Rev Document Number Author Approver / BFO Approver Signature Issue Date Review Date Page 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 1 of 17
TABLE OF CONTENTS 1 Purpose and scope...3 1.1 Background...3 1.1.1 Soils of the project area...3 1.1.2 Vegetation and weeds...7 1.1.3 Fugitive Dust control...11 1.1.4 Erosion control...11 1.2 Legislative requirements...11 1.2.1 Protection Act...11 1.2.2 Mining Proposal...12 1.3 Research and Development...15 2 Objectives and Targets...15 3 Management Actions...15 4 Definitions...16 5 Abbreviations...17 6 References...17 7 Review...17 TABLES Table 2-1: Clearing and soil management objectives and targets...15 Table 3-1: Clearing and soil management risks and associated management actions...16 Table 4-1: Definitions...16 Table 5-1: Short titles and acronyms...17 Table 6-1: Reference Documents...17 FIGURES Figure 1: Soil Mapping Units (SMU) for the Roy Hill Mine Project Area...5 Figure 2: Soil Management Areas (SMA) for the Roy Hill Mine Project Area...6 Figure 3: Vegetation Mapping of the Roy Hill Mine project area...8 Figure 4: Weed mapping of Roy Hill Mine project area...9 Figure 5: Ministerial Statement 824 (Stage 1) and MS 829 (Stage 2) boundaries within the Roy Hill Project area...14 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 2 of 17
1 Purpose and scope This plan outlines the standards and guidelines for soil (including topsoil and subsoil) stripping and handling and rehabilitation at the Roy Hill (RH) Mine. This plan is applicable to the RH Mine project area. The aims of this plan are to: 1. Provide background and support to the latest best practices and methods for maximising topsoil recovery, topsoil storage and soil viability to maximise rehabilitation success; and 2. Outline the specific standards, regulations or legislation that must be adhered to and inform the procedures associated with land disturbance and rehabilitation. This document is to provide background and support information to the Clearing and Soil Management Procedure (OP-PRO-00187), and is applicable to all clearing works carried out within the RH Mine project area. This includes all work carried out by RH and RH direct contractors at the Mine. As research and industry knowledge is gained, the management and associated procedures can be updated to reflect the new best practices. 1.1 Background This section will provide some context and rationale of some management actions outlined in this Management Plan. 1.1.1 Soils of the project area Arid zones, including the Pilbara, are often composed of poor quality soils with very little organic matter. Seeds accumulate in the top layer of the soil (topsoil) and this is a vital resource for rehabilitation activities. Topsoil is a finite resource and it is therefore important to take care when collecting and managing this resource in order to maximise rehabilitation success. The existing topsoil resources across the RH Mine project area have been mapped and characterised by Soilwater Consultants (SWC 2010). Further topsoil, subsoil and waste investigation work was then completed by Edith Cowan University in 2013 and 2014 (ECU 2014) and Landloch in 2015. RH topsoil exhibits optimal characteristics for stripping, stockpiling and re-spreading due to the friable gravelly nature; however, the finer soil matrix is microstructurally unstable and rapidly breaks down to bull-dust (very fine mobile soil particles). Following repeated disturbance, this type of soil has a tendency to hardset. Therefore, minimal handling and disturbance techniques should be implemented on topsoils. Three soil mapping units (SMU) have been mapped across the project area (Error! Reference source not found.) and these have been categorised into two soil management areas (SMA) (Error! Reference source not found.). The type of SMA present informs the management of these soils. The SMA present are described as follows: SMA 1: Mid-upper slope and ridgeline (SMU 1 & 2) supporting predominately hummock grasses (Triodia spp.) (Plate 1-1); SMA 2: Low-slope and plain (SMU 3) support predominately open Mulga woodland complex (Plate 1-2). The surface soil across these areas varies from shallow skeletal soil on rocky uplands (SMA 1) to gravelly loams on lower slopes to deep alluvium in valleys and drainage lines (SMA 2). Topsoil sourced from each of these landforms is likely to vary markedly in terms of the volume of topsoil available, the density of seed, and the composition and diversity of species contained within the topsoil. Species composition of the soil seed bank is 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 3 of 17
also likely to vary across different soil/landforms (reflecting patterns in the above-ground vegetation), although wind- and water-dispersed seed could be widely represented across the study area. Although not likely to contain seed, subsoils at the RH Mine were identified to potentially be used either as a growth medium or bulking medium on the surface of flat rehabilitated landforms (i.e. backfilled mine pits) (SWC 2010). This subsoil may have other benefits for plant growth, especially the deeper loams found on slopes, wash plains and alluvial flats. Subsoil is largely not available in SMA 1 but up to 3 m of subsoil is available in some areas within SMA 2. A Soil and Waste Characterisation study conducted by Landloch (Landloch, 2016) determined that subsoil, alluvial and detrital waste streams could all be used as a growth medium with the addition of fertiliser. The study also demonstrated that the highly erodible nature of the subsoil and the abundance of alluvials and detritals, it is recommended that the subsoil material is not used on the surface of any waste dump or pit backfill area. The identification of which SMA type prior to an area being cleared is important so SMA 1 and SMA 2 topsoil can be stockpiled separately and used on rehabilitation areas from the same SMA type.. Plate 1-1 Skeleton soils in SMA 1 Plate 1-2 Deeper surficial soils in SMA 2 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 4 of 17
Figure 1: Soil Mapping Units (SMU) for the Roy Hill Mine Project Area 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 5 of 17
Figure 2: Soil Management Areas (SMA) for the Roy Hill Mine Project Area 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 6 of 17
1.1.2 Vegetation and weeds Vegetation mapping across the RH project area was completed by Ecologia (2009; Error! Reference source not found.). The ridgeline and mid to upper-slope portions of the Chichester Range, corresponding to SMU 1 and SMU 2 (SMA 1), support a sparse to open low shrubs over Triodia sp. hummock grassland (Plate 1-3). With increasing soil depths downslope, the vegetation grades into an Acacia aneura (Mulga) complex low woodland and shrubland (Plate 1-4), SMU 3 (SMA 2). Riparian communities (along drainage lines) and Mulga woodlands are in relatively poor condition due to historical and recent pastoral activity. As a result several weed species, particularly *Cenchrus ciliaris (Buffel grass), are established in the project area, forming a dominant component of the understory along creek banks due to grazing pressure. Buffel grass is also a dominant species along water-gaining sites of the RH project area (Hussey et al. 2007; Ecologia 2009). Management of this weed and others during topsoil recovery, transportation and stockpiling is required under Ministerial Statement (MS) 824 and 829 (see Section 1.2.1). Additional measures where *Parkinsonia aculeata (Parkinsonia) is present will also be taken to prevent the spread of this major weed species. By contrast, the hummock grassland steppes of the mid-upper slopes and ridgelines are in good to very good condition with a much lower level of weed invasion and mostly intact understory strata. 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 7 of 17
Figure 3: Vegetation Mapping of the Roy Hill Mine project area 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 8 of 17
Figure 4: Weed mapping of Roy Hill Mine project area 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 9 of 17
Plate 1-3 Triodia spp. hummock grassland Plate 1-4 Acacia aneura (Mulga) complex low woodland and shrubland 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 10 of 17
1.1.3 Fugitive Dust control Dust released during land clearing and soil re-location may represent a significant loss of soil resources, particularly with regards to topsoil material. Traditional techniques to control dust include using water to stabilise the soil materials. However, all surface soils at RH have a high hard setting potential and will likely structurally degrade if water is continuously added to them for dust suppression (SWC 2010). To reduce sediment losses from stockpiled topsoils RH will instigate monitoring and trials using alternative methods of dust suppression that do not require water. For example, cover crops and chemical stabilizing agents (DustEx, Glu-on etc) have been effectively used in high wind coastal environments (e.g. mineral sands tenements) for many years to stabilise topsoil stockpiles. RH has recently received approval to use saline water on select areas at the mine site. The requirements are outlined in OEMP - Saline Water for Dust Suppression Management Plan (OP-PLN-00072). Saline water shall not be sprayed onto topsoil stockpiles. RH will update this document in accordance with the outcomes of the dust management strategies, monitoring and trials listed above for the purposes of continually improving the handling and utilisation procedures for topsoil materials. 1.1.4 Erosion control Sediment loss from topsoil stockpiles through surface water erosion can constitute a significant loss of soil resources. To reduce the potential for surface water erosion to occur, topsoil stockpiles need to be placed outside known drainage lines and flood areas. This includes areas where topsoil can be windrowed (i.e. water pipelines and other linear infrastructure). 1.2 Legislative requirements Roy Hill has commitments and legal obligations regarding rehabilitation and topsoil management that have been addressed in this document. Commitments made in referral documentation regarding topsoil and subsoil management have also been included. 1.2.1 Protection Act The RH Mine (Stages 1 and 2) was referred and assessed under Part IV of the Protection Act 1986 (EP Act). The mine was approved with Conditions under Ministerial Statement (MS) 824 and MS 829. Condition 10 of MS 824 and Condition 11 of MS 829 outline requirements for rehabilitation and conditions regarding weed coverage on site. These conditions apply to the management of soil, such as during soil recovery, transportation and stockpiling, as RH has to ensure topsoil to be used for rehabilitation will not increase the number of weeds. To ensure compliance with the MS 824 and MS 829, RHIO will undertake: Pre-clearance weed surveys to demarcate weed infested areas and segregate topsoil of these low quality areas from optimal stockpiles by a distance of no less than 30 m or treating as waste; and Monitoring and trials through Life of Mine (LOM) to identify appropriate storage, treatment and if reuse of weed infested (low quality) topsoils is possible, considering they are likely to comprise a significant proportion of topsoil volumes. 1.2.1.1 Ministerial Statement 824 Condition 10 10-1 The proponent shall undertake rehabilitation to achieve the following outcomes: 1. The waste rock dump and waste fines storage facilities shall be non-polluting and shall be constructed so that their final shape, stability, surface draining, resistance to erosion and ability to support local native vegetation are comparable to natural landforms in the area. 2. The mine pits shall be backfilled within overburden to the original ground level. 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 11 of 17
3. The waste rock dump, waste fines storage facilities and other areas disturbed through implementation of the proposal, shall be progressively rehabilitated with vegetation composed of native plant species of local provenance (as agreed by the CEO in consultation with the Department of and Conservation). 4. The percentage cover of living vegetation in all rehabilitation areas shall be comparable with that of nearby land which has not been disturbed during implementation of the proposal. 5. No new species of weeds (including both declared weeds and environmental weeds) shall be introduced into the area as a result of the implementation of the proposal. 6. The coverage of weeds (including both declared weeds and environmental weeds) within the rehabilitation areas shall be no greater than 10%. 10-2 Rehabilitation activities shall continue as necessary until such time as the requirements of Condition 10-1 are met, and are demonstrated by inspections of the CEO and the Chief Executive Officer of the Department of Mines and Petroleum. Error! Reference source not found. defines the boundaries applicable to MS 824. 1.2.1.2 Ministerial Statement 829 Condition 11 11-1 The proponent shall undertake rehabilitation to achieve the following outcomes: 1. The waste fines storage facilities and evaporation pond shall be non-polluting and shall be constructed so that their final shape, stability, surface drainage, resistance to erosion and ability to support local native vegetation are comparable to natural landforms within the local area. 2. The mine pits shall be backfilled to above the pre-mining water table and contoured to blend in with the natural topography. 3. The waste fines storage facilities, evaporation pond and other areas disturbed through implementation of the proposal, shall be progressively rehabilitated with vegetation composed of native plant species of local provenance (as agreed by the CEO in consultation with the Department of and Conservation). 4. The percentage cover of living vegetation in all rehabilitation areas shall be comparable with that of nearby land which has not been disturbed during implementation of the proposal. 5. No new species of weeds (including both declared weeds and environmental weeds) shall be introduced into the area as a result of the implementation of the proposal. 6. The coverage of weeds (including both declared weeds and environmental weeds) within the rehabilitation areas shall no exceed that identified in baseline monitoring undertaken prior to commencement of operation, or exceed that existent on comparable, nearby land which has not been disturbed during implementation of the proposal, whichever is less. 11-2 Rehabilitation activities shall continue until such time as the requirements of Condition 11-1 are demonstrated by inspection and reports to be met, for a minimum of five years to the satisfaction of the CEO on advice of the Department of and Conservation and the Department of Mines and Petroleum. Figure 5 defines the boundaries applicable to MS 829. 1.2.2 Mining Proposal The following commitments are outlined in the Roy Hill Iron Ore Mining Proposal Years 1 to 5 M46/518 & M46/519 Part A & B and the 2012 RH Preliminary Rehabilitation and Closure Plan (PRCP): Following approval, all topsoil being removed ahead of mining operations and separately stockpiles for replacement after backfilling and/or completion of operations; and A rehabilitation consultant will be engaged to provide technical advice on topsoil management and progressive rehabilitation (completed). 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 12 of 17
The 2012 PRCP has been superseded by the 2015 Mine Closure Plan (MCP). The mine closure plan further commits to the below: Further studies are proposed to confirm topsoil and sub soil values and to inform management of this material to achieve best possible rehabilitation outcomes. Growth trials on waste to determine use as growth medium and nutrient deficiencies A number of specific commitments regarding topsoil have been approved and these commitments, along with the outcomes from the research and trials, are included in the procedures detailed in Clearing and Soil Management Procedure (OP-PRO-00187). 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 13 of 17
Figure 5: Ministerial Statement 824 (Stage 1) and MS 829 (Stage 2) boundaries within the Roy Hill Project area 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 14 of 17
1.3 Research and Development To inform future practises and to feed into adaptive management systems designed to ensure a continual improvement in management of topsoil quality, RH will undertake: Regular field surveys of each topsoil stockpile using the field recording sheet (OP-FRM-00119 OEMP Stockpile Inspection Form); Ongoing monitoring and trials will be undertaken during LOM into handling and storage techniques for topsoils, including stabilising and weed treatments; Further studies on the properties of the topsoil seed bank; and Input of data into a centralised database linked with geographical information system (GIS) coverage To begin this research and development, RH approached Edith Cowen University (ECU) in 2013 to complete a study of topsoil of the proposed mining area to enable an evaluation of its potential to assist with post-mining restoration. To further investigate the topsoil properties, a six-month germination trial (July 2013 to January 2014) using topsoil and subsoil collected in the field, and an analysis of soil characteristics began in 2013. RH has undertaken numerous internal topsoil studies since (2014 and 2015) to identify areas across the mine site that contain viable seed store within the topsoil. This was achieved through the implementation of two monitoring programs (OP-REP-00197 and OP-REP-00031), one to identify flora species that have germinated within rehabilitated areas and the other to identify flora species which have germinated from a number of topsoil stockpiles on-site. Quadrats and transects were established and monitored at these locations with flora species presence (native and introduced) and plant count recorded at each site. Analysis of the data collected provided RH with a clearer understanding of species composition (presence of keystone), plant densities, weed composition and differences in SMA types within the topsoil seed bank. The results of these studies have been fed into the recommendations in this document and trials and tests will be further developed, to assist with methods to improve rehabilitation at Roy Hill. 2 Objectives and Targets The RH environmental objectives and targets relating to clearing and soil management are outlined in Error! Reference source not found. below. Table 2-1: Clearing and soil management objectives and targets Objectives Targets To minimise adverse impacts on the abundance, species diversity, geographic distribution and productivity of vegetation communities To minimise the spread and proliferation of declared and environmental weeds To conserve topsoil for use in rehabilitation To maintain ecological integrity and seed viability in stripped topsoil and cleared vegetation for use in rehabilitation To maximum use of soil in rehabilitation, reuse of soil within short timeframes and minimise cost of soil rehandling All clearing activities to occur within GDP approved areas Collection and reuse or storage of topsoil Weed infested topsoil reserves are treated as waste or segregated from non-infected resources. 3 Management Actions Risks identified as a threat to achieving the targets and objectives have been identified for the project. Those risks relating specifically to clearing and soil management, particularly topsoil and rehabilitation, are outlined 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 15 of 17
in Error! Reference source not found. along with the documents which reference the management actions to mitigate these risks. Table 3-1: Clearing and soil management risks and associated management actions Risk Unauthorised disturbance or breach of clearing boundary Loss of rehabilitation materials (soil, vegetation, mulch) Soil Management Area (SMA) contamination Reduction in topsoil viability Spread or introduction of weeds Erosion of stockpiles Impact on vegetation outside GDP boundary Incorrect vegetation type present after revegetation Fugitive dust control Action Refer to Ground Disturbance Permit Procedure (OP-PRO-00193) Refer to Learning Management System (Success Factors for employees, and DOTS for contractors) Refer to Ground Disturbance Permit Procedure (OP-PRO-00193) Refer to Rehabilitation Management Procedure (OP-PRO-0010) 4 Definitions Table 4-1: Definitions Term Growth medium Seed Bank Soil Management Area Definition Soil required for plant growth. Can be topsoil or subsoil or other suitable waste. The seeds which build up in the upper layers of soil and can be used for rehabilitation of plant species. The type of soil characterised across the Roy Hill project, considering volume of topsoil available, the density of seed, and the composition and diversity of species contained within the topsoil. The management of each SMA may different according to the soil properties. Soil resource type Subsoil Topsoil Type of soil or cleared substrate, e.g. vegetation, topsoil and subsoil. Soil that is located beneath topsoil and is a source of bulk material for the rehabilitation. This zone is typically referred to as the B horizon. This material is commonly used as a growth medium or bulking material for topsoil during rehabilitation. The top layer (100-200 mm) of the soil profile that is the most important for rehabilitation. It contains a seed bank and has a higher nutrient content than the layers below. 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 16 of 17
5 Abbreviations Table 5-1: Short titles and acronyms Abbreviation Definition EP Act Protection Act 1986 GDA Ground Disturbance Application GDP GIS LOM MS RH SMA SMU Ground Disturbance Permit Geographical Information System Life of Mine Ministerial Statement Roy Hill Soil Management Area Soil Mapping Unit 6 References Table 6-1: Reference Documents Document number/ Reference OP-PRO-00193 OP-PRO-00187 Title Roy Hill Ground Disturbance Permit Procedure Roy Hill Clearing and Soil Management Procedure 100RH-H413-1000-EN-REP-0002 Topsoil Investigation for Roy Hill Project Area Final Report (ECU, 2014) OP-FRM-00119 OP-PLN-00044 OP-PRO-00101 Ecologia 2009 Soil and Water Consultants (SWC) 2010 OEMP-Stockpile Inspection Form Mine Rehabilitation Plan Rehabilitation Management Procedure Roy Hill 1 Vegetation and Flora Assessment Roy Hill Soil and Waste Characterisation Landloch (2016) Soil and Waste Characterisation Project OP-REP-00031 Rehabilitation Vegetation Monitoring Report Sept 2014 OP-REP-00197 Topsoil Stockpile Vegetation Monitoring Report 7 Review Reviews are to examine the appropriateness of this Plan, taking into consideration corporate, system and compliance requirement changes since the last review was undertaken. Also, as more research and industry knowledge is gained, the management and procedures outlined in this document shall be updated to reflect the current best practices applicable to the region and specific area. 1 OP-PLN-00051 N Rubbo Manager and Approvals 02/12/2016 02/12/2017 17 of 17