Atmospheric Impact Report in support of the …...Atmospheric Impact Report in support of the National Minimum Emission Standard postponement application for Impala Platinum - Rustenburg

Address: 480 Smuts Drive, Halfway Gardens | Postal: P O Box 5260, Halfway House, 1685 Tel: +27 (0)11 805 1940 | Fax: +27 (0)11 805 7010

www.airshed.co.za

Report prepared by N Shackleton

Report reviewed by H Liebenberg-Enslin

Report No.: 18IMP01 Final v2.1 | Date: February 2019

Atmospheric Impact Report in support of the National Minimum Emission

Standard postponement application for

Impala Platinum Limited - Rustenburg Operations

Prepared for Impala Platinum Limited

Atmospheric Impact Report in support of the National Minimum Emission Standard postponement application for Impala Platinum - Rustenburg Operations

Report No.: 18IMP01 Final v2.1 i

ExecutiveSummary

The Impala Platinum Limited - Rustenburg Operations (Impala) is situated in the Rustenburg Local Municipality

on the Farm Beesfontein, about 15 km to the north northwest of the town of Rustenburg. Impala is an existing

facility with operational dryers that trigger listed activity sub-category 4.1 (drying and calcining) and converters

and furnaces that trigger listed activity sub-category 4.16 (smelting and converting of sulphide ores), under the

National Environmental Management: Air Quality Act (NEM:AQA), Act no. 39 of 2004. Airshed Planning

Professionals (Pty) Ltd (Airshed) was appointed to compile the Atmospheric Impact Report (AIR) in support of

the National Minimum Emission Standard (MES) postponement application.

The scope of work included:

• A review of regulations, guidelines and standards pertaining to air quality.

• A baseline study of the receiving environment to provide background and context, including:

o The identification of potential air quality receptors;

o A study of meteorological parameters governing the dispersion of pollutants in the atmosphere;

and

o Analysis of available baseline air quality data.

• An impact assessment, including:

o The establishment of a comprehensive emissions inventory for the operations using data from

emissions sampling and emission factors published by the United States (US) Environmental

Protection Agency (EPA) and the Australian Government’s Department of the Environment and

Energy (ADE) in the estimation of all relevant operations’ emissions. Particulate matter (PM),

oxides of nitrogen (NOx) and sulphur dioxide (SO2) were included in the inventory.

o The comparison of measured emissions with the MES.

o Level 2 atmospheric dispersion simulations, as defined in the South African Regulations

Regarding Air Dispersion Modelling (Government Notice no. R533, 11 July 2014) to determine

“worst case” ambient air quality concentrations for pollutants of relevance to the industry. Level

3 dispersion modelling was done using the BREEZE AERMOD model suite. It calculates worst

case 1-hour, 24-hour, monthly and annual average pollutant concentrations as well as the

frequency with which ambient air quality criteria are exceeded.

o The screening of measured and simulated ambient pollutant concentrations and dustfall rates

in comparison with national air ambient air quality standards (NAAQS) and national dust

control regulations (NDCR).

• A comprehensive AIR in the format as set out by the Department of Environmental Affairs (DEA) in

support of the AEL application.

The main findings of the baseline assessment are that:

• The wind field was dominated by winds from the east followed by winds from the south-south-west and

east-south-east. During the day, winds occurred more frequently from the easterly and east-south-


Report No.: 18IMP01 Final v2.1 ii

easterly sectors. Night-time airflow had winds from the south-south-westerly and south-westerly sectors.

In general, the wind speeds were low with less than 1% calm conditions.

• The main sources contributing to current background pollutant concentrations and dustfall rates likely

include mining and mineral processing activities, vehicle entrained dust from local roads, agricultural

activities, windblown dust from exposed areas, biomass burning, household fuel burning and vehicle

exhaust emissions.

• The overall land use pattern associated with the surrounding area is mainly mining activities and

agricultural cattle farming interspersed by pastures. Land use to the north of the smelter includes the

settlement of Luka, while the Phokeng settlement is located south of the smelter.

The main findings of the impact assessment are as follows:

• According to 2016 and 2017 isokinetic sampling PM emissions from Impala smelter regulated stacks do

comply with the 2015 limits set out in the current AEL but not the 2020 limits per new plant MES

(NMES). Spray dryer 5 (SD5) and flash dryer 1 (FD1) measured emissions are in exceedance of the

2020 limits set out in the current AEL. The baghouse for the flash dryer 1 (FD1) has been replaced

since the April 2017 isokinetic sampling and sampling undertaken in February and August 2018 show

no exceedances of the 2020 AEL limit per NMES.

• According to 2016 and 2017 continuous sampling PM emissions from Impala smelter regulated stacks

do comply with the 2015 limits set out in the current AEL but not the 2020 limits per new plant MES

(NMES). Spray dryer 1 (SD1), spray dryer 4 (SD4), spray dryer 5 (SD5), spray dryer 6 (SD6) and flash

dryer 1 (FD1) measured emissions are in exceedance of the 2020 limits set out in the current AEL. The

baghouse for the flash dryer 1 (FD1) has been replaced since the April 2017 isokinetic sampling and

sampling undertaken during 2018 show no exceedances of the 2020 AEL limit per NMES.

• According to recent isokinetic sampling SO2 emissions from Impala smelter regulated stacks do comply

with the 2015 limits set out in the current AEL but not the 2020 limits per NMES. The tailgas scrubber

stack (TGS) measured emissions are in exceedance of the 2020 limits set out in the current AEL.

• According to continuous sampling SO2 emissions from Impala smelter most of the regulated stacks do

comply with the 2015 limits set out in the current AEL and the 2020 limits per NMES. The tailgas

scrubber stack (TGS) measured emissions are in exceedance of the limits set out in the current AEL.

• According to recent isokinetic sampling NOx expressed as NO2 emissions from Impala smelter regulated

stacks do comply with the 2015 and 2020 limits set out in the current AEL.

• Total suspended particulates (TSP), PM10, PM2.5, NO2, SO2 and CO emissions were quantified and

modelled.

• The simulated results were as follows:

o Simulated PM2.5/PM10 and NO2 as a result of the Impala smelter operations with the stacks

emitting the measured emissions do not exceed the NAAQS.

o Simulated SO2 as a result of the Impala smelter operations with the stacks emitting the

measured emissions do not exceed the annual NAAQS. Simulated SO2 as a result of the

Impala smelter operations with the stacks emitting the measured emissions exceed the short-

term NAAQS off-site and at air quality sensitive receptors (AQSRs).


Report No.: 18IMP01 Final v2.1 iii

o Simulated PM2.5/PM10 as a result of the Impala smelter operations with the stacks emitting the

2015 AEL limits do not exceed the NAAQS.

o Simulated NO2 and SO2 as a result of the Impala smelter with the stacks emitting the 2015

AEL limits exceed the NAAQS off-site and at AQSRs.



o Simulated NO2 and SO2 as a result of the Impala smelter operations with the stacks emitting

the 2020 AEL limit do not exceed the annual NAAQS off-site or at any AQSRs. Simulated NO2

and SO2 as a result of the Impala smelter operations with the stacks emitting the 2020 AEL

limits exceed the short-term NAAQS off-site and AQSRs.

o Simulated nuisance dustfall rates as a result of the Impala smelter operations are found to be

low and are below the NDCR limit for residential areas off-site and at AQSRs and the NDCR

limit for non-residential areas on-site.

To ensure the lowest possible impact on AQSRs and the environment it is recommended that Impala ensure that

the mitigation and monitoring of sources of emission are undertaken as described in the technical sections of the

report.


Report No.: 18IMP01 Final v2.1 iv

TableofContents

1 Enterprise Details ........................................................................................................................................... 1

1.1 Enterprise Details .................................................................................................................................... 1

1.2 Location and Extent of the Plant ............................................................................................................. 2

1.2.1 Description of Surrounding Land Use (within 5 km radius) ............................................................. 2

1.3 Atmospheric Emission Licence and other Authorisations........................................................................ 3

2 Nature of the Process ..................................................................................................................................... 6

2.1 Listed Activity A ....................................................................................................................................... 6

2.2 Process Description ................................................................................................................................ 6

2.2.1 General Process Description ........................................................................................................... 6

2.2.2 Visual Representations of Impala Smelter Operations .................................................................. 12

2.3 Unit Process or Processes .................................................................................................................... 15

3 Technical Information ................................................................................................................................... 17

3.1 Raw Material Used ................................................................................................................................ 17

3.2 Appliances and Abatement Equipment Control Technology ................................................................. 19

3.3 Production Rates ................................................................................................................................... 23

3.4 Waste Rates .......................................................................................................................................... 23

3.5 Assumptions, Limitations and Exclusions ............................................................................................. 24

4 Atmospheric Emissions ................................................................................................................................ 26

4.1 Point Source Parameters ...................................................................................................................... 27

4.2 Point Source Maximum Emission Rates (Normal Operating Conditions) .............................................. 27

4.2.1 Point Source Emission Estimation Methods (Normal Operating Conditions) ................................ 28

4.3 Point Source Maximum Emission Rates during Start-up, Maintenance and/or Shut-down) .................. 29

4.3.1 Point Source Emission Estimation Methods (Start-up, Maintenance, Upset and/or Shut-down) .. 32

4.4 Fugitive Emissions (Area and Line Sources) ........................................................................................ 33

4.4.1 Fugitive Source Parameters .......................................................................................................... 33

4.4.2 Fugitive Sources Maximum Emission Rates during Normal Operating Conditions ....................... 34

4.4.3 Fugitive Sources Emission Estimation Methods............................................................................ 36

4.5 Emergency Incidents ............................................................................................................................. 39

5 Impact of Enterprise on the Receiving Environment .................................................................................... 40

5.1 Analysis of Emissions’ Impact on Human Health .................................................................................. 40


Report No.: 18IMP01 Final v2.1 v

5.1.1 Assessment Criteria for Human Health - National Ambient Air Quality Standards ........................ 40

5.1.2 Atmospheric Dispersion Potential ................................................................................................. 40

5.1.3 Screening of Simulated Concentrations for Potential Human Health Impacts (Normal Operating

Conditions) ................................................................................................................................................... 42

5.1.4 Model Validation ............................................................................................................................ 71

5.2 Analysis of Emissions’ Impact on the Environment ............................................................................... 75

5.2.1 Effects of Particulate Matter on Animals ....................................................................................... 75

5.2.2 Effects of Suphur Dioxide on Plants and Animals ......................................................................... 76

5.2.3 Assessment Criteria for Dustfall .................................................................................................... 76

5.2.4 Measured Dustfall Rates ............................................................................................................... 78

5.2.5 Screening of Simulated Dustfall Rates for Potential Environmental Impacts (Normal Operating

Conditions) ................................................................................................................................................... 88

6 Complaints ................................................................................................................................................... 93

7 Current or Planned Air Quality Management Interventions .......................................................................... 94

7.1 Mitigation measures .............................................................................................................................. 94

7.2 Monitoring ............................................................................................................................................. 94

8 Compliance and Enforcement Actions ......................................................................................................... 95

9 Additional Information ................................................................................................................................... 95

10 Formal Declarations ..................................................................................................................................... 95

10.1 Declaration of Accuracy of Information ................................................................................................. 95

10.2 Declaration of Independence of Practitioner ......................................................................................... 95

11 Main Findings ............................................................................................................................................... 95

12 References ................................................................................................................................................... 98

13 Annexure A: Declaration of Accuracy of Information – Applicant ............................................................... 100

14 Annexure B: Declaration of Independence – Practitioner ........................................................................... 101

15 Annexure C: Emissions Reports ................................................................................................................ 102

16 Annexure D: Other Relevant Legislation .................................................................................................... 103

16.1 National Minimum Emission Standards ............................................................................................... 103

16.2 Applying for an AEL ............................................................................................................................ 103

16.3 Reporting of Atmospheric Emissions .................................................................................................. 104

16.4 Atmospheric Impact Report ................................................................................................................. 105

16.5 Greenhouse Gas (GHG) Emissions .................................................................................................... 105


Report No.: 18IMP01 Final v2.1 vi

17 Annexure E: Atmospheric Dispersion Simulation Methodology .................................................................. 107


Report No.: 18IMP01 Final v2.1 vii

ListofTables

Table 1: Enterprise details ...................................................................................................................................... 1

Table 2: Contact details of responsible person ....................................................................................................... 1

Table 3: Location and extent of the plant ................................................................................................................ 2

Table 4: AEL details ................................................................................................................................................ 3

Table 5: Listed activities .......................................................................................................................................... 6

Table 6: Air emissions and pollutants associated with Impala Platinum Limited - Rustenburg Operations ............. 6

Table 7: List of unit processes considered listed activities under NEM:AQA ........................................................ 15

Table 8: Raw materials used ................................................................................................................................. 17

Table 9: Appliances and abatement equipment control technology for point sources .......................................... 19

Table 10: Area and/or line source – management and mitigation measures ........................................................ 22

Table 11: Production Rates ................................................................................................................................... 23

Table 12: By-product Rates .................................................................................................................................. 23

Table 13: Effluent Rates........................................................................................................................................ 23

Table 14: Solid Waste Rates ................................................................................................................................. 24

Table 15: Fugitive Emission Rates ........................................................................................................................ 24

Table 16: Point source parameters ....................................................................................................................... 27

Table 17: Point source emissions ......................................................................................................................... 27

Table 18: Point source emission estimation information ....................................................................................... 28

Table 19: Emission during start-up, maintenance, upset and/or shut-down.......................................................... 29

Table 20: Area and volume source parameters .................................................................................................... 33

Table 21: Area and volume source emissions ...................................................................................................... 34

Table 22: Area and volume source emission estimation information .................................................................... 36

Table 23: National Ambient Air Quality Standards for criteria pollutants ............................................................... 40

Table 24: Comparison of simulated and observed PM10 concentrations at the monitoring stations in the Impala

area ....................................................................................................................................................................... 71

Table 25: Comparison of simulated and observed SO2 concentrations at the monitoring stations in the Impala

area ....................................................................................................................................................................... 74

Table 26: Acceptable dustfall rates ....................................................................................................................... 76

Table 27: Planned stack emissions testing ........................................................................................................... 94

Table 28: NMES for subcategory 5.2 listed activities, drying .............................................................................. 103

Table 29: Model details ....................................................................................................................................... 108

Table 30: Simulation domain ............................................................................................................................... 108

ListofFigures

Figure 1: Location of Impala smelter in relation to the surrounding environment (regional setting); yellow circle

depicts 5 km radius and the red circle depicts 50 km radius ................................................................................... 4

Figure 2: Location of Impala smelter in relation to the surrounding sensitive areas (communities and hostels) ..... 5


Report No.: 18IMP01 Final v2.1 viii

Figure 3: Impala smelter process flow diagram (created by Impala Platinum Limited) ......................................... 14

Figure 4: Impala Smelter sources locations .......................................................................................................... 38

Figure 5: Period average wind rose (AERMET data, 2015 to 2017) ..................................................................... 42

Figure 6: Day-time and night-time wind roses (AERMET data, 2015 to 2017) ...................................................... 42

Figure 7: Impala smelter operations with measured stacks emissions (isokinetic sampling): simulated annual

average PM2.5/PM10 concentrations ...................................................................................................................... 43

Figure 8: Impala smelter operations with measured stacks emissions (isokinetic sampling): simulated 24-hour

average PM2.5/PM10 concentrations ...................................................................................................................... 44

Figure 9: Impala smelter operations with measured stacks emissions: simulated annual average NOx

concentrations ....................................................................................................................................................... 45

Figure 10: Impala smelter operations with measured stacks emissions: frequency of exceedance of the simulated

1-hour NOx concentration of 200 µ g/m³ ................................................................................................................ 46

Figure 11: Impala smelter operations with measured stacks emissions: simulated annual average SO2

concentrations ....................................................................................................................................................... 47


24-hour average SO2 concentration of 125 µ g/m³ ................................................................................................ 48


1-hour SO2 concentration of 350 µ g/m³ ................................................................................................................ 49

Figure 14: Impala smelter operations with measured stacks emissions (continuous and isokinetic sampling):

simulated annual average PM2.5/PM10 concentrations .......................................................................................... 51

Figure 15: Impala smelter operations with measured stacks emissions (continuous and isokinetic sampling):

simulated 24-hour average PM2.5/PM10 concentrations ......................................................................................... 52

Figure 16: Impala smelter operations with mass balance stacks emissions: simulated annual average SO2

concentrations ....................................................................................................................................................... 53

Figure 17: Impala smelter operations with mass balance stacks emissions: frequency of exceedance of the

simulated 1-hour SO2 concentration of 350 µ g/m³ ................................................................................................ 54

Figure 18: Impala smelter operations with 2015 AEL Limits: simulated annual average PM2.5/PM10 concentrations

.............................................................................................................................................................................. 56

Figure 19: Impala smelter operations with 2015 AEL Limits: simulated 24-hour average PM2.5/PM10

concentrations ....................................................................................................................................................... 57

Figure 20: Impala smelter operations with 2015 AEL Limits: simulated annual average NOx concentrations ...... 58

Figure 21: Impala smelter operations with 2015 AEL Limits: frequency of exceedance of the simulated 1-hour

NOx concentration of 200 µg/m³ ........................................................................................................................... 59

Figure 22: Impala smelter operations with 2015 AEL Limits: simulated annual average SO2 concentrations....... 60


average SO2 concentration of 125 µ g/m³ ............................................................................................................. 61


SO2 concentration of 350 µ g/m³ ........................................................................................................................... 62

Figure 25: Impala smelter operations with 2020 AEL Limits: simulated annual average PM2.5/PM10 concentrations

.............................................................................................................................................................................. 64


Report No.: 18IMP01 Final v2.1 ix


concentrations ....................................................................................................................................................... 65

Figure 27: Impala smelter operations with 2020 AEL Limits: simulated annual average NOx concentrations ...... 66


NOx concentration of 200 µg/m³ ........................................................................................................................... 67

Figure 29: Impala smelter operations with 2020 AEL Limits: simulated annual average SO2 concentrations....... 68


average SO2 concentration of 125 µ g/m³ ............................................................................................................. 69


SO2 concentration of 350 µ g/m³ ........................................................................................................................... 70

Figure 32: Fractional bias of means and standard deviation for PM10 ................................................................... 73

Figure 33: Fractional bias of means and standard deviation for SO2 .................................................................... 75

Figure 34: Sampling location for Impala Platinum Mine monitoring site part 1 (SGS, 2017) ................................. 78

Figure 35: Sampling location for Impala Platinum Mine monitoring site part 2 (SGS, 2017) ................................. 79

Figure 36: Sampling location for Impala Platinum Mine Shaft 16 monitoring site (SGS, 2017) ............................ 79

Figure 37: Sampling location for Impala Platinum Mine Shaft 15 and Shaft 17 monitoring site (SGS, 2017) ....... 80

Figure 38: Sampling location for Impala Platinum Mine Shaft 1 monitoring site (SGS, 2017) .............................. 80

Figure 39: Measured dustfall rates at non-residential areas in 2016 .................................................................... 82

Figure 40: Measured dustfall rates at non-residential areas in 2017 .................................................................... 84

Figure 41: Measured dustfall rates at residential areas in 2016 ............................................................................ 85

Figure 42: Measured dustfall rates at residential areas in 2017 ............................................................................ 87

Figure 43: Impala smelter operations with measured stacks emissions: the simulated 24-hour dustfall rates ..... 89

Figure 44: Impala smelter operations with 2015 AEL Limits: the simulated 24-hour dustfall rates ....................... 90

Figure 45: Impala smelter operations with 2020 AEL Limits: the simulated 24-hour dustfall rates ....................... 92


Report No.: 18IMP01 Final v2.1 x

ListofAbbreviations

ADE Australian Government: Department of the Environment and Energy

AEL Atmospheric Emission Licence

Airshed Airshed Planning Professionals (Pty) Ltd

AIR Air Impact Report

APPA Air Pollution Prevention Act

AQM Air Quality Management

AQO Air Quality Officer

AQSR(s) Air Quality Sensitive Receptor(s)

ASG Atmospheric Studies Group

ASTM American Society for Testing and Materials

CE Control Efficiency

DEA Department of Environmental Affairs

DEAT Department of Environmental Affairs and Tourism

EHS Environmental, Health and Safety

EMS Environmental Management Systems

GHG Greenhouse Gas(es)

GIIP Good International Industry Practice

GLC(s) Ground Level Concentration(s)

Impala Impala Platinum Limited - Rustenburg Operations

NAAQS National Ambient Air Quality Standard(s)

NDCR(s) National Dust Control Regulation(s)

NEM:AQA National Environmental Management: Air Quality Act 2004

NMES National Minimum Emission Standards

NPI National Pollutant Inventory

PM Particulate Matter

SABS South African Bureau of Standards

SAWS South African Weather Service

tpa Tonnes per annum

TSP Total Suspended Particulates

US EPA United States Environmental Protection Agency

WHO World Health Organisation

WRF Weather Research and Forecasting


Report No.: 18IMP01 Final v2.1 1

AtmosphericImpactReport

1 ENTERPRISE DETAILS

1.1 Enterprise Details

The details of Impala are summarised in Table 1. The contact details of the responsible person are provided in

Table 2.

Table 1: Enterprise details

Enterprise Name Impala Platinum Limited – Rustenburg Operations

Trading As Impala Platinum Limited – Rustenburg Operations

Type of Enterprise, e.g. Company/Close Corporation/Trust, etc

Company

Company/Close Corporation/Trust Registration Number (Registration Numbers if Joint Venture)

1957/001979/06

Registered Address Impala Platinum Limited – Rustenburg

Impala Operations

District Phokeng

Rustenburg

South Africa

Postal Address P. O. Box 5683

Rustenburg

0300

Telephone Number (General) +27 14 569 0000

Fax Number (General) +27 14 569 7056

Industry Type/Nature of Trade Production of Platinum Group Metals (PGM) matte

Land Use Zoning as per Town Planning Scheme Mining

Land Use Rights if outside Town Planning Scheme Not applicable

Table 2: Contact details of responsible person

Responsible Person Name or Emission Control Officer (where appointed)

Hennie Crafford

Telephone Number +27 14 569 7259

Cell Phone Number +27 82 809 0249

Fax Number +27 14 569 7056

E-mail Address [email protected]

After Hours Contact Details +27 82 809 0249



1.2 Location and Extent of the Plant

The details of Impala smelter location and extent are summarised in Table 3. The location of operations in

relation to the surrounding environment (regional setting) is shown in Figure 1; in this image, the yellow circle

depicts a 50 km area surrounding the smelter, while the red circle depicts a 5 km area surrounding the smelter.

The location of smelter in relation to the surrounding land use and individual air quality sensitive receptors

(AQSRs) is shown in Figure 2. The smelter is where the listed activities sub-category 4.1 and 4.16, under the

National Environmental Management: Air Quality Act (NEM:AQA), Act no. 39 of 2004 are located.

Table 3: Location and extent of the plant

Physical Address of the Plant Portion 2 of the farm Beerfontein 263 JQ, Phokeng

Description of Site (Where no Street Address) See Figure 2

Coordinates (decimal degrees) of Approximate Centre of Operations

Latitude:25.54°S

Longitude:27.185°E

Coordinates (UTM) of Approximate Centre of Operations UTM reference – Grid Zone: 35S

Northing: 7 175 243.6 mN

Easting: 518 585.9 mE

Property Registration Number (Surveyor-General Code) T0JQ00000000026300002

Extent (km²) ~ 0.463 (Smelter Area)

Elevation Above Mean Sea Level (m) 1 100

Province North West Province

Metropolitan/District Municipality Bojanala Platinum Municipality

Local Municipality Rustenburg Local Municipality

Designated Priority Area Waterberg Bojanala Priority Area

1.2.1 Description of Surrounding Land Use (within 5 km radius)

The Impala smelter is in the Rustenburg Local Municipality on the Farm Beesfontein, about 15 km to the north

northwest of the town of Rustenburg. The overall land use pattern associated with the surrounding area is mainly

mining activities and agricultural cattle farming interspersed by pastures. Land use to the north of the Impala

smelter includes the settlement of Luka, while the Phokeng settlement is located south of the smelter.

Other contributing activities in the Bojanala Platinum District Municipality

Bojanala Platinum District Municipality was declared a Priority Area in terms of Section 18(4) read with Section

57(1)(a) on the 15 June 2012 (gazette no. 35435 Notice Number 495). Based on this, the other contributing

activities in the region are identified. Current land uses in the region include numerous mining operations (both

underground and opencast), industries and small residential communities, business trade and agricultural

activities. Industries in the region include two platinum smelter operations (viz.: Anglo Platinum Waterval Smelter

Operation and Lonmin Western Platinum) and three ferro-chrome industries (viz. the Xstrata Rustenburg, Xstrata

Wonderkop and Merafe Ferrochrome). In addition, there are a number of smaller boiler operations and



incinerators. Fugitive dust sources include other mining and quarry operations and tailings storage facilities (viz.

Anglo Platinum and Lonmin). Other sources of gaseous and particulate emissions include vehicle tailpipe

emissions, domestic fuel burning, biomass burning and regionally transported pollutants from other areas.

1.3 Atmospheric Emission Licence and other Authorisations

The operation has an existing Atmospheric Emission Licence (AEL). The details of the AEL can be found in Table

4.

Table 4: AEL details

Name of Licensing Authority Bojanala Platinum District Municipality

Atmospheric Emission Licence Number BPDM – July2014 / Drying and Smelting

Atmospheric Emission Licence Issue Date 1 August 2014

Atmospheric Emission Licence Type Full

Review Date 30 July 2018

Renewal Date, not later than 30 July 2019

The following other authorisations, permits and licences have been issued in the past related to air quality

management:

• Air Pollution Prevention Act (APPA) Registration Certificates:

o Sulphuric Acid Process - Process 1 of the Second Schedule

o Roasting Process - Process 27 of the Second Schedule

• Atmospheric Emission License: NWPG/IMPALA/PAEL 4.1 & 4.6 /DEC11

o Provisional AEL – Valid until 31 December 2013



Figure 1: Location of Impala smelter in relation to the surrounding environment (regional setting); yellow

circle depicts 5 km radius and the red circle depicts 50 km radius



Figure 2: Location of Impala smelter in relation to the surrounding sensitive areas (communities and

hostels)



2 NATURE OF THE PROCESS

2.1 Listed Activity A

A summary of the National Environmental Management: Air Quality Act (NEM:AQA) listed activities undertaken

at Impala smelter is provided in Table 5.

Table 5: Listed activities

Category of Listed Activity

Sub-category of the Listed Activity Description of the Listed Activity

Category 4 – Metallurgical industry

Sub-category 4.1 – Drying and calcining Drying and calcining of mineral solids including ore

Category 4 – Metallurgical industry

Sub-category 4.16 – smelting and converting of sulphide ores

Processes in which sulphide ores are smelted, roasted calcined or converted

(excluding inorganic chemicals-related activities regulated under Category 7)

2.2 Process Description

Below is a description of the entire production process including reference to inputs, outputs and

emissions at the site of the works.

2.2.1 General Process Description

The main activity at Impala is the mining and processing of platinum. The ventilation shafts associated with the

underground mining operations, vehicles travelling on unpaved and paved roads, material handling, crushing and

screening, plant stacks, windblown dust and burning bays are sources of particulate emissions. Ventilation

shafts, vehicles exhausts, plant stacks and burning bays are sources of gaseous emissions. Impala currently

comprises various operating components. These activities are listed in Table 6 with the associated pollutants of

concern.

Table 6: Air emissions and pollutants associated with Impala Platinum Limited - Rustenburg Operations

Activity Description Sources of emission Main Pollutants

Mining operations

(Underground only)

See section 2.2.1.1 Materials handling

Vehicle entrainment

Vehicle exhaust

Sulphur dioxide (SO2), oxides of nitrogen (NOx), particulate matter (PM - TSP, PM10 and PM2.5), carbon monoxide (CO), volatile organic compounds (VOC) and others

Crushing and screening

See section 2.2.1.3.2 Crushing

Screening

PM



Activity Description Sources of emission Main Pollutants

Processing operations

See section 2.2.1.2 Vehicle entrainment

Vehicle exhaust

Windblown dust

Stacks

Furnace and converter fugitives

SO2, NO2, PM, CO, VOC and others

Tailings storage facilities

See section 2.2.1.3.3 Windblown dust PM

Vehicles and mining equipment

See section 2.2.1.3.1 Vehicle entrainment

Vehicle exhaust

SO2, NO2, PM, CO, VOC and others

Laboratory See section 2.2.1.3.4 Stacks HCl, nitric acid, H2S, PM, lead and metals

Burning bays (explosive packaging)

See section 2.2.1.3.5 Combustion SO2, NOx, PM

Various domestic facilities

VOC, H2S and others

The most significant pollutant from point and fugitive sources is PM (particulate matter), occurring from almost all

the activities at the Impala operations. For particulate matter, a distinction is made between Total Suspended

Particulates (TSP), thoracic particulates (PM10, particulate matter with an aerodynamic diameter of less than

10 µ m) and respirable particulates (PM2.5, particulate matter with an aerodynamic diameter of less than 2.5 µ m).

Whereas TSP is of interest due to its implications in terms of nuisance dust impacts, the PM10 fraction is taken

into account to determine the potential for human health impacts. Gaseous emissions are more prominent from

the processing operations and the mining fleet and equipment and regarded insignificantly low from the other

activities.

Each of the operations is briefly described below to provide an overview of the air pollution activities at Impala;

however, only the smelter related activities are of interest with regards to this AIR and so comprehensive

dispersion modelling was undertaken for the smelter area operations which included both the listed activity

sources and some fugitive sources.

2.2.1.1 Mining Operations

Impala Platinum mines two underground reef bodies, the Merensky reef and the UG2 reef. Merensky reef

contains more sulphide than the UG2 reef, and the minerals are found in a silicate substrate. The deposit is fairly

narrow and mined by underground mining to depths of 1 500m. All opencast mining operations have ceased with

the last opencast pit rehabilitated in December 2013.

Typical operations associated with underground mining include sub-surface drilling and blasting, sub-surface

crushing and screening, transferring reef and waste rock to surface with conveyors, material transfer points and

stockpiling. The waste rock dumps are located near the shaft areas with the reef transported via road or rail.



2.2.1.2 Processing Operations

Ore is mined from the Merensky and UG2 reefs at a number of shafts in the vicinity of the smelting operation and

is transported to two concentrator plants via rail where it is milled. The milled ore is introduced to flotation banks

where particles containing precious metals are separated as a concentrate, leaving non-valuable tails which are

deposited onto tailings dams.

The concentrate is pumped as slurry to the smelter operation where it is dried via spray dryers, smelted in

furnaces to remove gangue materials (predominantly silica) and converted in Peirce-Smith converters to remove

sulphur and iron. The Impala Platinum Rustenburg Smelter also treats third party materials that are introduced

into the furnaces in three different ways namely: via the spray driers, via the flash dryer or fed directly into the

furnaces. The converters produce a matte which is the final product from the processing section. The converter

matte is transported by truck to the Impala refinery in Springs (Gauteng).

The operation was upgraded in 2008/2009 to increase smelter production capacity to potentially 2.65 million

ounces of platinum per year; the project included an extensive upgrade of the smelter air quality management

system.

2.2.1.2.1 Drying

Concentrate drying is conducted by means of coal-fired spray dryers and a single coal-fired flash dryer.

Spray Dryers: The principle of the operation is to atomise (break up into small particles) the partially thickened

concentrate in the presence of hot gas. The hot gas is generated in a hot gas generator and utilises the

combustion of coal as heat source. Water is rapidly vaporised from the wet concentrate and the majority of the

dried concentrate (less than 1% moisture) falls into the drying chamber. The remaining concentrate dust passes

into electrostatic precipitators, where the dust is recovered. The dry concentrate is pneumatically transferred into

dried concentrate storage silos from where it is pneumatically transferred into the furnaces.

Dryer off-gas is a combination of small amounts of particulates and gases which evolve through the combustion

of coal and dust not recovered in the precipitators. The gases include low concentrations of sulphur dioxide (from

the presence of a small amount of sulphur in coal), carbon dioxide and carbon monoxide.

Flash Dryer: The flash dryer serves to rapidly evaporate moisture from mechanically de-clotted concentrate

filter cake in a stream of hot gas. The resulting product is a fine dry dust that is pneumatically transferred into

dried concentrate storage silos from where it is pneumatically transferred into the furnaces. The hot gas required

for the evaporation is generated in a hot gas generator and utilises the combustion of coal as a heat source. The

flash dryer is fitted with primary and secondary cyclones and a bag house for the capture of dust particles. The

flash dryer increases the potential throughput from the dryer section to the furnaces.



Dryer off-gas is a combination of small amounts of dust and gases which evolve through the combustion of coal

and dust not recovered in the bag house. The gases include low concentrations of sulphur dioxide (from the

presence of a small amount of sulphur in coal), carbon dioxide and carbon monoxide.

The filtration of third party concentrate to produce a filter cake does not take place at the Processing Plant.

Concentrate is delivered as filter cake to the Smelter, dried in the flash dryer and fed to the electric furnaces.

2.2.1.2.2 Furnaces

Dry concentrate from the dryers, which includes third party material, is pneumatically transferred into dried

concentrate storage silos from where it is pneumatically transferred into the furnaces and smelted. The furnaces

utilise AC electrical current, discharged through large electrodes positioned in the furnace bath, to melt the

concentrate. The furnaces are lined with refractory materials to contain the high temperature generated in the

furnaces and are operated under negative pressure by gas off-takes at either end of the furnaces.

The smelter complex houses three furnaces of which only two were previously operational. The furnaces have a

combined maximum operational electrical capacity of 108MW (2 x 38MW and 1x 32MW).

Concentrate charged into the furnaces separates into two distinctive layers, with a high density matte layer

forming below a lower density slag layer. The matte contains the base metal sulphides and precious metals. The

slag contains gangue materials, which consist largely of silica, magnesia and smaller amounts of other oxide

impurities.

Furnace slag is tapped from the furnaces into a high pressure water stream (granulator), which results in the

flash-freezing of the slag in a granulated form. The granulated slag is then transferred to the slag milling and

flotation plant, for recovery of precious metals entrained in the slag. Molten furnace matte is tapped from the

furnaces into large ladles that are transferred, by means of an overhead crane, into the converters.

Off-gas from the furnaces is directed to a gas cleaning plant, the SulfacidTM Plant. Before reaching the

SulfacidTM Plant, the gas first passes through an electrostatic precipitator circuit to remove the dust.

The off gas circuit consists of:

• Two large electrostatic precipitators (ESPs) in parallel, each able to accommodate the full off-gas

load of three furnaces;

• Two quench scrubbers (downstream of the ESP) facilitating gas cooling and cleaning;

• The SulfacidTM plant comprising 12 reactors which can accommodate the off-gas from three

furnaces; and

• Further cleaning of the off-gas from the SulfacidTM plant in a lime scrubber.



2.2.1.2.3 Converter

Molten matte is tapped from the furnaces into ladles. An overhead crane transports the full ladles across the

aisle where the furnace matte is tipped into the open mouth of a converter. The converters are cylindrical in

shape and are known as Peirce-Smith converters. When sufficient furnace matte has been charged, the entire

converter rotates so that an extraction hood covers the open port (the converter mouth). Pressurised air is

injected into the converters below the level of the molten material. This serves to remove sulphur and iron from

the furnace matte through oxidation reactions.

Sulphur is removed as sulphur dioxide gas, which is largely captured by the extraction hood and directed to a

radial flow scrubber and a conventional single-contact sulphuric acid plant. Iron is removed as an iron silicate

(fayalite) through the addition of silica sand to the molten materials in the converter. Fayalite is less dense than

the converter matte and forms a discrete slag layer on the surface. The slag layer is skimmed off into ladles,

granulated in a high pressure water stream and reprocessed through the slag plant to recover valuable materials

entrained in the slag. During the conversion, fugitive gases and dust may escape from the converter hoods.

The converting process is exothermic and produces heat as a by-product of the oxidation reactions that occur in

the converter. Following converter slag removal, converter matte is poured from the open converter port into

ladles and granulated in a high pressure water stream. The granulated converter matte is the final product and is

transported by road to the refinery in Springs.

The converter operation comprises six vessels with a combined throughput capacity of 370 tonnes per day.

Converter off-gas is the feed gas for the Acid Plant and has a minimum sulphur dioxide content of 4.35% at a

maximum rate of 15 cubic meters per second (normalised). This gas stream cannot be vented directly to the

atmosphere due to the high sulphur dioxide concentration. The function of the Acid Plant is primarily to remove

sulphur dioxide from the converter off-gas stream. The feed gas is routed through a wet scrubber, a primary and

two secondary wet electrostatic precipitators that removes sulphur trioxide and dust from the gas stream before

entering the Acid Plant. After moisture removal in the drying tower, sulphur dioxide is catalytically converted to

sulphur trioxide in a single stage conversion, which is then absorbed into a recirculating acid stream to form

industrial grade sulphuric acid.

2.2.1.2.4 Tail Gas and Fugitive Gas Scrubbers

The tail gas lime scrubber comprises the mixing of the cleaned off-gas from the SulfacidTM plant and the Acid

Plant and the scrubbing of the combined gas stream with a milk of lime slurry before being emitted to the

atmosphere. Gypsum is produced as a by-product in the process.

The furnace and converter abatement system also includes a fugitive gas lime scrubber in addition to the tail gas

lime scrubber described above. Approximately 50 % of the fugitive dust and gas from the off-gas streams are

captured in hoods and cleaned in the fugitive gas lime scrubber.



2.2.1.3 Other Activities

Support functions include the transport of reef between the shafts and the smelter. It also includes transportation

of employees and other vehicle activity on the roads.

2.2.1.3.1 Vehicle emissions

Impala Platinum’s Transport Department provided information on vehicles and equipment at the facility for a

transport study conducted in 2016. The current vehicle and equipment fleet were assumed to be similar to the

2016 inventory and comprise of light duty vehicles, earthmoving vehicles, busses, cranes, heavy duty vehicles,

etc. The 2016 inventory was allocated to the actual roads and activities at Impala Platinum.

2.2.1.3.2 Crushing and screening

Crushing and screening operations can be a significant dust-generating source if uncontrolled. Dust fallout in the

vicinity of crushers also gives rise to the potential for re-entrainment of dust by vehicles or by wind at a later date.

The large percentage of fines in the deposited material enhances the potential for it to become airborne.

Primary crushing, secondary crushing and screening of ore occur at Impala Platinum’s Rustenburg Operations.

Fugitive dust emissions due to the crushing and screening operations include emissions from the loading of

crusher hoppers, crushing and discharge of material from crushers.

2.2.1.3.3 Tailings Storage Facilities

Impala Platinum has two tailings impoundments, one dormant (No. 1 & 2) and one active (No. 3 & 4). Currently,

only pipeline spillage is disposed of at No. 3. The active tailings dam has a footprint of approximately 800 ha with

a surface area of ~410 ha. On the western side of the tailings impoundment is the buttress dam that serves as a

strong wall for the tailings dam. The buttress also comprises of tailings material. All the sidewalls of the tailings

dam seemed well covered with grass and crushed slag is placed on the crests of the step-ins. Crushed waste

rock is placed on the access roads, serving as a dust suppressant. The surface area has a constant wet beach

of approximately 50%. Most of the flat areas on the step-ins have grass.

2.2.1.3.4 Processing Laboratory in Rustenburg

Impala Platinum Processing Laboratory is situated in Rustenburg and it comprises of three core sections namely;

Fire Assay, Analytical and the individual platinum group metals (IPGM) sections. The Fire Assay section

determines platinum group metals (PGM) in samples by means of lead collection which takes place during fusion



of sample with a suitable flux followed by purification of PGM bead by cupellation and high temperature

cupellation. The Analytical Section includes the determination of base metals in samples that require various

sample preparation steps, mainly acid digestion and sodium peroxide fusion, prior to instrumental analysis by a

variety of techniques namely; Inductively coupled plasma optical emission spectroscopy (ICP-OES), flame

atomic adsorption spectroscopy (FAAS), X-ray fluorescence (XRF) and ultra-violet/visible spectroscopy (UV/Vis).

The Analytical Section also includes a Water Laboratory in which electrochemical and photometric techniques

are used to determine an array of analytes in shaft, borehole, surface and special water samples from various

mining operations. The IPGM section determines the individual platinum group elements by nickel sulphide

collection, acid dissolution and hotplate digestion followed by ICP-OES analysis

The PGM and IPGM sections are equipped with dust extraction systems at the flux preparation and sample

preparation areas. The Fire Assay furnace room process has three steps including (1) separation of the slag from

the lead button containing PGMs in fusion process, (2) separation of the lead from the silver/PGM bead by

volatilisation of the lead oxide in the cupellation process and (3) volatilisation of remaining lead and silver and

purification of PGM bead in high temperature cupellation process. These high temperature processes are carried

out by means of small smelting furnaces that are all fitted with extraction hoods. For step 1 the fusion furnace

emissions are vented to one stack fitted to electrostatic precipitator devices (ESP) in the form of cased dust

filters and for steps 2 and 3 the muffle furnace emissions are vented to a second stack also fitted with ESP in

dust control units. The fusion process and dust emission controls from the IPGM section are similar to that of

Fire Assay section except precious metal are collected in nickel sulphide button. The splitting rooms for Fire

Assay and Analytical sections are fitted with extraction units that are directly linked to bag filters. Maintenance is

done on the extraction filter units every month and bags are checked and emptied on a weekly basis.

Other processes at the laboratory resulting in off-gas emissions include the acid digestion steps in the IPGM

section whereby HCl and H2S fumes are generated, extracted and neutralised by means of scrubber systems in

place. The acid dissolution and sodium peroxide fusion steps in the Analytical ICP and FAAS preparation

sections also generate acidic fumes, to a much lesser extent than in IPGM, which are extracted to stacks without

scrubbing. The IPGM and Analytical base metal standards rooms are also equipped with extraction units for the

acidic fumes that are generated during standard preparation.

2.2.1.3.5 Waste Incineration Processes

In terms of the regulations to the Explosives Act, Impala Platinum has to destroy their explosives waste by

burning in the open air. All explosives packaging is burnt at designated burning bays located at the various

shafts. The explosives waste only comprises of bulk bags and paper with all other explosives waste destroyed

underground during actual blasts or removed from site by a licensed contractor.

2.2.2 Visual Representations of Impala Smelter Operations

The following visual representations of the Impala smelter operations are provided:

• Figure 1 is a map indicating location within the region (page 4);

• Figure 2 is map indicating the location of Impala smelter in relation to AQSRs (page 5); and



• Figure 3 is a process flow diagram for the Impala smelter operations.

• Figure 4 shows the locations of the sources provided in section 4.



Figure 3: Impala smelter process flow diagram (created by Impala Platinum Limited)



2.3 Unit Process or Processes

Unit process considered listed activities under NEM:AQA are summarised in Table 7.

Table 7: List of unit processes considered listed activities under NEM:AQA

Name of the Unit Process Unit Process Function Listed Activity Sub-category

Batch or Continuous

Process

Hours of Operation

Drying Process Concentrate from the flotation process is pumped to the thickener section of the smelter. This section initially consisted of four concrete thickeners. Thickened pulp is pumped to the four Niro spray dryers in the drying section. Dried concentrate is pneumatically charged into concentrate storage silos. A total dry storage capacity of 6 060 tons of concentrate is provided.

4.1 Continuous 00:00 to 23:59

365 days per year

Smelting Process Dried concentrate from the silos is pneumatically charged into the six-in-line submerged electric-arc furnaces. Currently the two operational furnaces are the two 38 MW no. 3 and no. 5 furnaces, with the 32 MW no. 4 furnace available for period when increased capacity is required. During the smelting process the concentrate, which at furnace feed stage comprises approximately 15% sulphide minerals and 85% oxide minerals, are separated into a silica-rich slag and a nickel-copper sulphide furnace matte which also contains all of the PGM’s. The furnace slag is granulated in water and transported to the slag plant where the slag is milled and losses in the slag are recovered through flotation. The furnace matte is tapped into ladles transporting the molten matte into one of the Peirce-Smith converters. Excess iron sulphide is converted into iron oxide and SO2. Following converter slag removal, converter matte is poured from the open converter port into ladles and granulated in water. The granulated converter matte is the final product and is transported by road to the refinery in Springs.

The SulfacidTM Plant receives off-gas generated by the furnaces and converts SO2 into weak sulphuric acid.

The Acid Plant receives off-gas generated by the converters and converts SO2 into strong sulphuric acid.

The tailgas from the SulfacidTM Plant (furnace section) and the Acid Plant (converter section) are mixed and sent to a Tailgas scrubber, where it is scrubbed with lime and gypsum is produced.

A portion of the fugitive gas from the operation is captured by means of hoods, mixed and sent

4.16 Continuous 00:00 to 23:59

365 days per year



to a Fugitive Gas Scrubber where it is scrubbed with lime and gypsum is produced.



3 TECHNICAL INFORMATION

Raw material consumption and production rates are included in Table 8 and Table 11 respectively. The pollution abatement technologies employed at Impala smelter for the

point source, and technical specifications thereof, are provided in Table 9.

3.1 Raw Material Used

Table 8: Raw materials used

Raw Material Type Maximum Permitted Consumption Rate

(Quantity)

Design Consumption Rate (Quantity)

Actual Average Consumption Rate

(Quantity)(a)

Unit (Quantity per Period)

Dryers (combined) 100 167 100 167 64 288 tonnes per month

Concentrate (feed) 90 000 90 000 58 057 tonnes per month

Coal 10 167 10 167 6 231 tonnes per month

Electric Furnaces 91 085 91 100 81 389 tonnes per month

Concentrate (from dryers) 90 000 90 000 80 462 tonnes per month

Other furnace feed 1 085 1 100 927 tonnes per month

Electric Furnace APCE: Scrubbing Medium Supply 27 328 27 328 27 328 tonnes per month

Make-up water 27 328 27 328 27 328 tonnes per month

Converters and Acid Plant 13 635 13 635 9 416 tonnes per month

Furnace matte (from furnaces) 10 611 10 611 7 235 tonnes per month

Other matte (third party) 415 415 415 tonnes per month

Silica sand 2 610 2 610 1 766 tonnes per month

Converters and Acid Plant APCE: Scrubbing Medium Supply

46 569 46 569 46 569 tonnes per month



Make-up and stripping water 46 569 46 569 46 569 tonnes per month

Tailgas Scrubber and Fugitive Scrubber 17 916 17 916 17 916 tonnes per month

Tailgas scrubbing medium (15.5% burnt lime slurry) 3 242 3 242 3 242 tonnes per month

Fugitive scrubbing medium (15.5% burnt lime slurry) 412 412 412 tonnes per month

Make-up liquor (tailgas scrubber) 6 635 6 635 6 635 tonnes per month

Make-up liquor (fugitive scrubber) 1 594 1 594 1 594 tonnes per month

Chevron spray water (tailgas scrubber) 1 395 1 395 1 395 tonnes per month

Chevron spray water (fugitive scrubber) 335 335 335 tonnes per month

Oxidation air (tailgas scrubber) 3 472 3 472 3 472 tonnes per month

Oxidation air (fugitive scrubber) 834 834 834 tonnes per month

Notes:

(a) Actual Average Consumption Rates as per Financial Year 2018



3.2 Appliances and Abatement Equipment Control Technology

Table 9: Appliances and abatement equipment control technology for point sources

Appliances Abatement Equipment Control Technology

ID Appliance / Process

Equipment Number

Appliance Type /

Description

Appliance Serial

Number

Abatement

Equipment

Manufacture Date

Abatement

Equipment Name,

Model and

Number

Abatement Equipment

Technology Type/

Name/

Description

Commission Date

Date of Significant

Modification /

Upgrade

Design

Capacity

Minimum

Control

Efficiency

(%)

Minimum

Utilization

(%)

SD1 Spray Dryer 1 Niro spray dryer Not available 1987 ESP (dust capture) Electrostatic precipitator 1987 2012 ESP designed

for 40% of dust

load (dryer –

25 t/hr)

99 99

SD4 Spray Dryer 4 Niro spray dryer Not available 1974 ESP (dust capture) Electrostatic precipitator 1974 2013 (25%

modification)

ESP designed

for 40% of dust

load (dryer –

25 t/hr)

99 99

SD5 Spray Dryer 5 Hatch/Niro spray dryer Not available 1991 ESP (dust capture) Electrostatic precipitator 1991 2012 (66%

modification)

ESP designed

for 40% of dust

load (dryer –

50 t/hr)

99 99

SD6 Spray Dryer 6 DryTech/Niro spray

dryer

Not available Jan 2003 ESP (dust capture) Electrostatic precipitator Jan 2003 None ESP designed

for 40% of dust

load (dryer –

60 t/hr)

99 99

FD1 Flash Dryer 1 DryTech flash dryer Not available Aug 2008 Bag filter (dust

capture)

Baghouse Aug 2008 None Baghouse

designed for

5% of dust

load (dryer –

45 t/hr)

99 99

TGS (furnace primary

offgas)

Furnace 3

Submerged arc furnace

(38 MW) – Hatch


(32 MW) – Hatch

Not available

Not available

2008 ESP (primary dust

capture – all

furnaces)

Electrostatic precipitator 2008 2013 Offgas from 3

furnaces at full

load

99 99





Equipment Number

Appliance Type /

Description

Appliance Serial

Number

Abatement

Equipment

Manufacture Date

Abatement

Equipment Name,

Model and

Number

Abatement Equipment

Technology Type/

Name/

Description

Commission Date

Date of Significant

Modification /

Upgrade

Design

Capacity

Minimum

Control

Efficiency

(%)

Minimum

Utilization

(%)

Furnace 4

Furnace 5


(38 MW) - Hatch

Not available

2002 SulfacidTM plant

(primary SO2

capture – all

furnaces)

Carbon based reactors 2002 2008 12 reactors /

offgas from 3

furnaces at full

load

75 96

2008* Dynawave lime

scrubber

(secondary SO2

capture – all

furnaces)

Lime based scrubber 2009 None 150 000

Nm³/hr

83 82.5

TGS (converter

primary offgas)

Converter 1 (small)

Converter 2 (small)

Converter 3 (small)

Converter 4 (small)

Converter 5 (large)

Converter 6 (large)

Converter 7 (large)

Pierce smith converter

– Treadwell


– Treadwell


– Treadwell


– Treadwell


– RSV


– RSV

Pierce smith converter -

DTEP

Not available

Not available

Not available

Not available

Not available

Not available

Not available

1974 Acid plant (primary

SO2 capture – all

converters)

Single contact sulphuric

acid plant

1974 2000; 2002; 2008 250 t/day

sulphuric acid

90.6 100

2008* Dynawave lime

scrubber

(secondary SO2

capture – all

converters)

Lime based scrubber 2009 None 150 000

Nm³/hr

83 82.5

FGS (furnace and Furnace 3 Submerged arc furnace Not available 2008 Dynawave lime Lime based scrubber 2009 None 90 000 Nm³/hr 94 92





Equipment Number

Appliance Type /

Description

Appliance Serial

Number

Abatement

Equipment

Manufacture Date

Abatement

Equipment Name,

Model and

Number

Abatement Equipment

Technology Type/

Name/

Description

Commission Date

Date of Significant

Modification /

Upgrade

Design

Capacity

Minimum

Control

Efficiency

(%)

Minimum

Utilization

(%)

converter fugitive

offgas)

Furnace 4

Furnace 5

Converter 1 (small)

Converter 2 (small)

Converter 3 (small)

Converter 4 (small)

Converter 5 (large)

Converter 6 (large)

Converter 7 (large)

(38 MW) – Hatch


(32 MW) – Hatch


(38 MW) – Hatch


– Treadwell


– Treadwell


– Treadwell


– Treadwell


– RSV


– RSV

Pierce smith converter -

DTEP

Not available

Not available

Not available

Not available

Not available

Not available

Not available

Not available

Not available

scrubber

(secondary SO2

capture – fugitives)

Notes:

* Same abatement equipment



Table 10: Area and/or line source – management and mitigation measures

ID Description of Specific Measures Timeframe for Implementation of Specific

Measures

Method of Monitoring Measure

Effectiveness

Contingency Measure

NKSP

Dedicated bunker storage area with roof. Nature of the toll material and moisture content limits fugitive emissions at storage areas.

Standard operating procedure is to keep material contained in dedicated roofed storage areas and to keep material wet to avoid

windblown dust.

Current mitigation measures are effective

Dust fallout and ambient stations

SSSP Dedicated bunker storage area. Area where silica sand is handled is kept clean by dedicated cleaning crews. Current mitigation measures are effective

CLSP Coal has a dedicated bunker storage area and because Grade A pea coal used, fewer fines are present. Current mitigation measures are effective

ASSP Dedicated bunker storage area. Ash is removed at regular intervals and area kept clean by dedicated cleaning crews. Current mitigation measures are effective

GypSP Dedicated bunker storage area. Gypsum is removed at regular intervals from site. Area kept clean by dedicated cleaning crews. Current mitigation measures are effective



3.3 Production Rates

Table 11: Production Rates

Product Name Maximum Permitted

Production Rate (Quantity)

Design Production Rate (Quantity)

Actual Average Production Rate

(Quantity)(a)



Concentrate dried 90 000 90 000 80 462 tonnes per month


Furnace matte 10 611 10 611 7 235 tonnes per month


Converter matte 3 000 3 000 2 352 tonnes per month

Notes:

(a) Actual Average Production Rates as per Financial Year 2018

Table 12: By-product Rates





(Quantity)(a)



APCE product: sulphuric acid

6 267 6 267 4 002 tonnes per month

Notes:


3.4 Waste Rates

Table 13: Effluent Rates



Design Production

Rate (Quantity)

Actual Average

Production Rate

(Quantity)(a)



APCE effluent: weak acid (< 25% H2SO4) 11 539 11 539 10 539 tonnes per month


APCE effluent: weak acid (< 25% H2SO4) 45 741 45 741 45 607 tonnes per month

Tailgas Scrubber and Fugitive Scrubber 13 348 13 348 13 348 tonnes per month

Liquid purge (gypsum dewatering) (minimum)

13 348 13 348 13 348 tonnes per month

Notes:




Table 14: Solid Waste Rates





(Quantity)(a)



Coal ash 2 663 2 663 2 663 tonnes per month


Furnace slag 80 193 80 193 71 883 tonnes per month


Converter slag and other reverts


Tailgas Scrubber and Fugitive Scrubber


Gypsum (tailgas scrubber) – dry (83% Efficiency)

955 955 955 tonnes per month

Gypsum (fugitive scrubber) – dry (94% Efficiency)

155 155 155 tonnes per month

Notes:


Table 15: Fugitive Emission Rates





(Quantity)



Electric furnace fugitives (total quantity of offgas, i.e. includes air and not pollutants only)

24 690 24 690 24 690 tonnes per month


Converter fugitives (total quantity of offgas, i.e. includes air and not pollutants only)

26 344 26 344 26 344 tonnes per month

3.5 Assumptions, Limitations and Exclusions

The following important assumptions, exclusions and limitations to the specialist study should be noted:

1. All information required to calculate emissions for the operations were provided by Impala Platinum

Limited.

2. The impact of the current operational phase was determined quantitatively through emissions

calculation, provided isokinetic sampling results and simulation.



3. Meteorology:

a. The National Code of Practice for Air Dispersion Modelling prescribes the use of a minimum of

1-year on-site data or at least three years of appropriate off-site data for use in Level 2

assessments. It also states that the meteorological data must be for a period no older than five

years to the year of assessment.

b. On-site meteorological data was available for 2016 and 2017.

c. The meteorological data used was for the period 1 January 2016 to 31 December 2017.

Therefore, the data set applied in this study complies with the requirements of the code of

practice.

4. The estimation of greenhouse gas (GHG) emissions was not included in the scope of work as under the

listed activity pertaining to this Atmospheric Emission Licence (AEL) application no Minimum Emission

Standards (MES) are specified for GHG pollutants. Reference is made to GHG emission reporting

regulations as all existing facilities are required to report emissions on the National Atmospheric

Emission Inventory System (NAEIS).

5. Emissions:

a. The impact assessment was limited to airborne particulates (including total suspended

particulates (TSP), inhalable particulate matter (PM) less than 10 µ m in diameter (PM10) and

inhalable PM less than 2.5 µm in diameter (PM2.5)) and gaseous pollutants from the stacks

which included oxides of nitrogen (NOx) and sulphur dioxide (SO2). These pollutants are either

regulated under MES or National Ambient Air Quality Standards (NAAQS).

b. The point sources (stacks) measured/actual emissions were based on the highest average

measured emission from isokinetic sampling undertaken during 2016 and 2017.

c. Emissions for other activities in the area, such as mining, processing, agricultural activities,

biomass burning, residential fuel burning, wind erosion from open areas, vehicles travelling on

public and private roads (comprising of vehicle entrainment on the roads and vehicle exhaust)

were not estimated due to their complexity and lack of information on these sources.

d. Air emissions from other industries and activities were not included in the simulations.

e. There are other industries adjacent to the smelter operations; however, only Impala operations

could be quantified and concentrations (as a result of all of Impala’s activities) at receptors

were determined through dispersion modelling.

6. Dispersion simulations:

a. All significant fugitive sources were simulated with the current mitigation measures applied.

b. Highest average stack emissions were included in the dispersion simulation task.

c. It was assumed that all NOx emitted is converted to NO2.



4 ATMOSPHERIC EMISSIONS

The establishment of a comprehensive emission inventory formed the basis for the assessment of the air quality

impacts from Impala smelter operations on the receiving environment. The smelter generates fugitive emissions

as well as process emissions. Fugitive emissions (discussed in Section 4.4) refer to emissions that are

distributed over a wide area and not confined to a specific discharge point as would be the case for process

related emissions (discussed in Section 4.1).

Point source emissions are included as single point sources since these are captured and vented to the

atmosphere via stacks. Source parameters and emission rates are included in Table 16 and Table 17. Methods

used in the estimation of these emissions are included in Table 18. Fugitive source parameters and emission

rates are included in Table 20 and Table 21. Methods used in the estimation of these emissions are included in

Table 22. Figure 4 shows the locations of the sources provided in this section.



4.1 Point Source Parameters

Table 16: Point source parameters

ID Source Name Stack Orientation Latitude (decimal

degrees) Longitude (decimal

degrees) Height of Release Above Ground (m)

Height Above Nearby Building (m)

Diameter at Stack Tip / Vent Exit (m)

Actual Gas Exit Temperature (°C)

Actual Gas Volumetric Flow

(m³/hr)

Actual Gas Exit Velocity (m/s)

SD1 Spray dryer 1 Vertical -25.5421700 27.1834200 40.0 Not applicable 2.5 90.0 38 877.21 2.2




FD1 Flash dryer 1 Vertical -25.5437900 27.1855200 35.6 Not applicable 1.5 100.0 95 425.88 15.0

TGS Tailgas scrubber stack Vertical -25.5433500 27.1844200 77.0 Not applicable 2.2 40.0 251 799.91 18.4

FGS Fugitive scrubber stack Vertical -25.5433000 27.1839400 40.0 Not applicable 1.3 26.0 71 675.44 15.0

Main Emergency stack (furnace and converters) Vertical -25.5423500 27.1840700 ~70.0 Not applicable 2.0 120.0 130 061.94 11.5

4.2 Point Source Maximum Emission Rates (Normal Operating Conditions)

Table 17: Point source emissions

ID Pollutant Name AEL Limits(a) Maximum Release Rate Emissions Hours Type of Emissions (Continuous / Routine but Intermittent /

Emergency Only) 2015 (mg/Nm³) 2020 (mg/Nm³) mg/Nm³ mg/Am³ g/s tpa

SD1

PM 100 50 11.8 6.6 0.143 4.52 24 hours/day Continuous

NOx expressed as NO2 1 000 500 273 153 3.31 105 24 hours/day Continuous

SOx expressed as SO2 1 000 1 000 273 153 3.31 105 24 hours/day Continuous

SD4


NOx expressed as NO2 1 000 500 5.23 3.24 0.192 6.05 24 hours/day Continuous


SD5


NOx expressed as NO2 1 200 500 79.9 45.1 3.33 105 24 hours/day Continuous

SOx expressed as SO2 1 000 1 000 171 96.4 7.13 225 24 hours/day Continuous

SD6




FD1




TGS



SOx expressed as SO2 3 500 1 000 2 880 2 078 116 3 658 24 hours/day Continuous



ID Pollutant Name AEL Limits(a) Maximum Release Rate Emissions Hours Type of Emissions (Continuous / Routine but Intermittent /

Emergency Only) 2015 (mg/Nm³) 2020 (mg/Nm³) mg/Nm³ mg/Am³ g/s tpa

FGS



SOx expressed as SO2 1 000 1 000 239 187 2.92 92.1 24 hours/day Continuous

Notes:

(a) This plant had to comply with 2015 AEL limits since 01 April 2015.

This plant must comply with 2020 AEL limits (new plant national minimum emission standards (NMES)) by 01 April 2020.

4.2.1 Point Source Emission Estimation Methods (Normal Operating Conditions)

Mainly measured emissions were used for the Impala Smelter operations. These are summarised, per source, in Table 18.

Table 18: Point source emission estimation information

ID Basis for Emission Rates

SD1

PM - Average of isokinetic sampling undertaken by C & M Consulting Engineers in April 2017

NOx expressed as NO2 - Average of isokinetic sampling undertaken by C & M Consulting Engineers in April 2017

SOx expressed as SO2 - Average of isokinetic sampling undertaken by C & M Consulting Engineers in April 2017

SD4




SD5

PM - Average of isokinetic sampling undertaken by C & M Consulting Engineers in November 2016

NOx expressed as NO2 - Average of isokinetic sampling undertaken by C & M Consulting Engineers in November 2016

SOx expressed as SO2 - Average of isokinetic sampling undertaken by C & M Consulting Engineers in November 2016

SD6




FD1




TGS




FGS

PM - Average of isokinetic sampling undertaken by C & M Consulting Engineers in November 2016

NOx expressed as NO2 - Average of isokinetic sampling undertaken by C & M Consulting Engineers in November 2016




4.3 Point Source Maximum Emission Rates during Start-up, Maintenance and/or Shut-down)

The scope of this study did not include the quantification of emissions during start-up, maintenance or shut down. Impala smelter is only required to conduct periodic

measurements which makes it difficult to establish maximum emissions during start-up, shut-down, maintenance or upset conditions, since periodic measurements cannot pin-

point exactly when the maximum emission rate will occur. The main reason maximum values cannot be predicted with periodic sampling, in this case, is that the sampling

methods prescribe fixed time periods during which a sample must be taken. In addition, the timing of specific conditions leading to an absolute maximum emission rate is not

predictable, meaning that the sampling period and the conditions resulting in the upsets are unlikely to occur concurrently; hence it cannot be guaranteed that a maximum

emission rate will be reached at a specific condition. Potential start up, maintenance, shut down, upset conditions and associated responses related to the operations at the

site of the works are however qualitatively discussed in Table 19.

Table 19: Emission during start-up, maintenance, upset and/or shut-down

Unit Process ID Description of Occurrence

of Potential Releases

Pollutants and associated amount of emissions

Pollutant mg/Nm³

Drying SD1

Start-up

PM Likely higher than normal operations emissions

NOx expressed as NO2 Likely similar to normal operations emissions

SO2 Likely similar to normal operations emissions

Shut-down

PM

Likely lower than operations emissions NOx expressed as NO2

SO2

Maintenance No emission generated during maintenance

Upset/Emergency

PM

Higher than normal operations emissions NOx expressed as NO2

SO2

SD4 Start-up PM Likely higher than normal operations emissions






Pollutant mg/Nm³



Shut-down

PM


SO2


Upset/Emergency

PM


SO2

SD5

Start-up




Shut-down

PM


SO2


Upset/Emergency PM







Pollutant mg/Nm³

SO2

SD6

Start-up




Shut-down

PM


SO2


Upset/Emergency

PM


SO2

FD1

Start-up




Shut-down

PM


SO2


Upset/Emergency PM Higher than normal operations emissions






Pollutant mg/Nm³

NOx expressed as NO2

SO2

Furnaces and Converters

TGS

Start-up and shut-down

PM

Likely higher than normal operations emissions NOx expressed as NO2

SO2


Upset/Emergency

PM None – upset/emergency emissions vent

through “Main” NOx expressed as NO2

SO2

FGS

Start-up and shut-down

PM

Likely similar to normal operations emissions NOx expressed as NO2

SO2


Upset/Emergency

PM


SO2

Main Upset/Emergency

PM Higher than normal operations emissions

NOx expressed as NO2 Similar to normal operational emissions

SO2 Higher than normal operations emissions

4.3.1 Point Source Emission Estimation Methods (Start-up, Maintenance, Upset and/or Shut-down)

Since isokinetic sampling is only required to be undertaken during routine (normal) operations there is no measurements to base the emissions on. Also, these events cannot

always be planned for in advance making it difficult to sample during these conditions.



4.4 Fugitive Emissions (Area and Line Sources)

All smelter fugitive emissions are included in this section. Source parameters and emission rates are included in Table 20 and Table 21. Methods used in the estimation of

these emissions are included in Table 22.

4.4.1 Fugitive Source Parameters

Table 20: Area and volume source parameters

ID Source Name Source Description

Latitude

(decimal

degrees)

Longitude

(decimal

degrees)

Height

of

Release

(m)

Length of Area

(m)

Width of Area

(m)

Angle of Rotation

from True North

(°)

NKSP Smelter Toll material SP Toll material stockpile: sources

of particulate matter are wind

disturbance (erosion) and

material handling

-25.543797 27.179673 3 Variable Variable Variable

SSSP Smelter Silica sand Silica material stockpile: sources of particulate matter are wind disturbance (erosion) and material handling


CLSP Smelter Coal SP Coal material stockpile: sources of particulate matter are wind disturbance (erosion) and material handling


ASSP Smelter Ash SP Ash material stockpile: sources of particulate matter are wind disturbance (erosion) and




ID Source Name Source Description

Latitude

(decimal

degrees)

Longitude

(decimal

degrees)

Height

of

Release

(m)

Length of Area

(m)

Width of Area

(m)

Angle of Rotation

from True North

(°)

material handling

GypSP Gypsum SP Gypsum material stockpile: sources of particulate matter are wind disturbance (erosion) and material handling


TC Tertiary Crusher Tertiary Crushing -25.541214 27.183057 5 10 10 0

4.4.2 Fugitive Sources Maximum Emission Rates during Normal Operating Conditions

Table 21: Area and volume source emissions

ID Pollutant Name Maximum Release Rate

(grams per second)

Average Annual Release

Rate (tonnes per year) Emission Hours

Type of Emission

(Continuous / Intermittent)

Wind Dependent (Yes /

No)

NKSP PM2.5 – Materials Handling

1.89x10-04 5.97x10-03 00h00 – 23h59

365 days per year

Intermittent Yes

PM10 – Materials Handling

1.25x10-03 0.039 00h00 – 23h59

365 days per year

Intermittent Yes

TSP – Materials Handling

2.64x10-03 0.083 00h00 – 23h59

365 days per year

Intermittent Yes

PM2.5 – Wind Erosion Negligible

Negligible Expected when wind speeds are >5.2 m/s

Intermittent Yes

PM10 – Wind Erosion Negligible Negligible Expected when wind speeds are >5.2 m/s

Intermittent Yes




(grams per second)



Type of Emission



No)

TSP – Wind Erosion Negligible Negligible Expected when wind speeds are >5.2 m/s

Intermittent Yes

SSSP PM2.5 Negligible Negligible 00h00 – 23h59

365 days per year

Intermittent Yes

PM10 Negligible Negligible 00h00 – 23h59

365 days per year

Intermittent Yes

TSP Negligible Negligible 00h00 – 23h59

365 days per year

Intermittent Yes

CLSP PM2.5 Negligible Negligible 00h00 – 23h59

365 days per year

Intermittent Yes


365 days per year

Intermittent Yes


365 days per year

Intermittent Yes

ASSP PM2.5 Negligible Negligible 00h00 – 23h59

365 days per year

Intermittent Yes


365 days per year

Intermittent Yes


365 days per year

Intermittent Yes

GypSP PM2.5 Negligible Negligible 00h00 – 23h59

365 days per year

Intermittent Yes


365 days per year

Intermittent Yes




(grams per second)



Type of Emission



No)


365 days per year

Intermittent Yes

TC PM2.5 0.040 1.25 00h00 – 23h59

365 days per year

Continuous No

PM10 0.079 2.49 00h00 – 23h59

365 days per year

Continuous No

TSP 1.38 43.6 00h00 – 23h59

365 days per year

Continuous No

4.4.3 Fugitive Sources Emission Estimation Methods

Table 22: Area and volume source emission estimation information

ID Basis for Emission Rates

NKSP Emission rates estimated using US EPA AP42 “13.2.4 Aggregate Handling and Storage Piles” emission factor for miscellaneous transfer and conveying – based on material used; moisture content assumed to be 4.8%; average wind speed of 3.31 m/s, from meteorological data. (US EPA, 2006a)

For the estimation of windblown dust emissions, use was made of the ADDAS model and the material specific particle size distribution. (Burger & Held, 1997)

SSSP Not quantified. Not enough information available to be able to quantify emissions. Assumed to be immaterial in relation to the other sources.

CLSP Not quantified. Not enough information available to be able to quantify emissions. Assumed to be immaterial in relation to the other sources.

ASSP Not quantified. Not enough information available to be able to quantify emissions. Assumed to be immaterial in relation to the other sources.

GypSP Not quantified. Not enough information available to be able to quantify emissions. Assumed to be immaterial in relation to the other sources.

TC Emission rates estimated using ADE NPI, “Mining” emission factors for miscellaneous low moisture ore crushing and screening – based on raw material processed; moisture content provided to be to be 3.93%. (ADE, 2012)





Figure 4: Impala Smelter sources locations



4.5 Emergency Incidents

No air quality related incidents that have been reported over the past two years.



5 IMPACT OF ENTERPRISE ON THE RECEIVING ENVIRONMENT

The assessment of the impact of the Impala smelter operations on the human health is discussed in this section.

5.1 Analysis of Emissions’ Impact on Human Health

5.1.1 Assessment Criteria for Human Health - National Ambient Air Quality Standards

Criteria pollutants are considered those pollutants most commonly found in the atmosphere, that have proven

detrimental health effects when inhaled and are regulated by ambient air quality criteria. South African NAAQS

for PM10, NO2 and SO2 were published on 24 December 2009. On 29 June 2012 standards for PM2.5 were also

published. These standards are listed in Table 23.

Table 23: National Ambient Air Quality Standards for criteria pollutants

Pollutant Averaging

Period Limit Value

(µg/m³) Frequency of Exceedance

Compliance Date

PM2.5

24-hour 40 4 Currently enforceable (1 Jan 2016 – 31 Dec 2029)

24-hour 25 4 Enforceable from 1 Jan 2030

1-year 20 - Currently enforceable (1 Jan 2016 – 31 Dec 2029)

1-year 15 - Enforceable from 1 Jan 2030

PM10 24-hour 75 4 Currently enforceable

1-year 40 - Currently enforceable

NO2 1-hour 200 88 Currently enforceable


SO2

10-minute 500 526 Currently enforceable

1-hour 350 88 Currently enforceable

24-hour 125 4 Currently enforceable


CO 1-hour 30 000 88 Currently enforceable

8-hour 10 000 11 Currently enforceable

5.1.2 Atmospheric Dispersion Potential

Meteorological mechanisms govern the dispersion, transformation, and eventual removal of pollutants from the

atmosphere. The analysis of land-use and topography as well as hourly average meteorological data is

necessary to facilitate a comprehensive understanding of the dispersion potential of the site. The horizontal

dispersion of pollution is largely a function of the wind field. The wind speed determines both the distance of

downward transport and the rate of dilution of pollutants.



On-site meteorological data, from the Shaft17 weather station was used in AERMET/AERMOD. Hourly

sequential data from January 2016 to December 2017 was used in dispersion modelling. Parameters useful in

describing the dispersion and dilution potential of a site i.e. wind speed, wind direction, temperature and

atmospheric stability. The wind field is subsequently discussed. The data described below is as processed by

AERMET from the measured data.

5.1.2.1 Surface Wind Field

The wind field determines both the distance of downward transport and the rate of dilution of pollutants. The

generation of mechanical turbulence is a function of the wind speed, in combination with the surface roughness.

The wind field for the study area is described with the use of wind roses.

Wind roses comprise 16 spokes, which represent the directions from which winds blew during a specific period.

The colours used in the wind roses below, reflect the different categories of wind speeds; the yellow area, for

example, representing winds in between 6 and 7 m/s. The dotted circles provide information regarding the

frequency of occurrence of wind speed and direction categories. The frequency with which calms occurred, i.e.

periods during which the wind speed was below 1 m/s are also indicated.

A wind rose for the period January 2016 to December 2017 is shown in Figure 5. Day-time and night-time wind

roses are included in Figure 6. 2016 94% data availability while 2017 had a data availability of only 80%.

Although it appears that the northerly winds are not being measured correctly, it is expected that the maximum

amount of time that the winds may originate from the north is 6% (this is the portion missing in 2016). The wind

field was dominated by winds from the east followed by winds from the east-south-east and south-south-west.

Calm conditions occurred less than 1% of the time. During the day, winds occurred more frequently from the

easterly and east-south-easterly sectors. Night-time airflow had winds from the south-south-westerly and south-

westerly sectors occurring most frequently. In general, the wind speeds are quite low.



Figure 5: Period average wind rose (AERMET data, 2015 to 2017)

Day-time

Night-time

Figure 6: Day-time and night-time wind roses (AERMET data, 2015 to 2017)

5.1.3 Screening of Simulated Concentrations for Potential Human Health Impacts (Normal Operating

Conditions)

Key pollutants with the potential to result in human health impacts and included in simulations for this study are

PM2.5, PM10, NOx, SO2 and CO. It should be noted that simulated concentrations only reflect those associated

with atmospheric emissions from Impala smelter as quantified in Section 4. The emissions account for the routine

use of abatement equipment associated with source.

5.1.3.1 Impala Smelter Operations – Measured Emissions (Isokinetic Sampling)

The dispersion simulation results described below are as a result of the drying and smelting/converting

operations. These results include process operations that are taking place at the Impala smelter, these include

the point sources discussed in Section 4. The stack emissions are based on the isokinetic emission sampling

undertaken by C&M Consulting Engineers during 2016 and 2017.

Simulated Ambient PM2.5/PM10 Concentrations

Simulations were undertaken based on the assumption that all the PM measured was 2.5 µ m in diameter or less

(PM2.5). The simulated annual average PM2.5/PM10 concentrations as a result of the Impala smelter operations do

not exceed the current PM2.5 NAAQS of 20 µ g/m3, the future PM2.5 NAAQS of 15 µ g/m3 or PM10 NAAQS of

40 µ g/m³ on-site, off-site or at any residences, schools or hospitals (Figure 7). The maximum simulated annual

average PM2.5/PM10 concentration is 1.68 µ g/m³. The current 24-hour PM2.5 NAAQS (4 days of exceedance of

40 µ g/m3), future PM2.5 24-hour NAAQS (4 days of exceedance of 25 µ g/m3) and PM10 24-hour NAAQS (4 days



of exceedance of 75 µ g/m3) are not exceeded on-site, off-site or at any residences, schools or hospitals (Figure

8). The simulated 24-hour PM2.5/PM10 concentration is 8.96 µg/m³.

Figure 7: Impala smelter operations with measured stacks emissions (isokinetic sampling): simulated

annual average PM2.5/PM10 concentrations



Figure 8: Impala smelter operations with measured stacks emissions (isokinetic sampling): simulated 24-

hour average PM2.5/PM10 concentrations

Simulated Ambient NO2 Concentrations

The simulated NOx concentrations were compared to the NO2 NAAQS. The simulated annual average NOx

concentrations as a result of the Impala smelter operations did not exceed the NO2 NAAQS of 40 µ g/m3 on-site,

off-site or at any residences, schools or hospitals (Figure 9). The 1-hour NAAQS (88 hours of exceedance of

200 µ g/m3) is not exceeded on-site, off-site or at any residences, schools or hospitals (Figure 10).



Figure 9: Impala smelter operations with measured stacks emissions: simulated annual average NOx

concentrations



Figure 10: Impala smelter operations with measured stacks emissions: frequency of exceedance of the

simulated 1-hour NOx concentration of 200 µg/m³

Simulated Ambient SO2 Concentrations

The simulated annual average SO2 concentrations as a result of the Impala smelter operations do not exceed the

NAAQS of 50 µ g/m3 (Figure 11). The 24-hour NAAQS (4 days of exceedance of 125 µ g/m3) is not exceeded on-

site but is off-site and at residences (Figure 12). The 1-hour NAAQS (88 hours of exceedance of 350 µ g/m3) is

exceeded on-site, off-site and at residences (Figure 13).



Figure 11: Impala smelter operations with measured stacks emissions: simulated annual average SO2

concentrations




simulated 24-hour average SO2 concentration of 125 µg/m³




simulated 1-hour SO2 concentration of 350 µg/m³

5.1.3.2 Impala Smelter Operations – Measured Emissions (Continuous and Isokinetic Sampling)



the point sources discussed in Section 4. The dryer stack emissions are based on the continuous emission



sampling undertaken by Impala. The tailgas scrubber and fugitive gas scrubber are based on the continuous

emission sampling undertaken by C&M Consulting Engineers during 2016 and 2017.


Simulations were undertaken based on the assumption that all the PM measured was 2.5 µ m in diameter or less

(PM2.5). The simulated annual average PM2.5/PM10 concentrations as a result of the Impala smelter operations do

not exceed the current PM2.5 NAAQS of 20 µ g/m3, the future PM2.5 NAAQS of 15 µ g/m3 or PM10 NAAQS of

40 µ g/m³ on-site, off-site or at any residences, schools or hospitals (Figure 14). The maximum simulated annual

average PM2.5/PM10 concentration is 4.73 µ g/m³. The current 24-hour PM2.5 NAAQS (4 days of exceedance of

40 µ g/m3), future PM2.5 24-hour NAAQS (4 days of exceedance of 25 µ g/m3) and PM10 24-hour NAAQS (4 days

of exceedance of 75 µg/m3) are not exceeded on-site, off-site or at any residences, schools or hospitals Figure

15). The maximum simulated 24-hour PM2.5/PM10 concentration is 24.4 µ g/m³.



Figure 14: Impala smelter operations with measured stacks emissions (continuous and isokinetic

sampling): simulated annual average PM2.5/PM10 concentrations



Figure 15: Impala smelter operations with measured stacks emissions (continuous and isokinetic

sampling): simulated 24-hour average PM2.5/PM10 concentrations

5.1.3.3 Impala Smelter Operations – Mass Balance Emissions



the point sources discussed in Section 4. The stack emissions are based on the mass balance completed by

Impala during 2016.





NAAQS of 50 µ g/m3 (Figure 16). The 24-hour NAAQS (4 days of exceedance of 125 µ g/m3) is not exceeded on-

site, off-site or at any residences, schools or hospitals. The 1-hour NAAQS (88 hours of exceedance of

350 µ g/m3) is not exceeded on-site, off-site or at any residences, schools or hospitals (Figure 17).

Figure 16: Impala smelter operations with mass balance stacks emissions: simulated annual average

SO2 concentrations



Figure 17: Impala smelter operations with mass balance stacks emissions: frequency of exceedance of

the simulated 1-hour SO2 concentration of 350 µg/m³



5.1.3.4 Impala Smelter Operations – AEL Limits for 2015

The dispersion simulation results described below are as a result of the Impala smelter operations. These results

include all the process operations that are taking place at Impala smelter, these include the point sources

discussed in Section 4. The stack emissions are based on the limits set out to be achievable from 2015 in the

current AEL.


Simulations were undertaken based on the assumption that all the PM is 2.5 µ m in diameter or less (PM2.5). The

simulated annual average PM2.5/PM10 concentrations as a result of the Impala smelter operations do not exceed

the current PM2.5 NAAQS of 20 µ g/m3, the future PM2.5 NAAQS of 15 µ g/m3 or PM10 NAAQS of 40 µ g/m³ on-site,

off-site or at any residences, schools or hospitals (Figure 18). The maximum simulated annual average

PM2.5/PM10 concentration is 5.91 µ g/m³. The current 24-hour PM2.5 NAAQS (4 days of exceedance of 40 µ g/m3),

future PM2.5 24-hour NAAQS (4 days of exceedance of 25 µ g/m3) and PM10 24-hour NAAQS (4 days of

exceedance of 75 µ g/m3) are not exceeded on-site, off-site or at any residences, schools or hospitals (Figure

19). The simulated 24-hour PM2.5/PM10 concentration is 24.6 µ g/m³.



Figure 18: Impala smelter operations with 2015 AEL Limits: simulated annual average PM2.5/PM10

concentrations




concentrations



concentrations as a result of the Impala smelter operations exceed the NO2 NAAQS of 40 µ g/m3 off-site and

residences (Figure 20). The maximum simulated annual average NOx concentration at the boundary is 55 µ g/m³,

near the smelter plant (where the stacks are located). The 1-hour NAAQS (88 hours of exceedance of 200

µ g/m3) is exceeded off-site and at residences (Figure 21). The simulated frequency of exceedance of the 1-hour

NO2 NAAQ limit of 200 µ g/m³ off-site is 205 hours, south-west and west of Phokeng.



Figure 20: Impala smelter operations with 2015 AEL Limits: simulated annual average NOx

concentrations



Figure 21: Impala smelter operations with 2015 AEL Limits: frequency of exceedance of the simulated 1-

hour NOx concentration of 200 µg/m³



NAAQS of 60 µ g/m3 off-site or at any residences, schools or clinics (Figure 22). The maximum simulated annual

average SO2 concentration at the boundary is 35.4 µ g/m³, near the smelter plant (where the stacks are located).

The 24-hour NAAQS (4 days of exceedance of 125 µ g/m3) is exceeded off-site and at residences (Figure 23).

The simulated frequency of exceedance of the 24-hour SO2 NAAQ limit of 125 µg/m³ at the boundary is 35 days,

south-west and west of Phokeng. The 1-hour NAAQS (88 hours of exceedance of 350 µ g/m3) is exceeded off-



site but not at any residences, schools or clinics (Figure 24). The simulated frequency of exceedance of the 1-

hour SO2 NAAQ limit of 350 µg/m³ at the boundary is 191 hours, south-west and west of Phokeng.

Figure 22: Impala smelter operations with 2015 AEL Limits: simulated annual average SO2

concentrations




hour average SO2 concentration of 125 µg/m³




hour SO2 concentration of 350 µg/m³



5.1.3.5 Impala Smelter Operations – AEL Limits for 2020/New Plant Minimum Emission Standards


include the operations that are taking place at smelter plant, these include the point sources discussed in Section

4. The stack emissions are based limits set out to be achievable from 2020 in the current AEL.


Simulations were undertaken based on the assumption that all the PM is 2.5 µ m in diameter or less (PM2.5). The

simulated annual average PM2.5/PM10 concentrations as a result of the Impala smelter operations do not exceed

the current PM2.5 NAAQS of 20 µ g/m3, the future PM2.5 NAAQS of 15 µ g/m3 or PM10 NAAQS of 40 µ g/m³ on-site,

off-site or at any residences, schools or hospitals (Figure 25). The maximum simulated annual average

PM2.5/PM10 concentration is 2.95 µ g/m³. The current 24-hour PM2.5 NAAQS (4 days of exceedance of 40 µ g/m3),

future PM2.5 24-hour NAAQS (4 days of exceedance of 25 µ g/m3) and PM10 24-hour NAAQS (4 days of

exceedance of 75 µ g/m3) are not exceeded on-site, off-site or at any residences, schools or hospitals (Figure

26). The simulated 24-hour PM2.5/PM10 concentration is 12.3 µ g/m³.



Figure 25: Impala smelter operations with 2020 AEL Limits: simulated annual average PM2.5/PM10

concentrations




concentrations



concentrations as a result of the Impala smelter operations did not exceed the NO2 NAAQS of 40 µg/m3 off-site

or at any residences, schools or hospitals (Figure 27). The maximum simulated annual average NOx

concentration at the boundary is 14.9 µ g/m³, near the smelter plant (where the stacks are located). The 1-hour

NAAQS (88 hours of exceedance of 200 µg/m3) is exceeded off-site and at residences (Figure 28). The



simulated frequency of exceedance of the 1-hour NO2 NAAQ limit of 200 µg/m³ off-site is 164 hours, south-west

and west of Phokeng.

Figure 27: Impala smelter operations with 2020 AEL Limits: simulated annual average NOx

concentrations




hour NOx concentration of 200 µg/m³


The simulated annual average SO2 concentrations as a result of the Impala smelter operations exceed the

NAAQS of 50 µ g/m3 off-site but not at any residences, schools or clinics (Figure 29). The maximum simulated

annual average SO2 concentration at the boundary is 50 µg/m³, near the smelter plant (where the stacks are

located). The 24-hour NAAQS (4 days of exceedance of 125 µ g/m3) is exceeded off-site and at residences

(Figure 30). The simulated frequency of exceedance of the 24-hour SO2 NAAQ limit of 125 µ g/m³ at the

boundary is 13 days, south-west and west of Phokeng. The 1-hour NAAQS (88 hours of exceedance of



350 µ g/m3) is exceeded off-site but not at any residences, schools or clinics (Figure 31). The simulated

frequency of exceedance of the 1-hour SO2 NAAQ limit of 350 µ g/m³ at the boundary is 179 hours, south-west

and west of Phokeng.

Figure 29: Impala smelter operations with 2020 AEL Limits: simulated annual average SO2

concentrations




hour average SO2 concentration of 125 µg/m³




hour SO2 concentration of 350 µg/m³



5.1.4 Model Validation

Measured concentrations of PM10 (Boschhoek, Lebone, Luka and Services) and SO2 (Boschhoek, Lebone, Luka,

Ratanang and Services) at the Impala monitoring stations help provide an understanding of existing ambient air

concentrations, as well as provide a means of verifying the dispersion model results.

The aim was to illustrate the contribution from all quantified source groups to ground level concentrations at the

various receptors. Unaccounted emissions include those from the burning bays, laboratory, air emissions from

other industries, emissions from activities occurring within the communities, biomass burning (especially during

winter time), as well as long-range transport into the modelling domain. These emissions, when combined, may

potentially add up to be a significant portion of the observed concentrations in the modelling domain. In terms of

the current investigation, the portion of air quality due to air emission sources that could not be included in the

model’s emissions inventory, constitutes the background concentration.

In order to establish model performance under average emission conditions, it is not uncommon to use a certain

percentile of modelled and observed concentrations for comparison. Although these may range from a 90th to

99.9th percentile, it was decided to use the DEA NAAQS for guidance. For criteria pollutants, including PM10 and

SO2, the NAAQS requires compliance with the 99th percentile. As hourly averages, this allows exceedances of

the limit value of eighty-eight (88) hours per year. As daily averages, this allows exceedances of the limit value of

four (4) days per year.

Estimates of background concentrations were obtained from the measured values at the ranked position where

no contributions from the simulated sources were predicted. This was done by comparing the modelled hourly

concentrations against the measured hourly concentrations at the ranked position. Measured concentrations

include the "background" sources unaccounted for in the modelling results, thus percentiles from each dataset

(modelled and measured) were compared against each other to determine the fraction unaccounted for.

Summarized in Table 24 are the comparisons between simulated and measured PM10 concentrations at the

monitoring stations in the study area. Ninety percent (90%) of the measured peak concentrations could not be

accounted for at Boschhoek, 95% at Lebone and 65% at Luka. The difference between simulated and measured

increases significantly when considering long-term comparisons (i.e. 50th percentile and annual average) at these

stations. The contribution of emission sources not included in the dispersion model’s emissions inventory were

taken where the modelled concentration is close to 0 µ g/m³ - a threshold modelled concentration of 0.1 µ g/m³

was used. At the Services station, the simulated peak PM10 concentration is higher than what was measured, but

over long-term comparisons (i.e. 50th percentile and lower) the same difference can be seen as at the other

stations.

Table 24: Comparison of simulated and observed PM10 concentrations at the monitoring stations in the

Impala area

PM10 concentration (µg/m³) Unaccounted



Simulated Measured Unaccounted Fraction(a)

Boschhoek

Peak 131 1295 1164 0.90

99th Percentile 37 195 158 0.81

90thPercentile 1 72 71 0.99

50th Percentile 0.13 27 27 1

Annual Average 1 37 36 0.96

Background (46th percentile)(b) 0.10 25 25 1

Lebone

Peak 126 2516 2390 0.95

99th Percentile 53 175 122 0.70


50th Percentile 0.24 11 11 0.98



Luka

Peak 677 1938 1261 0.65

99th Percentile 202 289 87 0.30


50th Percentile 1.80 34 32 0.95



Services

Peak 1524 866 -658 -0.76

99th Percentile 616 205 -411 -2.01

90thPercentile 136 80 -56 -0.69

50th Percentile 8 27 20 0.72

Annual Average 50 40 -10 -0.26

Background (1st percentile)(b) 0.10 3 3 1

Notes:

(a) unaccounted fraction as a percentage of observed concentration

(b) observed value when simulation indicated little contribution (0.1 µ g/m³)

The performance evaluation was completed using the fractional bias method. Fractional bias is one of the

evaluation methods recommended by the U.S. EPA for determining dispersion model performance (U.S. EPA,

1992). Fractional bias provides a comparison of the means and standard deviation of both modelled and

measured concentrations for any given number of locations.

In this assessment, the background concentrations were added to the simulated concentrations prior to the

calculation of the fractional bias. The 99th percentile (with background concentration) was compared to the same

ranked monitored concentrations.

The fractional bias was plotted with the means on the X-axis and the standard deviations on the Y axis (see

Figure 32). The box on the plot encloses the area of the graph where the model predictions are within a fractional

bias between -2 and +2; indicating an acceptable correlation. The U.S. EPA states that predictions within a factor



of two are a reasonable performance target for a model before it is used for refined regulatory analysis (U.S.

EPA, 1992). Data points appearing on the left half of the plot indicate an over-prediction and those on the right

half of the plot represent under-predictions.

At Boschhoek, Lebone and Luka, the fractional bias of the means is less than 2, indicating an acceptable

correlation even though it is an underestimation (Figure 32). The Services station shows an over prediction but

also within the acceptable correlation (fractional bias of the means is less than 2) (Figure 32).

Figure 32: Fractional bias of means and standard deviation for PM10

Summarized in Table 24 are the comparisons between simulated and measured SO2 concentrations at the

monitoring stations in the study area. Eighty-one percent (81%) of the measured peak concentrations could not

be accounted for at Boschhoek, 37% at Lebone, 10% at Luka and 50% at Services. The difference between

simulated and measured increases significantly when considering long-term comparisons (i.e. 50th percentile and

annual average) at these stations. The contribution of emission sources not included in the dispersion model’s

emissions inventory were taken where the modelled concentration is close to 0 µ g/m³ - a threshold modelled

concentration of 0.1 µ g/m³ was used. At the Ratanang station, the simulated peak SO2 concentration is higher

than what was measured, but over long-term comparisons (i.e. 50th percentile and annual average) the same

difference can be seen as at the other stations.



Table 25: Comparison of simulated and observed SO2 concentrations at the monitoring stations in the

Impala area

SO2 concentration (µg/m³) Unaccounted Fraction(a) Simulated Measured Unaccounted

Boschhoek

Peak 56 299 243 0.81



50th Percentile 0.09 6 6 0.98


Background (53rd percentile)(b) 0.1 6 6 1

Lebone

Peak 115 182 68 0.37






Luka

Peak 174 193 19 0.1

99th Percentile 99 42 -57 -1.3





Ratanang

Peak 117 70 -47 -0.7

99th Percentile 46 43 -4 -0.1





Services

Peak 428 783 355 0.5

99th Percentile 171 112 -59 -0.5





Notes:

(a) unaccounted fraction as a percentage of observed concentration

(b) observed value when simulation indicated little contribution (0.1 µ g/m³)



The fractional bias of the means of less than 1 at Lebone and Ratanang clearly shows a good model

performance. At Boschhoek, Luka and Services the fractional bias of the means is less than 2, indicating an

acceptable correlation even though it is an underestimation. The Services station shows an over prediction but

also within the acceptable correlation (fractional bias of the means is less than 2).

Figure 33: Fractional bias of means and standard deviation for SO2

5.2 Analysis of Emissions’ Impact on the Environment

5.2.1 Effects of Particulate Matter on Animals

As presented by the Canadian Environmental Protection Agency (CEPA/FPAC Working Group, 1998)

experimental studies using animals have not provided convincing evidence of particle toxicity at ambient levels.

Acute exposures (4-6 hour single exposures) of laboratory animals to a variety of types of particles, almost

always at concentrations well above those occurring in the environment have been shown to cause decreases in

lung function, changes in airway defence mechanisms and increased mortality rates.

The epidemiological finding of an association between 24-hour ambient particle levels below 100 µ g/m3 and

mortality has not been substantiated by animal studies as far as PM10 and PM2.5 are concerned. With the

exception of ultrafine particles (0.1 µ m), none of the other particle types and sizes used in animal inhalation

studies cause such acute dramatic effects, including high mortality at ambient concentrations. The lowest

concentration of PM2.5 reported that caused acute death in rats with acute pulmonary inflammation or chronic

bronchitis was 250 g/m3 (3 days, 6 hr/day), using continuous exposure to concentrated ambient particles.



5.2.2 Effects of Suphur Dioxide on Plants and Animals

Experimental studies on animals have shown the acute inhalation of SO2 produces bronchioconstriction,

increases respiratory flow resistance, increases mucus production and has been shown to reduce abilities to

resist bacterial infection in mice (Costa & Amdur, 1996). Short exposures to low concentrations of SO2

(~2.6 mg/m³) have been shown to have immediate physiological response without resulting in significant or

permanent damage. In rabbits, acute exposures (16 mg/m³ for 4 hours) to SO2 gas was irritating to the eyes and

resulted in conjunctivitis, infection and lacrimation (Von Burg , 1995). Short exposures (<30 min) to

concentrations of 26 mg/m³ produced more significant respiratory changes in cats but were usually completely

reversible once exposure had ceased (Corn, Kotsko, Stanton, Bell, & Thomas, 1972).

SO2 can produce mild bronchial constriction, changes in metabolism and irritation of the respiratory tract and

eyes in cattle (Blood & Radostits, 1989 as cited in Coppock & Nostrum (1997). An increase in airway resistance

was reported in sensitized sheep after four hours of exposure to 13 mg/m³. Studies report chronic exposure can

affect mucus secretions and result in respiratory damage similar to chronic bronchitis. These effects were

reported at concentrations above typical ambient concentrations (26-1053 mg/m³) (Dalhamn, 1956 as cited in

Amdur (1978).

Application of sulphur (no concentrations specified) to crops can reduce plant uptake of selenium (an essential

nutrient for livestock), deposition of SO2 might therefore also affect the selenium content of forage plants (Khan,

Mostrom, & Campbell, 1997).

Exposure to air pollutants is expected to result in similar adverse effects in wildlife as in laboratory and domestic

animals (Newman & Schreiber, 1984).

5.2.3 Assessment Criteria for Dustfall

5.2.3.1 National Dust Control Regulations

NDCR were published on the 1st of November 2013 (Government Gazette No. R. 827). Acceptable dustfall rates

per the Regulation are summarised in Table 26.

Table 26: Acceptable dustfall rates

Restriction areas Dustfall rate (D) in mg/m2-day over a

30-day average Permitted frequency of exceedance

Residential areas D < 600 Two within a year, not sequential

months.

Non-residential areas 600 < D < 1 200 Two within a year, not sequential

months.



The regulation also specifies that the method to be used for measuring dustfall and the guideline for locating

sampling points shall be ASTM D1739 (1970), or equivalent method approved by any internationally recognized

body. Dustfall is assessed for nuisance impact and not inhalation health impact.

5.2.3.2 Screening Criteria for Animals and Vegetation

Suspended particulate matter can produce a wide variety of effects on the physiology of vegetation that in many

cases depend on the chemical composition of the particle. Heavy metals and other toxic particles have been

shown to cause damage and death of some species as a result of both the phytotoxicity and the abrasive action

during turbulent deposition (Harmens, Mills, Hayes, Williams, & De Temmerman, 2005). Heavy loads of particle

can also result in reduced light transmission to the chloroplasts and the occlusion of stomata (Harmens, Mills,

Hayes, Williams, & De Temmerman, 2005) (Naidoo & Chirkoot, 2004), decreasing the efficiency of gaseous

exchange (Harmens, Mills, Hayes, Williams, & De Temmerman, 2005) (Naidoo & Chirkoot, 2004) (Ernst, 1981)

and hence water loss (Harmens, Mills, Hayes, Williams, & De Temmerman, 2005). They may also disrupt other

physiological processes such as bud break, pollination and light absorption/reflectance (Harmens, Mills, Hayes,

Williams, & De Temmerman, 2005). The chemical composition of the dust particles can also affect the plant and

have indirect effects on the soil pH (Spencer, 2001).

Naidoo and Chirkoot conducted a study during the period October 2001 to April 2002 to investigate the effects of

coal dust on Mangroves in the Richards Bay harbour. The investigation was conducted at two sites where 10

trees of the Mangrove species (Avicennia marina) were selected and mature, fully expose, sun leaves tagged as

being covered or uncovered with coal dust. From the study it was concluded that coal dust significantly reduced

photosynthesis of upper and lower leaf surfaces. The reduced photosynthetic performance was expected to

reduce growth and productivity. In addition, trees in close proximity to the coal stockpiles were in poorer health

than those further away. Coal dust particles, which are composed predominantly of carbon, were not toxic to the

leaves; neither did they occlude stomata as they were larger than fully open stomatal apertures (Naidoo &

Chirkoot, 2004).

In general, according to the Canadian Environmental Protection Agency (CEPA), air pollution adversely affects

plants in one of two ways; either the quantity of output or yield is reduced, or the quality of the product is lowered.

The former (invisible) injury results from pollutant impacts on plant physiological or biochemical processes and

can lead to significant loss of growth or yield in nutritional quality (e.g. protein content). The latter (visible) may

take the form of discolouration of the leaf surface caused by internal cellular damage. Such injury can reduce

the market value of agricultural crops for which visual appearance is important (e.g. lettuce and spinach). Visible

injury tends to be associated with acute exposures at high pollutant concentrations whilst invisible injury is

generally a consequence of chronic exposures to moderately elevated pollutant concentrations. However, given

the limited information available, specifically the lack of quantitative dose-effect information, it is not possible to

define a Reference Level for vegetation and particulate matter (CEPA/FPAC Working Group, 1998).

Limited information is available on the impact of dust on vegetation and grazing quality. While there is little direct

evidence of the impact of dustfall on vegetation in the South African context, a review of European studies has



shown the potential for reduced growth and photosynthetic activity in sunflower and cotton plants exposed to

dust fall rates greater than 400 mg/m²/day (Farmer, 1993). In addition, there is anecdotal evidence to indicate

that over extended periods, high dustfall levels in grazing lands can soil vegetation and this can impact the teeth

of livestock (Farmer, 1993).

5.2.4 Measured Dustfall Rates

The fallout dust sampling locations at Impala are shown in Figure 34 to Figure 38. Although the dustfall rates at

Shaft 17 Site 8 and Southern Big Tailings were in excess of the NDCR limit for non-residential areas in March

2016 and September 2017, respectively (Figure 39 and Figure 40); the NDCR allows for two exceedances per

year. Based on the data for 2016 and 2017 the Impala dustfall rates comply with the NDCR (Figure 39 to Figure

42).

Figure 34: Sampling location for Impala Platinum Mine monitoring site part 1 (SGS, 2017)



Figure 35: Sampling location for Impala Platinum Mine monitoring site part 2 (SGS, 2017)

Figure 36: Sampling location for Impala Platinum Mine Shaft 16 monitoring site (SGS, 2017)



Figure 37: Sampling location for Impala Platinum Mine Shaft 15 and Shaft 17 monitoring site (SGS, 2017)

Figure 38: Sampling location for Impala Platinum Mine Shaft 1 monitoring site (SGS, 2017)





Figure 39: Measured dustfall rates at non-residential areas in 2016





Figure 40: Measured dustfall rates at non-residential areas in 2017



Figure 41: Measured dustfall rates at residential areas in 2016





Figure 42: Measured dustfall rates at residential areas in 2017



5.2.5 Screening of Simulated Dustfall Rates for Potential Environmental Impacts (Normal Operating

Conditions)

5.2.5.1 Impala Smelter Operations – Measured Emissions


include processing operations that are taking place at Impala, these include all the point sources discussed in

Section 4. The stack emissions are based on the isokinetic emission sampling undertaken by C & M Consulting

Engineers during 2016 and 2017. Simulated off-site dustfall rates are not in exceedance of 400 mg/m²-day at any

agricultural or vegetated areas (Figure 43). Simulated off-site dustfall rates are not in exceedance of the NDCR

limit for residential areas at any residences, schools, hospitals or clinics (Figure 43). Simulated on-site dustfall

rates are not in exceedance of the NDCR limit for non-residential areas (Figure 43).



Figure 43: Impala smelter operations with measured stacks emissions: the simulated 24-hour dustfall

rates

5.2.5.2 Impala Smelter Operations – 2015 AEL Limits



Section 4. The stack emissions are based on limits achievable in 2015 according to the current AEL. Simulated



off-site dustfall rates are not in exceedance of 400 mg/m²-day at any agricultural or vegetated areas (Figure 44).

Simulated off-site dustfall rates are not in exceedance of the NDCR limit for residential areas at any residences,

schools, hospitals or clinics (Figure 44). Simulated on-site dustfall rates are not in exceedance of the NDCR limit

for non-residential areas (Figure 44).

Figure 44: Impala smelter operations with 2015 AEL Limits: the simulated 24-hour dustfall rates



5.2.5.3 Impala Smelter Operations – 2020 AEL Limits



Section 4. The stack emissions are based on limits achievable in 2020 according to the current AEL. Simulated

off-site dustfall rates are not in exceedance of 400 mg/m²-day at any agricultural or vegetated areas (Figure 45).

Simulated off-site dustfall rates are not in exceedance of the NDCR limit for residential areas at any residences,

schools, hospitals or clinics (Figure 45). Simulated on-site dustfall rates are not in exceedance of the NDCR limit

for non-residential areas (Figure 45).



Figure 45: Impala smelter operations with 2020 AEL Limits: the simulated 24-hour dustfall rates



6 COMPLAINTS

Impala has an active complaint register where complaints from surrounding land users can be

registered. No complaints have been received in the past two years.



7 CURRENT OR PLANNED AIR QUALITY MANAGEMENT INTERVENTIONS

7.1 Mitigation measures

It is planned that the mitigation measures indicated in Table 9 and Table 10 will be continued.

7.2 Monitoring

Under Section 21 of the NEM:AQA it is compulsory to measure PM, NOx expressed as NO2 and SO2 emissions

from the dryers stacks and the stacks associated with the furnaces and converters. It further requires the holder

of an AEL to submit an emission report in the format specified by the National Air Quality Officer or Licensing

Authority on an annual basis. Impala plans to continue to undertake monitoring as set out in their current AEL, as

shown in Table 27.

Table 27: Planned stack emissions testing

Point

Source ID

Pollutants

to

measure

Emission

sampling/monitoring method

Sampling

frequency Motivation

SD1

SD4

SD5

SD6

FD1

TGS

FGS

PM As per methods and sampling

analysis prescribed in Annex A

of Section 21 of NEM:AQA.

Annual Confirmation of compliance

with AEL limits.

NOx

expressed

as NO2

As per methods and sampling




with AEL limits.

SO2 As per methods and sampling




with AEL limits.



8 COMPLIANCE AND ENFORCEMENT ACTIONS

No compliance notices have been issued or any enforcement actions have been instituted against the Impala

operation in the last five years.

9 ADDITIONAL INFORMATION

No additional information not mentioned in the report above is of relevance to this Atmospheric Impact Report

and AEL application.

10 FORMAL DECLARATIONS

10.1 Declaration of Accuracy of Information

Annexure A contains a declaration of accuracy of information by the applicant.

10.2 Declaration of Independence of Practitioner

Annexure B contains a declaration of independence by the practitioner preparing the AIR.

11 MAIN FINDINGS

The main findings of the baseline assessment are that:

• The wind field was dominated by winds from the east followed by winds from the south-south-west and

east-south-east. During the day, winds occurred more frequently from the easterly and east-south-

easterly sectors. Night-time airflow had winds from the south-south-westerly and south-westerly sectors.

In general, the wind speeds were low with less than 1% calm conditions.

• The main sources contributing to current background pollutant concentrations and dustfall rates likely

include mining and mineral processing activities, vehicle entrained dust from local roads, agricultural

activities, windblown dust from exposed areas, biomass burning, household fuel burning and vehicle

exhaust emissions.

• The overall land use pattern associated with the surrounding area is mainly mining activities and

agricultural cattle farming interspersed by pastures. Land use to the north of the smelter includes the

settlement of Luka, while the Phokeng settlement is located south of the smelter.

The main findings of the impact assessment are as follows:

• According to 2016 and 2017 isokinetic sampling PM emissions from Impala smelter regulated stacks do

comply with the 2015 limits set out in the current AEL but not the 2020 limits per new plant MES

(NMES). Spray dryer 5 (SD5) and flash dryer 1 (FD1) measured emissions are in exceedance of the

2020 limits set out in the current AEL. The baghouse for the flash dryer 1 (FD1) has been replaced



since the April 2017 isokinetic sampling and sampling undertaken in February and August 2018 show

no exceedances of the 2020 AEL limit per NMES.

• According to continuous sampling PM emissions from Impala smelter regulated stacks do comply with

the 2015 limits set out in the current AEL but not the 2020 limits per new plant MES (NMES). Spray

dryer 1 (SD1), spray dryer 4 (SD4), spray dryer 5 (SD5), spray dryer 6 (SD6) and flash dryer 1 (FD1)

measured emissions are in exceedance of the 2020 limits set out in the current AEL. The baghouse for

the flash dryer 1 (FD1) has been replaced since the April 2017 isokinetic sampling and sampling

undertaken during 2018 show no exceedances of the 2020 AEL limit per NMES.

• According to recent isokinetic sampling SO2 emissions from Impala smelter regulated stacks do comply

with the 2015 limits set out in the current AEL but not the 2020 limits per NMES. The tailgas scrubber

stack (TGS) measured emissions are in exceedance of the 2020 limits set out in the current AEL.

• According to continuous sampling SO2 emissions from Impala smelter most of the regulated stacks do

comply with the 2015 limits set out in the current AEL and the 2020 limits per NMES. The tailgas

scrubber stack (TGS) measured emissions are in exceedance of the limits set out in the current AEL.

• According to recent isokinetic sampling NOx expressed as NO2 emissions from Impala smelter regulated

stacks do comply with the 2015 and 2020 limits set out in the current AEL.

• Total suspended particulates (TSP), PM10, PM2.5, NOx and SO2 emissions were quantified and

modelled.

• The simulated results were as follows:

o Simulated PM2.5/PM10 and NO2 as a result of the Impala smelter operations with the stacks

emitting the measured emissions do not exceed the NAAQS.

o Simulated SO2 as a result of the Impala smelter operations with the stacks emitting the

measured emissions do not exceed the annual NAAQS. Simulated SO2 as a result of the

Impala smelter operations with the stacks emitting the measured emissions exceed the short-

term NAAQS off-site and at air quality sensitive receptors (AQSRs).



o Simulated NO2 and SO2 as a result of the Impala smelter with the stacks emitting the 2015

AEL limits exceed the NAAQS off-site and at AQSRs.



o Simulated NO2 and SO2 as a result of the Impala smelter operations with the stacks emitting

the 2020 AEL limit do not exceed the annual NAAQS off-site or at any AQSRs. Simulated NO2

and SO2 as a result of the Impala smelter operations with the stacks emitting the 2020 AEL

limits exceed the short-term NAAQS off-site and AQSRs.

o Simulated nuisance dustfall rates as a result of the Impala smelter operations are found to be

low and are below the NDCR limit for residential areas off-site and at AQSRs and the NDCR

limit for non-residential areas on-site.



To ensure the lowest possible impact on AQSRs and the environment it is recommended that Impala ensure that

the mitigation and monitoring of sources of emission are undertaken as described in the technical sections of the

report.



12 REFERENCES

ADE. (2012, January). National Pollutant Inventory - Emission Estimation Technique Manual for Mining.

Canberra: Australian Government: Department of Sustainability, Environment, Water, Population and

Communities. Retrieved from www.npi.gov.au

Amdur, M. O. (1978). Effects of Sulfur Oxides on Animals. Sulphur in the Environment. Part II: Environmental

Impacts. John Wiley and Sons, Toronto. pp 61-74.

Burger, L., & Held, G. S. (1997). Revised User's Manual for the Airborne Dust Dispersion Model from Area

Sources (ADDAS). Eskom TSI Report No. TRR/T97?066.

CEPA/FPAC Working Group. (1998). National Ambient Air Quality Objectives for Particulate Matter. Part 1:

Science Assessment Document, A Report by the Canadian Environmental Protection Agency (CEPA)

Federal-Provincial Advisory Committee (FPAC) on Air Quality Objectives and Guidelines. Ontario:

Canadian Environmental Protection Agency (CEPA) Federal-Provincial Advisory Committee (FPAC).

Coppock, R., & Nostrum, M. (1997). Toxicology of oilfiend pollutants in cattle and other species. Alberta

Research Council, ARCV97-R2, Vegreville, Alberta pp 45-114.

Corn, M., Kotsko, N., Stanton, D., Bell, W., & Thomas, A. P. (1972). Response of Cats to Inhaled Mixtures of

SO2 and SO2-NaCl Aerosol in Air. Arch. Environ. Health, 24, 248-256.

Costa, D. L., & Amdur, M. O. (1996). Air Pollution. In: Klaasen, CD, Amdur, MO, Doull, J (eds) Casarett and

Doull’s Toxicology. The Basic Science of Poisons. 5th ed. pp 857-882. 857-882.

Department of National Treasury. (2013). Carbon Tax Policy Paper.

Ernst, W. (1981). Monitoring of particulate pollutants. In L. Steubing, & H.-J. Jager, Monitoring of Air Pollutants by

Plants: Methods and Problems. The Hague: Dr W Junk Publishers.

Farmer, A. M. (1993). The Effects of dust on vegetation-A review. Environmental Pollution, 63-75.

Hanna, S. R., Egan, B. A., Purdum, J., & Wagler, J. (1999). Evaluation of ISC3, AERMOD, and ADMS

Dispersion Models with Observations from Five Field Sites.

Harmens, H., Mills, G., Hayes, F., Williams, P., & De Temmerman, L. (2005). Air Pollution and Vegetation. The

International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops

Annual Report 2004/2005.

Jongikhaya, W. (2015, August 6). Technical Guidelines for Monitoring, Reporting and Verification of Greenhouse

Gas Emissions by Industry.

Khan, A. A., Mostrom, M. S., & Campbell, C. A. (1997). Sulfur-Selenium Antagonism in Ruminants. In:Chalmers,

GA (ed) A Literature Review and Discussion of the Toxicological Hazards of Oilfield Pollutants in Cattle.

Alberta Research Council, ARCV97-R2, Vergeville, Alberta. pp 197-208.

Naidoo, G., & Chirkoot, D. (2004). The effects of coal dust on photosynthetic performance of the mangrove,

Avicennia marina in Richards Bay, South Africa. Environmental Pollution, 359–366.

Newman, J. R., & Schreiber. (1984). Animals as Indicators of Ecosystem Responses to Air Emissions. Environ.

Mgmt., 8(4)309-324.

SGS. (2017). mpala Platinum Mine Annual Report July 2016 - June 2017, Report no. EN086 37.537 A_IMP.

Johannesburg.

Spencer, S. (2001). Effects of coal dust on species composition of mosses and lichens in an arid environment.

Arid Environments 49, 843-853.



U.S. EPA. (1992). Protocol for Determining the Best Performing Model. EPA-454/R-92-025. Research Triangle

Park, 2 NC. : U.S. Environmental Protection Agency.

US EPA. (2006a). AP-42, 5th Edition, Volume I, Chapter 13: Miscellaneous Sources, 13.2.4 Introduction to

Fugitive Dust Sources, Aggregate Handling and Storage Piles. Retrieved from

https://www3.epa.gov/ttn/chief/ap42/ch13/final/c13s0204.pdf

Von Burg , R. (1995). Toxicological Update. J .Appl. Toxicol 16(4), 365-371.



13 ANNEXURE A: DECLARATION OF ACCURACY OF INFORMATION – APPLICANT



14 ANNEXURE B: DECLARATION OF INDEPENDENCE – PRACTITIONER



15 ANNEXURE C: EMISSIONS REPORTS

Due to the extensivity of these reports they have not been in included in the annexure but is available from

Impala at the request of the authority.



16 ANNEXURE D: OTHER RELEVANT LEGISLATION

16.1 National Minimum Emission Standards

The minister has under Section 21 of the NEM:AQA (Act No. 39 of 2004) published Listed Activities and NMES

on 22 November 2013 in Government Gazette No. 37054. Drying is considered a listed activity under Section 21

of the NEM:AQA. NMES and special arrangements for these activities are included in Table 28.

Table 28: NMES for subcategory 5.2 listed activities, drying

Description: The drying of mineral solids including ore, using dedicated combustion installations

Application: Facilities with capacity more than 100 tonnes/month product.

Substance or mixture of substance: Plant status mg/Nm3 under normal conditions of 273 K and

101.3 kPa Common name Chemical symbol

Particulate matter n/a New 50

Existing 100

Sulphur dioxide SO2 New 1 000

Existing 1 000

Oxides of nitrogen NOx expressed as NO2 New 500

Existing 1 200

Notes:

• Existing plants must comply with minimum emission standards for existing plant by 01 April 2015.

• Existing plants must comply with minimum emission standards for new plant by 01 April 2020.

16.2 Applying for an AEL

Tronox Mineral Sands (Pty) Ltd will be required to apply for a new AEL. An AEL must include all sources of

emission, not only those considered listed activities. In terms of the AEL application, the applicant should take

into account the following sections of NEM:AQA:

37. Application for atmospheric emission licences:

(1) A person must apply for an AEL by lodging with the licensing authority of the area in which the listed

activity is to be carried out, an application in the form required.

(2) An application for an AEL must be accompanied by –

(a) The prescribed processing fee; and

(b) Such documentation and information as may be required by the licensing authority.

38. Procedure for licence applications:

(1) The licensing authority –



(a) May, to the extent that is reasonable to do so, require the applicant, at the applicant’s expense,

to obtain and provide it by a given date with other information contained in or submitted in

connection with the application;

(b) May conduct its own investigation on the likely effect of the proposed license on air quality;

(c) May invite written comments from any organ of state which has an interest in the matter; and

(d) Must afford the applicant an opportunity to make representations on any adverse statements or

objections to the application.

(2) Section 24 of the NEMA and section 22 of the Environmental Conservation Act apply to all applications

for atmospheric emission licenses, and both an applicant and the licensing authority must comply with

those sections and any applicable notice issued or regulations made in relation to those sections.

(3) –

(a) An applicant must take appropriate steps to bring the application to the attention of relevant

organs of state, interested persons and the public.

(b) Such steps must include the publication of a notice in at least two newspapers circulating the

area in which the listed activity is applied for is or is to be carried out and must-

(i) Describe the nature and purpose of the license applied for;

(ii) Give particulars of the listed activity, including the place where it is to be carried out;

(iii) State a reasonable period within which written representations on or objections to the

application may be submitted and the address or place where it must be submitted;

and

(iv) Contain such other particulars as the licensing authority may require.

16.3 Reporting of Atmospheric Emissions

The National Atmospheric Emission Reporting Regulations (Government Gazette No. 38633) came into effect on

2 April 2015. The purpose of the regulations is to regulate the reporting of data and information from an identified

point, non-point and mobile sources of atmospheric emissions to an internet-based National Atmospheric

Emissions Inventory System (NAEIS). The NAEIS is a component of the South African Air Quality Information

System (SAAQIS). Its objective is to provide all stakeholders with relevant, up to date and accurate information

on South Africa's emissions profile for informed decision making.

Emission sources and data providers are classified according to groups. Impala would be classified under Group

A (“Listed activity published in terms of section 21(1) of the Act”). Emission reports from Group A must be made

in the format required for NAEIS and should be in accordance with the AEL or provisional AEL.

As per the regulation, Tronox and/or their data provider should already be registered on the NAEIS. Data

providers must inform the relevant authority of changes if there are any:

• Change in registration details;

• Transfer of ownership; or

• Activities being discontinued.



A data provider must submit the required information for the preceding calendar year to the NAEIS by 31 March

of each year. Records of data submitted must be kept for a period of 5 years and must be made available for

inspection by the relevant authority.

The relevant authority must request, in writing, a data provider to verify the information submitted if the

information is incomplete or incorrect. The data provider then has 60 days to verify the information. If the verified

information is incorrect or incomplete the relevant authority must instruct a data provider, in writing, to submit

supporting documentation prepared by an independent person. The relevant authority cannot be held liable for

cost of the verification of data. A person guilty of an offence in terms of section 13 of these regulations is liable

for penalties.

16.4 Atmospheric Impact Report

Under section 30 of NEM:AQA, an air quality officer may require any person to submit an AIR in the format

prescribed if a review of provisional AEL or AEL is undertaken. The format of the AIR is stipulated in the

Regulations Prescribing the Format of the Atmospheric Impact Report, Government Gazette No. 36904 dated 11

October 2013.

16.5 Greenhouse Gas (GHG) Emissions

Regulations pertaining to GHG reporting using the NAEIS was published on 3 April 2017 (Government Gazette

40762, Notice 257 of 2017). The South African mandatory reporting guidelines focus on the reporting of Scope 1

emissions only. The three broad scopes for estimating GHG are:

• Scope 1: All direct GHG emissions.

• Scope 2: Indirect GHG emissions from consumption of purchased electricity, heat or steam.

• Scope 3: Other indirect emissions, such as the extraction and production of purchased materials and

fuels, transport-related activities in vehicles not owned or controlled by the reporting entity, electricity-

related activities not covered in Scope 2, outsourced activities, waste disposal, etc.

The NAEIS web-based monitoring and reporting system will also be used to collect GHG information in a

standard format for comparison and analyses. The system forms part of the National Atmospheric Emission

Inventory component of SAAELIP.

The DEA is working together with local sectors to develop country specific emissions factors in certain areas;

however, in the interim the Intergovernmental Panel on Climate Change’s (IPCC) default emission figures may

be used to populate the SAAQIS GHG emission factor database. These country specific emission factors will

replace some of the default IPCC emission factors. It has been indicated that these factors will only be published

towards the end of 2015 (Jongikhaya, 2015).

Also, a draft carbon tax bill was introduced for a further round of public consultation. The Carbon Tax Policy

Paper (CTPP) (Department of National Treasury, 2013) stated consideration will be given to sectors where the



potential for emissions reduction is limited. Certain production processes indicated in Annexure A of the notice

(Government Gazette No. 40996 dated 21 July 2017) with GHG in excess of 0.1 Mt, measured as CO2-eq, are

required to submit a pollution prevention plan to the Minister for approval. The project operations do not fall

under any of the production process specified in Annexure A.



17 ANNEXURE E: ATMOSPHERIC DISPERSION SIMULATION METHODOLOGY

The impact of the operations at Impala on the atmospheric environment was determined through simulation of

ambient pollutant concentrations. Simulated air quality impacts represent only those associated with the Tronox

Mineral Sands operations.

The South African Regulations Regarding Air Dispersion Modelling (Government Notice no. R533, 11 July 2014)

provide guidance on the use of a tiered approach in defining the levels of assessment required in a modelling

application. This Code of Practice also recommends a number of dispersion models to be used in regulatory

applications in South Africa. This requires a modeller to assess the application and identify which model would

best provide the essential information to the regulatory authority with the detail and accuracy required in the

application. Air quality assessments can vary in their level of detail and scope, which in turn is determined by the

objectives of the modelling effort, technical factors and the level of risk associated with the emissions.

Based on the surrounding land-use, requirements from Tronox Mineral Sands and given the relatively size of the

property and emission levels, a Level 2 study was conducted.

17.1.1.1 Dispersion Model Selection

Gaussian-plume models are best used for near-field applications where the steady-state meteorology

assumption is most likely to apply. One of the most widely used Gaussian plume model is the US EPA AERMOD

model (Table 29) that was used in this study. AERMOD is a model developed with the support of AERMIC,

whose objective has been to include state-of the-art science in regulatory models (Hanna, Egan, Purdum, &

Wagler, 1999). AERMOD is a dispersion modelling system with three components, namely: AERMOD (AERMIC

Dispersion Model), AERMAP (AERMOD terrain pre-processor), and AERMET (AERMOD meteorological pre-

processor).

AERMOD is an advanced new-generation model. It is designed to predict pollution concentrations from

continuous point, flare, area, line, and volume sources. AERMOD offers new and potentially improved algorithms

for plume rise and buoyancy, and the computation of vertical profiles of wind, turbulence and temperature

however retains the single straight line trajectory limitation. AERMET is a meteorological pre-processor for

AERMOD. Input data can come from hourly cloud cover observations, surface meteorological observations and

twice-a-day upper air soundings. Output includes surface meteorological observations and parameters and

vertical profiles of several atmospheric parameters. AERMAP is a terrain pre-processor designed to simplify and

standardise the input of terrain data for AERMOD. Input data includes receptor terrain elevation data. The terrain

data may be in the form of digital terrain data. The output includes, for each receptor, location and height scale,

which are elevations used for the computation of air flow around hills.

A disadvantage of the model is that spatial varying wind fields, due to topography or other factors cannot be

included. Input data types required for the AERMOD model include: source data, meteorological data (pre-



processed by the AERMET model), terrain data and information on the nature of the receptor grid. Version

(version 7.12) of AERMOD and its pre-processors were used in the study.

Table 29: Model details

Model and Version AERMOD 7.12

Executable US EPA 16216r

17.1.1.2 Meteorological Requirements

Measured on-site data for the period January 2016 to December 2017 (Section 5.1.2).

17.1.1.3 Simulation Domain

The dispersion of pollutants expected to arise from operations was simulated for an area covering 5 km (east-

west) by 5 km (north-south) (Table 30). The area was divided into a grid matrix with a resolution of 50 m. The

selected individual sensitive receptors (section 1.2.1) were included as discrete receptors. AERMOD calculates

ground-level (1.5 m above ground level) concentrations and dustfall rates at each grid and discrete receptor

point.

Table 30: Simulation domain

Simulation domain

South-western corner of simulation domain Northing: 513 300 m;

Easting: 7 170 700 m

Domain size 5 x 5 km

Projection Grid: UTM Zone 35S, Datum: WGS 84

Resolution 50 m

17.1.1.4 Presentation of Results

Dispersion simulations was undertaken to determine 98th percentile hourly, highest hourly, highest daily and

annual average ground level concentrations and dustfall rates for each of the pollutants considered in the study

as well as the frequency at which short term criteria are exceeded. Averaging periods were selected to facilitate

the comparison of simulated pollutant concentrations to relevant ambient air quality and inhalation health criteria

as well as dustfall regulations.

Ground-level concentration (GLC) isopleths plots presented in this section depict interpolated values from the

concentrations predicted by AERMOD for each of the receptor grid points specified. Plots reflecting hourly (daily)

and averaging periods contain only the 99.99th (99.73th) percentile of predicted ground level concentrations, for

those averaging periods, over the entire period for which simulations were undertaken. It is therefore possible

that even though a high hourly (daily) average concentration is predicted to occur at certain locations, that this

may only be true for one hour (day) during the year. Results are also provided in tabular form as discrete values

predicted at AQSRs.



Ambient air quality criteria apply to areas where the Occupational Health and Safety regulations do not apply;

which is generally outside the property or lease area. Ambient air quality criteria are therefore not occupational

health indicators but applicable to areas where the general public has access. In the case of this study the

ambient criteria are seen to be applicable outside the boundary and at all AQSRs (inside or outside of the

boundary). Section 5.1 deals with impacts on human health and the nuisance impact of odour. Dustfall is

assessed for nuisance impact on the environment (Section 5.1.3.5) and not inhalation health impact.

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Atmospheric Impact Report in support of the …...Atmospheric Impact Report in support of the National Minimum Emission Standard postponement application for Impala Platinum - Rustenburg