & Kjær Sound & Vibration Measurement A/S, 2000). Based on observations, ground cover was found to be acoustically mixed (only somewhat conducive to noise attenuation). 3.3 Sampled Background and Baseline Noise Levels Background noise is the sound level at a given location and time, measured in the absence of intermittent noises, any other extraneous or alleged noise nuisance sources. It is also referred to as the ambient or residual noise. In this case, background noise would be noise levels in the study area without the influence of DPM Tsumeb smelter activities. Baseline noise on the other hand, would be representative of current noise levels in the study area, considering all sources of noise, including current activities at the DPM Tsumeb. Two noise surveys were conducted at the five locations shown in Figure 2 (page 12). During the first survey (15 September 2016), the DPM Tsumeb smelter complex was off-line. The second, conducted on 5 and 6 October, was done by SLR under the guidance of Airshed, while the smelter complex was fully operational. The survey methodology, which closely followed guidance provided by the IFC General EHS Guidelines (IFC, 2007) and SANS (2008), is summarised below: Surveys were designed and conducted by trained specialists. Sampling was carried out using a Type 1 sound level meter (SLM) that meet all appropriate International Electrotechnical Commission (IEC) standards and is subject to annual calibration by an accredited laboratory. Equipment details are included in Table 3. Calibration certificates are included in Annex A The acoustic sensitivity of SLM was tested with a portable acoustic calibrator before and after each sampling session. Samples, 15 to 30 minutes in duration, representative and sufficient for statistical analysis were taken with the use of portable SLM s capable of logging data continuously over the time. Samples representative of the day- and night-time acoustic climate was taken. The IFC defines day-time as between 07:00 and 22:00 and night-time between 22:00 and 07:00. As recommended, LAeq (T); LAFmax; LAFmin; L90 and 3 rd octave frequency spectra were recoded. The SLM was located approximately 1.5 m above the ground and no closer than 3 m to any reflecting surface. Report Number: 16SLR01-02 Draft 13

22 SANS states that one must ensure (as far as possible) that the measurements are not affected by the residual noise and extraneous influences, e.g. wind, electrical interference and any other non-acoustic interference, and that the instrument is operated under the conditions specified by the manufacturer. A detailed electronic log and record was kept. Records included site details, weather conditions during sampling and observations made regarding the acoustic climate of each site. Table 3: SLM details Equipment Serial Number Purpose Last Calibration Date SVANTEK SV977 Class 1 SLM S/N Attended 15 to 30-minute sampling. 26 January 2016 SVANTEK 7052E ½ Prepolarized microphone. S/N Attended 15 to 30-minute sampling. 26 January 2016 SVANTEK SV33 Class 1 Acoustic Calibrator S/N Testing of the acoustic sensitivity before and after each daily sampling session. 14 June 2016 The locations of survey sites in relation to the smelter complex shown in Figure 2 (page 12). A short description of each site, including a photograph and account of acoustic observations are provided in Table 4. Sampled day- and night-time LAeq, and LA90 values are shown in Figure 4 and Figure 5 respectively. Detailed time history, frequency spectra and statistical noise level results are included in Annex B. The following was found: The only NSR where activities from the smelter complex were audible, was the farmstead on the property of Mr. Danie Potgieter. Noise levels in the study area are greatly affected by community activities and highly dependent on wind speed. Although not considered disturbing, bird, insect and domestic animals also add to the acoustic climate. The effect of insect noise on sampled noise levels is illustrated in the 3 rd octave frequency spectra as peaks at around 4 to 8 khz (Refer to Annex B). The day-time NLG off 55 A was only exceeded at site 3 and 4 during the first survey. During the night, the NLG of 45 A was exceeded at site 2 because of loud music and site 5 because of strong winds. From the survey results, it was determined that an average of 44.8 A during the day, and 39.4 A during the night would be representative of noise levels currently experienced by NSRs. Noise levels at these locations are not affected by noise from the smelter, the exception being residents of the farmstead north-west of the complex. Report Number: 16SLR01-02 Draft 14

23 Table 4: Survey site descriptions and acoustic observations Site Photo Site Details and Observations Site: Site 1 Coordinates: 19 12'50.92"S; 17 42'51.15"E Description: On the farm of Mr. Danie Potgieter, approximately 650 north-west of the smelter complex boundary and 600 m east of the M75. Day-time acoustic environment: Farm activities (workers, cars, truck, compressor), domestic animals (chickens, dogs), birds and insects. During the second survey, a generator was running for approximately 5 minutes. Tsumeb smelter complex activities were not audible at this location during the day of the second survey in October. Night-time acoustic environment: Generally, audible noise sources included birds and insects as well as wind. During the first survey in September, the smelter complex was off-line but the oxygen plant was running. When the wind turned towards the sampling location, the oxygen plant was audible as a low frequency hum. During the second survey in October, the smelter complex was audible as a low frequency hum and reverse/warning sirens were clearly discernible. Site: Site 2 Coordinates: 19 14'24.73"S; 17 42'16.14"E Description: At the Nomtsoub (Comboni) community approximately1.2 km south-west of the smelter complex boundary. Day-time acoustic environment: During both surveys, day-time noise levels were influenced by community noise (music, conversation, work activities), animals (dogs, chickens and cats), and noise from birds and insects. The smelter complex was not audible at this location during the day. Night-time acoustic environment: During both surveys, night-time noise levels were influenced by loud music from a community venue. Barking dogs, occasional traffic and insects further contributed to the acoustic climate. The smelter complex was not audible at this location during the night. Site: Site 3 Coordinates: 19 14'50.64"S; 17 43'1.51"E Description: Within Tsumeb on the side of the road at the Tsumeb Secondary School sports field., approximately 1 km south of the hazardous waste disposal site. Day-time acoustic environment: Community noise and traffic contributed most notably to noise at this location. Levels were also influenced by birds, insects and the wind. The smelter complex was not audible at this location during the day of the second survey. Night-time acoustic environment: Barking dogs, insects, wind gusts and distant traffic were audible at this location at night during both surveys. The smelter complex was not audible during the second survey. Report Number: 16SLR01-02 Draft 15

24 Site Photo Site Details and Observations Site: Site 4 Coordinates: 19 14'26.19"S; 17 43'17.26"E Description: Along an unpaved road near the Tsumeb Private Hospital, 350 m south of the hazardous waste disposal site. Day-time acoustic environment: Main day-time noise sources were traffic along the unpaved road, pedestrians, barking dogs, birds, insects and the wind. The plant was not audible at this location during the day of the second survey. Night-time acoustic environment: Like the day-time noise climate, sources were traffic along the unpaved road, birds, insects and the wind. The plant was not audible at this location during the day of the second survey. The ridge between the site and the facility provides acoustic shielding. Site: Site 5 Coordinates: 19 14'24.74"S; 17 43'36.26"E Description: At community 600 south-east of hazardous waste disposal site and 1 km south of smelter complex boundary. Day-time acoustic environment: Day-time noise levels were affected by community noise, occasional vehicle traffic, passing pedestrians, barking dogs, birds, insects and the wind. The plant was not audible at this location during the day of the second survey. Night-time acoustic environment: Day-time noise levels were affected by community noise, barking dogs, birds, insects and the wind. The plant was not audible at this location. The first survey measurement at this site was discontinued after 5 minutes because of strong winds. Report Number: 16SLR01-02 Draft 16

25 DAY-TIME BROADBAND SURVEY RESULTS Survey 1 Survey 1 Survey 2 Survey 2 NLG DBA Site 1 Site 2 Site 3 Site 4 Site 5 Survey Survey Survey Survey NLG Figure 4: Day-time noise survey results NIGHT-TIME BROADBAND SURVEY RESULTS Survey 1 Survey 1 Survey 2 Survey 2 NLG DBA Site 1 Site 2 Site 3 Site 4 Site 5 Survey Survey Survey Survey NLG Figure 5: Night-time noise survey results Report Number: 16SLR01-02 Draft 17

26 During the survey in September, it was observed that the no. 2 oxygen plant was generating high noise levels during its start-up cycle. An additional noise measurement was therefore made about 27 m from the source (Figure 6). At 27 m from the plant exhaust, which is located along the north-facing wall of the plant, an LAeq of 99.7 A was recorded (Figure 7). If we assume hemispherical sound propagation it would imply a sound power or emission level of 136 A. From personal communication with Mr Nico Potgieter from DPM it is understood that start-up noise levels persist for 30 minutes to an hour. It is also understood that the oxygen plant starts up before the rest of the smelter complex to ensure sufficient oxygen supply. Mr Potgieter further explained that the silencer does not work as per specification due to changes to the system to improve pressure regulation within the plant. Figure 6: No. 2 oxygen plant exhaust Logger 1/3 Octave, 15/09/ :44: Freq [Hz] Start 1/3 Oct LZeq (SR) Info - Ch1, Z Main cursor Total A 99.7 Figure 7:3 rd octave frequency spectra of measurement conducted 27 m from the exhaust of the no. 2 oxygen plant Total A Report Number: 16SLR01-02 Draft 18

27 4 Impact Assessment The noise source inventory, noise propagation modelling and results are discussed in Section 4.1and Section 4.2 respectively. 4.1 Noise Sources and Sound Power Levels Given the complexity of the smelter complex and number of noise generating components/activities, an approach was adopted wherein emissions of the noisiest equipment (furnaces, converters, gas cleaning systems, crushers and milling) were included separately and noise from ancillary operations, or process for which data was not available, were included as area wide noise emissions. The European Commission (EC) established a Working Group for the Assessment of Environmental to Noise (WG-AEN) who published a position paper in The WG-AEN Good Practice Guide for Strategic Noise Mapping and the Production of Associated Data on Noise Exposure, provides default sound power levels, LW s, for different types of industry, to be used when sufficient information for a detailed noise emissions inventory is not available. Default LW s of 60 A/m 2 during the day and 45 A/m 2 during the night were applied to office and changeroom areas. The default LW of 65 A/m 2 was applied to all operational areas of the smelter complex, including the hazardous waste disposal site. This factor was applied to take into account all on site vehicle movement, materials handling, feeders, feed hoppers and conveyors, electrical motors, motor driven pumps and fans, pumping and compressed air noise, rail loading as well as the acid plant and oxygen plants under normal operating conditions. To account for increase traffic, material handling etc. resulting from increased production rates a result of the expansion, area wide general industrial emissions were scaled by the logarithmic ratio of the nominal expansion concentrate processing rate to the base/current concentrate processing rate. Noise from the proposed RHF and its gas cleaning system were also added. The reader is reminded of the non-linearity in the addition of LW s. If the difference between the sound power levels of two sources is nil the combined sound power level is 3 more than the sound pressure level of one source alone. Similarly, if the difference between the sound power levels of two sources is more than 10, the contribution of the quietest source can be disregarded (Brüel & Kjær Sound & Vibration Measurement A/S, 2000). Therefore, although some sources of noise could not be quantified, the incremental contributions of such sources are expected to be minimal given that the noisiest as well as majority of sources are considered in the source inventory. The source inventory and estimated LW s for the base and project scenario, as established using the approach detailed in above, is summarised in Table 5 and Table 6 respectively. Octave band LW s are included in Table 7. Report Number: 16SLR01-02 Draft 19

28 Table 5: Source noise inventory (Base scenario) Source Source Type Default LWA/m 2 (A/m 2 ) Area (m2) LWA (A) per source General noise from offices and changerooms Area Day-time 60 Night-time 45 ~5.7 ha Day-time Night-time 92.6 General heavy industry noise Area 65 ~33.5 ha General light industry noise (hazardous waste disposal site) Area 60 ~10.8 ha Ausmelt furnace and converters Point n/a n/a Gas cleaning systems (primary and secondary for the Ausmelt and converters) Point n/a n/a Crushing (furnace feed and slag) Point n/a n/a Milling Point n/a n/a Table 6: Source noise inventory (Project scenario) Source Source Type Default LWA/m 2 (A/m 2 ) Area (m2) LWA (A) per source General noise from offices and changerooms Area Day-time 60 Night-time 45 ~5.7 ha Day-time Night-time 92.6 General heavy industry noise Area 66.9 ~33.5 ha General light industry noise (hazardous waste disposal site) Area 61.9 ~10.8 ha Ausmelt furnace and converters Point n/a n/a Gas cleaning systems (primary and secondary for the Ausmelt and converters) Point n/a n/a Crushing and screening (furnace feed and slag) Point n/a n/a Milling (slag milling) Point n/a n/a RHF Point n/a n/a RHF gas cleaning system Point n/a n/a Table 7: Octave band LW s Equipment/Activity Octave band LWi () at octave band centre frequencies (Hz) LWA (A) LW () Offices (day) per m Offices (night) per m Light industry per m Heavy industry per m Furnaces and converters Gas cleaning systems Crushing and screening Milling Report Number: 16SLR01-02 Draft 20

29 4.2 Noise Propagation and Simulated Noise Levels Normal Operating Conditions The propagation of noise from the base and project scenarios was calculated with CadnaA in accordance with ISO Meteorological and site specific acoustic parameters as discussed in Section along with source data discussed in 4.1, were applied in the model. Results are presented in tabular form (Table 8) and isopleth form (Figure 8 to Figure 15). Simulations indicate that neither the base, nor the project scenario will result in exceedances of NLG at noise sensitive receptors. The increases in noise levels above the background of 44.8 A during the day and 39.4 during the night are also less than 3 A at all noise sensitive receptors. Presently, residents on the farm of Mr. Potgieter and close to the Tsumeb Private hospital are able to hear DMP Tsumeb smelter activities under calm wind conditions and especially at night. The increases in noise levels are however less than 3 A and not sufficiently higher to result in annoyance. The overall increase in noise levels from the base scenario to levels as a result of the project scenario, is less than 1 A. Since, for a person with average hearing acuity an increase of less than 3 A in the general ambient noise level is not detectable, it is unlikely that noise sensitive receptors will be affected by the expansion project from an environmental noise perspective. Table 8: Noise propagation simulation results at nearby receivers Noise sensitive receptor Simulated daytime LAeq (A) Simulated daytime LAeq (A) Increase in daytime noise levels above the background of 44.7 A (A) Increase in night-time noise levels above the background of 38.4 A (A) Base scenario 1 Tsumeb community south of smelter complex Tsumeb Private Hospital Nomtsoub community Negligible Negligible 4 Farmstead on the farm of Mr. Danie Potgieter Farmstead Negligible Negligible Negligible Negligible Project scenario 1 Tsumeb community south of smelter complex Tsumeb Private Hospital Nomtsoub community Negligible Negligible 4 Farmstead on the farm of Mr. Danie Potgieter Farmstead Negligible Negligible Negligible Negligible Report Number: 16SLR01-02 Draft 21

30 Figure 8: Base scenario, simulated day-time noise level (LAeq) Report Number: 16SLR01-02 Draft 22

31 Figure 9: Base scenario, simulated increase in day-time noise level ( LAeq) above the background Report Number: 16SLR01-02 Draft 23

32 Figure 10: Base scenario, simulated night-time noise level (LAeq) Report Number: 16SLR01-02 Draft 24

33 Figure 11: Base scenario, simulated increase in night-time noise level ( LAeq) above the background Report Number: 16SLR01-02 Draft 25

34 Figure 12: Project scenario, simulated day-time noise level (LAeq) Report Number: 16SLR01-02 Draft 26

35 Figure 13: Project scenario, simulated increase in day-time noise level ( LAeq) above the background Report Number: 16SLR01-02 Draft 27

36 Figure 14: Project scenario, simulated night-time noise level (LAeq) Report Number: 16SLR01-02 Draft 28

37 Figure 15: Project scenario, simulated increase in night-time noise level ( LAeq) above the background Report Number: 16SLR01-02 Draft 29

38 4.2.2 No. 2 Oxygen Plant Start-up Noise Impacts The results of additional simulations included to assess the impact noise from the no. 2 oxygen plant during its start-up cycle are summarised in Table 9. Simulations indicate that residents on the farm of Mr Danie Potgieter are exposed noise levels that are close to the night-time NLG of 45 A. At day and night-time background levels of 44.8 A and 38.4 A, the plant will result in an increase of 2.9 A during the day and 6.6 during the night. According to SANS little to medium reaction with sporadic complaints to widespread complaints can be expected. Although not considered part of normal operating conditions, it is essential that noise from this plant be addressed to improve the overall acoustic performance of the smelter complex. Table 9: Noise propagation simulation results at nearby receivers during the start-up cycle of the no. 2 oxygen plant Noise sensitive receptor Simulated daytime LAeq (A) Simulated daytime LAeq (A) Increase in daytime noise levels above the background of 44.7 A (A) Increase in night-time noise levels above the background of 38.4 A (A) 1 Tsumeb community south of smelter complex Negligible Tsumeb Private Hospital Negligible Negligible Negligible Negligible 3 Nomtsoub community Negligible Negligible Negligible Negligible 4 Farmstead on the farm of Mr. Danie Potgieter Farmstead Negligible Negligible Negligible Negligible Report Number: 16SLR01-02 Draft 30

39 5 Management, Mitigation, and Recommendations In the quantification of noise emissions and simulation of noise levels because of base and proposed expansion activities at the DPM Tsumeb smelter, it was calculated that ambient noise evaluation criteria for human receptors will not be exceeded under normal operating conditions. To ensure noise are kept within acceptable limits, especially at noise sensitive receptors closest to activities, the general good practice measures for mitigating and managing noise as set out below, are recommended. 5.1 Good Engineering and Operational Practices For general activities, the following good engineering practice should be applied: All diesel-powered equipment and plant vehicles should be kept at a high level of maintenance. This should particularly include the regular inspection and, if necessary, replacement of intake and exhaust silencers. Any change in the noise emission characteristics of equipment should serve as trigger for withdrawing it for maintenance. For new equipment to be installed as part of the upgrade and expansion, equipment with lower sound power levels must be selected. Vendors should be required to guarantee optimised equipment design noise levels. In managing noise specifically related to truck and vehicle traffic, efforts should be directed at: o Minimizing individual vehicle engine, transmission, and body noise/vibration. This is achieved through the implementation of an equipment maintenance program. o Maintain road surface regularly to avoid corrugations, potholes etc. o Avoid unnecessary idling times. o Minimizing the need for trucks/equipment to reverse. This will reduce the frequency at which disturbing but necessary reverse warnings will occur. Alternatives to the traditional reverse beeper alarm such as a self-adjusting or smart alarm could be considered. These alarms include a mechanism to detect the local noise level and automatically adjust the output of the alarm is so that it is 5 to 10 above the noise level near the moving equipment. The promotional material for some smart alarms does state that the ability to adjust the level of the alarm is of advantage to those sites with low ambient noise level (Burgess & McCarty, 2009). Where possible, noisy activities such as construction, decommissioning, start-up and maintenance, should be limited to day-time hours. 5.2 No. 2 Oxygen Plant Exhaust Noise Emissions The impact of the no. 2 oxygen plant during its start-up cycle was identified as an existing, albeit non-routine, source of noise that need to be addressed as part of improving the current acoustic performance of the smelter complex. The silencer on the outlet need to be replaced or maintained as a matter of priority. 5.3 Monitoring If noise related complaints are received short term (24-hour) ambient noise measurements should be conducted as part of investigating the complaints. The results of the measurements should be used to inform any follow up interventions. The procedure set out in Section 3.3 should be adopted for all environmental noise measurements. Note that: Any surveys should be designed and conducted by a trained specialist. Report Number: 16SLR01-02 Draft 31

40 Sampling should be carried out using a Type 1 SLM that meets all appropriate IEC standards and is subject to annual calibration by an accredited laboratory. The acoustic sensitivity of the SLM should be tested with a portable acoustic calibrator before and after each sampling session. Samples of 1 to 24 hours in duration and sufficient for statistical analysis should be taken with the use of portable SLM s capable of logging data continuously over the time-period. Samples representative of the day- and nighttime acoustic climate should be taken. The following acoustic indices should be recoded and reported: o o o o LAeq (T) Statistical noise level LA90 LAmin and LAmax Octave band or 3 rd octave band frequency spectra. The SLM should be located approximately 1.5m above the ground and no closer than 3m to any reflecting surface. Efforts should be made to ensure that measurements are not affected by residual noise and extraneous influences, e.g. wind, electrical interference and any other non-acoustic interference, and that the instrument is operated under the conditions specified by the manufacturer. It is good practice to avoid conducting measurements when the wind speed is more than 5 m/s, while it is raining or when the ground is wet. A detailed log and record should be kept. Records should include site details, weather conditions during sampling and observations made regarding the acoustic climate of each site. Report Number: 16SLR01-02 Draft 32

41 6 Impact Significance The significance of environmental noise impacts was determined using the methodology adopted by SLR for the ESIA. The significance of the base/current scenario, which is also representative of the no-go option, was found to be low (Table 10). The expansion project will not change the significance of noise impacts. It should be noted that the significance of impacts during the start-up of the no. 2 oxygen plant is considered medium. With the implantation of mitigation measures, the significance will be reduced to low. Report Number: 16SLR01-02 Draft 33

42 Table 10: Impact significance of the base (current) scenario Unmitigated assessment Mitigated assessment Impact of base (current) operations at DPM Tsumeb smelter on the acoustic environment under normal operating conditions. Severity Duration Spatial Scale Consequence Probability Significance Mitigation/management measures Severity Duration Spatial Scale Consequence Probability Significance Potential for annoyance as a result of increase noise levels. Severity: Negative impacts associated with noise currently generated by the facility is low, with no exceedances of NLG at NSRs. Duration would be for the life of the facility and is thus considered medium term as per the impact rating guidelines provided. Spatial scale: Impacts are localised and the rating is considered low. Consequence: Based on the above assessment, consequence of current noise impacts is low. Probability: Probability of occurrence is definite. Significance: Summarising the above assessment, the overall significance is rated as low. Note that the significance of impacts during the start-up of the no. 2 oxygen plant is considered medium. With the implantation of mitigation measures, the significance will be reduced to low. L M L L L L Objective: Minimise impact on NSRs by ensuring NLGs are not violated. Actions: General good practice measures. Recording and responding to complaints by conducting monitoring. Limiting activities such as construction, start-up and maintenance to day-time hours. Replacing or maintaining the exhaust silencer at the no. 2 oxygen plant. L M L L L L Report Number: 16SLR01-02 Draft 34

43 Table 11: Impact significance of the project scenario Unmitigated assessment Mitigated assessment Impact of DPM Tsumeb smelter with the proposed expansion project on the acoustic environment under normal operating conditions. Severity Duration Spatial Scale Consequence Probability Significance Mitigation/management measures Severity Duration Spatial Scale Consequence Probability Significance Potential for annoyance as a result of increase noise levels. Severity: Negative impacts associated with noise is low, with no exceedances of NLG at NSRs. Duration would be for the life of the project and is thus considered medium term as per the impact rating guidelines provided. Spatial scale: Impacts will be localised and the rating is considered low. Consequence: Based on the above assessment, consequence of future noise impacts is low. Probability: Probability of occurrence is definite. Significance: Summarising the above assessment, the overall significance is rated as low. L M L L L L Objective: Minimise impact on NSRs by ensuring NLGs are not violated. Actions: General good practice measures. Recording and responding to complaints by conducting monitoring. Limiting activities such as construction, start-up and maintenance to day-time hours. Vendors should be required to guarantee optimised equipment design noise levels L M L L L L Report Number: 16SLR01-02 Draft 35

44 7 References Brüel & Kjær Sound & Vibration Measurement A/S, [Online] Available at: [Accessed 14 October 2011]. Burgess, M. & McCarty, M., Review of Alternatives to 'Beeper' Alarms for Construction Equipment, Canberra: University of New South Wales. Crocker, M. J., Handbook of Acoustics. s.l.:john Wiley & Sons, Inc. Golder Associates, Environmental and Social Impact Assessment (ESIA) for the New Sulphuric Acid Plant, Tsumeb, Namibia, s.l.: s.n. IFC, General Environmental, Health and Safety Guidelines, s.l.: s.n. SANS 10103, The measurement and rating of environmental noise with respect to annoyance and to speech communication, Pretoria: Standards South Africa. Skyside, Dundee Precious Metals Emission Testing: Tsumeb Smelter, s.l.: s.n. WHO, Guidelines to Community Noise. s.l.:s.n. Worley-Parsons, Tsumeb Smelter Expansion Basis of Design, s.l.: s.n. Worley-Parsons, Tsumeb Smelter Expansion Pre-Feasibility Study, s.l.: s.n. Worley-Parsons, Tsumeb Smelter Expansion Pre-Feasibility Study Process Design Criteria, s.l.: s.n. Report Number: 16SLR01-02 Draft 36

45 8 Annex A: Calibration Certificates Report Number: 16SLR01-02 Draft 37

46 Report Number: 16SLR01-02 Draft 38