LAKE MAITLAND URANIUM PROJECT

Transcription

1 LAKE MAITLAND URANIUM PROJECT Mega Lake Maitland Pty Ltd. - Lake Maitland Uranium Project Air Quality Impact Assessment Submitted to: Mega Lake Maitland Pty Ltd. 57 Havelock Street, West Perth, WA 6005 REPORT Report Number R-RevA

2 Table of Contents 1.0 INTRODUCTION Atmospheric Contaminants SITE DESCRIPTION Description of the Activity NATURE OF DISCHARGES Phase One Construction Year Phase Two: Operation - Year Estimation Summary Point Sources Volume Sources Area Sources Overview THE RECEIVING ENVIRONMENT Climate Meteorology Temperature Rainfall Wind Topography Background Air Quality / Deposited Dust Particulate Metals Radon Adopted Background Concentrations Summary Sensitive Receptor Locations ASSESSMENT METHODOLOGY Assessment Criteria Report No R-RevA i

3 6.0 AIR QUALITY MODELLING Meteorological Modelling Model Configuration Validation Dispersion Modelling Modelling Results Deposited Dust Aluminium Strontium Vanadium Uranium Radon Model Validation ASSESSMENT OF EFFECTS RECOMMENDATIONS ABBREVIATIONS REFERENCES TABLES Table 1: Baseline Sediment Monitoring Data... 2 Table 2: Atmospheric Contaminant Summary... 4 Table 3: LMUP Key Characteristics... 6 Table 4: Summary of Sources - Construction Year Table 5: Summary of Sources - Year Table 6: Representative Mining Equipment Table 7: Heavy Vehicle Distance Travelled Table 8: Model Input Data: Point Sources Table 9: Construction Year Model Input Data: Volume Sources Particulate Matter Table 10: Construction Year Model Input Data: Volume Sources Particulate Metals Table 11: Year 7 Model Input Data: Volume Sources Particulate Matter Table 12: Year 7 Model Input Data: Volume Sources Particulate Metals Report No R-RevA ii

4 Table 13: Construction Year Model Input Data: Area Sources Particulate Matter Table 14: Construction Year Model Input Data: Area Sources Particulate Metals Table 15: Construction Year Model Input Data: Area Sources Radon Table 16: Year 7 Model Input Data: Area Sources Particulate Matter Table 17: Year 7 Model Input Data: Area Sources Particulate Metals Table 18: Year 7 Model Input Data: Area Sources Radon Table 19: Background Air Quality: Adopted Concentrations Table 20: Modelling Criteria Table 21: Air Dispersion Modelling Results: Table 22: Air Dispersion Modelling Results: Table 23: Air Dispersion Modelling Results: Table 24: Air Dispersion Modelling Results: Deposited Dust Table 25: Air Dispersion Modelling Results: Vanadium Table 26: Air Dispersion Modelling Results: Radon Table 27: Model Validation Results FIGURES Figure 1: Sediment Sampling Results: Metals Fraction... 3 Figure 2: Site Location... 5 Figure 3: Construction Year Mine Plan... 7 Figure 4: Year 7 Mine Plan Figure 5: RLM16 and RLM17 Moisture Content Summary Figure 6: RLM16 and RLM17 Silt Content Summary Figure 7: RLM3 Moisture Content Summary Figure 8: RLM3 Silt Content Summary Figure 9: Particle Size Distribution Construction Sites, Borrow Pit and Roads Figure 10: Particle Size Distribution Deposit and Overburden Stockpiles Figure 11: Construction Year: Particulate Matter Sources Figure 12: Construction Year: Particulate Metals Sources Figure 13: Construction Year: Radon Sources Figure 14: Year 7: Particulate Matter Sources Figure 15: Year 7: Particulate Metals Sources Figure 16: Year 7: Radon Sources Figure 17: Monthly average maximum and minimum temperatures - Leinster Aerodrome Figure 18: Monthly Average Rainfall - Leinster Aerodrome Figure 19: Leinster Aerodrome Windrose Report No R-RevA iii

5 Figure 20: Leinster Aerodrome Seasonal Windroses Figure 21: Background Air Quality: Monitoring Results Figure 22: Background Air Quality: Monitoring Results Figure 23: Background Air Quality: Monitoring Results Figure 24: Sensitive Receptor Locations Figure 25: Observed Laverton Aerodrome AWS 2004/2005 Annual and Seasonal Wind Roses Figure 26: TAPM Synthesised Laverton Aerodrome Annual and Seasonal Wind Roses Figure 27: Isopleth Plot for (24 hour averaging period) Construction Year Figure 28: Isopleth Plot for (24 hour averaging period) Year Figure 29: Isopleth Plot for (24 hour averaging period) Construction Year Figure 30: Isopleth Plot for (24 hour averaging period) Year Figure 31: Isopleth Plot for (24 hour averaging period) Construction Year Figure 32: Isopleth Plot for (annual averaging period) Construction Year Figure 33: Isopleth Plot for (24 hour averaging period) - Year Figure 34: Isopleth Plot for (annual averaging period) - Year Figure 35: Isopleth Plot for Deposited Dust, Insoluble Solids, (1 month averaging period) Construction Year Figure 36: Isopleth Plot for Deposited Dust, Insoluble Solids, (1 month averaging period) Year Figure 37: Isopleth Plot for Deposited Dust, Aluminium, (1 month averaging period) Construction Year Figure 38: Isopleth Plot for Deposited Dust, Aluminium, (1 month averaging period) Year Figure 39: Isopleth Plot for Deposited Dust, Strontium, (1 month averaging period) Construction Year Figure 40: Isopleth Plot for Deposited Dust, Strontium, (1 month averaging period) Year Figure 41: Isopleth Plot for Vanadium Concentration (24 hour averaging period) Construction Year Figure 42: Isopleth Plot for Vanadium Concentration (24 hour averaging period) Year Figure 43: Isopleth Plot for Deposited Dust, Vanadium, (1 month averaging period) Construction Year Figure 44: Isopleth Plot for Deposited Dust, Vanadium, (1 month averaging period) Year Figure 45: Isopleth Plot for Deposited Dust, Uranium, (1 month averaging period) Construction Year Figure 46: Isopleth Plot for Deposited Dust, Uranium, (1 month averaging period) Year Figure 47: Isopleth Plot for Radon (24 hour averaging period) Construction Year Figure 48: Isopleth Plot for Radon (24 hour averaging period) Year APPENDICES APPENDIX A Limitations APPENDIX B Mineral Processing Plant Mass and Energy Balance Report No R-RevA iv

6 Report No R-RevA v

7 1.0 INTRODUCTION Mega Lake Maitland engaged Golder Associates to conduct an air quality impact assessment for the development of a uranium mine at Lake Maitland, Western Australia. The Lake Maitland Uranium Project (LMUP) consists of construction and operation of a uranium mine and processing facility and related infrastructure including roads, accommodation village, power and water supply and waste management system. The processed mineral, uranium peroxide, will be road transported to a designated uranium export facility in sealed drums. The principal atmospheric contaminants associated with this development will be particulate matter generated from construction and mining activities and radon gas released from the exposed uranium ore. Other aspects of mine operation included in the assessment are exhaust emissions from various plant equipment and, more notably, emissions to air from the mineral processing facility located on site. The air quality impact assessment has been conducted for two phases of the project; construction and operation. This technical report provides an assessment of the potential impacts of emissions to air from the two project phases. The air quality impact assessment has been conducted using a standard air dispersion modelling approach. Modelling is used to predict atmospheric contaminant ground level concentrations (GLCs) at sensitive receptors, which are then added to background contaminant levels and assessed against relevant air quality guidelines and standards. Your attention is drawn to the document Limitations, which is included as Appendix A to this report. The statements presented in this document are intended to advise you of what your realistic expectations of this report should be. The document is not intended to reduce the responsibility accepted by Golder Associates, but rather to ensure that all parties who may rely on this report are aware of the responsibilities each assumes in so doing. 1.1 Atmospheric Contaminants The LMUP construction and mining phases will result in particulate matter emissions to air from the excavation and removal process and products of combustion from fuel use in vehicles/machinery and fixed plant. Products of combustion typically include oxides of nitrogen, sulphur dioxide, carbon monoxide, carbon dioxide, particulate matter and volatile organic compounds. Although products of combustion will contribute to air emissions, the dominant emission will be airborne dust from the movement of vehicles on unpaved roads, windblown dust from exposed areas and emissions from the uplift and deposit of material through bulldozer and front end loader action, and stockpile creation. Therefore non-particulate matter products of combustion are not considered further in this assessment. Airborne particulate matter is defined as total suspended particulate matter () or classified based on particle size. represents particles with an equivalent aerodynamic diameter less than 10 micrometres and represents particles with an equivalent aerodynamic diameter less than 2.5 micrometres. The risks to human health from inhalation of and have been well demonstrated, with particles in these size fractions able to pass through the nose and throat and deposit in the lower regions of the respiratory tract. impacts are generally associated with nuisance and aesthetic impacts, with large particles rapidly settling from air causing amenity issues. The assessment of particulate matter emissions can also be expressed in terms of deposited dust. Deposited dust refers to particles which are brought to the surface through the combined processes of turbulent diffusion and gravitational settling. Once near the surface, they may be removed from the atmosphere and deposited on the surface. (EPA Victoria) The modelling assessment will include,, and the calculation of deposited dust. Report No R-RevA 1

8 Particulate matter generated from mining activities may also incorporate a number of metallic minerals due to the nature of Lake Maitland sediments. A baseline sediment sampling programme has been conducted by Outback Ecology Services to determine the aquatic ecology of Lake Maitland. The baseline analysis of sediments has been repeated six times since May 2007 (December 2008 and then March, May, June, July and November 2010) at ten locations. Sites were selected based on the surface hydrology of Lake Maitland and the position of the resource area. Within each of the ten sites, sediment was collected from three randomly selected sampling points from the surface, no deeper than 5 cm. A summary of the baseline sediment data collected during 2007, 2008 and 2010 is provided in Table 1. Table 1: Baseline Sediment Monitoring Data Metal Maximum Concentration (mg/kg) (2010, 2008, 2007) Median Concentration (mg/kg) Aluminium 15,800 2,620 4,870 3,550 Antimony 1.3 <0.1 <2.5 <0.5 Arsenic < Barium <5 3.3 Boron Cadmium <0.5 <0.5 Chromium Cobalt 4 1 <1 1.6 Copper < Iron 17,500 5,535 5,650 6,410 Lead < Manganese Nickel Selenium <2.5 <1 Silver Not detected 0.05 <1 <0.5 Strontium 8, Tellurium < Thallium <0.05 Not tested Thorium Tin <2.5 <0.5 Uranium Vanadium Not tested Not tested Zinc The sediment sampling results were converted to a percentage to assess the contribution of each metal within the particulate matter fraction. The results are displayed in Figure 1. This analysis assumes that airborne dust comprises particles from the sediment layer only, neglecting the influence of subsurface particulate matter. This assumption is considered appropriate since subsurface horizons have a moisture content in the range 19 97%, dependent on depth and location, with a resultant low dust generating potential. No consideration has been given to the metals content of soil from beyond the boundaries of the Lake Maitland sediments, as the proposed area of disturbance is centred on the Lake. Report No R-RevA 2

9 Non metalic PM Aluminium Iron Strontium Figure 1: Sediment Sampling Results: Metals Fraction The percentage analysis of Lake Maitland sediment samples indicates that the principal metals associated with airborne particulate matter are aluminium (1.6%), iron (1.8%) and strontium (0.85%). Uranium and vanadium dominate subsurface horizons, but at the surface they comprise % and 0.010% respectively. Aluminium, strontium, uranium and vanadium will be considered in the air quality impact assessment, iron has been excluded due to its non-toxic properties. The uranium decay series consists of 14 radionuclides, including radon. Radon is a non-reactive gas which is both colourless and odourless and has the potential to impact on human health due its radioactive properties. Consequently radon has also been included in the air quality impact assessment, for sources which potentially contain uranium. A summary of the atmospheric contaminants and identified sources included in the impact assessment are presented in Table 2. Report No R-RevA 3

10 Table 2: Atmospheric Contaminant Summary Atmospheric Contaminants Deposited dust (insoluble solids) Metals (aluminium, strontium, uranium and vanadium) Radon Identified Sources Construction and mining activities Construction and mining activities Diesel fuel combustion by mobile fleet Diesel fuel combustion by power station Mineral processing plant Construction and mining activities Diesel fuel combustion by mobile fleet Diesel fuel combustion by power station Mineral processing plant Construction and mining activities Mining activities Mining activities Mineral processing plant Report No R-RevA 4

11 2.0 SITE DESCRIPTION The proposed mine and processing facility will be located at Lake Maitland, approximately 100 km south of Wiluna, and 750 km north-east of Perth, Western Australia. Access to the site from Wiluna is via Barwidgee- Yandal Road or from Leinster via the private access road to Bronzewing Gold Mine. The project area is located on Barwidgee Pastoral Station, which is owned by Mega Lake Maitland and sublet for pastoral purposes. A site locality map is presented in Figure 2. The uranium deposit is located along the western margin of Lake Maitland and is essentially crescentshaped; with three arms representing paleo-drainage channels extending towards the north-west. The mineralisation is flat lying and thin, averaging 1.9 m (range 0.5 m to 4.5 m) in thickness. The uranium generally occurs within a single coherent horizon located 1.5 m to 5.0 m below the surface of Lake Maitland. Figure 2: Site Location 2.1 Description of the Activity The LMUP has a 13 year mine life cycle with an average extraction rate of 1.2 million tonnes per annum (mtpa). Uranium ore will be extracted using the conventional excavator and truck method. Blasting is not required due to the near surface location of the mineral. The mine plan incorporates the use of mined out pits for permanent tailings storage and temporary or permanent water management facilities (WMF), which will require mining one or more active pits simultaneously. Mined out pits not required for tailings or water management will be progressively backfilled with overburden and rehabilitated by covering the area with topsoil, or other suitable material to mimic the pre-mining landform. Below-ground water management facilities will also be backfilled with overburden and topsoil when they are no longer required. Tailings within the tailings storage facility (TSF) will be progressively covered with a layer of appropriately selected overburden material and topsoil when the facilities have reached capacity. All mining disturbances will be enclosed by flood protection bunds. Ore will be stockpiled at the central ore stockpile pad during the Construction Year before commencement of operation of the mineral processing facility and in later years to facilitate blending and efficient use of equipment and cycle times. Topsoil and overburden will be removed at an average rate of 0.8 mtpa and will be stockpiled in controlled areas or backfilled progressively into mined out pit voids for rehabilitation. Overburden is defined as below grade ore, containing less than 100 parts per million (ppm) uranium. Mining and processing will be continuous throughout the operational life of the project, with the exception of plant shut-down and maintenance periods and interruptions to mining due to inclement weather. Ore excavated from mine pits will be processed to produce uranium peroxide concentrate. The mineral processing method selected for LMUP is tank alkaline leaching followed by direct precipitation for uranium recovery. The production rate is expected to be up to 1,000 tonnes per annum of uranium peroxide concentrate. The LMUP will be supported by a diesel fuelled power station located within the footprint of the mineral processing plant. The plant will have a maximum capacity of 10 MW with the expected load in the order of 8 MW. Mine access will be achieved by a new road constructed between the mine site and the existing Barwidgee- Yandal road. A new road will also be installed between the accommodation village and mineral processing plant. These roads and internal haul roads will be constructed using lateritic gravel sheeting sourced from local borrow pits. The accommodation village will be constructed to the north-west of the site and will house a workforce of approximately 180 personnel at full production capacity. Report No R-RevA 5

12 Other supporting facilities included in the proposal are: Administration building Laboratory Security gate house Mining office Workforce amenities Machinery and equipment hard-stand areas Maintenance workshops and storage areas Reagent and product storage areas. A summary of the key characteristics of the LMUP is presented in Table 3. Table 3: LMUP Key Characteristics Project Element Description Schedule Construction Construction period of approximately 1 year, Mining Targeted to commence in 2013 Production Targeted to commence in 2014 Operational life Approximately 12 years Geological Setting Mineralisation footprint Large areal extent, approximately 6 km long (N-S) and around 2 km wide (E-W). The uranium mineralisation is flat-lying and thin, averaging around 1.7 m (range 0.02 Nature of mineralisation to 3.8 m) in thickness at 100 parts per million (ppm) eu 3O 8 cut-off grade. The uranium generally occurs within a single coherent horizon located 2 to 5 metres (m) below the ground surface. Mining and Production Mining rate (ore) Up to approximately 1.2 million tonnes per annum (Mtpa) Mining method Conventional excavator and truck. No blasting required. Overburden Temporarily stockpiled and/or backfilled progressively into the pits or over Tailings Storage Facilities Processing plant and rate Alkaline leach using direct precipitation up to 1.2 Mtpa Main process reagents and fuels Sodium carbonate, flocculent, sodium bicarbonate, sodium hydroxide, sulphuric acid, hydrogen peroxide and diesel fuel. Tailings storage strategy Tailings will be stored in selected, specially prepared mined out pits. Flocculent will be used to assist with physical and chemical stabilisation of the tailings. Other Key Infrastructure Power supply Up to a 10 megawatt (MW) diesel fired power station. Water Supply Up to 2 gigalitres per annum (GLpa) supplied from a borefield and pipeline. A 5 km access road will be established from Barwidgee - Yandal Road. Access Fly-in/ fly-out personnel will arrive and depart from the existing Bronzewing Gold Mine airstrip. Village A village will be constructed approximately 5 km northwest of the processing plant to accommodate the LMUP workforce. Workforce Construction Phase Approximately 450 personnel Operational Phase Approximately 180 personnel Report No R-RevA 6

13 Project Element Mechanism Volume Route Description Product Transport Product will be placed in sealed drums and secured in a shipping container for transport by road in trucks. Approximately 4 to 5 trucks per month By road via Wiluna along the Goldfields Highway to Kalgoorlie and on to licensed uranium export facilities at Port Adelaide or Darwin. 3.0 NATURE OF DISCHARGES The air quality impact assessment has been conducted for two scenarios; construction phase and operations phase. Year 7 of mine operations has been selected to characterise the operations phase, as this year represents a period where most of the mine is active and consequently represents worst case emissions. A description of the identified sources and their emission characteristics is presented in Sections 3.1 and 3.2 for both project phases. Section 3.3 outlines the techniques used to estimate emissions and the associated assumptions, whilst Section 3.4 outlines the discharge parameters for all identified sources. 3.1 Phase One Construction Year 1 The construction phase occurs for a period of one year at the beginning of the LMUP, encompassing construction of the mineral processing plant, preparation of flood protection bunds, water management facilities and topsoil stripping and stockpiling for initial mining activities. Mining will occur from one active pit, however mineral processing will not commence until the following year. Excavated ore will be stockpiled on the central ore stockpile pad. The mine plan for the construction year is presented in Figure 3. Figure 3: Construction Year Mine Plan Particulate matter emission sources during this period consist of all activities that have the potential to generate dust, including the following: Vehicle traverse of access roads Mobile plant diesel consumption Mineral processing plant construction Ore extraction from the active pit Flood protection bund construction Borrow pit stockpiles and excavation Central ore stockpile pad construction Water management facility construction Power plant diesel consumption. Completed flood protection bunds have not been included as a particulate matter source as they will be constructed from overburden stripped from mining pits, covered with ballast-size rock sourced from the local Report No R-RevA 7

14 region. Similarly surfaces that have not been stripped have also been discounted as dust sources due to the natural crusting, compaction and vegetation that protects the surface from wind erosion. Particulate metal sources of emission include all dust generating activities located on the deposit. This includes ore extraction from the active pit, flood protection bund construction and water management facility construction. Similarly, radon sources in the Construction Year include all activities associated with ore extraction and handling. Identified radon sources include: Water management facility abstracted water Central ore stockpile Ore extraction from the active pit. Identified activities/sources for the Construction Year are described in the following sections: Access Roads Lateritic gravel will be used for surface sheeting of access roads between the accommodation village and mineral processing plant, the Barwidgee-Yandal Road link and roads connecting the bulk ore stockpile, active mine pit, borrow pit and mineral processing plant construction site. It is anticipated that seven 33 tonne articulated dump trucks will travel on all internal access roads during the construction period for the entire 24 hour work day. The accommodation village road and the Barwidgee-Yandal Road link will mostly be traversed by light vehicles. For the purpose of estimating emissions it has been assumed that the accommodation village road will be subject to 20 light vehicles at the commencement and conclusion of each shift. (6 am and 6 pm). One vehicle per hour is assumed to traverse the Barwidgee-Yandal Road link. Water will be applied to unpaved road surfaces, resulting in dust control equivalent to Level 2 watering as defined in the National Pollutant Inventory (NPI) Estimation Technique Manual for Mining. Water trucks have been excluded as particulate matter sources. Mineral Processing Plant Construction Construction of the mineral processing plant will generate dust during the first three months of the construction process. The plant area will be cleared, stripped and excavated and the foundations laid. A 30,000 m 2 stockpile will be generated from this process which will be located on the plant site until consumed by other structures such as flood protection bunds. One bulldozer/compactor will be used for topsoil clearing, stockpile grooming and compaction of the site in preparation for construction. The exposed surfaces will also be a source of windblown dust. Water will be applied to exposed surfaces and stockpiles, resulting in dust control equivalent to Level 1 watering as defined in the National Pollutant Inventory (NPI) Estimation Technique Manual for Mining. Ore Extraction Ore extraction will occur in the single active pit using one excavator and one articulated dump truck. The activity of the excavator and truck on overburden and topsoil is anticipated to be a particulate metals and dust source, however once the ore material is accessed; the natural ore moisture content will prohibit dust generation. The exposed active pit will also be a source of windblown dust and particulate metals; however the surface will be watered to prohibit excessive dust generation. For the purpose of emission estimation, half the pit has been assumed to be exposed and subject to wind blow dust, with excavator activity assumed to occur on overburden and topsoil for half the time and wet ore for the remainder of the time. Excavator generated dust and particulate metals therefore have been included every second hour of the 24 hour work period. Report No R-RevA 8

15 The exposed ore will also be a source of radon gas. Using the assumptions applied for dust generation, the model includes half the active pit as a radon gas source. Flood Protection Bund Construction Flood protection bunds will be established around the active pit, central ore stockpile pad and water management facility. Construction of the bunds will require the use of one excavator and truck, both of which have been included as dust and particulate metal sources for the first three months of the Construction Year. Borrow Pit Stockpile and Excavation The borrow pit will be active for the entire Construction Year, providing material for the access roads, mineral processing plant and flood protection bunds. Over the course of one year a stockpile on the south west corner will be generated and one excavator and truck will be active. For the purpose of the model, the stockpile will be assumed to be full size for the entire Construction Year and the borrow pit subject to windblown dust, with the mining equipment forming additional sources. Dust generation from borrow pit sources will be minimised through the application of water equivalent to Level 1 watering. Central Ore Stockpile Pad Construction and Operation The ore stockpile pad is centrally located and will be used for stockpiling whilst the processing facility is constructed. This location is subject to two types of emission sources. Initially, preparation of the pad will involve topsoil stripping, compaction and excavation. These activities will be a source of windblown dust together with the exposed surface. Dust suppression watering will be conducted during this period. Therefore one excavator, bulldozer/compactor and truck are included as particulate matter sources for the first three months of the construction year. The entire surface has also been included as a source of windblown dust during this period. Following completion of the pad the ore stockpile will be a radon source. Uranium ore has been discounted as a particulate matter source due to its high moisture content. The stockpile will expand in size as the Construction Year progresses; however the full size stockpile has been included in the model for the remaining nine months of the Construction Year for the purpose of worst case emission estimation. Water Management Facility The water management facility is similar to the central ore stockpile in that construction of the facility will be a source of dust, whilst the completed receptacle will form a radon source. Construction will involve topsoil stripping, compaction and excavation. Consequently an excavator and compactor/bulldozer have been included as dust and particulate metal sources for the first month of the Construction Year. This month will also include windblown dust from the receptacle as another source of dust and particulate metals, with water suppression employed. The water management facility will form a radon source for the remaining eleven months. Power Plant Construction of the power plant will occur during the first part of the Construction Year, however for the purpose of worst case emission estimates the plant has been assumed to be fully operational for the entire period. Source characteristics are not as yet available Construction Year, consequently a single 0.32 m diameter stack discharging at a height of 9 m above ground level has been assumed. Mobile Plant Diesel combustion by mobile plant, e.g. bulldozers, articulated dump trucks etc, has been included as a source of and for all identified equipment. Construction Year Overview A summary of identified sources for the Construction Year is presented in Table 4. Report No R-RevA 9

16 Table 4: Summary of Sources - Construction Year Source Description Timing Internal access roads Seven 33 tonne trucks 24 hours per day, continuous Accommodation Village Road Barwidgee-Yandal Road link 20 light vehicles 1 light vehicle per hour 5 am - 6 am 5 pm - 6 pm 12 hours per day, 6 am to 6 pm In front of active pit Topsoil stockpile 24 hours per day, continuous Mineral processing plant construction Mineral processing plant construction Mineral processing plant construction Ore extraction Topsoil stockpile Bulldozer/compactor Exposed surface Excavator January March, 24 hours per day January March, 6 am to 6 pm January March, 24 hours per day Every second hour of the 24 hour work period Ore extraction Exposed surface 24 hours per day, continuous Flood protection bund construction Flood protection bund construction Excavator Truck dumping overburden January March, 6 am to 6 pm January March, 6 am to 6 pm Borrow pit Topsoil stockpile 24 hours per day, continuous Borrow pit Exposed surface 24 hours per day, continuous Borrow pit Excavator 6 am 6 pm Borrow pit Central ore stockpile pad construction Central ore stockpile pad construction Truck dumping overburden Bulldozer/compactor Exposed surface 6 am 6 pm January March, 6 am 6 pm January March, 24 hours continuous Atmospheric contaminant Metals Metals Radon Metals Metals Metals Control Water truck dust suppression Water truck dust suppression Water truck dust suppression Water truck dust suppression Water truck dust suppression None Water truck dust suppression None Water truck dust suppression None None Water truck dust suppression Water truck dust suppression None None None Water truck dust suppression Report No R-RevA 10

17 Source Description Timing Atmospheric contaminant Control Central ore stockpile pad construction Central ore stockpile pad Water management facility construction Water management facility construction Water management facility Truck dumping overburden Ore stockpile Bulldozer/compactor Exposed surface Operation January March, 6 am 6 pm April December, 24 hours continuous January February, 6 am 6 pm January February, continuous February December, 24 hours continuous Radon Metals Metals Radon None None None Water truck dust suppression None Power plant Operation 24 hours per day, continuous None 3.2 Phase Two: Operation - Year 7 Year 7 represents the period where most of the mining lease is active. The borrow pit will continue to be a source of lateritic gravel and will include a topsoil stockpile. The northern arm of the deposit will be prestripped and the flood protection bund constructed in preparation for active ore extraction in following years. A water management facility for abstracted water will be formed in the northern pit, whilst the pit directly adjacent will be completely rehabilitated. The active tailings storage facility is located further south and will consist of tailings slurry, with less than 20% solids content. Further south a swamp dozer equipped with track rollers will be preparing a tailings storage facility for future years. This pit is separated from the mined pit to the south by a rehabilitated section that forms the walls between sections. Active ore extraction will be occurring in two pits at the south end of the deposit. This area includes two water management facilities for supernatant water and another rehabilitated pit. The central ore stockpile will continue to be an intermediate ore deposit. Year 7 includes significantly sized overburden stockpiles located along the central section of the mining lease. The mine plan for Year 7 is presented in Figure 4. Figure 4: Year 7 Mine Plan Year 7 also includes full operation of the mineral processing plant, where uranium ore will be processed to uranium peroxide concentrate utilising tank alkaline leaching followed by direct precipitation. In simple overview, mineral processing involves crushing of stockpiled ore followed by conveyor transfer to a semi-autogenous grinding (SAG) mill where a slurry is formed through mixing and grinding with recovered process solutions. Flocculent is added to promote settling and the remaining solution is re-carbonated using exhaust gas from the site diesel fuelled power station. Further carbonation occurs with the addition of sodium carbonate which is followed by heating and agitation to promote leaching of uranium and vanadium. Leached uranium is extracted from the slurry through counter current washing and the addition of flocculent. The settled by-product forms the tailings which are extracted from the facility to the tailings storage facility via a slurry pump. Precipitation follows the leaching process, where sodium diuranate and sulphuric acid are used to wash the uranium bearing solution to precipitate vanadium and remove residual solids. The final step involves precipitation of uranium oxide through the addition of hydrogen peroxide, followed by washing and drying to create solid uranium peroxide ready for packaging and transport. The identified particulate matter sources and activities for Year 7 are as follows: Report No R-RevA 11

18 Mineral processing plant Mining activities: Northern pit preparation for future mining Borrow pit activities and topsoil stockpile Rehabilitated pits Ore extraction Overburden stockpiles Vehicle traverse on access roads. Sources of particulate metal emissions include all dust generating activities located on the deposit. This includes northern pit preparation, pit rehabilitation, ore extraction and topsoil and overburden stockpiles. The identified radon sources in Year 7 are as follows: Mineral processing plant Mining activities: Water management facility extracted water Water management facility supernatant water Active tailings facility Ore extraction Central ore stockpile Overburden stockpiles. Identified activities/sources for Year 7 are described in the following sections: Mineral Processing Plant The processing facility contains a number of point source emissions to air as well as fugitive sources. The ROM pad is located at the northern end of the processing facility and will be used to stockpile ore prior to processing. The ore will be transferred via a wheel loader, which has been discounted as a particulate matter source due to the high moisture content of the ore. The ROM pad has been included as a radon source. Particulate matter emissions will be limited to front end processing where ore is crushed and conveyor transferred to the SAG mill, where a slurry is formed. The crusher will be equipped with water misting which will be used either continuously or as required. It is expected that emissions to air from this component of the process will be negligible due to the high moisture content of the ore and the proposed control equipment. Therefore the air quality impact assessment has not considered this source further. The mineral processing plant and accommodation village will be powered by a 10 MW diesel fuelled power station. Diesel exhaust will be ducted to the recarbonation column where carbon dioxide in the exhaust gases will be used to recarbonate the slurry following flocculation. The recarbonation column will be equipped with a wet chemical scrubber to control carbon monoxide and oxides of nitrogen generated by the power plant and to provide a process vent for the column. The scrubber specifications have not been determined, however it is envisaged that a caustic scrubbing solution will be used. Report No R-RevA 12

19 Oxides of nitrogen and carbon monoxide have not been included in the modelling assessment, due to the limited number of sources and the likely minimal impact on air quality. Diesel combustion also generates particulate matter in the and size fractions. The use of the wet chemical scrubber and ducting emissions through the recarbonation column will reduce particulate matter emission rates, however the magnitude of the reduction is unknown. Consequently the recarbonation column wet chemical scrubber has been included as a and emission source in the impact assessment, with emission rates based on a 50% removal efficiency. Similarly the stack height, exit diameter and velocity have been assumed to be 9 m (release height), 0.35 m (diameter) and 12 m/s (velocity) due to the absence of detailed design information. The exhaust gas exit temperature and volumetric flowrate have been specified in the mass and energy balance for the plant. The process includes four enclosed heated leaching tanks each equipped with a single localised vent, which is discharged 3 m above the tanks through a 0.15 m diameter pipe. The vents are not equipped with an active discharge system. The leaching process will release radon from the slurry and these four vents will form the principal radon emission points for mineral processing. The counter current decanting system consists of six open tanks with mechanical agitation to promote the formation of washed tailings. The process will generate water vapour and carbon dioxide emissions to air. The two precipitation steps also include process vents which are used to discharge carbon dioxide and consequently have not been considered further. The final stage includes drying of the uranium peroxide filter cake to remove all moisture before transport. The dryer is powered by the on-site power station, with process emissions to air controlled by wet chemical scrubber. The plant mass and energy balance specifies a 100% water vapour emission from this discharge point; hence it has not been considered further. To support uranium processing, three sodium carbonate silos are located on site. The silos are equipped with fabric filters on the exhausts to control particulate matter emissions to air during product transfer. The silo design specifications are not known, however it is conservatively assumed that the fabric filters will result in a / discharge concentration no greater than 50 mg/nm 3. Silo emissions to air have been calculated using a refill rate of 3 tonnes/hour for a period of one hour every day, nominally 7 am to 8 am. characteristics are based on a silo height of 9 m and diameter of 4 m. Mining Activities Northern Pit Preparation Preparation of the northern pit involves topsoil stripping using a bulldozer and truck, and construction of the flood protection bund utilising an excavator and truck. Three topsoil stockpiles will be located around the edges of the pit, with these surfaces and the stripped area subject to windblown dust, although water will be applied to limit dust generation. calculations for the excavator and truck have been based on a worst case assumption of excavation and transfer of 0.8 mtpa of topsoil/overburden. Northern pit sources have been included in the modelling assessment for dust and particulate metals. Borrow Pit and Topsoil Stockpiles The borrow pit will be a constant source of activity with one bulldozer working in the pit. The exposed surface and topsoil stockpile will also be a source of windblown dust in Year 7; however water will be applied to aid dust suppression. Particulate metals have not been included for borrow pit sources as the pit is located outside the footprint of the uranium deposit. Water Management Facilities Three water management facilities will be in operation during Year 7. Although not a source of dust or particulate metals the facilities will emit radon from the supernatant and abstracted water. Report No R-RevA 13

20 Rehabilitated Pits Year 7 includes two rehabilitated pits and two small rehabilitated wedges between the active and future tailings facilities. All rehabilitated areas will be restored to pre-mining status through replacement of overburden and topsoil and compaction of the surface using a compaction roller. For the purpose of emission estimation the rehabilitated areas have been excluded as sources of windblown dust with the only dust and particulate metal generation activity being one roller located on the northern pit closest to the sensitive receptors. Active Tailings Storage Facility The active tailings facility has been discounted as a potential source of dust and particulate metals as the tailings slurry comprises only 20% solids. However tailings are a source of radon and have been included in the model as a radon area source. Future Tailings Storage Facility and Mined Out Pit The future tailing storage facility and mined out pit have not been included in the modelling assessment as either sources of dust or radon. Particulate matter emissions have been discounted as it is anticipated that both pits will be water logged. Ore Extraction Ore extraction will occur from two pits in Year 7, with one excavator and articulated dump truck located in each pit for the duration of the year. These activities will generate dust and particulate metals through the movement of topsoil and overburden, however the transfer of ore is considered to be relatively dust free due to its high moisture content. For the purpose of emission estimation, the same assumptions used for the Construction Year have been applied, e.g. truck and excavator activity on overburden is assumed to occur every second hour of the 24 hour work period and half of each pit is assumed to be a source of windblown dust. Correspondingly radon emissions have been incorporated from half the exposed pit for the entire year. Central Ore Stockpile The central ore stockpile will continue to be a source of radon in Year 7. As noted above this activity has been discounted as a dust and particulate metals source due to the high moisture content of the material. The stockpile will expand and contract over the year however the maximum capacity stockpile has been included in the model for the purpose of worst case radon emission estimation. Dust and particulate metals emissions to air will, however, be possible from the topsoil stockpile located adjacent to the central ore stockpile, within the flood protection bund. Overburden Stockpiles The overburden stockpiles located north-south adjacent to the deposit and close to the central ore stockpile pad will be a source of dust, particulate metals and radon during Year 7. The piles will be managed by a wheel loader and dump truck which have both been included in the assessment. For the purpose of worst case emission estimation it has been assumed that both the wheel loader and truck transfer 0.8 mtpa of overburden during Year 7. A topsoil stockpile is located adjacent to the overburden topsoil, which has been included in the assessment as a source of windblown dust and particulate metals. Access Roads Twelve 33 tonne articulated dump trucks have been assumed to travel on all internal access roads during Year 7. Light vehicles on the accommodation village road have been assumed to be at peak volumes (20 vehicles) at the commencement and conclusion of each shift. One light vehicle per hour is assumed to traverse the Barwidgee-Yandal Road. Report No R-RevA 14

21 Water will be applied to unpaved road surfaces, resulting in dust control equivalent to Level 2 watering as defined in the NPI Estimation Technique Manual for Mining. Water trucks have been excluded as dust sources. Southern Pit Preparation The final element of activities during Year 7 will be preparation of the southern pit for future ore extraction. Preparation will involve stripping of five discrete areas of topsoil. The model assessment has conservatively included all five areas as dust and particulate metal sources for the entire year. Mobile Plant Diesel combustion by mobile plant, e.g. bulldozers, articulated dump trucks etc, has been included as a source of and for all identified equipment. Year 7 Overview A summary of identified sources for Year 7 is presented in Table 5. Table 5: Summary of Sources - Year 7 Source Description Timing Atmospheric contaminant Control Mineral processing plant Mineral processing plant Mineral processing plant Mineral processing plant Northern pit preparation Northern pit preparation Northern pit preparation Northern pit preparation Northern pit preparation ROM pad Recarbonation column Leach tanks vent Sodium carbonate silos Bulldozer Excavator Exposed surface Truck dumping overburden Topsoil stockpile (3 off) 24 hours per day, continuous 24 hours per day, continuous 24 hours per day, continuous 1 hour per day, 7 am 8 am 6 am 6 pm 6 am 6 pm 24 hours continuous 6 am 6 pm 24 hours continuous Borrow pit Bulldozer 6 am 6 pm Borrow pit Exposed surface 24 hours per day, continuous Radon Radon Metals Metals Metals Metals Metals None Wet chemical scrubber None Fabric filter None None Water cart dust suppression None Water cart dust suppression None Water cart dust suppression Report No R-RevA 15

22 Source Description Timing Atmospheric contaminant Control Borrow pit Water management facility north Water management facility west Water management facility south Rehabilitated pit - north Active tailings storage facility Ore extraction Ore extraction Ore extraction Central ore stockpile Overburden stockpile Topsoil stockpile Abstracted water Supernatant water Supernatant water Roller/compaction Tailings Northern pit excavator Northern pit exposed surface Southern pit excavator Southern pit exposed surface Exposed surface North south/adjacent to the deposit 24 hours per day, continuous 24 hours per day, continuous 24 hours per day, continuous 24 hours per day, continuous 6 am 6 pm 24 hours per day, continuous Every second hour of the 24 hour work period 24 hours per day, continuous Every second hour, of the 24 hour work period 24 hours per day, continuous 24 hours per day, continuous 24 hours continuous Overburden stockpile Wheel loader 6 am 6 pm Overburden stockpile Topsoil stockpile Topsoil stockpiles Near to central ore stockpile Adjacent to the central ore stockpile Southern pit (5 off) 24 hours per day, continuous 24 hours per day, continuous 24 hours per day, Radon Radon Radon Metals Radon Metals Metals Radon Metals Metals Radon Radon Metals Radon Metals Metals Radon Metals Water cart dust suppression None None None None None None Water cart dust suppression None Water cart dust suppression None Water cart dust suppression None Water cart dust suppression Water cart dust suppression Water cart dust Report No R-RevA 16

23 Source Description Timing Atmospheric contaminant Control continuous Metals suppression Topsoil stockpiles Adjacent to the central overburden stockpiles 24 hours per day, continuous Metals Water cart dust suppression Internal access roads Accommodation Village Road Barwidgee Yandal Road link Twelve 33 tonne trucks 20 light vehicles 1 light vehicle per hour 24 hours per day continuous 5 am - 6 am 5 pm - 6 pm 12 hours per day, 6 am to 6 pm Water cart dust suppression Water cart dust suppression Water cart dust suppression 3.3 Estimation rates for each of the identified mining sources have been calculated using Estimation Technique Manuals published by the National Pollutant Inventory (NPI) and AP-42 emission factors published by the United States Environmental Protection Agency (USEPA). rates for mineral processing plant sources have been derived from the mass and energy balance prepared by Independent Metallurgical Operations for Mega Lake Maitland (Appendix B). Application of emission factors requires a detailed understanding of the project area and proposed operations. LMUP emission estimation has been conducted to assess worst case operating conditions; consequently it has been assumed that all identified surfaces will be exposed simultaneously and that all activities occur constantly throughout the designated time. Other parameters used for estimating LMUP emissions to air are described in the following sections. Timing Construction activities have been limited to 12 hours between 6 am and 6 pm whilst all mining activities have been assumed to occur continuously over the 24 hour work day. Mining Equipment The following representative mining equipment has been included in the assessment. Table 6: Representative Mining Equipment Equipment Type Articulated dump truck Excavator Wheel loader Bulldozer Compactor/roller Manufacturer/Model Caterpillar 740 or equivalent Caterpillar 365C or equivalent Caterpillar 924 or equivalent Caterpillar 740/773F or equivalent Caterpillar CS433 or equivalent Calculated particulate matter emissions to air from fuel consumption from the listed mining fleet were based on the projected annual diesel consumption. Power Plant Particulate matter emissions to air from the diesel fuelled power plant were calculated utilising the projected annual diesel consumption and the NPI emission factor for combustion in boilers smaller than 30 MW. Report No R-RevA 17

24 Access Roads Light vehicles have been assumed to travel an average of 10 km per trip during both phases of operation. The distance travelled by heavy vehicles on internal access roads has been calculation using the volume of material to be extracted each year, together with the vehicle capacity and typical route distance. A summary of the calculation parameters for both phases of operation is presented in Table 7. Table 7: Heavy Vehicle Distance Travelled Parameter Construction Year Year 7 Volume of material to be moved 1.2 mtpa ore 0.8 mtpa topsoil and overburden Number of trucks 7 12 Truck capacity 33 tonnes 33 tonnes Typical route distance 9.7 km 14.7 km 1.2 mtpa ore 0.8 mtpa topsoil and overburden Site Characterisation The majority of emission sources listed for the Construction Year and Year 7 are due to the uplift of surface sediment into the air column via the action of mining equipment or wind. Silt and moisture content are important surface parameters; with moisture content acting as a limited factor for dust generation and high silt content sediments more prone to disturbance and conversion to airborne dust. Silt content is defined as particles smaller than 75 microns. Outback Ecology Services has conducted a number of Lake Maitland surficial sediment monitoring programmes from 17 survey locations. Two survey positions, RLM 16 and RLM 17, were located on the resource where dust generating activities will occur in the Construction Year and Year 7. The average results from these survey locations and events have been used to represent silt and moisture content for all activities occurring on the deposit, including windblown dust from exposed surfaces and topsoil stockpiles. A summary of the RLM16 and RLM 17 Outback Ecology Services results for the period 2007 to 2010 is presented Figure 5 and Figure Moisture Content (%) RLM16 RLM17 Average Figure 5: RLM16 and RLM17 Moisture Content Summary Report No R-RevA 18

25 80 70 Silt content (%) RLM16 RLM17 Average Figure 6: RLM16 and RLM17 Silt Content Summary The surficial sediment sampling programme did not include surface characterisation at the proposed location of the mineral processing plant. The closest sampling position was RLM3, above the northern arm of the deposit. The RLM3 average results were used to quantify particulate matter emissions to air from the mineral processing plant and central ore stockpile construction phase. A summary of Outback Ecology results from RLM3, for the period 2007 to 2010 is presented in Figure 7 and Figure Moisture content (%) RLM3 Average Figure 7: RLM3 Moisture Content Summary Report No R-RevA 19

26 60 Silt content (%) RLM3 Average Figure 8: RLM3 Silt Content Summary Lateritic gravel sourced from the borrow pit has been characterised by Golder Associates during feasibility studies. The test results demonstrated a silt content of 6% and a moisture content of 1.6%. These results will be used for calculation of all Lake Maitland haul roads and borrow pit emissions to air. The final sources that require characterisation are the overburden stockpiles. These stockpiles comprise material that lies between the topsoil and ore, typically up to 1.5 m below the surface. Golder Associates test results for costeans between this depth range have an average moisture content of 55% and silt content of 34%. These results have been used for calculation of overburden stockpile emissions to air. Deposition Characteristics The particle size of airborne particulate matter affects the rate at which particles settle from the air to form deposited dust. Large particles settle quickly, whilst small particles are retained in the air column. The air quality impact assessment has applied a worst case approach, assuming dry deposition characteristics only, with particulate matter removal due to rain events not included. The deposition rate is dependent on the size distribution of particles within the fraction. For example comprising a high percentage of large particles will have higher deposition rates, than comprised of fines. The particle size distribution of Lake Maitland suspended particulate matter has been assumed to fall into two broad categories; Particulate matter from surface material at the mineral processing plant, roads, borrow pit and central ore stockpile construction sites Particulate matter from the surface material on the deposit, including overburden stockpiles. The particle size distribution data for each category has been calculated from the surficial sediment sampling programme conducted by Outback Ecology Services, described above. The distribution for each group is presented graphically in Figures 9 and 10. Report No R-RevA 20

27 100% Cumulative Frequency (%) 80% 60% 40% 20% 0% Particle size (microns) Figure 9: Particle Size Distribution Construction Sites, Borrow Pit and Roads 100% Cumulative Frequency (%) 80% 60% 40% 20% 0% Particle size (microns) Figure 10: Particle Size Distribution Deposit and Overburden Stockpiles Control Mechanisms A number of dust control mechanisms have been included in the calculation of emission rates. All exposed surfaces have been assumed to be controlled by wind breaks afforded by flood protection bunds, surface crusting due to the high mineral content and watering at a rate of 2 litres/m 2 /hour. The controls have assumed to be multiplicative with the following efficiencies: Flood protection bund wind breaks: 30% Surface crusting: 50% Watering: 50% Report No R-RevA 21

28 s to air from haul roads have been calculated assuming a watering rate of > 2 litres/m 2 /hour equating to an emission reduction of 75%. Radon Radon gas emission estimates have been based on the following assumptions: Half the radon contained within the ore is released during extraction and haulage 100% of radon contained within the ore will be released during tank leaching Stockpiles consist of 30 days production (ore and overburden) 10% of radon contained within stockpiled ore will be released from the voids 100% of radon contained within abstracted water is released during pumping Tailings radon emanation can be characterised by an emanation rate of 0.22 and a diffusion length of 2.4 cm. Other Where no emission factor exists, emissions have been assumed to comprise 10% of emissions. 3.4 Summary Dust, particulate metals and radon emission sources were modelled as either point, volume or areas sources. Discharge parameters for each of these categories are described in the following sections Point Sources Point sources are sources that emit pollutants from a single location, usually, with a degree of elevation and a mechanical mechanism for creating plume rise. The power plant exhaust stack is the only point source included for the Construction Year whilst the recarbonation column and leach tank vent are additional point sources included for Year 7. The emission rates and model input data for LMUP point sources are presented in Table 8. Table 8: Model Input Data: Point Sources Parameter Construction Year Power Plant Exhaust Stack Year 7 Recarbonation Column Year 7 Tank Leach Vent ID PWRSTN RC LT Location, easting, northing (m) , , , Elevation (m) Stack height (m) Exit temperature ( o C) Exit velocity (m/s) Diameter (m) emission rate (g/s) Not applicable emission rate (g/s) Not applicable Radon emission rate (g/s) Not applicable Not applicable Hours of emission Continuous Continuous Continuous Report No R-RevA 22

29 3.4.2 Volume Sources Volume sources are bulky diffuse sources that emit or release pollutants over large areas in three dimensions. Volume sources identified in the Construction Year and Year 7 include mining equipment such as bulldozers, excavators, compactors and wheel loaders. The action of trucks dumping overburden and trucks and light vehicles travelling on internal and external access roads have also been included as volume sources for both phases of operation. Year 7 includes an additional volume source to represent filling of the sodium carbonate silos at the mineral processing plant. Effective release height and initial vertical and horizontal spreads were calculated from the dimensions and application of the proposed equipment. Volume sources were positioned in the model to minimise distances between the source and the nearest sensitive receptor, with the exception of unpaved roads, where vehicles were evenly distributed across the proposed road locations. rates for Construction Year volume sources are presented in Table 9 and Table 10 for dust and particulate metals respectively. Year 7 emission rates are presented in Table 11 and Table 12. No radon volume sources have been included for either phase of operation. Table 9: Construction Year Model Input Data: Volume Sources Particulate Matter Source ID HT1-7 LV1-20 LV21 MPBC OEEX FPBEX Description Internal access road trucks (7 sources to represent road emissions) Accommodation Village Road light vehicles (20 sources to represent road emissions) Barwidgee -Yandal Link Road (1 source to represent road emissions) Bulldozer/compactor (mineral processing plant) Excavator (ore extraction) Excavator (flood protection bund) Units Timing g/s Continuous g/s 5 am 6 am 5 pm 6 pm g/s 6 am 6 pm g/s g/s g/s January March 6 am 6 pm 12 am 1 am 2 am 3 am 4 am 5 am 6 am 7 am 8 am 9 am 10 am 11 am 12 pm 1 pm 2 pm 3 pm 4 pm 5 pm 6 pm 7 pm 8 pm 9 pm 10 pm 11 pm January March 6 am 6 pm HT8 Truck dumping g/s January Report No R-RevA 23

30 Source ID BPEX HT9 COBC HT10 Description overburden (flood protection bund) Excavator (borrow pit) Truck dumping overburden (borrow pit) Bulldozer/compactor (central ore stockpile construction) Truck dumping overburden (Central ore stockpile construction) Units Timing March 6 am 6 pm g/s 6 am 6 pm g/s 6 am 6 pm g/s g/s January March 6 am 6 pm January March 6 am 6 pm WMFBC Bulldozer/compactor (water management facility construction) g/s January February 6 am 6 pm Table 10: Construction Year Model Input Data: Volume Sources Particulate Metals Source ID Description Aluminium Strontium Uranium Vanadium Units Timing OEEX Excavator (ore extraction) g/s 12 am 1 am 2 am 3 am 4 am 5 am 6 am 7 am 8 am 9 am 10 am 11 am 12 pm 1 pm 2 pm 3 pm 4 pm 5 pm 6 pm 7 pm 8 pm 9 pm 10 pm 11 pm FPBEX HT8 WMFBC Excavator (flood protection bund) Truck dumping overburden (flood protection bund) Bulldozer/compactor (water management facility construction) g/s g/s g/s January March 6 am 6 pm January March 6 am 6 pm January February 6 am 6 pm Table 11: Year 7 Model Input Data: Volume Sources Particulate Matter Source ID SCS HT10 Description Sodium carbonate silo Truck dumping overburden (northern pit preparation) Not applicable Units Timing g/s 7 am 8 am g/s 6 am 6 pm NPPB Bulldozer g/s 6 am 6 pm Report No R-RevA 24

31 Source ID NPPEX BPB RHBPC OENPEX OESPEX HT8 OBTAWL HT1-7 - HT9 HT11-15 LV1-20 LV21 Description (northern pit preparation) Excavator (northern pit preparation) Bulldozer (borrow pit) Roller/compactor (rehabilitated pits) Excavator (northern pit ore extraction) Excavator (southern pit ore extraction) Truck dumping overburden (overburden stockpile) Wheel loader (overburden stockpile) Internal access road trucks (12 sources to represent road emissions) Accommodation Village Road light vehicles (20 sources to represent road emissions) Barwidgee -Yandal Link Road (1 source to represent road emissions) Units Timing g/s 6 am 6 pm g/s 6 am 6 pm g/s 6 am 6 pm g/s g/s 12 am 1 am 2 am 3 am 4 am 5 am 6 am 7 am 8 am 9 am 10 am 11 am 12 pm 1 pm 2 pm 3 pm 4 pm 5 pm 6 pm 7 pm 8 pm 9 pm 10 pm 11 pm 12 am 1 am 2 am 3 am 4 am 5 am 6 am 7 am 8 am 9 am 10 am 11 am 12 pm 1 pm 2 pm 3 pm 4 pm 5 pm 6 pm 7 pm 8 pm 9 pm 10 pm 11 pm g/s 6 am 6 pm g/s 6 am 6 pm g/s Continuous g/s 5 am 6 am 5 pm 6 pm g/s 6 am 6 pm Report No R-RevA 25

32 Table 12: Year 7 Model Input Data: Volume Sources Particulate Metals Source ID HT10 NPPB NPPEX RHPBC OENPEX OESPEX HT8 OBTAWL Description Truck dumping overburden (northern pit preparation) Bulldozer (northern pit preparation) Excavator (northern pit preparation) Roller/compactor (rehabilitated pits) Excavator (northern pit ore extraction) Excavator (southern pit ore extraction) Truck dumping overburden (overburden stockpile) Wheel loader (overburden stockpile) Aluminium Strontium Uranium Vanadium Units Timing g/s 6 am 6 pm g/s 6 am 6 pm g/s 6 am 6 pm g/s 6 am 6 pm g/s g/s 12 am 1 am 2 am 3 am 4 am 5 am 6 am 7 am 8 am 9 am 10 am 11 am 12 pm 1 pm 2 pm 3 pm 4 pm 5 pm 6 pm 7 pm 8 pm 9 pm 10 pm 11 pm 12 am 1 am 2 am 3 am 4 am 5 am 6 am 7 am 8 am 9 am 10 am 11 am 12 pm 1 pm 2 pm 3 pm 4 pm 5 pm 6 pm 7 pm 8 pm 9 pm 10 pm 11 pm g/s 6 am 6 pm g/s 6 am 6 pm Area Sources An area source is a source that emits pollutants at or near ground level over a large area without mechanical plume rise. Area sources included in the modelling assessment for the Construction Year and Year 7 include stockpiles, exposed surfaces, ROM pad, water management facilities and tailing storage facilities. rates for each of the Construction Year area sources are presented in Table 13, Table 14 and Table 15. Year 7 area source emission rates are presented in Table 16, Table 17 and Table 18. Report No R-RevA 26

33 Table 13: Construction Year Model Input Data: Area Sources Particulate Matter Source ID MPTS APTS MPES OEES BPTS BPES COWBD WMFES Description Topsoil stockpile (Mineral processing plant) Topsoil stockpile (In front of active pit) Mineral processing plant exposed surface Active pit exposed surface Topsoil stockpile (Borrow pit) Borrow pit exposed surface Central ore stockpile pad exposed surface Water management facility exposed surface Units Timing g/m 2 /s January March, continuous g/m 2 /s Continuous g/m 2 /s January March, continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s January - March, continuous g/m 2 /s January, continuous Table 14: Construction Year Model Input Data: Area Sources Particulate Metals Source ID APTS OEES WMFES Description Topsoil stockpile (In front of active pit) Active pit exposed surface Water management facility exposed surface Aluminium Strontium Uranium Vanadium Units Type g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s January March, continuous Table 15: Construction Year Model Input Data: Area Sources Radon Source ID Description Radon Units Timing OEES Active pit exposed surface 0.42 Bq/m 2 /s Continuous COWBD Central ore stockpile 0.90 Bq/m 2 /s April - December, continuous WMF Water management facility Bq/m 2 /s February December, continuous Table 16: Year 7 Model Input Data: Area Sources Particulate Matter Source ID Description Units Timing NPPES NPPTS1-3 Exposed surface (northern pit preparation) Topsoil stockpile (northern pit g/m 2 /s Continuous g/m 2 /s Continuous Report No R-RevA 27

34 Source ID Description preparation) Units Timing BPES Borrow pit g/m 2 /s Continuous BPTS OENPES OESPES OBTAS1-2 OBTBS1 COTS SPPES1-5 OBTBS3 Topsoil stockpile (Borrow pit) Active pit exposed surface (north) Active pit exposed surface (south) Overburden stockpiles (North south adjacent to deposit) Overburden stockpile (near to central ore stockpile) Topsoil stockpile (near to central ore stockpile) Exposed surface (southern pit preparation) Topsoil stockpiles (adjacent to central overburden stockpiles) g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous Table 17: Year 7 Model Input Data: Area Sources Particulate Metals Source ID NPPES NPPTS1 OENPES OESPES OBTAS1-3 OBTBS1 NPPTS2 Description Exposed surface (northern pit preparation) Topsoil stockpile (northern pit preparation) Active pit exposed surface (north) Active pit exposed surface (south) Overburden stockpiles (North-south adjacent to deposit) Overburden stockpile (near to central ore stockpile) Topsoil stockpile (near to central ore stockpile) Aluminium Strontium Uranium Vanadium Units Timing g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous g/m 2 /s Continuous SPPES Exposed surface g/m 2 /s Continuous Report No R-RevA 28

35 Source ID NPPTS3 Description (southern pit preparation) Topsoil stockpiles (adjacent to central overburden stockpiles) Aluminium Strontium Uranium Vanadium Units Timing g/m 2 /s Continuous Table 18: Year 7 Model Input Data: Area Sources Radon Source ID Description Radon Units Timing ROMPS ROM Pad Stockpile 93 Bq/m 2 /s Continuous WMFN Water management facility north Bq/m 2 /s Continuous WMFW Water management facility west Bq/m 2 /s Continuous WMFS Water management facility south Bq/m 2 /s Continuous ATS Active tailings facility 0.78 Bq/m 2 /s Continuous OENPES OESPES Active pit exposed surface - north Active pit exposed surface - south 0.10 Bq/m 2 /s Continuous 0.20 Bq/m 2 /s Continuous COES Central ore stockpile 0.90 Bq/m 2 /s Continuous OBTAS1-3 OBTBS1 Overburden stockpiles adjacent to the deposit Overburden stockpiles near to central ore stockpile 0.70 Bq/m 2 /s Continuous 0.10 Bq/m 2 /s Continuous 3.5 Overview An overview of the sources and their locations is presented in Figures 11 to 13 for the Construction Year and Figures 14 to 16 for Year 7. Figure 11: Construction Year: Particulate Matter Sources Figure 12: Construction Year: Particulate Metals Sources Figure 13: Construction Year: Radon Sources Figure 14: Year 7: Particulate Matter Sources Figure 15: Year 7: Particulate Metals Sources Figure 16: Year 7: Radon Sources Report No R-RevA 29

36 4.0 THE RECEIVING ENVIRONMENT The receiving environment refers to the environmental setting of the project site, encompassing climate and meteorology, topography, air quality and the location of sensitive receptors. 4.1 Climate The proposed LMUP site is located approximately 90 km north-east of Leinster in the Goldfields district of Western Australia. The general climate classification for Lake Maitland is desert with a sub-division classification of hot (persistently dry). Hot desert climates are typically found under the subtropical ridge where there is largely unbroken sunshine for the whole year, due to the stable descending air and high pressure, typically featuring very hot periods during the year. In many areas it is not uncommon to experience maximum temperatures over 40 C during summer. Conversely during winter periods night-time temperatures can drop below freezing due to exceptional radiation loss under clear skies. A hot desert climate has very little horizontal temperature gradient with dry air over land. Hence, the LMUP site climate will be very similar to that at the nearest Bureau of Meteorology Automatic Weather Station (BoM AWS) located at Leinster Aerodrome (Station ), 90 km south west of the LMUP site. At the synoptic scale, the wind regime is largely determined by the seasonal position of the Subtropical High Pressure Belt. During summer the Belt is centred between 35 and 40 degrees south (i.e. south of the study area). During this season the goldfields region experiences winds largely from the east and southeast as a result of winds rotating anticlockwise around high pressure cells. During winter the Subtropical High Pressure Belt is situated between 25 and 30 degrees south (i.e. north of the study area). This can produce storm force winds from the northwest, west and southwest under the influence of low pressure cells in coastal areas, further inland providing a greater distribution of winds from these sectors. 4.2 Meteorology Mesoscale meteorology includes interactions with land, ocean, urban areas and topography. As Lake Maitland is located in a relatively low latitude of 28 it is principally affected by the subtropical high pressure belt. The site experiences relatively high average wind speeds reflecting the location of the subtropical high pressure belt. Summer wind conditions provide strong easterly winds with the belt located south of the study area, winter conditions provide slightly weaker wind speeds as the pressure belt moves to the north of the site Temperature The annual mean maximum temperature for Leinster is 28.1 C whilst the annual mean minimum temperature is 14.7 C. Maximum and minimum monthly average temperatures, using data measured at Leinster Aerodrome, is shown in Figure 17. Report No R-RevA 30

37 Temperature ( C) Month Average monthly maximum temperature Average monthly minimum temperature Figure 17: Monthly average maximum and minimum temperatures - Leinster Aerodrome Rainfall Average annual rainfall at Leinster Aerodrome AWS is mm with the majority falling over the summer and autumn months. Leinster Aerodrome s inland location means it experiences less rainfall than coastal locations, with an average of 32.4 rain days per year. Figure 18 shows average monthly rainfall for Leinster Aerodrome, indicating a maximum of 41.5 mm in February and a minimum of 4.2 mm in September. Report No R-RevA 31

38 Rainfall (mm) Month Average monthly rainfall Figure 18: Monthly Average Rainfall - Leinster Aerodrome Wind Local wind climate largely determines the pattern of off-site or site specific pollutant dispersion. The characterisation of local wind patterns requires accurate site-representative hourly recordings of wind direction and speed over a period of at least a year. The nearest weather station that measures wind speed and direction is Leinster Aerodrome (BoM, AWS), about 90 km from the LMUP site. The meteorological measurement equipment at Leinster Aerodrome has been operating since There is very little intervening topographical features as the surrounding area has a very low topography and both sites are influenced mostly by the subtropical high pressure belt. Therefore Leinster measurements can be considered to provide site-specific climatic data for the LMUP site. The effect of wind on pollutant dispersion patterns can be examined using general wind distribution, most readily displayed by means of wind rose plots, giving the incidence of winds from different directions for various wind speed ranges. The annual wind rose for the period 1 January 2004 to 31 December 2005 is shown in Figure 19, indicating that the predominant wind directions are from the east, with an annual average wind speed of 4.3 m/s. Calms only occur on 2.2% of occasions. The dominance of the subtropical pressure belt can be seen in the seasonal wind roses of Figure 20 where: The winds are predominantly from the east with a lesser extent from the north and south Higher wind speeds (over 5 m/s) are evenly distributed reflecting the transient nature of the subtropical pressure belt over the seasons The lower wind speeds show a similar distribution. Figure 20 presents wind roses showing the average seasonal distribution over the years 2004 and Prevailing wind directions vary seasonally, with winter being predominantly northerly to easterly and summer easterly. Autumn and spring are transitional, with significant incidences in both directions. The seasonal influence of high winds (>5 m/s) is greatest in summer, and lowest in winter. The incidence of light winds (<2 m/s) is greatest in autumn, followed by summer with the least in winter. Report No R-RevA 32

39 16% 12.8% 9.6% 6.4% WEST 3.2% EA ST SOUTH Figure 19: Leinster Aerodrome Windrose Report No R-RevA 33

40 Summer Autumn 12.6% 16.8% 21% 12.6% 16.8% 21% 8.4% 8.4% 4.2% 4.2% WEST EA ST WEST EA ST SOUTH SOUTH Winter Spring 12.8% 16% 12.8% 16% 9.6% 9.6% 6.4% 6.4% 3.2% 3.2% WEST EA ST WEST EA ST SOUTH SOUTH Figure 20: Leinster Aerodrome Seasonal Windroses 4.3 Topography The LMUP site is essentially flat with an elevation of 472 m consistent across the western portion of the mining lease. Beyond the deposit to the east, elevation rises to 478 m, creating a slight north-south ridge. A small hill of 478 m is also present to the south. 4.4 Background Air Quality Baseline air quality may be broadly determined by the limited number and type of local industries in the area of the LMUP site. The site is currently pastoral, however a number of other mines are located in the immediate vicinity, including: Report No R-RevA 34

41 Bronzewing gold mine Leinster nickel mine Mt. Keith nickel mine Wiluna gold mine Quandrie gold mine. Anthropogenic sources of dust in the region include: Motor vehicle exhaust Industrial processes Heating and power generation. Natural sources of dust in the region include: Wind erosion Scrub fires initiated by lightning strikes. Regional industry in the area is heavily focused on mining, with some diesel power generation at mining facilities and cattle stations. However there is little urbanization in the project area, and the fine particulate matter from combustion engines is not produced in great quantities. The major source of particulate matter in the region is wind eroded crustal dust. Larger eroded dust particles tend to settle out, leaving finer particles of less than 10 microns to represent the majority of dust entrained in the atmosphere over long distances. Golder Associates was commissioned by Mega Lake Maitland Pty. Ltd. to prepare an Air Quality Monitoring Plan (AQMP) for the LMUP. The objective of the monitoring programme was to provide background data for the Air Quality Impact Assessment. The data forms the basis of the mathematical modelling to assist in evaluating the environmental impact of mining operations. The potential air quality impacts associated with uranium mining are anticipated to be principally associated with particulate matter emissions to air. Consequently ambient air quality monitoring has been conducted for the following size fractions: Total suspended particulate matter () (nominally particles with an equivalent aerodynamic diameter less than 50 microns) Particulate matter with an equivalent aerodynamic diameter less than 10 microns ( ) Particulate matter with an equivalent aerodynamic diameter less than 2.5 microns ( ) Insoluble solids deposition monitoring using high volume air samplers has been conducted at thirteen locations since June Monitoring locations have coincided with ongoing radiation monitoring, with samples collected primarily to determine alpha radioactivity through analysis of filter papers. Consequently samples were collected over extended sample periods, exceeding twenty four hours. Sampling was conducted in accordance with the method described by Australian Standard AS/NZS Determination of Suspended Particulate Matter Total Suspended Particulate Matter () High Volume Sampler Gravimetric Method. The maximum measured result from this programme was transformed to a 24 hour average and used to represent the background concentration. Report No R-RevA 35

42 The results are displayed graphically in Figure µg/m Figure 21: Background Air Quality: Monitoring Results / and sampling has been conducted at Barwidgee Station and the Lake Maitland Camp since June Samples have been collected using a dichotomous sampler in accordance with the method described in Australian Standard AS/NZS Determination of Suspended Particulate Matter - Dichotomous Sampler (, coarse PM and ) - Gravimetric Method. The results from the monitoring programme are displayed in Figure 22 ( ) and Figure 23 ( ) µg/m Barwidgee Station Lake Maitland Camp Figure 22: Background Air Quality: Monitoring Results Report No R-RevA 36

43 µg/m Barwidgee Station Lake Maitland Camp Figure 23: Background Air Quality: Monitoring Results Both figures illustrate the relatively low levels of background particulate matter at the LMUP site. is also assessed against an annual average criterion. The background concentration assumed for the annual average impact assessment is the average of all monitoring results Deposited Dust Limited dust deposition monitoring has been conducted at Barwidgee Station and Lake Maitland Camp. Sampling and analysis has been conducted in accordance with the method described by AS/NZS Methods for Sampling and Analysis of Ambient Air - Determination of Particulate Matter - Deposited Matter - Gravimetric Method. Samples were analysed for insoluble solids, with the results ranging between 1.3 and 1.9 g/m 2 /month. Although the dataset is limited, the results are in the range suggested by the Victorian Department of Health for dust deposition in rural zones, 0.4 to 2.0 g/m 2 /month (Department of Health, 1966). The maximum Department of Health result was used to represent background dust deposition rates at the project site Particulate Metals The background concentration of particulate metals was determined through analysis of filter papers from the alpha radioactivity monitoring programme. Six filters, representing the highest particulate matter loading, were analysed for twenty one metals. The analytical results indicated that all particulate metals were less than the analytical method limit of detection. Therefore no background concentration has been included for any of the particulate metals targeted within the air quality impact assessment Radon Background radon gas measurements at the project site indicate a site-wide radon gas level of 150 Bq/m 3. This is significantly greater than the typical radon gas concentration of 10 Bq/m 3 expected in the outdoor environment. (World Health Organization Regional Office for Europe, 2000) Report No R-RevA 37

44 4.4.6 Adopted Background Concentrations Summary Table 19: Background Air Quality: Adopted Concentrations Atmospheric Contaminant Background Concentration Units Averaging Period 39* µg/m 3 24 hours 19 µg/m 3 24 hours 17 µg/m 3 24 hours 2.3 µg/m 3 Annual Deposited dust 2.0 g/m 2 /month 1 month Particulate aluminium 0 µg/m 3 24 hours Particulate iron 0 µg/m 3 24 hours Particulate strontium 0 µg/m 3 24 hours Particulate uranium 0 µg/m 3 24 hours Particulate vanadium 0 µg/m 3 24 hours Radon 150 Bq/m 3 Annual * Adjusted value from 4 day average 4.5 Sensitive Receptor Locations Before undertaking the dispersion modelling assessment, potentially sensitive locations around the LMUP site must be identified. The location of the proposed LMUP is remote with restricted public access. The main sensitive receivers, from the perspective of human health considerations, are the Barwidgee Station residence and the LMUP accommodation village, both located to the north-west of the proposed mineral processing plant. The location of discrete receptors is displayed in Figure 24. Figure 24: Sensitive Receptor Locations Report No R-RevA 38

45 5.0 ASSESSMENT METHODOLOGY Assessment Criteria The National Environment Protection Council (NEPC), consisting of environment ministers from the Australian Government and each state and territory, was an outcome of the Intergovernmental Agreement on the Environment reached at a Special Premiers Conference in October 1990, coming into effect in May NEPC was incorporated into the Environment Protection and Heritage Council (EPHC) in June However, because NEPC has law making powers under the NEPC Act, it retains its status within EPHC. The purpose of NEPC is to ensure that: Australians enjoy the benefit of equivalent protection from air, water or soil pollution and from noise, wherever they live Business decisions are not distorted and markets are not fragmented by variations in major environment protection initiatives between member governments. Section 14 of the National Environment Protection Council Act 1994 provides for the making of measures by NEPC and the matters to which they may relate. The environmental matters to be considered by NEPC include ambient air quality. The National Environment Protection (Ambient Air Quality) Measure (Air NEPM), as varied in August 2003, outlines agreed national objectives for protecting or managing air quality. Western Australia implemented the framework for the Air NEPM through the promulgation of the National Environment Protection Council (Western Australia) Act Measurement of compliance with Air NEPM standards and goals is assessed at a performance monitoring station, as defined in the Air NEPM. A performance monitoring station is meant to be located such that it provides a representative measure of the air quality in a region with a population of 25,000 people or more. However, in December 2000, DEC (then Department of Environmental Protection) outlined an interim approach for adopting ambient air quality guideline values throughout Western Australia. This approach, which is still current, adopts the NEPM standards and goals for ambient air quality (DEC, 2004). In the absence of a NEPM standard, DEC will adopt the World Health Organization (WHO) guidelines for air quality (WHO, 2000), with appropriate amendments. In the absence of either an Air NEPM standard or WHO guideline, DEC will adopt criteria from another jurisdiction, subject to review. The Air NEPM standard for is 50 µg/m 3 (24 hour average), with a maximum of 5 days of exceedences per year as a goal. NEPC is currently undergoing a review of the Air NEPM. It is understood that the review will recommend the retention of the 24 hour average standard and the introduction of an annual average standard to protect against long-term health effects. The Air NEPM advisory reporting standards for are 25 µg/m 3 (24 hour average) and 8 µg/m 3 (annual average), with the goal of gathering sufficient data to facilitate a review. The NEPC review is understood to recommend that the 24 hour average and annual average numerical values be retained; however it is proposed that they be made compliance standards. samples associated with the LMUP are principally to be collected for measurement of alpha radioactivity. concentrations will however be determined as a consequence. Although strictly only applicable to the Kwinana region, the Environmental Protection (Kwinana) (Atmospheric Wastes) Regulations 1992 specify standards of 150 µg/m 3 and 90 µg/m 3 (24 hour averages), depending on the area, with corresponding limits of 260 µg/m 3 and 150 µg/m 3 (24 hour averages). The historical ambient air quality goal used in Australia was 90 µg/m 3 (annual average), as recommended by the National Health and Medical Research Council (NHMRC). The reference document was however rescinded by NHMRC in Report No R-RevA 39

46 DEC has indicated that the Environmental Protection (Kwinana) (Atmospheric Wastes) Regulations 1992 standard of 90 µg/m 3 (24 hour average) should apply to the evaluation of data obtained from the LMUP. There are no national standards relating to dust deposition. The Environment Protection Authority of Victoria (EPAV) has however implemented regulatory requirements through establishment of a Protocol for Environmental Management under the State Environment Protection Policy (Air Quality Management) Deposited dust is noted as an indicator of the effectiveness of site management practices and the potential for off-site nuisance in the Protocol for Environmental Management (Mining and Extractive Industries) (Mining PEM) (EPAV, 2007), with monitoring recommended at the site boundary for most operations. Under the Mining PEM insoluble solids monitoring results should not exceed 4 g/m 2 /month (no more than 2 g/m 2 /month above background) as a monthly average. EPAV notes that the averaging period has been set as monthly to enable an assessment of nuisance dust in a timely manner, ensuring that people s amenity is not adversely impacted. This represents a significantly more stringent requirement than the annual average which formed the basis of the criterion. It is however proposed that the LMUP ambient air quality objective for insoluble solids deposition be 4 g/m 2 /month. Particulate metals and radon are neglected by national ambient air quality criteria; however the WHO Air Quality Guidelines for Europe stipulate an ambient air quality criterion for vanadium of 1 µg/m 3 over a 24 hour averaging period. The WHO publication also examines radon exposure with reference to indoor air contaminants and concludes that no safe level of exposure can be determined. However in order to assess the model predictions in ambient, an air quality criterion of 1000 Bq/m 3 as an annual average has been adopted. The WHO does not list ambient or indoor air criteria for the other targeted particulate metals. Indeed, the WHO suggests that environmental exposure to airborne strontium, and aluminium is insignificant when compared with exposure through adsorption from drinking water and food. Similarly the development of drinking water guidelines for uranium suggest that typical exposure from airborne exposure is in the nanogram range whilst ingestion of uranium through drinking water is in the microgram range. Consequently the primary impact associated with particulate metals emissions relate to deposition of metals and subsequent uptake by plants and animals. The assessment of environmental risk due to particulate metal deposition has been conducted by Golder Associates in Report R. The air quality impact assessment includes the determination of deposition rates, with assessment of compliance and impact reported in the environmental risk assessment report. The LMUP criteria for assessment of modelling results are summarised in Table 20. The criteria specified for and should be reassessed following finalisation of the review by NEPC of the Air NEPM. Report No R-RevA 40

47 Table 20: Modelling Criteria Atmospheric Contaminant Criteria Averaging Period 50 µg/m 3 24 hour 25 µg/m 3 24 hour 8 µg/m 3 Annual 90 µg/m 3 24 hour Insoluble solids deposition 4 g/m 2 /month 1 month Particulate aluminium Deposition to be assessed using an environmental risk assessment approach 1 month Particulate strontium Deposition to be assessed using an environmental risk assessment approach 1 month Particulate vanadium 1 µg/m 3 Deposition to be assessed using an environmental risk assessment approach Particulate uranium Deposition to be assessed using an environmental risk assessment approach 1 month Radon 1000 Bq/m 3 Annual 24 hour - concentration 1 month - deposition Report No R-RevA 41

48 6.0 AIR QUALITY MODELLING Air quality impacts from LMUP were assessed using the USEPA regulatory air dispersion model, AERMOD. The meteorological component of the model was created using The Air Pollution Model (TAPM) Version 4. Further details on both components, meteorology and air dispersion, are presented in the following sections. 6.1 Meteorological Modelling The simulation of air quality impacts from the project site requires the use of hourly site representative meteorological data spanning an entire calendar year. Local sources of meteorological data include the Bureau of Meteorology (BOM) sites at Wiluna, Yeelirrie, Leinster, Laverton and Leonora. However these measurements of wind, temperature and other parameters, in isolation, were not considered suitable for direct use with the pollutant dispersion assessment due to differences in geography and the large distances between the meteorological stations and the project site. Whilst the wind direction distribution and speeds may be comparable, site specific variability over these distances could be significant leading to a significant under or over prediction of ground level concentrations from the dispersion model. As a consequence of the lack of site specific meteorological data, a state-of-the-art prognostic multi-layered three dimensional (3D) model was used to simulate the meteorological processes, with recorded data from Leinster and Leonora assimilated into the model and data from Laverton used to validate the model to ensure its adequate configuration. This model was used to produce hourly site-representative winds and micrometeorological information that (in conjunction with an emissions inventory from the site) was used with the AERMOD plume dispersion model to assess the impacts of emissions to air on surrounding land uses. The Air Pollution Model (TAPM) (Version 4) was developed at CSIRO Marine and Atmospheric Research and is a PC-based prognostic modelling system that can predict regional scale 3D-meteorology. It is suitable for use with complex geographical sites and/or where the available site-representative meteorology is inadequate, which is the case for the far-field data recorded at the Leinster, Laverton and Leonora sites. The model accesses databases of synoptic weather analysis from the BOM. TAPM provides the link between the synoptic large-scale flows and the local climatology Model Configuration TAPM was initially configured with a nested model grid coverage designed to capture: Broad scale synoptic flows Regional and broader scale sea breezes and land breezes Regional and broader wind channelling around terrain features The influence of land use. The nested grids were then configured with the surface characteristics, such as terrain elevation, surface roughness/vegetation type, soil type and monthly varying (initial) deep soil moisture content. The terrain elevation data, at a 9-second (300m) resolution, was obtained from Geoscience Australia. The characterised vegetation and land use was determined from the use of aerial photographs. Soil type information was derived from a geological map of the region, in conjunction with the coarser default US Geological Dataset provided with the model. The synoptic analysis for the year 2004/5 was used within the model. After the model was run, hourly varying surface winds, temperatures and measures of atmospheric stability were extracted at the location of the Laverton automatic weather station (AWS) site for validation purposes. Report No R-RevA 42

49 Data was also extracted from the surface location centred over the project site for use as input into the AERMOD dispersion model, and this is described below. Specific model settings were as follows: 4 nested grids at 500 m, 1,500 m, 5,000 m, 15,000 m resolution; 71 x 71 grid points 25 vertical levels, ranging up to 8,000 m Grids centred at the mine site at a local grid centre of E S (MGA 94) Topography generated from AUSLIG 9-second (250m resolution) terrain elevation datasets provided with the model Characterised vegetation and land use was initially determined from the datasets provided with the model, but then manually adjusted to reflect greater accuracy with reference to aerial imagery Default deep soil volumetric moisture content and air-sea temperature differences Surface vegetation and precipitation processes included (snow processes and non-hydrostatic processes were excluded) Validation The distribution of wind speeds and directions as predicted by TAPM can be validated against a local observed source of meteorology, if available. In this regard, the observed winds at the Laverton Aerodrome AWS meteorological site were available for validation (MGA coordinates of m Easting and m Northing). The observed data for the Laverton Aerodrome AWS is presented in Figure 25, and the predicted data from the TAPM simulated meteorological file in Figure 26. Each are presented as annual and seasonal wind roses. Comparisons of the annual wind roses shown in the figures indicate that TAPM predictions generally represent the observed meteorology, with the following meteorological phenomena reproduced by the model: Western sector winds are the least likely to occur A high incidence of winds from the easterly direction with a bias toward the summer, autumn and spring months when the sub-tropical high pressure belt is most active Wind speeds are in the mid range with an annual average wind speed of 3.0 m/s. Summer (3.4 m/s) and spring (3.3 m/s) are the windiest seasons and winter (2.4 m/s) the calmest Winter shows an increased frequency of north-west winds, noting the transition of the sub-tropical high pressure belt. TAPM however predicts a lower annual average wind speed (3.0 m/s) than the observed data (4.9 m/s). This is mostly due to calmer winds during the cooler winter months, with TAPM greatly underpredicting higher winds speeds (over 8 m/s). This will lead to an over-estimation of the predicted pollutant concentrations as the dilution is directly linked to wind speed. This can be accepted as the modelling outcomes will be deemed more conservative. Report No R-RevA 43

50 Annual Summer Autumn 26% 20.8% 15.6% 10.4% 26% 20.8% 15.6% 10.4% 5.2% 5.2% WEST EA ST WEST EA ST 26% 20.8% 15.6% 10.4% SOUTH SOUTH 5.2% WEST EA ST Winter Spring 26% 20.8% 15.6% 10.4% 26% 20.8% 15.6% 10.4% SOUTH WEST 5.2% EA ST WEST 5.2% EA ST SOUTH SOUTH Figure 25: Observed Laverton Aerodrome AWS 2004/2005 Annual and Seasonal Wind Roses Report No R-RevA 44

51 Annual Summer Autumn 26% 26% 20.8% 20.8% 26% 15.6% 10.4% 15.6% 10.4% 20.8% WEST 5.2% EA ST WEST 5.2% EA ST 15.6% 10.4% 5.2% WEST EA ST SOUTH SOUTH Winter Spring SOUTH 26% 20.8% 15.6% 10.4% 26% 20.8% 15.6% 10.4% 5.2% 5.2% WEST EA ST WEST EA ST SOUTH SOUTH Figure 26: TAPM Synthesised Laverton Aerodrome Annual and Seasonal Wind Roses Report No R-RevA 45

52 6.2 Dispersion Modelling The AMS/EPA Regulatory Model (AERMOD) was specifically designed to support USEPA s regulatory modelling programmes. AERMOD is a regulatory steady-state plume modelling system with three components: AERMOD (AERMIC dispersion model), AERMAP (AERMOD terrain pre-processor), and AERMET (AERMOD meteorological pre-processor). The AERMOD model was used to predict ground level concentrations (GLCs) at discrete and gridded receptors across the modelling domain. The domain consisted of a nested 10 km square grid with the mine deposit at the centre and the accommodation village to the north-west. The accommodation village is located within the nested grid, whilst Barwidgee Station is located approximately 40 km to the north west, within the larger terrain grid domain. For the terrain and nested grids, nodes were equally spaced at 250 m intervals. Terrain modifications resulting from mining activities have not been included in the modelling assessment as these features are dynamic and expected to be of limited depth. GLC predictions within the nested grid and at discrete receptor locations were calculated using the averaging periods specified by the air quality impact assessment criteria. The maximum predicted GLC was defined as the highest GLC predicted at a sensitive receptor. 6.3 Modelling Results Air dispersion modelling predictions at the two sensitive receptors are presented in Table 21. Table 21: Air Dispersion Modelling Results: Results Construction Year Year 7 Averaging period 24 hours 24 hours LMUP Accommodation Village GLC (Project impacts only) 34 µg/m 3 52 µg/m 3 LMUP Accommodation Village GLC (Cumulative impacts including background concentration) 73 µg/m 3 84 µg/m 3 Barwidgee Station (Project Impacts only) 6.45µg/m µg/m 3 Barwidgee Station (Cumulative impacts including background concentration) 45 µg/m 3 49 µg/m 3 Criterion 90 µg/m 3 Compliance Yes Model predictions for the nested grid are displayed in Figure 27 and Figure 28 for the Construction Year and Year 7 respectively. Figure 27: Isopleth Plot for (24 hour averaging period) Construction Year Figure 28: Isopleth Plot for (24 hour averaging period) Year Maximum predicted concentrations at Barwidgee Station and the accommodation village are presented in Table 22. Report No R-RevA 46

53 Table 22: Air Dispersion Modelling Results: Results Construction Year Year 7 Averaging period 24 hours 24 hours LMUP Accommodation Village GLC (Project impacts only) 32 µg/m 3 31 µg/m 3 LMUP Accommodation Village GLC (Cumulative impacts including background concentration) 46 µg/m 3 45 µg/m 3 Barwidgee Station (Project Impacts only) 4.7 µg/m µg/m 3 Barwidgee Station (Cumulative impacts including background concentration) 19 µg/m 3 19 µg/m 3 Criterion 50 µg/m 3 Compliance Yes Predicted concentrations for the gridded receptors centred on the mining lease are presented in Figure 29 and Figure 30. Figure 29: Isopleth Plot for (24 hour averaging period) Construction Year Figure 30: Isopleth Plot for (24 hour averaging period) Year The maximum predicted concentrations at the two sensitive receptors are presented in Table 23. The isopleth plot representing the nested grid results for both averaging periods and phases of operation are presented in Figures Table 23: Air Dispersion Modelling Results: Results Construction Year Year 7 Construction Year Year 7 Averaging period 24 hours 24 hours Annual Annual LMUP Accommodation Village GLC (Project impacts only) 3.1 µg/m µg/m µg/m µg/m 3 LMUP Accommodation Village GLC (Cumulative impacts including background 20 µg/m 3 22 µg/m µg/m µg/m 3 concentration) Barwidgee Station (Project Impacts only) 0.44 µg/m µg/m µg/m µg/m 3 Barwidgee Station (Cumulative impacts including background concentration) 18 µg/m 3 18 µg/m µg/m µg/m 3 Criterion 25 µg/m 3 8 µg/m 3 Compliance Yes Figure 31: Isopleth Plot for (24 hour averaging period) Construction Year Figure 32: Isopleth Plot for (annual averaging period) Construction Year Figure 33: Isopleth Plot for (24 hour averaging period) - Year 7 Report No R-RevA 47

54 Figure 34: Isopleth Plot for (annual averaging period) - Year Deposited Dust The maximum predicted dust deposition rates for insoluble solids are presented in Table 24 for sensitive receptors and Figures 35 and 36 for nested grid results. Table 24: Air Dispersion Modelling Results: Deposited Dust Results Construction Year Year 7 Averaging period 1 month 1 month LMUP Accommodation Village GLC (Project impacts only) 0.28 g/m 2 /month 0.14 g/m 2 /month LMUP Accommodation Village GLC (Cumulative impacts including background concentration) 2.3 g/m 2 /month 2.1 g/m 2 /month Barwidgee Station (Project Impacts only) g/m 2 /month g/m 2 /month Barwidgee Station (Cumulative impacts including background concentration) 2.1 g/m 2 /month 2.0 g/m 2 /month Criterion 4 g/m 2 /month Compliance Yes Figure 35: Isopleth Plot for Deposited Dust, Insoluble Solids, (1 month averaging period) Construction Year Figure 36: Isopleth Plot for Deposited Dust, Insoluble Solids, (1 month averaging period) Year Aluminium Maximum predicted deposition rates for aluminium are presented in Figures 37 and 38 for the Construction Year and Year 7. Figure 37: Isopleth Plot for Deposited Dust, Aluminium, (1 month averaging period) Construction Year Figure 38: Isopleth Plot for Deposited Dust, Aluminium, (1 month averaging period) Year Strontium Maximum predicted deposition rates for strontium are presented in Figures 39 and 40 for the Construction Year and Year 7. Figure 39: Isopleth Plot for Deposited Dust, Strontium, (1 month averaging period) Construction Year Figure 40: Isopleth Plot for Deposited Dust, Strontium, (1 month averaging period) Year Vanadium Maximum predicted concentrations of vanadium at the two sensitive receptors are presented in Table 25. Table 25: Air Dispersion Modelling Results: Vanadium Report No R-RevA 48

55 Results Construction Year Year 7 Averaging period 24 hours 24 hours LMUP Accommodation Village GLC (Project impacts only) Barwidgee Station (Project Impacts only) µg/m µg/m µg/m µg/m 3 Criterion 1 µg/m 3 Compliance Yes Isopleth plots illustrating the maximum predicted vanadium concentrations on the nested grid for both phases of operation are presented in Figures 41 and 42. Isopleth plots illustrating the maximum predicted deposition rates for vanadium are presented in Figures 43 and 44 for both phases of operation. Figure 41: Isopleth Plot for Vanadium Concentration (24 hour averaging period) Construction Year Figure 42: Isopleth Plot for Vanadium Concentration (24 hour averaging period) Year 7 Figure 43: Isopleth Plot for Deposited Dust, Vanadium, (1 month averaging period) Construction Year Figure 44: Isopleth Plot for Deposited Dust, Vanadium, (1 month averaging period) Year Uranium Maximum predicted deposition rates for uranium are presented in Figures 45 and 46 for the Construction Year and Year 7. Figure 45: Isopleth Plot for Deposited Dust, Uranium, (1 month averaging period) Construction Year Figure 46: Isopleth Plot for Deposited Dust, Uranium, (1 month averaging period) Year Radon The air dispersion modelling results for radon are presented in Table 26, for the sensitive receptors locations. Isopleth plots for the gridded domain are presented in Figures 47 and 48. Table 26: Air Dispersion Modelling Results: Radon Results Construction Year Year 7 Averaging period 24 hours 24 hours LMUP Accommodation Village GLC (Project impacts only) 21 Bq/m Bq/m 3 LMUP Accommodation Village GLC (Cumulative impacts including background concentration) 170 Bq/m Bq/m 3 Barwidgee Station (Project Impacts only) 2.9 Bq/m 3 29 Bq/m 3 Barwidgee Station (Cumulative impacts including background concentration) 150 Bq/m Bq/m 3 Criterion 1000 Bq/m 3 Compliance Yes Figure 47: Isopleth Plot for Radon (24 hour averaging period) Construction Year Report No R-RevA 49

56 Figure 48: Isopleth Plot for Radon (24 hour averaging period) Year Model Validation Air dispersion models are static applications for dynamic processes, where the level of uncertainty is compounded by the emissions inventory assumptions. The LMUP air quality impact assessment has incorporated a number of assumptions to calculate proposed emissions, however in most cases assumptions have been based on measured data and a clear understanding of the proposed activities. Golder Associates participated in the LMUP test pit programme conducted in November 2010, where two test pits where exposed, excavated, back filled and rehabilitated. The purpose of the programme was to trial the mining method, water extraction techniques, road sheeting and general mining operations. Participation in the programme has enabled Golder to gain an understanding of the receiving environment and proposed emissions in order to critically assess the assumptions and results of the air dispersion modelling exercise. The receiving environment is a complex ecosystem subject to extreme temperatures and ancient lake systems. The subsurface horizons are typically moist, with ore observed during the extraction phase of the test pit programme sufficiently wet that the material had a clay like consistency. By contrast, surface sediments appear much drier, but are protected from wind erosion by a natural crusting which forms as mineral salts are exposed and dried. Test pit programme topsoil and overburden stockpiles all had a degree of crusting which rapidly formed following material disturbance and placement. The emissions inventory assumed a constant and uniform emission rate for windblown dust from all exposed surfaces, topsoil stockpiles and overburden stockpiles. The emission rate included an element of dust control, assuming that water was applied at a rate of 2 litres/m 2 /hour. It is anticipated that some exposed surfaces will not required watering due to natural crusting whereas newly formed stockpiles and exposed surfaces in less saline environments, for example the borrow pit, will require frequent watering to achieve adequate dust suppression. The inclusion of these sources, with a controlled emission rate is considered appropriate and realistic as water will be applied as required and natural crusting will occur. The test pit programme was conducted using the same extraction method as that proposed for the LMUP, although the equipment and scale of operations was smaller. Despite this, the programme demonstrated that emissions to air during mining will be dominated by movement of overburden and topsoil, particularly during pit preparation and rehabilitation. Ore extraction and handling did not produce any visible dust emissions. These observations are mirrored in the emissions inventory where ore emissions are limited to radon, with dust and particulate metals included for mining activities on topsoil and overburden only. Mining activities were also observed with excavators, articulated dump trucks and bulldozers working on Test Pit 1. In general, dust was visible from the bulldozer blade as material was transferred and stockpiles were depleted. s from excavators appeared to be lesser in volume, as were dust emission from articulated trucks dumping material. These observations are reflected in the relative rates calculated from established emission factors. The final component of test pit programme observations were haul road emissions to air. Vehicle movements on haul roads dominated dust emissions, with vegetation staining evident up to 30 m from the road surface. The emissions inventory and model predictions confirm this observation, with haul road vehicle movements one of the major particulate matter emission sources. The test pit programme also enabled collection of samples for model validation. Samples were collected from a number of locations utilising low volume samplers in accordance with Australian Standard AS/NZS Determination of Suspended Particulate Matter Low Volume Sampler - Gravimetric Method. Sample locations were selected with reference to test pit programme mining activities. The air dispersion model and LMUP emissions inventory was used to predict concentrations at similar locations to those measured during the test pit programme. The purpose of the model validation was to ensure that both the emissions inventory and model configuration were appropriate for application to the Report No R-RevA 50

57 LMUP. Model calibration and adjustment of emission rates was not conducted; rather the results were used to ground proof the model predictions. The results of the model validation assessment are presented in Table 27. Table 27: Model Validation Results- Test Pit Programme Sample Description Measured Result µg/m 3 AERMOD Predicted Result µg/m 3 TP1: Long arm excavator working ore and below grade material 20 m from activity area (upwind) TP1: Bulldozer working overburden across surface 30 m east of activity (fluctuating wind) TP1: Bulldozer working overburden across surface 20 m west of activity (fluctuating wind) TP1: Bulldozer working overburden stockpile - 50 m from activity (upwind) TP1: Bulldozer working overburden stockpile 50 m from activity (downwind) m downwind of Tigger s Run (20 vehicles over 3.5 hours) m downwind of Jade s Strait (13 vehicles over 3 hours) Overall the observations and model validation measurements from the test pit programme indicate that the air dispersion model, including meteorology and emission inventory components are suitable for application to the LMUP. Report No R-RevA 51

58 7.0 ASSESSMENT OF EFFECTS Overall the modelling assessment indicates that all modelled contaminants comply with the established modelling criteria. It should be noted that the assessment included a number of worst case elements. Firstly the modelling assessment was conducted for the Construction Year and Year 7 where activity on site is expected to be at a maximum. s to air from other years of operation are expected to be less. Other worst case elements of the modelling assessment are as follows: Exposed surfaces are assumed to be subject to windblown dust continuously, making no allowance for natural crusting or sequential removal of cover Assessment of cumulative impacts assumes a maximum measured background concentration for all particulate matter size fractions Plume depletion by deposition was only calculated for and vanadium. Other particulate matter fractions are assumed to be retained in the air column Deposition calculations assume the worst case, with no allowance for rain event removal of entrained dust; Haul road emissions assume that all trucks will travel the same typical distance All activities have been assumed to occur continuously within the nominated timeframes. Report No R-RevA 52

59 8.0 RECOMMENDATIONS A comprehensive Environmental Management Plan should be implemented for the LMUP. The plan should designate responsibilities for the management of dust and implementation of ongoing control mechanisms. The management plan should include practical control procedures such as routine watering of haul roads and the possible scheduling of dust generating activities under favourable wind conditions. The management plan should be all inclusive, including responsibilities for contractors, visitors, managers and include an environmental induction programme. In particular the plan should include implementation of controls assumed in the air quality impact assessment. In summary these are as follows: Wheel generated dust from unpaved roads reduced by 75% through the application of water at a minimum rate of 2 litres/m 2 /hour Windblown dust from exposed areas reduced by 50% through the application of water at a minimum rate of 2 litres/m 2 /hour Windblown dust from stockpiles reduced by 50% through the application of water at a minimum rate of 2 litres/m 2 /hour Control of emissions from crushing and screening through wet suppression techniques. Finally the Environmental Management Plan should include ambient air quality monitoring for, insoluble solids dust deposition, and at the Accommodation Village. Monitoring results should be assessed against project ambient air quality criteria and used to inform site operations and minimise off-site impacts. Report No R-RevA 53

60 9.0 ABBREVIATIONS Air NEPM National Environment Protection (Ambient Air Quality) Measure AQMP BoM AWS DEC EPAV EPHC GLC LMUP Mining PEM mtpa MW NEPC NHMRC NPI ROM USEPA WHO WMF Air Quality Monitoring Plan Bureau of Meteorology Automatic Weather Station Department of Environment and Conservation Environment Protection Authority of Victoria Environment Protection and Heritage Council Ground Level Concentration Lake Maitland Uranium Project Protocol for Environmental Management (Mining and Extractive Industries) Million tonnes per annum Megawatt National Environment Protection Council National Health and Medical Research Council National Pollutant Inventory Particulate matter with an equivalent aerodynamic diameter less than 2.5 microns Particulate matter with an equivalent aerodynamic diameter less than 10 microns Run of Mine Total Suspended Particulate matter United States Environmental Protection Agency World Health Organization Water Management Facility Report No R-RevA 54

61 10.0 REFERENCES AS/NZS Determination of Suspended Particulate Matter - Total Suspended Particulate Matter () - High Volume Sampler Gravimetric Method. (n.d.). AS/NZS Determination of Suspended Particulate Matter - Dichotomous Sampler (PM10 course PM and PM2.5) - Gravimetric Method. (n.d.). Department of Environment. (2006, March). Air Quality Modelling Guidance Notes. Perth: Government of Western Australia. Department of Health. (1966). Air Pollution Measurement in Victoria. Victoria. Department of the Environment, Water, Heritage and the Arts. (2008, June). NPI Estimation Technique Manual for Combustion Engines. Version 3.0. Canberra: Commonwealth of Australia. Department of the Environment, Water, Heritage and the Arts. (2010, September). NPI Estimation Technique Manual for Combustion in Boilers. Version 3.3. Canberra: Commonwealth of Australia. Department of the Environment, Water, Heritage and the Arts. (2001, December 5). NPI Estimation Technique Manual for Mining. Version 2.3. Canberra: Commonwealth of Australia. Environment Protection (Kwinana) (Atmospheric Wastes) Regulations, (n.d.). EPA Victoria. (n.d.). AUSPLUME Users Manual. EPA Victoria. (2007). Protocol for Environmental Management (Mining and Extractive Industries). National Environment Protection (Ambient Air Quality) Measure, (n.d.). National Environment Protection Council (Western Australia) Act, (n.d.). National Environment Protection Council Act, (n.d.). NPI Estimation Technique Manual for Mining. Version 2.3. (2001, December). Commonwealth of Australia. State Environment Protection Policy (Air Quality Management), (2001, December). Victoria Government Gazette. Victorian Government Printer. United States Environment Protection Agency. (82, August). Ap 42, Fifth Edition, Volume I Chapter 13: Miscellaneous Sources, Metallic Minerals Processing. USEPA. United States Environment Protection Agency. (2006, June). AP 42, Fifth Edition, Volume I Chapter 13: Miscellaneous Sources, Unpaved Roads. USEPA. United States Environment Protection Agency. (1995, January). Ap 42, Fifth Edition, Volume I Chapter 13: Miscellaneous Sources, Heavy Construction Operations. USEPA. United States Environment Protection Agency. (2006, November). AP 42, Fifth Edition, Volume I Chapter 13: Miscellaneous Sources, Aggregate Handling and Storage Piles. USEPA. United States Environment Protection Agency. (2006, November). AP 42, Fifth Edition, Volume I Chapter 13: Miscellaneous Sourcess, Industrial Wind Erosion. USEPA. World Health Organization. (1998). Guidelines for Drinking Water Quality. Volume 2. Health Criteria and Other Supporting Documents, Addendum. Geneva: WHO Publications. World Health Organization. (1996). Iron in Drinking Water. Background Document for the Development of Drinking Water Guidelines. Geneva: WHO Publications. World Health Organization Regional Office for Europe. (2000). Air Quality Guidelines for Europe. Copenhagen: WHO Regional Publications. Report No R-RevA 55

62 World Health Organization. (2010). Strontium and Strontium Compounds. Concise International Chemical Assessment Document 77. WHO Publications. World Health Organization. (2004). Uranium in Drinking Water. Background Document for Development of WHO Guidelines for Drinking-Water Quality. WHO Publications. Report No R-RevA 56

63 Report Signature Page GOLDER ASSOCIATES PTY LTD Jacinda Shen Geoff White Frank Fleer Air and Noise Group Hub Manager Environmental Scientist Principal JS/FF/jshen A.B.N Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation. m:\jobs409\mining\ _lake_maitland\correspondence out (including report)\ r reva air quality impact assessment.docx Report No R-RevA

64 APPENDIX A Limitations Report No R-RevA

65 APPENDIX B Mineral Processing Plant Mass and Energy Balance Author: Independent Metallurgical Operations Document No P-002 Report No R-RevA

66 MEGA LAKE MAITLAND PTY. LTD. LAKE MAITLAND URANIUM PROJECT DIRECT PRECIPITATION FLOWSHEET OPTION STUDY MASS AND ENERGY BALANCE DOCUMENT NUMBER 5097-P-002 Independent Metallurgical Operations 88 Thomas St West Perth WA B 13/09/10 ISSUED FOR INTECH COSTING AW DF DK A 3/09/10 ISSUED FOR INFORMATION/REVIEW AW DF DK REV. DATE DESCRIPTION BY REVIEW APPROVE CLIENT APPROVE

67 Stream Number Stream Description Mass Flowrate ROM Ore Scrubber Discharge Scrubber Screen Undersize Scrubber Screen Oversize Mill Discharge Mill Cyclone Feed Mill Cyclone Overflow Mill Cyclone Underflow Fines Preleach Discharge Fines Cyclone Feed Fines Cyclone Uflow Fines Cyclone Oflow Feed Thickener Overflow to Fines Mass flow t/h Solids mass flow t/h Liquid mass flow t/h Vapour mass flow t/h Solids Fraction %w/w Volume Flowrate Slurry volume flow m³/h Solids volume flow m³/h Liquid volume flow m³/h Gas volume flow Nm³/h Densities Slurry density t/m Solids density t/m Liquid density t/m Gas density t/m Operating Conditions Temperature C Pressure kpa (abs) Solids Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration %w/w Uranium Concentration ppm Resin U 3 O 8 Concentration g/l Resin V 2 O 5 Concentration g/l U 3 O 8 Concentration ppm equiv Vanadium Concentration %w/w Vanadium Concentration ppm Iron Concentration %w/w Magnesium Concentration %w/w Aluminium Concentration %w/w Carbonate Concentration %w/w Calcium Concentration %w/w Sulphate Concentration %w/w Liquor Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration g/l Uranium Concentration ppmv U 3 O 8 Concentration g/l U 3 O 8 Concentration ppmv equiv Vanadium Concentration g/l Vanadium Concentration ppmv V 2 O 5 Concentration ppmv equiv Chloride Concentration g/l Magnesium Concentration g/l Calcium Concentration g/l Sodium Carbonate Conc. g/l Sodium Bicarbonate Conc. g/l Sodium Hydroxide Conc. g/l Sulfuric Acid Concentration g/l Sulphate Concentration g/l Gas Composition Water Concentration %v/v Oxygen Concentration %v/v Carbon Dioxide Concentration %v/v Feed Thickener Overflow to Grinding Mill Mill Thickener Flocc Mill Thickener Underflow Mill Thickener Overflow Mill Thickener Floc Dilution Thickener Overflow to Mill Cyclone Recarb Column Feed Boiler Offgas to Recarb Column Recarb Column Bottoms Recarb Column Vent Scrubber Dilution Scrubber Screen Wash U Leach Feed Preheat1 Leach Feed Disch Preheated Leach Feed U Leach Tank 1 Discharge INDEPENDENT METALLURGICAL OPERATIONS PTY. LTD. PROJECT 88 Thomas St West Perth WA 6005 P: LAKE MAITLAND URANIUM PROJECT DIRECT PRECIPITATION FLOWSHEET OPTION STUDY CLIENT TITLE MEGA LAKE MAITLAND PTY. LTD. MASS BALANCE B ISSUED FOR INTECH COSTING 13/09/10 AW A ISSUED FOR INFORMATION/REVIEW 3/09/10 AW REV. DESCRIPTION DATE BY 5097-P-002

68 Stream Number Stream Description U Leach Tank 1 Vent U Leach Tank 2 Discharge U Leach Tank 2 Vent U Leach Tank 3 Discharge U Leach Tank 3 Vent U Leach Tank 4 Discharge U Leach Tank 4 Vent U Leach Tank Vents Leach Discharge CCD 1 Underflow CCD1 Overflow CCD Overflow CCD1 Floc Dilution CCD 2 Underflow CCD2 Overflow CCD2 Overflow Discharge CCD2 Floc Dilution CCD 3 Underflow CCD3 Overflow CCD3 Overflow Discharge CCD3 Floc Dilution CCD 4 Underflow CCD4 Overflow CCD4 Overflow Discharge CCD4 Floc Dilution CCD5 Underflow CCD5 Overflow CCD5 Overflow Discharge CCD5 Floc Dilution Mass Flowrate Mass flow t/h Solids mass flow t/h Liquid mass flow t/h Vapour mass flow t/h Solids Fraction %w/w Volume Flowrate Slurry volume flow m³/h Solids volume flow m³/h Liquid volume flow m³/h Gas volume flow Nm³/h Densities Slurry density t/m Solids density t/m Liquid density t/m Gas density t/m Operating Conditions Temperature C Pressure kpa (abs) Solids Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration %w/w Uranium Concentration ppm Resin U 3 O 8 Concentration g/l Resin V 2 O 5 Concentration g/l U 3 O 8 Concentration ppm equiv Vanadium Concentration %w/w Vanadium Concentration ppm Iron Concentration %w/w Magnesium Concentration %w/w Aluminium Concentration %w/w Carbonate Concentration %w/w Calcium Concentration %w/w Sulphate Concentration %w/w Liquor Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration g/l Uranium Concentration ppmv U 3 O 8 Concentration g/l U 3 O 8 Concentration ppmv equiv Vanadium Concentration g/l Vanadium Concentration ppmv V 2 O 5 Concentration ppmv equiv Chloride Concentration g/l Magnesium Concentration g/l Calcium Concentration g/l Sodium Carbonate Conc. g/l Sodium Bicarbonate Conc. g/l Sodium Hydroxide Conc. g/l Sulfuric Acid Concentration g/l Sulphate Concentration g/l Gas Composition Water Concentration %v/v Oxygen Concentration %v/v Carbon Dioxide Concentration %v/v INDEPENDENT METALLURGICAL OPERATIONS PTY. LTD. PROJECT 88 Thomas St West Perth WA 6005 P: LAKE MAITLAND URANIUM PROJECT DIRECT PRECIPITATION FLOWSHEET OPTION STUDY CLIENT TITLE MEGA LAKE MAITLAND PTY. LTD. MASS BALANCE B ISSUED FOR INTECH COSTING 13/09/10 AW A ISSUED FOR INFORMATION/REVIEW 3/09/10 AW REV. DESCRIPTION DATE BY 5097-P-002

69 Stream Number a 175b 175c 175d 175e 175f Stream Description Mass Flowrate CCD Underflow to Tails CCD6 Overflow CCD6 Overflow Discharge Raw Water to CCD Flocc Dilution Flocc to CCD 1 Flocc to CCD 2 Flocc to CCD 3 Flocc to CCD 4 Flocc to CCD 5 Flocc to CCD 6 Recarb Liquor Wash to CCD 5 Recarb Liquor Wash to CCD 4 Recarb Liquor Wash to CCD 3 Recarb Liquor Wash to CCD 2 CCD Wash Water Evap Pond Discharge PLS SDU Precip Recycle to Feed Leach Feed Mass flow t/h Solids mass flow t/h Liquid mass flow t/h Vapour mass flow t/h Solids Fraction %w/w Volume Flowrate Slurry volume flow m³/h Solids volume flow m³/h Liquid volume flow m³/h Gas volume flow Nm³/h Densities Slurry density t/m Solids density t/m Liquid density t/m Gas density t/m Operating Conditions Temperature C Pressure kpa (abs) Solids Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration %w/w Uranium Concentration ppm Resin U 3 O 8 Concentration g/l Resin V 2 O 5 Concentration g/l U 3 O 8 Concentration ppm equiv Vanadium Concentration %w/w Vanadium Concentration ppm Iron Concentration %w/w Magnesium Concentration %w/w Aluminium Concentration %w/w Carbonate Concentration %w/w Calcium Concentration %w/w Sulphate Concentration %w/w Liquor Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration g/l Uranium Concentration ppmv U 3 O 8 Concentration g/l U 3 O 8 Concentration ppmv equiv Vanadium Concentration g/l Vanadium Concentration ppmv V 2 O 5 Concentration ppmv equiv Chloride Concentration g/l Magnesium Concentration g/l Calcium Concentration g/l Sodium Carbonate Conc. g/l Sodium Bicarbonate Conc. g/l Sodium Hydroxide Conc. g/l Sulfuric Acid Concentration g/l Sulphate Concentration g/l Gas Composition Water Concentration %v/v Oxygen Concentration %v/v Carbon Dioxide Concentration %v/v Evap Pond Vent Caustic to SDU Precip SDU Precip Tank 1 Disch SDU Precip Tank 2 Disch SDU Precip Thick Underflow SDU Precip Thickener Overflow SDU Precip Filter Feed SDU Precip Seed Recycle SDU Precip Filter Cake SDU Precip Filter Filtrate SDU Floc Dilution INDEPENDENT METALLURGICAL OPERATIONS PTY. LTD. PROJECT 88 Thomas St West Perth WA 6005 P: LAKE MAITLAND URANIUM PROJECT DIRECT PRECIPITATION FLOWSHEET OPTION STUDY CLIENT TITLE MEGA LAKE MAITLAND PTY. LTD. MASS BALANCE B ISSUED FOR INTECH COSTING 13/09/10 AW A ISSUED FOR INFORMATION/REVIEW 3/09/10 AW REV. DESCRIPTION DATE BY 5097-P-002

70 Stream Number Stream Description Mass Flowrate SDU Thickener Flocc SDU Barren Liquor Recycle Repulped SDU Slurry Acid to SDU Leach SDU Leach Tank Vent SDU Leach Tank Discharge SDU Releach Discharge SDU Releach Filter Solids Peroxide to Peroxide Precip Caustic to Peroxide Precip Peroxide Precip Tank 1 Disch Peroxide U Product to Precip Tank Dewatering 2 Disch Peroxide Precip Thick Overflow Peroxide Polish Filter Polishing Cake Filter Filtrate Mass flow t/h Solids mass flow t/h Liquid mass flow t/h Vapour mass flow t/h Solids Fraction %w/w Volume Flowrate Slurry volume flow m³/h Solids volume flow m³/h Liquid volume flow m³/h Gas volume flow Nm³/h Densities Slurry density t/m Solids density t/m Liquid density t/m Gas density t/m Operating Conditions Temperature C Pressure kpa (abs) Solids Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration %w/w Uranium Concentration ppm Resin U 3 O 8 Concentration g/l Resin V 2 O 5 Concentration g/l U 3 O 8 Concentration ppm equiv Vanadium Concentration %w/w Vanadium Concentration ppm Iron Concentration %w/w Magnesium Concentration %w/w Aluminium Concentration %w/w Carbonate Concentration %w/w Calcium Concentration %w/w Sulphate Concentration %w/w Liquor Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration g/l Uranium Concentration ppmv U 3 O 8 Concentration g/l U 3 O 8 Concentration ppmv equiv Vanadium Concentration g/l Vanadium Concentration ppmv V 2 O 5 Concentration ppmv equiv Chloride Concentration g/l Magnesium Concentration g/l Calcium Concentration g/l Sodium Carbonate Conc. g/l Sodium Bicarbonate Conc. g/l Sodium Hydroxide Conc. g/l Sulfuric Acid Concentration g/l Sulphate Concentration g/l Gas Composition Water Concentration %v/v Oxygen Concentration %v/v Carbon Dioxide Concentration %v/v Peroxide Precip Thick Underflow Peroxide Precip Thick Uflow Recycle Refinery Barren Liquor V Precip Thickener Flocculant Vanadium Precip Acid Vanadium Precip Discharge Vanadium Precip Thick Oflow V Precip Thickener Underflow V Precip Filter Feed V Precip Seed Recycle Vanadium Precip Cake V Precip Filter Filtrate Peroxide Precip Feed Liquor INDEPENDENT METALLURGICAL OPERATIONS PTY. LTD. PROJECT 88 Thomas St West Perth WA 6005 P: LAKE MAITLAND URANIUM PROJECT DIRECT PRECIPITATION FLOWSHEET OPTION STUDY CLIENT TITLE MEGA LAKE MAITLAND PTY. LTD. MASS BALANCE B ISSUED FOR INTECH COSTING 13/09/10 AW A ISSUED FOR INFORMATION/REVIEW 3/09/10 AW REV. DESCRIPTION DATE BY 5097-P-002

71 Stream Number b 905c 905d 905e 905g 905h 905i Stream Description Mass Flowrate V Precip Thickener Floc Dilution Vanadium Releach Feed Vanadium Releach Caustic Vanadium Leach Discharge Uranium Recovery Filter Filtrate Uranium Recovery Filter Cake Vanadium Releach Discharge Liquor Product Centrifuge Feed Centrifuge 1 Cake Centrifuge 1 Centrate Product Centrifuge Centrate Uranium Product Product Dryer Vent Centrifuge 2 Feed Centrifuge 2 Centrate Centrifuge 2 Cake Wet Scrubber Vent Wet Scrubber Bottoms Tails Slurry to Tailings Dam Sod Carb to Leach Feed SDU Precip RO Water to RO Water to RO Wash to SDU Repulp RO Water to RO Wash to Filter RO Demin Plant Distribution Centrifuge 1 RO Water Acid Dilution Centrifuge 2 Wash Centrifuge Cake RO Water to Repulp RO Scrubber Water Mass flow t/h Solids mass flow t/h Liquid mass flow t/h Vapour mass flow t/h Solids Fraction %w/w Volume Flowrate Slurry volume flow m³/h Solids volume flow m³/h Liquid volume flow m³/h Gas volume flow Nm³/h Densities Slurry density t/m Solids density t/m Liquid density t/m Gas density t/m Operating Conditions Temperature C Pressure kpa (abs) Solids Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration %w/w Uranium Concentration ppm Resin U 3 O 8 Concentration g/l Resin V 2 O 5 Concentration g/l U 3 O 8 Concentration ppm equiv Vanadium Concentration %w/w Vanadium Concentration ppm Iron Concentration %w/w Magnesium Concentration %w/w Aluminium Concentration %w/w Carbonate Concentration %w/w Calcium Concentration %w/w Sulphate Concentration %w/w Liquor Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration g/l Uranium Concentration ppmv U 3 O 8 Concentration g/l U 3 O 8 Concentration ppmv equiv Vanadium Concentration g/l Vanadium Concentration ppmv V 2 O 5 Concentration ppmv equiv Chloride Concentration g/l Magnesium Concentration g/l Calcium Concentration g/l Sodium Carbonate Conc. g/l Sodium Bicarbonate Conc. g/l Sodium Hydroxide Conc. g/l Sulfuric Acid Concentration g/l Sulphate Concentration g/l Gas Composition Water Concentration %v/v Oxygen Concentration %v/v Carbon Dioxide Concentration %v/v INDEPENDENT METALLURGICAL OPERATIONS PTY. LTD. PROJECT 88 Thomas St West Perth WA 6005 P: LAKE MAITLAND URANIUM PROJECT DIRECT PRECIPITATION FLOWSHEET OPTION STUDY CLIENT TITLE MEGA LAKE MAITLAND PTY. LTD. MASS BALANCE B ISSUED FOR INTECH COSTING 13/09/10 AW A ISSUED FOR INFORMATION/REVIEW 3/09/10 AW REV. DESCRIPTION DATE BY 5097-P-002

72 Stream Number 905j 905k 905l b 911c 911e 911f Stream Description Mass Flowrate Vanadium Leach Repulp RO Water Vanadium Precip Filter RO Wash Uranium Recovery Filter RO Wash Demin Water to Boiler Steam to Distribution Steam to Leach Steam to SDU Precip Heater Raw Water to Distribution Mass flow t/h Solids mass flow t/h Liquid mass flow t/h Vapour mass flow t/h Solids Fraction %w/w Volume Flowrate Slurry volume flow m³/h Solids volume flow m³/h Liquid volume flow m³/h Gas volume flow Nm³/h Densities Slurry density t/m Solids density t/m Liquid density t/m Gas density t/m Operating Conditions Temperature C Pressure kpa (abs) Solids Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration %w/w Uranium Concentration ppm Resin U 3 O 8 Concentration g/l Resin V 2 O 5 Concentration g/l U 3 O 8 Concentration ppm equiv Vanadium Concentration %w/w Vanadium Concentration ppm Iron Concentration %w/w Magnesium Concentration %w/w Aluminium Concentration %w/w Carbonate Concentration %w/w Calcium Concentration %w/w Sulphate Concentration %w/w Liquor Composition Uranium Flow kg/h U 3 O 8 Flow kg/h equiv Vanadium Flow kg/h V 2 O 5 Flow kg/h equiv Uranium Concentration g/l Uranium Concentration ppmv U 3 O 8 Concentration g/l U 3 O 8 Concentration ppmv equiv Vanadium Concentration g/l Vanadium Concentration ppmv V 2 O 5 Concentration ppmv equiv Chloride Concentration g/l Magnesium Concentration g/l Calcium Concentration g/l Sodium Carbonate Conc. g/l Sodium Bicarbonate Conc. g/l Sodium Hydroxide Conc. g/l Sulfuric Acid Concentration g/l Sulphate Concentration g/l Gas Composition Water Concentration %v/v Oxygen Concentration %v/v Carbon Dioxide Concentration %v/v Raw Water to CCD Thickeners CCD Thickener Flocc Raw Water to Caustic Dilution RO Plant Feed Hot Water Supply to Preheat1 Hot Water Disch ex Preheat1 Sodium Carbonate Supply Sulphuric Acid Supply Peroxide Supply Caustic Supply INDEPENDENT METALLURGICAL OPERATIONS PTY. LTD. PROJECT 88 Thomas St West Perth WA 6005 P: LAKE MAITLAND URANIUM PROJECT DIRECT PRECIPITATION FLOWSHEET OPTION STUDY CLIENT TITLE MEGA LAKE MAITLAND PTY. LTD. MASS BALANCE B ISSUED FOR INTECH COSTING 13/09/10 AW A ISSUED FOR INFORMATION/REVIEW 3/09/10 AW REV. DESCRIPTION DATE BY 5097-P-002

73 Golder Associates Pty Ltd Building 7, Botanicca Corporate Park Swan Street Richmond, Victoria 3121 Australia T: