works approval supporting document

Works Approval Supporting Document

Yandicoogina Iron Ore Mine – L7340/1997/9

Date October 2020

RTIO-HSE-0347235

RTIO-HSE-0347235

Disclaimer and Limitation This report has been prepared by Rio Tinto Iron Ore (Rio Tinto), on behalf of Pilbara Iron Ore Company (Services) Pty Ltd, specifically for the Yandicoogina Iron Ore Mine. Neither the report nor its contents may be referred to without the express approval of Rio Tinto, unless the report has been released for referral and assessment of proposals.

Document Status

Rev Author Reviewer/s Date Approved for Issue

To Whom Date

A J. Ennis-John

D. Doherty F. Bell

T. Walsh

C. Gumina A. Richards

J. Naaykens C. LasoSkold

E. Tongue

K. Sanderson N. Phillips

October 2020 Department of Water and Environmental Regulation

October 2020

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TABLE OF CONTENTS 1 APPLICANT DETAILS.......................................................................................... 6

2 INTRODUCTION................................................................................................... 7

3 PREMISES DETAILS ........................................................................................... 9

3.1 Premises Description ............................................................................................ 9

3.1 Land Tenure ....................................................................................................... 11

4 PROPOSED INFRASTRUCTURE AND EQUIPMENT ......................................... 13

4.1 Overview............................................................................................................. 13

4.2 Construction Phase ............................................................................................. 16

4.3 Environmental Commissioning ............................................................................ 16

4.4 Time Limited Operations ..................................................................................... 16

4.5 Operations .......................................................................................................... 16

4.6 Detailed Design................................................................................................... 20

4.7 Pit Wall Material Characterisation ........................................................................ 22

5 CLEARING ......................................................................................................... 22

6 STAKEHOLDER AND COMMUNITY CONSULTATION ...................................... 23

6.1 Regulator Consultation ........................................................................................ 23

6.2 Community Consultation ..................................................................................... 23

7 OTHER APPROVALS, LICENCES AND PERMITS............................................. 23

7.1 State Agreement Act ........................................................................................... 23

7.2 Environmental Protection Act 1986 (Part IV) ........................................................ 23

7.1 Environmental Protection Act 1986 (Part V) ......................................................... 24

7.1 Environmental Protection Act 1986 (Part V Clearing) ........................................... 24

7.2 Mining Act ........................................................................................................... 24

8 SITING AND LOCATION .................................................................................... 25

9 ENVIRONMENTAL SITING CONTEXT ............................................................... 35

9.1 Climate ............................................................................................................... 35

9.2 Topography......................................................................................................... 35

9.3 Geology .............................................................................................................. 35

9.4 Surface Water ..................................................................................................... 35

9.5 Groundwater ....................................................................................................... 36

9.6 Ecology............................................................................................................... 38

9.7 Aboriginal Heritage.............................................................................................. 39

10 RISK IDENTIFICATION AND ASSESSMENT ..................................................... 41

11 REHABILITATION AND CLOSURE.................................................................... 45

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12 PROJECT COSTS .............................................................................................. 45

13 References ........................................................................................................ 46

Appendix 1...................................................................................................................... 47

TABLES

Table 3-1 Indicative coordinates of the proposed WFC3A Extension ................................. 9

Table 4-1 Summary of Proposed Infrastructure and Equipment ......................................... 14

Table 4-2: Proposed waste fines storage facility water quality monitoring schedule........... 18

Table 7-1 Prescribed Premise category details under existing Licence L7340/1997/9 ...... 24

Table 8-1 Nearby environmentally sensitive receptors and aspect ..................................... 26

Table 10-1:Risk Rating Matrix .......................................................................................... 41

Table 10-2:Consequence Matrix ....................................................................................... 41

Table 10-3:Likelihood Matrix............................................................................................. 42

Table 10-4:Risk Assessment ............................................................................................ 43

Table 12-1 Estimated Project Costs .................................................................................. 45

Table 12-2 Prescribed Premise category related to application.......................................... 45

FIGURES Figure 2-1: Project Location ................................................................................................ 8

Figure 3-1 Extent of WFC3A Extension in JSE Pit (Golder, 2020a) ...................................... 9

Figure 3-2: Prescribed Premises Boundary and Project Tenure ......................................... 10

Figure 3-3 Proposed Project Area ..................................................................................... 12

Figure 4-1 Typical WFC3A Extension long section (Golder, 2020a) ................................... 13

Figure 4-2 Oblique model of WFC3, WFC3A and WFC3A Extension (Golder, 2020a) ........ 13

Figure 4-3 Proposed Project Infrastructure ........................................................................ 15

Figure 4-4 Groundwater Monitoring Bore Locations and Groundwater Contours ................ 19

Figure 8-1 - Nearest Human Sensitive Receptors .............................................................. 29

Figure 8-2 - Project Siting - Ecological Receptors – Surrounding Priority Flora and Vegetation Types ............................................................................................................. 30

Figure 8-3 Project Siting - Ecological Receptors – Surrounding Priority Flora and Vegetation Types – Vegetation Types Legend .................................................................. 31

Figure 8-4 Project Siting - Ecological Receptors – Surrounding Priority Fauna and Fauna Habitats .......................................................................................................... 32

Figure 8-5 Project Siting - Hydrological Receptors - Surrounding Water Bodies within project area ............................................................................................................... 33

Figure 8-6 Project Siting - Hydrological Receptors - Surrounding Regional Water Bodies ... 34

Figure 9-1 Schematic representation of aquifers at Yandi Mine site (RTIO, 2020a) ........... 37

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APPENDICES Appendix A: Part V Supporting Document for Works Approval Application – Waste Fines Cell 3A Extension – Yandicoogina Mine (Golder, 2020))

ABBREVIATIONS

AMD acid and metalliferous drainage ANCOLD Australian National Committee on Large Dams ANZECC Australian and New Zealand Environment and Conservation Council ANZG Australian and New Zealand Guidelines CID channel iron deposit DBCA Department of Biodiversity, Conservation and Attractions DGV Default Guideline Value DMIRS Department of Mines and Industry Regulation DTV Default Trigger Values DWER Department of Water and Environmental Regulation EP Act Environmental Protection Act 1986 EPBC Act Environment Protection and Biodiversity Conservation Act 1999 ERP Emergency Response Plan FoS Factor of Safety GAC Gumala Aboriginal Corporation GDE Groundwater Dependent Ecosystem HIY Hamersley Iron- Yandi Pty Limited HSEC Health, Safety, Environment and Communities and Social IBRA Interim Biogeographic Regionalisation of Australia JSE Pit Junction South East LOR Limit of Reporting ML Metal Leaching M&L Monitoring and Liaison Committee MNES Matters of National Environmental Significance MS Ministerial Statement Mt Million tonnes NAF Non-acid Forming PC3 Processing Plant 3 PDSWA Public Drinking Water Source Area PEC Priority Ecological Community PICS Pilbara Iron Company (Services) Pty Ltd RTIO Rio Tinto SSGV Site Specific Guideline Values TEC Threatened Ecological Communities WAA Works Approval Application WFC Waste Fines Cell Yandi Yandicoogina Iron Ore Mine YLUA Yandi Land Use Agreement

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1 APPLICANT DETAILS This report provides the supporting information for the Works Approval Application (WAA) being submitted by Pilbara Iron Company (Services) Pty Ltd (PICS) (Applicant; the Licensee) for the construction and operation of waste fines cell (WFC) 3A Extension. The Applicant (the Licensee) of the land subject to this Works Approval application is: Pilbara Iron Company (Services) Pty Ltd L 22, Central Park 152-158 St Georges Terrace Perth, WA, 6000 ACN: 107 210 248 The scope of this approval includes:

• extension of the operational WFC3A within Junction South East (JSE) Pit (WFC3A Extension)

• deposition of waste fines into WFC3A Extension.

The Authorised representative for the Works Approval application is: Tahlia Walsh Advisor – Government Approvals Rio Tinto 152-158 St Georges Terrace Perth, WA, 6000 Mobile: 0436 947 277 Email: [email protected]

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2 INTRODUCTION This Works Approval application seeks approval for the development and operation of an in-pit WFC, WFC3A Extension. The Licensee proposes to deposit waste fines produced from the PC3 process plant into WFC3A Extension, an extension of the currently approved, active, WFC3A, also within JSE pit. WFC3A Extension will be located within the existing JSE pit at the Yandicoogina Iron Ore Mine (Yandi) approximately 90 km north-west of Newman on Mineral Lease M 274SA (Figure 2-1). The proposed WFC3A Extension is classified as a Low Hazard, Category 3 facility according to the Department of Mines, Industry Regulation and Safety (DMIRS) Code of Practice for Tailings Storage Facilities in Western Australia (DMP 2013), as a Class III/Class IV according to the Rio Tinto HSEC risk management procedure (RTIO 2017), and as a Very Low consequence facility according to the ANCOLD (2019) Guidelines on Tailings Dams. It is proposed that deposition into WFC3A Extension will commence in Quarter 2 2021 and will continue for 14 years. Modelling estimates approximately 46 million tonnes of waste fines will be produced by the PC3 processing plant and deposited into the WFC3A Extension during this time. Waste fine delivery will be via existing pipework from a single location point in the south-west corner of JSE pit at approximately RL 507 m for an extended period. There will be no additional clearing or disturbance outside the existing JSE Pit and pipeline routes. The proposed works and extra storage requirements will not change the currently approved capacity under Category 5 of the Environmental Protection Act 1986 (EP Act). Potential environmental impacts from the proposed works are low, with studies completed indicating that during operations deposition of waste fines material are likely to result in the WFC becoming an area of lower transmissivity than the surrounding aquifer. The reduction in transmissivity may result a reduction of in aquifer throughflow and a slight steepening of the ground groundwater gradient within the JSE area. At closure JC and Bina Bina South pits will act as groundwater sinks such that groundwater flow through WFC3A Extension will ultimately migrate towards these sinks. Therefore, environmental risks during operation and closure are low as seepage throughflow outward towards the sensitive receptors of Marillana and Weeli Wolli Creeks is reduced. WFC3A Extension for waste fines storage has several benefits relative to alternative sites or above-ground storage. These include the use of land already disturbed by mining activities, improved geotechnical stability through containment of waste fines below ground, reduced risk of seepage migration by operating the WFC as a groundwater sink; and improved closure outcomes for long-term stability and overall disturbance/rehabilitation footprint minimisation.

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Figure 2-1: Project Location

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3 PREMISES DETAILS

3.1 Premises Description

The indicative coordinates of the WFC3A Extension are provided in Table 3-1 and Figure 3-1 below. The facility is located within the Shire of East Pilbara and the proposed WFC3A Extension will be located wholly within the JSE Pit at the Yandi mine within the existing Prescribed Premise boundary (Figure 3-2). Table 3-1 Indicative coordinates of the proposed WFC3A Extension Corner Easting (m) Northing (m) MGA 94 Zone 50 1 65 363 5 409 2 65 947 5 106 3 66 610 5 732 4 66 223 7 494 5 65 215 8 293

6 64 646 7 992 7 65 175 7 240 8 65 769 7 115 9 65 838 6 874 10 66 018 6 184

Figure 3-1 Extent of WFC3A Extension in JSE Pit (Golder, 2020a)

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Figure 3-2: Prescribed Premises Boundary and Project Tenure

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3.2 Land Tenure

The Yandicoogina mine is 100% owned by Hamersley Iron- Yandi Pty Limited (HIY), a member of the Rio Tinto Group of Companies (Rio Tinto). HIY has engaged PICS, another member of the Rio Tinto Group, to act as occupier and licence holder. PICS (the licensee) currently holds Licence L7430/1997 for the Yandicoogina Iron Ore Mine Prescribed Premises, granted under Part V of the Environmental Protection Act 1986 (EP Act).

As identified in Figure 3-2 the proposed works are located on State Agreement Mineral Lease M274SA granted pursuant to the Iron Ore (Yandicoogina) Agreement Act 1996. The development of WFC3A Extension, as well as the existing WFC1, WFC3, WFC3A, WFC4 (previously known as WFC2) and WFC5 will occur within M274SA. The location of WFC3, WFC3A and WFC3A Extension within the Prescribed Premises Boundary are shown on Figure 3-3.

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Figure 3-3 Proposed Project Area

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4 PROPOSED INFRASTRUCTURE AND EQUIPMENT

4.1 Overview

Currently, WFC3A receives all the waste fines produced at the PC3 processing plant. It is expected that capacity of WFC3A will be reached in Q2 2021 and development of WFC3A Extension is proposed to increase the operation’s waste fines storage capacity. WFC3A Extension will provided an extra 14 years of capacity with a life of facility estimated until the end of 2034. WFC3A comprises an interim cell (WFC3A-IC), situated to the immediate north of the decommissioned WFC3, and a final cell configuration (WFC3A-FC) bounded by an embankment north of the interim cell footprint, within the JSE pit as shown in Figure 4-1. The interim cell was submersed by waste fines as part of the development of the final cell. The locations of WFC3, WFC3A and WFC3A Extension within JSE pit are shown in Figure 4-2.

Figure 4-1 Typical WFC3A Extension long section (Golder, 2020a)

Figure 4-2 Oblique model of WFC3, WFC3A and WFC3A Extension (Golder, 2020a)

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Once WFC3A-Extension is operational, waste fines slurry will be transported from the PC3 plant by pipelines currently used for WFC3A with deposition occurring under both subaerial and subaqueous conditions along the JSE pit. The proposed WFC3A-Extension is classified as a Low Hazard, Category 3 facility according to the DMIRS Code of Practice for Tailings Storage Facilities in Western Australia, as a Class III/Class IV according to the Rio Tinto HSEC risk management procedure (RTIO, 2017), and as a Very Low consequence facility according to the Australian Committee on Large Dams (ANCOLD) guidelines on tailings dams.

Table 4-1 provides a summary of the proposed infrastructure associated with this works approval application and Figure 4-3 shows the proposed infrastructure on an aerial photo. Table 4-1 Summary of Proposed Infrastructure and Equipment

Infrastructure and Equipment Relevant Categories (if known)

Site Plan Reference

CCI Required

Enviro Commiss-ioning

1 WFC3A Extension

• Total capacity for 46.3 Million dry tonnes of w aste f ines.

5 Refer Figure 4-3

Y N

2

Waste f ines pumping and pipelines

• Use of WFC3A delivery pipeline and relocation of existing deposition pipelines.

• Installation of a contingency pipeline w ithin existing pipeline corridor.

N Y

3

Decant w ater pumping and pipeline

• A skid-mounted pump and decant return w ater pipeline betw een the pond and PC3 Turkeys nest in approximately 2028.

N Y

4 Stormw ater infrastructure

• Existing stormw ater diversion drains w ill be used.

N N

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Figure 4-3 Proposed Project Infrastructure

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4.2 Construction Phase

The construction phase will be minimal and short in duration with no new embankments or retaining structures required as part of the proposed works. The WFC3A Extension facility will utilise the existing delivery pipelines and pipeline corridor as well as stormwater diversion drains and access roads.

In Q4 2020, the delivery pipeline to WFC3A will be reconfigured and upgraded to improve asset life, allowing waste fines to be deposited from a single point in the south-west corner of WFC3A. A contingency pipeline will also be installed within the existing pipeline corridor to the south-west ramp of the WFC3A to supplement and provide redundancy to the single deposition location.

A compliance document detailing compliance with commitments made in the Works Approval will be submitted to the Department.

In approximately 2028, prior to the pond water level reaching RL 485 m, a decant water pump and pipeline will be installed in the pit. The return water pipeline will supply decanted water for use by Plant operations.

4.3 Environmental Commissioning

Due to the minimal construction works required the commissioning phase will be limited. Commissioning will involve testing of pipework and related infrastructure altered for the WFC3A Extension. The are no additional emissions related to this phase of work. The potential for emission and the controls in place for the commissioning phase are the same for Time Limited Operations and Operations and are detailed below in Sections 4.4, 4.5 and Appendix A.

4.4 Time Limited Operations

It is requested that Time Limited Operation be undertaken under the Works Approval, to allow for the assessment and determination of a Licence Amendment application. Conditions are proposed to be included in the Works Approval to regulate the proposed tailing deposition during the time limited operational phase. The conditions of the Works Approval are proposed to be transferred, as appropriate, into the Licence and transition to operation under Licence conditions will commence once a Licence Amendment is approved. Pumping rates and proposed emissions are the same as operations and are detailed below in section 4.5

4.5 Operations

Once operational, waste fines slurry will be transported from the PC3 plant by existing pipelines currently used for WFC3A with deposition occurring under both subaerial and subaqueous conditions along the JSE pit. Waste fine deposition is expected to commence Quarter 2 2021 and will continue until capacity is reached, approximately 14 years. Modelling has indicated that approximately 46 Mt of waste fines at a dry density of 1.4 t/m3 will be deposited during its operation. A summary of the operational strategy and design criteria

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is provided below, and more information is provided in the attached supporting document Supporting Document for Works Approval Application Waste Fines Cell 3A Extension - Yandicoogina Mine (Golder, 2020a) provided in Appendix A.

Potential emissions related to operation of the facility have also been assessed and included in the Part V Supporting Document (Golder (2020a).

4.5.1 Operating Procedures

Operating procedures will be developed for the operation and management of WFC3A Extension based on the existing WFC3 facility. Procedures will include:

• A waste fines deposition plan

• A water management plan that will include surface water management and seepage management

• Erosion control, focussed primarily on reducing wind erosion of waste fines

• Instrumentation and monitoring procedures.

An updated operating manual will be prepared for WFC3A Extension prior to commissioning the facility, consistent with the DMIRS (2013) Code of Practice 15 and will incorporate the items listed above.

4.5.2 Deposition Plan

Waste fines will be transported from the PC3 processing plant to WFC3A Extension via the distribution pipeline currently being used for WFC3A as shown in Figure 4-3 Deposition is anticipated to be partially subaerial and partially subaqueous. Waste fines will be deposited into WFC3A Extension from a single point in the south-west corner of WFC3A (approximately RL 507 m). Waste fines will be deposited subaerially resulting in formation of a supernatant pond at the northern end of JSE pit. Deposition will continue from this location for the remaining life of PC3, including deposition into WFC3A Extension. However, the design allows for waste fines to be deposited from the south-west ramp if needed (i.e. for maintenance on the west discharge spigot or to control the location of the pond). Additional information on the deposition strategy and pond formations is provided in section 7.3.2 of Part V Supporting Document (Appendix A).

4.5.3 Operational Freeboard

During operations, the supernatant water will be pumped to maintain an operational pond level at or below RL 485 m which is the approximate natural pre-mining groundwater level. This pond elevation is driven by the requirement to maintain a groundwater sink during operations, thereby limiting the potential for groundwater outflow from the facility and provides sufficient freeboard to accommodate the inflows from the 1 in 100 AEP, 72 hours rainfall event, with a 1 m contingency (Golder, 2020a). The freeboard is designed to meet the DMIRS (DMP,

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2015) and ANCOLD (ANCOLD, 2019) recommended freeboard for Very Low consequence facilities.

4.5.4 Emergency Response Plan (ERP)

An Emergency Response Plan (ERP) will be designed to limit potential risk to life and property and minimise impact on the surrounding environment and will be included in the updated Operating Manual for WFC3A Extension.

4.5.5 Monitoring

Groundwater monitoring proximal to WFC3A Extension will be carried out in accordance with the Yandicoogina Groundwater Operating Strategy (RTIO-HSE-0057642) (RTIO, 2017) (RTIO, 2015); Yandicoogina Monitoring and Management Plan (RTIO-HSE-0171024) (RTIO, 2015) and WFC3A Updated Operating Manual. The proposed monitoring bores are shown in Figure 4-4 and the proposed monitoring schedule and parameters are detailed Table 4-2 .

Table 4-2: Proposed waste fines storage facility water quality monitoring schedule

Monitoring Location

Monitoring parameter Criteria Frequency

MB10YRN001 MB10YRN002 MB10YRN008 MB10YRN009S MB10YRN009D MB10YRN010 MB10YRN013 MB10YMA006 MB09YJSB006 MB09YJSB009 MB09YJSB004 MB09YJSB008 MB09YJSB002 MB16YBIL0017 MB16YBIL0018 MB16YBIL0009 MB16YBIL0010 MB15YBIL044 MB15YBIL045

As per existing licence conditions Depth to w ater (mAHD)1 pH (pH Units)1 Total Dissolved Solids mg/L Electrical conductivity (μS/cm)1 Total hardness (CaCO3) (mg/L)

*2: Comparison against the 99% protection level in ANZECC 2000 is required. *3: Comparison against the USEPA National Primary Drinking Water Table of Contaminants 2009 is required.

Six-monthly

Major ions (mg/L): Sodium (Na) Potassium (K) Calcium (Ca) Chloride (Cl) Magnesium (Mg) Fluoride (F) Bromide (Br) Sulphate (SO4)

Metals (mg/L): Copper (Cu) Lead (Pb) Iron (Fe) Mercury (Hg) Manganese (Mn) Arsenic (As)2 Cadmium (Cd)2 Chromium (Cr)2 Nickel (Ni)2 Cobalt (Co)2 Selenium (Se)2 Boron (B) Molybdenum (Mo) Tin (Sb) Vanadium (V) Zinc (Zn)2 Thallium (Tl)3

Note 1: In-f ield non NATA analysis permitted

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Figure 4-4 Groundwater Monitoring Bore Locations and Groundwater Contours

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4.6 Detailed Design

Golder (Golder, 2020a) completed the design of the proposed facility following an assessment of tailings disposal options. The indicative location and layout of the proposed WFC3A Extension is shown on Figure 3-1. The design of the proposed facility as well as an assessment of environmental impacts related to the operation and closure of the facility is included within the Part V Supporting Document (Appendix A). A summary of the key design studies and findings is provided below in Sections 4.6.1 to 4.6.5.

4.6.1 Stability analysis

The geotechnical stability of the southern pit slope, at three different cross sections, was assessed using the ANCOLD guidelines (ANCOLD, 2019) recommended methods and conducted under the following conditions:

• Pre-deposition

• Post-deposition

• Long-term (closure).

The results from the analyses indicate that the estimated minimum factor of safety (FoS) against slope failure is significantly greater than the recommended minimum FoS for all three conditions. Additional information on the material parameters and stability analyses results is provided in section 6.4 of Part V Supporting Document (Appendix A).

4.6.2 Water balance

A water balance was undertaken to assess the volume and rate of water inflows (groundwater, waste fines supernatant and rainfall minus evaporative loss) relative to the level of waste fines solids. The outcomes of the water balance were used to inform the deposition plan, operating philosophy and decommissioning plan. The assessment approach and findings are detailed in WFC3A Extension Groundwater Model and Water Balance Study (Golder, 2020b) provided as Appendix A to the Part V Supporting Document (Golder, 2020a). The maximum pond elevation of 485 mRL was estimated to be the natural pre-mining groundwater level. The water balance modelled that this level is expected to be reached in 2028 and will be maintained by decanting excess water at a rate of approximately 4000 – 8000m3/day for reuse in processing or mining operations. This estimated decant volume will be refined as WFC3A Extension deposition progresses. The volume of water in the pond will become progressively smaller as water is pumped out and the tailings beach above water increases. Following the cessation of deposition in 2034, pond elevations decline slightly to regional groundwater levels (approximately 482 m RL) by 2038 (Golder, 2020b). At the conclusion of fines deposition (Q4 2034), a small pond will be confined to the northern end of WFC3A Extension with an estimated maximum depth of 40 m. This area will be backfilled with mine waste in accordance with the closure plan for the JSE pit to prevent the formation of a pit lake.

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4.6.3 Seepage analysis

The analytical water balance model (Golder, 2020b) indicates that during operation of the WFC3A Extension the direction of groundwater flow will be towards the pit, and the risk of seepage migration away from the WFC3A Extension is considered to be low to negligible.

4.6.4 Flow direction

The Groundwater Model and Water Balance Assessment (Golder, 2020b) reviewed potential changes to groundwater flow during operations and post decommissioning. Deposition of waste fines material is likely to result in the waste fines cell becoming an area of lower transmissivity than the surrounding aquifer. The reduction in transmissivity may result in a localised reduction in groundwater throughflow and a slight steepening of the groundwater gradient within the JSE area. The water balance model indicates that groundwater flow will be towards the pit reducing any impact from seepage migration away from WFC3A Extension. At closure JC and Bina Bina South pits will act as groundwater sinks such that groundwater flow through WFC3A Extension will ultimately migrate towards these sinks

4.6.5 Waste fine characterisation

Waste fines produced at PC3 comprise of a mixture of water and solids derived from crushing and beneficiation of the work from local channel iron deposit (CID). The only chemicals added to the process are flocculants used promote solid aggregation and accelerate consolidation from the waste fines prior to deposition.

Geochemical characterisation of five waste fines samples produced from the PC3 processing plant was completed in 2018 and 2019. The bulk chemistry of the fines was found to be generally similar to that of previous sampling events completed in 2011, 2012 and 2013 suggesting low variability in geochemical characteristics of waste fines (Golder, 2020a).

The main findings of these studies have been summarised by Golder (2020a) as follows: • The five waste fines samples were characterised by circum-neutral pH, and negligible

acid production potential and acid neutralisation capacity, thus classified as non-acid forming and barren – NAF (barren). This is consistent with the classification of historical waste fines samples, suggesting that waste fines with similar properties to those tested in this study and previously are likely to remain near neutral under oxidising conditions in the long term and that the risk of acid and metalliferous drainage (AMD) is negligible.

• Neither sulfides nor carbonates were identified by X-ray diffraction in any current or historical waste fines samples, and the mineralogical test results confirmed the NAF (barren) nature of waste fines.

• The bulk geochemistry data indicated that waste fines materials were likely enriched with some trace elements such as As, Ag, Hg and Se, and the concentrations of these trace elements in waste fines solids may vary depending on the ore feed materials. However, these enriched elements showed very low leachability as the elemental

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concentrations were generally below or close to Limit of Reporting (LOR) in waste fines liquors and various leachates, as demonstrated in Appendix E.

• Test results for waste fines liquors indicated that concentrations of dissolved elements of environmental significance were typically below LOR or at low concentrations (close to LOR), suggesting a low risk of metal leaching (ML). However, the average nitrate concentration (NO3- as N) in the waste fines liquors (22.28 mg/L) exceeded the ANZG (2018) freshwater 95% species protection level (default guideline value) DGV (2.4 mg/L).

• Assessment of the geochemistry of the ore and waste fines from the Yandi Mine site (Appendix E) demonstrated that the leachable constituents from the waste fines were source-term limited, and did not differ significantly from the CID ore, although exceedances of nitrate and (sometimes) Cu and Zn were observed in waste fines liquors.

Discussion of the test method, analysis of the full results and copies of the laboratory results is provided in WFC3A Extension Waste Fines Geochemical Characterisation (Golder, 2020c) provided as Appendix E to the Part V Supporting Document (Golder, 2020a). An electronic copy of the data results in excel is also provided as attachment 8B.

4.7 Pit Wall Material Characterisation

Several AMD/ML studies associated with waste rock at the Yandi Mine site have been undertaken by RTIO in the last decade. The overall AMD risk is low for all rock types at the Yandi Mine site, including JSE pit area. Based on available information and test results, the pit wall materials are inert with respect to AMD risk, and limited loading of contaminants to the pit void is expected during the operational and post-closure periods.

A summary of the previous studies and results is provided in WFC3A Extension Waste Fines Geochemical Characterisation (Golder, 2020c) provided as Appendix E to the Part V Supporting Document (Golder, 2020a).

5 CLEARING As the proposed works will utilise the JSE pit and existing corridor for waste fines delivery, there is no need for further land clearing.

Any minor clearing that may be required for implementation of the proposed waste fines storage facility will be managed under the existing Ministerial Statement 1038, published 3 October 2016 and will be controlled through the Rio Tinto Approvals Coordination process. This ensures that the following is completed prior to commencing clearing activities: all heritage and biological reviews are undertaken; legal access to the land is in place; other necessary approvals are obtained; and the critical clearing boundary is inspected prior to clearing commencing.

Ground disturbance activities will be planned to ensure minimal disturbance is achieved using appropriate ground engaging plant, designated tracks, roadways and preferential use of pre‐existing disturbed areas.

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6 STAKEHOLDER AND COMMUNITY CONSULTATION

6.1 Regulator Consultation

Rio Tinto meets with the DWER regularly to provide an overview of upcoming proposals and provided DWER with updates on this proposal in March, September and December 2019, April 2020, and a detailed scoping meeting held in May 2020.

6.2 Community Consultation

The licensee has a long-term commitment to working with Pilbara communities and recognises that local communities have a direct interest in their activities. Specific strategies and initiatives are outlined within the Annual Sustainable Development Report. Substantial stakeholder consultation and public review of mining activities at Yandicoogina has occurred historically, as part of environmental approval processes for the existing mine operations. The licensee has sought to keep relevant stakeholders up-to-date with studies relating to future mining activities in the area. Key issues identified by stakeholders during previous consultation processes include:

• Water management, particularly surplus water discharge • Cumulative hydrological impacts from other mining activities in the area • Closure management • Vegetation disturbance, particularly riparian vegetation and any impacts on priority

flora • Disturbance of Aboriginal heritage values.

The above issues raised by stakeholders have been addressed throughout statutory approval processes, with new issues addressed through regular stakeholder consultation. The WFC3A extension is consistent with existing waste fines storage facilities and forms a minor part of the mine operations at Yandicoogina. Potential hydrological and hydrogeological issues have been addressed in the overall stakeholder consultation process. No additional stakeholder consultation has been carried out specifically for the proposed WFC3A Extension. However, the inclusion of multiple WFCs in JSE was discussed during approval processes and during agency consultation in relation to closure plans.

7 OTHER APPROVALS, LICENCES AND PERMITS

7.1 State Agreement Act

The Premises falls entirely within tenure granted pursuant to the Iron Ore (Yandicoogina) Agreement Act 1996.

7.2 Environmental Protection Act 1986 (Part IV)

PICS operates the Yandicoogina Iron Ore Project on behalf of HIY under Ministerial Statement 1038 (MS 1038) published on 3 October 2016. Ministerial Statement 1038 supersedes historical Ministerial Statements 417, 523, 695 and 914.

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The construction of WFCs within the Junction Central and Junction South East areas have been assessed and approved as part of MS 1038.

7.1 Environmental Protection Act 1986 (Part V)

The existing Yandicoogina mine site has been assessed as ‘Prescribed Premises’, as defined by Schedule 1 of the Environmental Protection Regulations 1987 (as amended). The Licensee currently holds Part V Operating Licence L7340/1997/9 (expiry 31 May 2036) for the Prescribed Premises, which includes the categories and design capacities shown in Table 7-1.

Table 7-1 Prescribed Premise category details under existing Licence L7340/1997/9 Category Number

Category Description

Category Premises Production or Design Capacity

This Application

5 Processing or beneficiation of metallic or non-

metallic ore

50,000 tonnes or more per year

60,000,000 tonnes per annual period

Works Proposed. No change to

category/capacity.

6 Mine dew atering 50 000 tonnes or more per year

As authorised by the Ministerial Statement issued under Part IV

of the EP Act

No w orks proposed. Not applicable to this

Works Approval Application (WAA)

12 Screening, etc. of material

50,000 tonnes or more per year

10,000,000 tonnes or more per annual

period


WAA

54 Sew age facility 1,192 cubic metres per day


WAA

64 Class II or III putrescible landfill site

20 tonnes or more per year

7,500 tonnes per annual period


WAA

73 Bulk storage of chemicals, etc

1,000 cubic metres in aggregate

1,770 cubic metres in aggregate


WAA

7.1 Environmental Protection Act 1986 (Part V Clearing)

As the proposed works will utilise the JSE pit and existing corridor for waste fines delivery, no additional approval is sought for clearing. Any minor clearing that may be required will be conducted as authorised by MS 1038.

7.2 Mining Act

The Premises falls entirely within tenure granted pursuant to the Iron Ore (Yandicoogina) Agreement Act 1996 and therefore is not subject to the approval requirements of the Mining Act 1978

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8 SITING AND LOCATION Table 8-1 summarises the nearby environmentally sensitive receptors and proposed controls to prevent or mitigate any potential adverse impacts. Receptors identified in Table 8-1 are shown in Figures Figure 8-1 to Figure 8-6.

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Table 8-1 Nearby environmentally sensitive receptors and aspect

Classification Description Distance from Prescribed Premises

Proposed controls to prevent or mitigate adverse impacts (if applicable)

Nearest Human Sensitive Land use

The nearest tow n is New man located approximately 75 km south-east Any potential impacts are mitigated by the distance to the receptor.

Phil’s Creek Accommodation village 5.5 km south

BHP Yandicoogina Camp 17 km north-w est

Recreational users of Marillana and Weeli Wolli Creeks Less than 1 km Any potential impacts to the creeks are mitigated by the operation of the supernatant pond below RL 485 m to create a groundw ater sink during operations and the low -permeability w aste f ines w hich w ill reduce groundw ater f low -through to the creeks.

Further information is provided below under Rivers, lakes, oceans and other bodies of surface water, etc. and in section 4.5, 4.6 and 9.4.

Threatened Ecological Communit ies (TEC)

The Project area is heavily disturbed, and no TEC w ere recorded in the proposed w ork area.

The Fortescue Marsh is classif ied by the Department of Biodiversity, Conservation and Attractions (DBCA) as a Priority Ecological Community (PEC) and has been classif ied as having Priority 1 conservation status (RTIO, 2020a). The Fortescue Marsh is the largest ephemeral w etland in the Pilbara region and is listed on the Directory of Important Wetlands of Australia as a w etland of national signif icance. The diverse ecosystem includes endemic f lora, fauna and supports a rich diversity of restricted aquatic and terrestrial invertebrates.

40 km north east Any potential impacts are mitigated by the distance to the receptor. Refer to section 9.4 for more information.

Threatened and/or priority f lora

Flora studies have previously been completed for the development of the JSE Pit. No threatened f lora w ere identif ied w ithin the JSE area through these studies and priority f lora w ere found w ithin 400 m of the w orks. How ever, as the development and operation of WFC3A Extension w ill be

- Any potential impacts are mitigated by the w orks occurring in already disturbed

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w ithin the existing JSE-Pit, it w ill not cause any additional physical disturbance of the surrounding vegetation.

environment (i.e. pit void and existing pipeline routes). Refer to section 9.6.

Threatened and/or priority fauna

Fauna studies have previously been completed for the development of the JSE-Pit. No threatened fauna w ere identif ied w ithin the JSE area through these studies and priory fauna have been recorded approximately w ithin 1 km. As the development and operation of WFC3A Extension w ill be w ithin the existing JSE-Pit, it w ill not cause any additional physical disturbance of the surrounding fauna habitats.

- Any potential impacts are mitigated by the w orks occurring in already disturbed environment (i.e. pit void and existing pipeline routes). Refer to section 9.6.

Groundw ater Dependent Ecosystems (GDEs)

Communit ies along the majority of Marillana and Weeli Wolli creeks can be considered GDEs, w ith some areas (near oxbow , near the confluence of Marrillana and yandi creeks, and some parts of w eeli w olli near the southern end of the JSE pit) clearly representing GDE's. In most cases the riparian vegetation in question represents a potential GDE and in cases w here Melaleuca argentea w as present pre-mining such vegetation clearly represents a GDE. Perennial discharge of surplus mine w ater in the area has also rendered the majority of riparian vegetation groundw ater dependent and as such riparian groundw ater receptors occur in the area. Any potential impacts to groundw ater from seepage or pipeline failure or changes to groundw ater f low s w ill be minimised by engineering and design controls and groundw ater f low w hich has been modelled during operations to f low tow ards the pit.

Any potential impacts to GDEs are mitigated by the operation of the supernatant pond below RL 485 m to create a groundw ater sink during operations and the low -permeability w aste f ines w hich w ill reduce groundw ater f low -through to the creeks. In addition, w orks occurring in already disturbed environment (i.e. pit void and existing pipeline routes).

Further information is provided below under Rivers, lakes, oceans and other bodies of surface water, etc. Refer to section 9.6 and 4.6.4.

Aboriginal and other heritage sites

Extensive Aboriginal cultural heritage surveys have been conducted in and around the site prior to the construction of the existing facilities. The closest heritage site (Y00/05) is located 1.4km to the south-east of the existing WFC3. This heritage site w ill not be impacted by the proposed WFC3A extension.

1.4km to the south-east Any potential impacts are mitigated by the distance to the receptor.

Public Drinking Water Source Area (PDWSA)

The nearest PDWSA is the P1 New man Water Drinking Reserve approximately 55 km aw ay from the WFC3A extension. It w ill not be impacted on by these w orks.

55 km Any potential impacts are mitigated by the distance to the receptor.

Additionally, the direction of groundw ater f low during operations is tow ards the pit, aw ay from the PDWSA.

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Rivers, lakes, oceans and other bodies of surface w ater, etc.

Weeli Wolli Creek (drains to Fortescue Marsh)

Marillana Creek (drains to Fortescue Marsh)

2 km directly and (6.5 km (to w aterhole) and 11 km (to springs)).

Less than 1 km

Impacts are mitigated by the operation of the supernatant pond below RL 485 m to create a groundw ater sink during operations and the low -permeability w aste f ines w hich w ill reduce groundw ater f low -through to the creeks. Additionally, the follow ing controls w ill be integrated into operation of WFC3A Extension: • Groundw ater quality and level w ill be

monitored in bores located around the JSE pit (refer to section 4.5.5).

• The w ater quality and level of the pond in WFC3A Extension w ill be monitored for comparison w ith nearby groundw ater monitoring.

• The production bores located along the northern boundary betw een JSE pit and Marillana Creek w ill remain in place and can be used to draw dow n w ater levels along this boundary, if required to create a containment zone.

• The operating strategy for WFC3A Extension w ill be review ed regularly during operations and can be amended as needed based on monitoring data.

Refer to sections 4.5 and 9.4 for more information.

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Figure 8-1 - Nearest Human Sensitive Receptors

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Figure 8-2 - Project Siting - Ecological Receptors – Surrounding Priority Flora and Vegetation Types

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Figure 8-3 Project Siting - Ecological Receptors – Surrounding Priority Flora and Vegetation Types – Vegetation Types Legend

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Figure 8-4 Project Siting - Ecological Receptors – Surrounding Priority Fauna and Fauna Habitats

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Figure 8-5 Project Siting - Hydrological Receptors - Surrounding Water Bodies w ithin project area

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Figure 8-6 Project Siting - Hydrological Receptors - Surrounding Regional Water Bodies

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9 ENVIRONMENTAL SITING CONTEXT

9.1 Climate

The Yandi Mine site is located in the inland arid Pilbara Region of Western Australia, with a climate characterised by hot wet summers, and cool dry winters. High rainfall events during the summer months are usually associated with tropical lows and cyclones. Temperature varies from a mean maximum of 39°C in summer to a mean minimum of 6°C in winter; average annual rainfall is approximately 333 mm and annual A-Pan evaporation is about 3 143 mm (Bureau of Meteorology 2018).

9.2 Topography

The topography of the Yandicoogina area has been shaped by alluvial processes with the existing streams winding between low lying mesas and hills. Three major landforms can be distinguished as:

• Low stony hills: These areas generally consist of hills, ridges and breakaways supporting a scattered over storey of small trees (Eucalyptus and Acacia species) over moderately dense Spinifex (Triodia species) hummock grassland

• Valleys: These areas consist of low stony plains in valleys supporting scattered overstorey of small trees (Eucalyptus and Acacia species) over sparse mixed shrubs and Spinifex (Triodia species).

• Alluvial flats are dominated by Acacia shrublands with a moderately rich understorey of shrubs, herbs and tussock grasses;

• Drainage lines: These areas vary from small gullies in upper hills to more major creeklines. Minor drainage lines differ very little from the vegetation type surrounding them and are usually species poor. Major creeklines support Eucalyptus dominated woodlands and open forest over a mixed understorey of shrubs and grasses.

9.3 Geology

The proposed WFC3A Extension is located within the JSE deposit, which is part of the Marillana-Yandicoogina-Weeli Wolli Paleochannel system. The Marillana-Yandicoogina-Weeli Wolli Paleochannel system is a channel iron deposit (CID). The CID materials have high porosity, which enables them to drain freely. In excess of 80% of the CID is below the water table and forms an aquifer. A Basal Clayey Conglomerate (BCC) layer lies beneath the CID, which is overlain by overburden comprised of alluvial gravels (ALL). Overburden in the project area is up to 20 m thick.

9.4 Surface Water

The Yandi Mine site is located within the catchment of the Weeli Wolli Creek and its major tributary the Marillana creek. Streamflow across the Pilbara is highly seasonal and variable, are typically short-lived in duration with stream flows generally associated with rain bearing depressions or high intensity cyclonic rainfall. However, in the vicinity of the Weeli Wolli and Marrillana Creeks, stream flow is perennially supported by base flow derived from surplus mine water discharge.

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Weeli Wolli Creek is a major Pilbara drainage system, with a catchment area of 4 769 km2, and length of approximately 71 km. Weeli Wolli Creek and its tributaries are altered systems, receiving surplus water from existing mining projects specifically Yandi Operations, BHP’s Marillana Creek (Yandi) operations and Hamersley HMS’s Hope Downs 1 operation. Weeli Wolli Creek flows north for approximately 40 km before eventually discharging into the Fortescue River via the Fortescue Marsh. However, it should be noted that the two systems are only connected during flooding associates with intense cyclonic events (Kendrick, 2001). Marillana Creek runs west-east through the Yandi Mine site (along the northern end of WFC3A Extension), to the confluence with the Weeli Wolli Creek in the east of the Yandicoogina Mine site. Marillana Creek has a total catchment area of 2 250 km2 and is estimated to contribute approximately 50% of flow into the Fortescue Marshes from the overall Weeli Wolli Creek System (MWH Australia and Equinox Environmental, 2011).

9.4.1 Surface Water Quality

Golder (2020a) assessed surface water quality data available from 1998 to May 2020 against relevant guidelines. Upstream surface water locations on the Weeli Wolli Creek and DPWW013 (located downstream of the Marillana Creek confluence) were dominated by magnesium, while the other Weeli Wolli and Marillana Creek locations had no dominant cation. Recent surface water quality results from Marillana and Weeli Wolli Creeks did not exceed the adopted recreational water or livestock guidelines (Golder, 2020a). However, nitrate concentrations have been exceeded at the discharge outlet D09 (Located on Marillana Creek to the east of WFC 3A Extension). Additional information and further assessment are provided in Section 4.4 and Appendix C of the Supporting Document for Works Approval Application Waste Fines Cell 3A Extension - Yandicoogina Mine (Golder, 2020) provided in Appendix A.

9.5 Groundwater

Groundwater moves principally within two aquifer systems at the Yandi Mine site, the CID (paleochannel, historical drainage) and alluvial (current drainage) aquifers both of which are bound by the Weeli Wolli Formation Basement rock (Figure 9-1). Hydraulic interconnectivity between the Alluvium and CID groundwater systems along Marillana Creek is considered minor, likely due to a higher degree of cementation in the lower Alluvium. Conversely, along Weeli Wolli Creek there is a good connection between the two aquifers units due to a lower degree of cementation. The depth to groundwater at the Yandi Mine site varies from approximately 2 m below ground level (bgl) adjacent to the Marillana Creek (e.g. at northern end of WFC3A Extension), to up to 30 m bgl in areas further away from the Marillana Creek. The groundwater elevation in the CID is observed to fluctuate considerably in response to significant rainfall events. For example, groundwater levels increased by approximately 10 m following substantial rainfall events associated with ex-tropical cyclones Claire, Emma, Glenda and Hubert in 2006. Pre-mining groundwater levels at the JSE pit area range between RL 485 m at the northern end of WFC3A Extension, near Marillana Creek, and RL 475 m at the southern end, near Weeli Wolli Creek, with southward groundwater flow occurring primarily through the CID and

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overlying alluvials. Eastward groundwater throughflow along the alignment of Marillana Creek, to the north of WFC3A Extension, would primarily be through recent alluvial deposits, as there is no CID underlying the stretch of Marillana Creek between the WFC3A Extension and the confluence of the Marillana and Weeli Wolli Creeks. Additional information and further assessment of the site wide groundwater system is provided in Section 4.5 and Appendix B of the Supporting Document for Works Approval Application Waste Fines Cell 3A Extension - Yandicoogina Mine (Golder, 2020) provided in Appendix A.

Figure 9-1 Schematic representation of aquifers at Yandi Mine site (RTIO, 2020a)

9.5.1 Groundwater Quality

Historical and recent groundwater and surface water quality data collected in JSE Pit, Marillana Creek and Weeli Wolli Creek between 1998 and 2020 were reviewed and summarised by Golder (Golder, 2020a). Data were compared to Site Specific Guideline Values (SSGVs) and (ANZG, 2018) 95% species protection level for freshwaters and marine waters, as well as NHMRC (2008) recreational water guidelines and (ANZECC and ARMCANZ, 2000) livestock drinking water DTVs for surface water only. Groundwater underlying the JSE pit was characterised as neutral to basic (alkaline), fresh and very hard, with elevated concentrations of major ions. Major ions (i.e. calcium, chloride, magnesium, potassium, sodium and sulphate) concentrations consistently exceeded the SSGVs in groundwater bores associated with the Weeli Wolli Creek (i.e. WW4 and WWA) and Temporal and spatial variability was observed in major ion concentrations in groundwater bores associated with the Marillana Creek, with concentrations typically fluctuating around the SSGVs. Additional information, including monitoring results, are included in WFC3A Extension Waste Fines Groundwater and Surface Water Quality (Golder, 2020d) provided as Appendix E to the Part V Supporting Document (Golder, 2020a) and electronically, as Attachment 8B – Water Data with the application package.

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9.6 Ecology

The Project Area occurs within the Pilbara Bioregion (Hamersley and The Fortescue Plains sub‐regions) as classified by the Interim Biogeographic Regionalisation for Australia (IBRA).

As the proposed works will utilise the JSE pit and existing corridor for waste fines delivery, there is no need for further land clearing. Any minor clearing that may be required for implementation of the proposed waste fines storage facility will be managed under the existing Ministerial Statement 1038, published 3 October 2016 and will be controlled through the Rio Tinto Approvals Coordination process.

A number of biological surveys have been undertaken across the Yandicoogina Prescribed Premises envelope. The following is a summary of the survey results within the work area, defined as the development of the WFC3A Extension and associated pipelines:

• None of the Vegetation represents a PEC or TEC

• Riparian vegetation within parts of Marillana and Weeli Wolli creeks in the vicinity of the Yandi operations and the WFC3 extension represent Groundwater Dependent Ecosystems (GDEs). At present these systems are supported by surplus mine water discharge. However, none are located specifically within the WFC3A Extension or pipelines.

• None of the weeds are declared pests.

• No threatened flora occurs within the vicinity of the proposed works or are expected to occur.

• No habitat for the protected Pilbara olive python (Liasis olivaceus barroni) and northern quoll (Dasyurus hallucatus) (RTIO, 2015); (RTIO, 2020a) will be impacted upon.

Additional details are provided in Section 5.5 of the Supporting Document for Works Approval Application Waste Fines Cell 3A Extension - Yandicoogina Mine (Golder, 2020) provided in Appendix A

9.6.1 Terrestrial Flora and Fauna

Vegetation disturbance in the overall project area has occurred as a result of historical mining activities at Yandicoogina and the proposed works are located within existing disturbed areas.

Priority (P) 3 and P4 priority flora and fauna species have been identified during ecological surveys completed within the prescribed premises boundary, however as the proposed works are already occurring within a disturbed environment, impacts will be avoided. The P4 flora species Lepidium catapycnon (Hamersley Lepidium) and P4 fauna species Pseudomys chapmani (western pebble-mound mouse) were recorded within one km of JSE Pit. The location of this species and others further from the pit are shown in Figures 8.3 and 8.4.

9.6.2 Subterranean Fauna

The Yandi Mine site is known to contain a number of stygofauna species endemic to the Marillana-Weeli Wolli catchment (RTIO, 2015). Potential impacts arise from direct removal of

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habitat (excavation) and indirectly through changes to the groundwater regime (abstraction and discharge) (RTIO, 2020a). Any species within JSE Pit will have already been impacted by mining and any indirect potential impacts from seepage or pipeline failure will be minimised by engineering controls and groundwater flow which has been modelled during operations to flow towards the pit.

9.6.3 Groundwater Dependant Ecosystems

Riparian vegetation along Marillana and Weeli Wolli Creeks is regarded as being locally significant, due to the relatively limited extent of this vegetation type compared with other locally occurring vegetation types and the ecological services that it provides. The keystone phreatophytic species Eucalyptus camaldulensis and E. victrix occur extensively along Marillana and Weeli Wolli Creeks in the project area and can be classed as potentially groundwater dependent (RTIO, 2011)(RTIO, 2015). Communities with an overstorey dominated by these species and also at times possessing the obligate phreatophyte Melaleuca argentea occur on both these creeks in the vicinity of the proposed infrastructure. In most cases the riparian vegetation in question represents a potential GDE and in cases where Melaleuca argentea was present pre-mining such vegetation clearly represents a GDE. Perennial discharge of surplus mine water in the area has also rendered the majority of riparian vegetation groundwater dependent and as such riparian groundwater receptors occur in the area. Any potential impacts to groundwater from seepage or pipeline failure or changes to groundwater flows will be minimised by engineering and design controls and groundwater flow which has been modelled during operations to flow towards the pit.

9.7 Aboriginal Heritage

The Yandicoogina Iron Ore Mine spans two determined native title areas: Banjima native title area (WCD2014/001) and Nyiyaparli native tile area (WCD2018/008). While RTIO has separate agreements with both native title groups the Yandicoogina mine falls under the Yandi Land Use Agreement (YLUA). At the time the YLUA was entered into, the Innawonga (now ‘Yinhawangka’), Bunjima (now ‘Banjima’) and Niapaili (now ‘Nyiyaparli’) claimant application (NNTT number: WC 96/61 (IBN Claim) was registered over the Yandicoogina project area. However, since then the native title claims for the area have undergone some significant changes, namely Yinhawangka and Banjima separated out their claims and Nyiyaparli, Yinhawangka and Banjima have separate Claim Wide Participation Agreements with RTIO in their own right. However, the YLUA is not superseded by the existence of these newer commercial agreements.

Members of the Banjima, Yinhawangka and Nyiyaparli people elected Gumala Aboriginal Corporation (GAC) to act as their representative corporate body for the YLUA area. GAC and RTIO have established a Monitoring and Liaison Committee (M&L) to implement the Agreement. The role of the Gumala M&L is to collaboratively manage and oversee the conduct of consultation and other cultural heritage management procedures referred to in the Heritage Protocol which is contained in the YLUA.

The heritage values of the Yandicoogina mine site are well understood (through extensive surveys and consultation). The identification and management of cultural heritage within the traditional lands of the Nyiyaparli and Banjima People is in accordance with the principles and practices outlined within Rio Tinto’s Communities and Social Performance Standard, the Rio

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Tinto Cultural Heritage Group Procedure, and the heritage protocols within the Yandi Land Use Agreement.

Extensive Aboriginal cultural heritage surveys have been conducted in and around the site prior to the construction of the existing facilities. The closest heritage site (Y00/05) is located 1.4km to the south-east of the existing WFC3. This heritage site will not be impacted by the proposed WFC3A extension.

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10 RISK IDENTIFICATION AND ASSESSMENT A risk assessment has been prepared to identify the potential emissions from the proposed activities and the potential sources, pathways and receptors of those emissions, and proposed controls to manage potential emissions to determine a risk rating. The risk assessment has been based on the DWER Guidance Statement: Risk Assessments (released by the then named Department of Environmental Regulation in 2017) and the Rio Tinto risk assessment process, based on the following risk rating matrix (Table 10-1): Table 10-1: Risk Rating Matrix

Consequence

Likelihood Slight Minor Moderate Major Severe

Almost Certain Medium High High Extreme Extreme

Likely Medium Medium High High Extreme

Possible Low Medium Medium High Extreme

Unlikely Low Medium Medium Medium High

Rare Low Low Medium Medium High

Risk = consequence x likelihood The following criteria (DWER 2017) are used to determine the consequence and likelihood of a risk event occurring (Table 10-2 and

Table 10-3).

Table 10-2: Consequence Matrix Consequence Consequence description

Environment Health

Severe

On-site impacts: catastrophic Off-site impacts (local scale): high level Off-site impacts (wider scale): mid level Mid to long term or permanent impact to an area of high conservation value or special signif icance

Loss of life Adverse health effects: high level or ongoing medical treatment Local scale impacts: permanent loss of amenity

Major

On-site impacts: high level Off-site impacts (local scale): mid level Off-site impacts (wider scale): low level Short term impact to an area of high conservation value or special signif icance

Adverse health effects: mid level or frequent medical treatment Local scale impacts: high level impact to amenity

Moderate On-site impacts: mid level Off-site impacts local scale: low level Off-site impacts wider scale: minimal

Adverse health effects: low level or occasional medical treatment Local scale impacts: mid level impact to amenity

Minor On-site impacts: low level Off-site impacts (local scale): minimal Off-site impacts (wider scale): not detectable

Local scale impacts: low level impact to amenity

Slight On-site impacts: minimal Local scale impacts: minimal impacts to amenity

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Table 10-3: Likelihood Matrix

Likelihood Likelihood description

Almost certain The risk event is expected to occur in most circumstances.

Likely The risk event w ill probably occur in most circumstances.

Possible The risk event could occur at some time.

Unlikely The risk event w ill probably not occur in most circumstances.

Rare The risk event may only occur in exceptional circumstances.

The potential emissions, sources, pathways and receptors that have been identified for the construction, commissioning and operation of the proposal are outlined in Table 10-4. This table also identifies the potential impacts, proposed controls and associated risk ratings.

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Table 10-4: Risk Assessment

Source Potential Emissions Potential Pathway Potential Receptors Potential Impacts Proposed Controls Consequence Likelihood Risk Rating Detailed Assessment

Required?

Category 5: Construction of WFC3A Extension

Dust: Release of particulate matter from construction activities and vehicular movements.

Air: Transport through air then transport through the respiratory system

Residential: None, the nearest receptors are the residents of the township of Paraburdoo, more than 6 km away.

Human health Impacts – respiratory i l lness. Given the distance to the nearest receptor, impacts to public health or amenity from nuisance dust are expected to be limited.

Dust will be managed via the requirements of the Works Approval, Part V Licence L7340/1997/9 and standard operating procedures, including:

- Clearing will be managed to ensure that areas are only cleared as required and rehabilitation of cleared areas is implemented as construction is completed; and

- Dust suppression will be implemented (including use of water trucks, control of vehicle movements / restricted speeds).

Standard management procedures are expected to effectively mitigate the risk of dust emissions during construction.

Minor Rare Low Risk pathway is low, detailed assessment is not required.

Air: Transport through air then deposition

Riparian vegetation along the Maril lana and Weeli Wolli creeks.

Smothering and the potential suppression of photosynthetic and respiratory functions of vegetation.

Terrestrial ecosystems: Native fauna

Dust may impact habitats which represent shelter, foraging and dispersal habitats for native fauna. Given the distance from potential dust sources, dust is expected to have a negligible impact on native fauna.

Noise and vibration: associated with construction activities and vehicular movements.

Air or other physical medium: Vibration of particles.

Residential: None, the nearest receptors are the residents of Phil ’s Creek Accommodation Village are more than 5 km away.

Human health Impacts – respiratory i l lness. Given the distance to the nearest receptor, impacts to public health or amenity from nuisance dust are expected to be limited.

Environmental Protection (Noise) Regulations 1997 and standard operating procedures are expected to effectively mitigate the risk of noise during construction. Specific controls are not proposed.


Terrestrial ecosystems: Nocturnal native fauna

Noise may disrupt nocturnal foraging behaviour. Noise is expected to be limited at night when nocturnal native fauna are expected to be foraging and as such, noise is expected to have a negligible impact on native fauna.

Light Air: l ight spil l generated during construction activities.

Residential: None, the nearest receptors are the residents of Phil ’s Creek Accommodation Village are more than 5 km away.

Health and amenity: Given the distance to the nearest receptor, impacts to public health or amenity from light spil l are expected to be limited.

Standard operating procedures are expected to effectively mitigate the risk of l ight spil l during construction. Specific controls are not proposed.


Terrestrial ecosystems: Nocturnal native fauna

Light may disrupt nocturnal foraging behaviour: Light spil l is expected to be limited, and inline with existing operations, at night when nocturnal native fauna are expected to be foraging and as such, l ight is expected to have a negligible impact on native fauna.

Hydrocarbons Hydrocarbon spil l causing soil contamination

Land Soil contamination. Hydrocarbons will be managed via relevant legislation (including Australian Standard AS 1940-2004: Storage and handling of flammable and combustible l iquids), the requirements of the Works Approval, Part


Seepage of hydrocarbon spill to groundwater causing contamination

Groundwater of beneficial use (l ivestock watering).

Groundwater contamination (and declining health of any

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Source Potential Emissions Potential Pathway Potential Receptors Potential Impacts Proposed Controls Consequence Likelihood Risk Rating Detailed Assessment

Required?

Terrestrial ecosystems (vegetation communities dependant on groundwater):

groundwater dependent vegetation): Given the direction of groundwater flow, and depth to groundwater any hydrocarbon spil ls are not expected to seep to groundwater (or affect any associated groundwater dependent ecosystems). Additionally, construction works are minimal and short in duration with no new embankments or retaining structures required as part of the proposed works which will further minimise risk.

V Licence L7340/1997/9 and standard operating procedures, including: - Fuel storage tanks will be designed and

constructed to AS 1940-2004: The storage and handling of flammable and combustible l iquids;

- Management structures (bunding / secondary containment) wil l be installed at all hydrocarbon storage and refuell ing facilities to ensure any spil ls are contained; and

- Spil l response will be provided. Standard hydrocarbon management procedures are expected to effectively mitigate the risk of hydrocarbon spil ls during construction

Migration of hydrocarbon spill to surface water causing contamination

Surface waters: The nearest receptors are Maril lana and Weeli Wolli creeks more than 1 km and 2 km away from WFC3A Extension respectively.

Surface water contamination (and declining health of any riparian vegetation): Given the distance to the nearest receptors, groundwater flow direction and short construction duration, any hydrocarbon spil ls are not expected to migrate to surface waters (or affect any associated terrestrial ecosystems).

Terrestrial ecosystems (riparian vegetation): The nearest receptors are vegetation along Marillana and Weeli Wolli creeks more than 1 km and 2 km away from WFC3A Extension respectively.

Wastes General wastes generated during construction activities

Residential: None, the nearest receptors are the residents of the township of Paraburdoo, more than 6 km away.

Health and amenity: Given the distance to the nearest receptor, impacts to public health or amenity from general wastes are expected to be limited.

General wastes will be managed via the requirements of the Works Approval, Part V Licence L7340/1997/9 and standard operating procedures including: - Sufficient recycling and general waste collection

areas will be established and labelled with the relevant waste type to facil itate the management of waste;

- Recyclable materials will be separated from other waste and recycled wherever possible; and

- Non-recyclable materials will be disposed of at an approved landfil l facility.

Standard waste management procedures are expected to effectively mitigate the risk of general wastes during construction.


Terrestrial ecosystems: Native fauna.

Local increase in feral fauna (scavengers attracted to putrescible wastes) could result in predation and replacement of native fauna.

Category 5: In-pit Waste Fines Storage Facility

Operation of waste fines storage facility

The detailed risk assessment for the operation of the in-pit waste fines storage facility is included in Section 5.2 of the Supporting Document for Works Approval Application Waste Fines Cell 3A Extension - Yandicoogina Mine (Golder, 2020a) provided in Appendix A.

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11 REHABILITATION AND CLOSURE WFC3A Extension will be closed in accordance with the Yandicoogina Mine Closure Plan (RTIO, 2020a). The current closure strategy for the JSE pit involves:

• Removal of pipeline infrastructure and footings.

• Placement of mine waste at the northern end of JSE pit to avoid formation of a permanent pit lake and to buttress the pit walls for long-term stability. Water in the WFC pond displaced by waste backfill will be removed from the pit. This water may be disposed of through groundwater reinjection, pumping to a pit lake that is a groundwater sink or other disposal strategies informed by the water quality.

• Covering the waste fines with a minimum 2 m of inert backfill.

• Removal of surface water diversions along the east and west of the pit, allowing surface water to drain into the pit and over the backfilled waste fines.

• Rehabilitation of the final surface consistent with similar infrastructure areas at the site, which may include contouring and seeding.

The closure plan indicates that the JSE pit void may not be backfilled to surface, which will result in a local low point in the catchment. Surface water runoff may periodically accumulate within the void but is expected to infiltrate and is not expected to form a permanent pit lake. The interactions between the closure landform, surface water and groundwater systems at the Yandi Mine site are complex. The performance of closure measures for JSE pit will depend on the performance of the other pits and mine closure measures implemented upstream and downstream of the facility. Ongoing review and update of the water models is required throughout the life of the operation to improve model predictions, which in turn will inform refinements to the closure strategy.

12 PROJECT COSTS The following information has been provided to support the Total Works Approval Fee calculation of $9 135.00. Table 12-1 Estimated Project Costs

Proposed Costs Description Costs

WFC3A Extension - Approximate Total Cost $3 206 000.00

Cost category More than $3 000 000 but not more than $3 500 000

Table 12-2 Prescribed Premise category related to application

Category Number

Category Description Capacity Range

5 Processing or beneficiation of metallic or non-metallic ore

More than 5 000 000 tones per year

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13 References ANCOLD. (2019). Guidelines on Tailings Dams: Planning, Design, Construction, Operation

and Closure, Australian National Committee on Large Dams. Including 2019 Addendum. ANCOLD.

ANZECC and ARMCANZ. (2000). Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, . Canberra : National Water Quality Management Strategy Paper No. 4 Volume 1 - The Guidelines.

ANZG. (2018). Australian and New Zealand Governments and Australian state and territory governments. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Canberra. Available at http://waterquality.gov.au/anz-guidelines. Accessed May 2020.

DMP. ( 2015). Guide to the preparation of a design report for tailings storage facilities (TSFs). Government of Western Australia.

Golder. (2020a). Supporting Document for Works Approval Application. Perth: Golder. Golder. (2020b). WFC3A Extension Groundwater Model and Water Balance Study - Technical

Memorandum. Perth : Golder . Golder. (2020c). WFC3A Extension - Waste Fines Geochemical Characterisation - Technical

Memorandum. Perth: Golder Associates, September 2020. Golder. (2020d). Groundwater and Surface Water Quality Waste Fines Cell 3A Extension -

Yandicoogina Mine . Perth: Golder Associates. September 2020. Kendrick. (2001). Pilbara 2 (PIL - Fortescue Plains Subregion) in McKenzie NL, May JE and

Mc Kenna S (eds) A Biodiversity Audit of Western Australia's 53 Biogeographic Subregions in 2002. Kensington: Department of Conservation and Land Management.

MWH Australia and Equinox Environmental. (2011). Yandicoogina Junction South West and Oxbow Iron Ore Project: Public Environmental Review: report and appendices. Prepared for Rio Tinto. Perth.

RTIO. (2011). Yandicoogina Junction South West and Oxbow Iron Ore Project - Public Enviornmental Review. Perth: Rio Tinto.

RTIO. (2015). Yandicoogina Iron Ore Project - Revised Proposal Public Enviornmental Review. Perth: Rio Tinto.

RTIO. (2015). Yandicoogina Monitoring and Management Plan. Water Discharge Monitoring and Management. Vegetation and Groundwater Dependent Ecosystems Monitoring and Management. Document No. RTIO-HSE-0171024. Rio Tinto. October 2015.

RTIO. (2017). Groundwater Operating Strategy. Perth.

RTIO. (2018). Yandicoogina Regional Model. Document No. RTIO-PDE-0160576. Perth. RTIO. (2020a). Yandicoogina Mine Closure Plan. Document No. RTIO-HSE-0208486.

Published by Hamersley Iron – Yandi Pty Ltd. April 2020.

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Appendix 1

Part V Supporting Document for Works Approval Application – Waste Fines Cell 3A Extension – Yandicoogina Mine (Golder, 2020a) (provided separately due to size)

works approval supporting document

Documents