APPENDIX B MSP By-product Disposal at Douglas mine site...

APPENDIX B

MSP By-product Disposal at Douglas mine site

Decommissioning Plan

MSP By-product Disposal at Douglas mine site Decommissioning Plan

TABLE OF CONTENTS

1. Introduction 1

2. End Use 1

3. Landform Restoration 1 3.1 Pit Area 1

3.1.1 Backfilling cover and capping 2 3.1.2 Topsoil and subsoil reinstatement 2 3.1.3 Landform stability 3

3.2 Other Areas 3

4. Revegetation 4 4.1 Pit Area 4

4.2 Other Areas 5

5. Rehabilitation Maintenance 6 5.1 Weed Management 6

5.2 Feral Species Management 6

6. Water Management 6 6.1 Surface Water 6

6.2 Groundwater 7

7. Rehabilitation Monitoring 7 7.1 Landform and Soils 7

7.1.1 Landform survey 7 7.1.2 Soil profile assessment 7 7.1.3 Landscape function analysis 8

7.2 Vegetation 9

7.3 Surface Water 10

7.4 Groundwater 10

7.5 Radiation 10

8. Rehabilitation Criteria 10

9. Stakeholder Consultation 12

10. Rehabilitation Plan Review 13


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1. Introduction

This document is supplementary to the application for Works Approval which includes a Rehabilitation Plan and should be read in conjunction with that document. While this document includes all of the additional information required the coverage of some matters in the application is repeated here. These matters include:

the proposal that rehabilitation works be the subject of detailed rehabilitation plan to be approved by the regulatory authorities post grant of a planning permit and Works Approval but prior to commencement of work under such approvals;

justification of reasonable expectation of a stable landform; and

proposed arrangements for a rehabilitation bond.

The information on these matters in the application for Works Approval remains part of the application and the absence from this document should not be taken as any indication that the contents of the application are no longer relevant.

2. End Use

Site rehabilitation requirements are primarily determined by the proposed end use of the site. In this case it is proposed that the end uses of the land are:

biodiversity conservation for the land currently occupied by Pit 23 plus an appropriate buffer; and

agriculture for the remainder of the land.

There is no need to restrict the end use of the areas outside of that currently occupied by the Pit 23 to any greater extent than restrictions that currently apply under the Farming Zone.

As a precautionary measure, it is proposed that the future use of the land in the vicinity of Pit 23 will be restricted to reduce, if not eliminate, the possibility of the integrity of the cap that will be installed over radioactive by-products being compromised by human intervention. It is proposed that the area of Pit 23 and an appropriate buffer surrounding the pit will be the subject of an agreement under Section 173 of the Planning and Environment Act 1987 that will have the effect of restricting the use of the land to biodiversity conservation after rehabilitation is complete.

3. Landform Restoration

3.1. Pit Area

Restoration of the Pit 23 landform consists of the backfilling of the pit and reinstatement of subsoil and topsoil over the area.

It is proposed that the final landform be required to meet the following criteria:

a separation of distance of five metres between radioactive by-products and the finished surface;

a finished surface that at no point is higher than the highest point on the natural surface pre-mining; and

a rehabilitated landform that: o is stable and resistant to wind and water erosion; and


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o as near as is practicable, resembles the surrounding landform with accurate restoration of pre-mining natural drainage lines ensuring the return of surface water flows to their original sub-catchments.

3.1.1. Backfilling cover and capping

At the completion of by-product disposal, Pit 23 will be backfilled with overburden currently stockpiled adjacent to Pits 22 and 23.

Backfilling of the pit will involve the use of a fleet of earthmoving equipment that may include, from time to time depending on the conditions, the following:

excavators;

dozers;

graders;

water trucks;

trucks;

scrapers; and

tractor scoops/carry graders.

The techniques used will be those that have been used for the backfilling of other pits on the Douglas mine site that have been found to produce stable backfill with a very low propensity for subsidence. The overburden has been found to require little compaction beyond earthmoving equipment driving over it and limiting the height of tip heads to four metres or less.

The area will be monitored for subsidence and if any does occur remedial works will be completed.

The estimated quantity of overburden required to backfill the pit is 1,040,000 m3 which is significantly less than that available in stockpiles in the vicinity of pits 22 and 23.

The remaining overburden will be used to rehabilitate of other parts of the Douglas mine site as work under the mining licence and is therefore outside the scope of this plan.

3.1.2. Topsoil and subsoil reinstatement

Subsoil and topsoil, which were removed and stockpiled separately at the commencement of mining, will then be spread using techniques that will include the following:

subsoil and topsoil will be placed in layers with the same or similar thickness as the layers of those soils that were present pre-mining;

where the topsoil has a high clay content that may impede water infiltration, gypsum will be incorporated into its surface;

the use of scrapers and/or tractor scoops for soil placement will be preferred to minimise compaction of the growth medium;

soil placement will commence from the top of slopes to minimise erosion damage by stormwater run-off from bare upslope areas;


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prior to seeding, the soils may be cross ripped to encourage rainfall infiltration and minimise run-off; and

if required, the risk of excessive dust generation will be reduced by, as far as practically possible, scheduling earthmoving activities to periods when moist but not wet soil conditions prevail.

The plans and cross-sections contained in Attachment A show details of the proposed final landform.

3.1.3. Landform stability

The final landform design has been assessed by Jacobs Australia Pty Ltd. The results of this assessment, which included landform evolution modelling, are reported in Iluka Douglas Pit 23, Assessment of the Proposed Surface Design Structure Jacobs Jan 2016. The results of the assessment led Jacobs to conclude that:

minimal erosion is expected; however

there is a potential for gully erosion to penetrate the topsoil/subsoil cover; and

smoothing, reduction in slope angle or incorporation of drainage line in some areas would be effective in reducing the risk of gully formation.

In light of this result, a detailed survey of the surface of the overburden placed in the pit will be conducted and the actual shape subjected to landform evolution modelling to identify areas at risk of gully erosion. This will enable the profile to be modified so that the risk is minimised.

3.2. Other Areas

The areas of land to be rehabilitated in addition to that of Pit 23 include:

the mine access road to the office area;

the haul road from the office area to Pit 23;

the road leading to and from the truck wash;

the area occupied by the office complex and associated vehicle parking area; and

catch drains and bunds directing surface run-off and ponds.

The locations of these features are shown in Attachment B to the application for Works Approval.

The rehabilitation of these areas will be subject to consideration of whether the infrastructure is of value to the use of the land for agriculture as it may be that roads, drains and dams add value to the land.

Decommissioning and rehabilitation works will include:

mobile equipment o thorough cleaning to remove any by-products and other potential sources of

contamination; o testing for the presence of and, if necessary, removal of radioactive materials in

accordance with the requirements of the Radiation Management Plan and Radioactive Waste Management Plan; and

o removal from site;


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fixed equipment (truck wash, buildings etc.) o complete dismantling and thorough washing; o sorting into the following components:

suitable for reuse; suitable for sale; suitable for sale as scrap (recycle); and requiring disposal because of:

- radioactivity (will be disposed of to Pit 23); or - another reason (will be disposed of at a suitably licenced facility off-

site); o removal from site of all items suitable for reuse, sale, recycle and not radioactive; o testing of the area for contamination and, if required, removal of contaminated

soil to Pit 23; o ripping of compacted areas; o placement of subsoil and topsoil;

roads, car parking areas and hardstand areas: o testing of the area for contamination and, if required, removal of contaminated

soil to Pit 23; o ripping of compacted areas; o placement of subsoil and topsoil; and

water diversion bund, channels and ponds: o controlled discharge of water from collection ponds to transfer all water to the

Fresh Water Dam; o reshaping of bunds and filling of channels; o as far as practical return of flow paths to pre-mining sub-catchments; o testing of the area for contamination and, if required, removal of contaminated

soil to Pit 23; o ripping of compacted areas; o placement of subsoil and topsoil

4. Revegetation

4.1. Pit Area

To minimise the risk of erosion a cover crop will be planted at the earliest possible time following topsoil placement and it expected that this will provide an erosion resistant surface within a period of one two months after planting.

Since the desired end use of the area is biodiversity conservation, revegetation will be aimed at the restoration of a selected Ecological Vegetation Community (EVC). The selection of the EVC to be restored will be made in consultation with relevant authorities and other stakeholders. Consideration will be given to the EVCs present on the area prior to European settlement and those existing immediately to the north in the Red Hill State Forest, which include 882 Shallow Sands Woodland and 693 Plains Woodland/Plains Grassy Woodland.

The EVC benchmark published by the Department of Environment, Land , Water and Planning lists the following species as typical in Shallow Sands Woodlands in the Wimmera Bioregion


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Species Common Name Eucalyptus spp. Lemon Scented Gum Eucalyptus Leucoxylon Yellow Gum Allocasurina luehmannii Buloke Callitris gracilis ssp. Murrayensis Slender Cypress-pine Allocasuarina verticillata Drooping Sheoke Calytrix tetragona Common Fringe-myrtle Acacia pycnantha Golden Wattle Hibbertia stricta s.l. Upright Guinea-flower Eutaxia microphylla Common Eutaxia Pultenaea hispidula Rusty Bush-pea Astroloma humifusum Cranberry Heath Microseris scapigera spp. agg. Yam Daisy Acaena echinata Sheep's Burr Daucus glochidiatus Australian Carrot Hydrocotyle laxiflora Stinking Pennywort Drosera whittakeri ssp. Aberrans Scented Sundew Austrostipa mollis Supple Spear-grass Schoenus apogon Common Bog-sedge Neurachne alopecuroidea Fox-tail Mulga-grass Lomandra nana Dwarf Mat-rush Arthropodium strictum s.l. Chocolate Lily Centrolepis strigosa ssp. strigosa Hairy Centrolepis Centrolepis aristata Pointed Centrolepis Aphelia pumilio Dwarf Aphelia Thysanotus patersonii Twining Fringe-lily

Species will be selected from those listed above to suit the particular conditions.

Planting will be by a combination of direct seeding, cuttings and tube stock with, to the extent that it is practical, seed and cuttings being collected locally.

4.2. Other Areas

Revegetation will initially be to establish pasture. Fertiliser and gypsum will be applied to the topsoil in line with requirements determined by soil and plant analysis and known regional crop and soil requirements.

Crop or pasture species will be sown mechanically into the restored landform using agricultural machinery typically used in region. Leguminous crops may be incorporated into the soil to enhance nitrogen levels.

Grazing of re-established pastures will not be permitted until it has been demonstrated that grazing will not cause plants to be pulled from the soil to create clodding of restored soil surfaces.


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5. Rehabilitation Maintenance

Rehabilitated areas will be assessed against performance indicators (see Section 8) and regularly inspected for the following:

evidence of any erosion or sedimentation;

success of initial cover establishment;

weed infestation;

integrity of banks, diversion drains and catchment dams; and

general stability.

Where rehabilitation criteria have not been met, maintenance works will be undertaken and may include:

re-seeding and, where necessary, re-topsoiling;

use of materials such as composted mulch in areas with poor vegetation establishment;

installation of tree guards or construction of temporary fencing to exclude fauna species; and

replacement of drainage controls if they are found to be inadequate or compromised by vegetation.

5.1. Weed management

The presence of weed species has the potential to have a major impact on revegetation and regeneration outcomes including the biodiversity value of rehabilitated areas. Weeds will be managed by the following means:

washing equipment prior to entry to the rehabilitated area;

herbicide spraying of weeds from topsoil stockpiles prior to placement;

inspections of revegetated areas to identify potential weed infestations; and

Spot-spraying of identified weed infestations within revegetated areas.

5.2. Feral species management

A feral animal control strategy will be implemented to contain the spread of weeds and other detrimental impacts on rehabilitation areas by feral animals.

6. Water Management

6.1. Surface Water

The proposed surface water management plan is detailed in Section 6.5 of the application for Works Approval and Appendix C to Response to Notice to Supply Further Information Non Hydrogeological or Groundwater Related Matters but may be summarised as follows:

risks to surface waters are related to the potential for run-off from disturbed areas;

the standards to be met are specified in the State Environment Protection Policy (Waters of Victoria);

the proposed mitigation measures are aimed at the prevention of uncontrolled discharge of run-off from disturbed areas by interception, diversion and direction to the Fresh Water Dam;


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the adequacy of the existing facilities during by-product disposal is demonstrated by the fact that no uncontrolled discharge of water from disturbed areas associated with by-product disposal has occurred during periods of high rainfall and significant rainfall events; and

a commitment to undertake further , detailed modelling and review and, if necessary, upgrading of the system prior the pit being backfilled.

The interception, diversion and direction system will remain in place while the landform is restored and the area revegetated. During this time uncontrolled discharge of run-off from the area will be prevented.

The quality of run-off from the area will be monitored to determine when that quality is such that the run-off can be returned to its original catchment without adverse impact.

6.2. Groundwater

During the rehabilitation phase the potential impact on groundwater will be reduced as the infiltration rate reduces. During this period of time, implementation of the Groundwater Monitoring and Management Plan, detailed elsewhere, will continue therefore any impacts on groundwater will be detected and, if required, the hydrogeological model will be reviewed to determine the likelihood of adverse impacts in the future.

7. Rehabilitation Monitoring

Regular monitoring of the rehabilitated areas by suitably qualified and experienced personnel will be performed during the initial vegetation establishment period and beyond to demonstrate whether:

a sustainable and stable landform has been provided; and

the objectives of the rehabilitation are being achieved.

In addition to the rehabilitated areas, analogue sites will be established and monitored to enable comparisons to be made.

The various aspects of the rehabilitation monitoring program are described below.

7.1. Landform and soils

7.1.1. Landform survey

Detailed topographic surveys of restored areas to enable comparison with the area pre-mining landform

In addition, monitoring points will be established in the Pit 23 area and resurveyed on an annual basis to detect any changes due to movement or subsidence.

7.1.2. Soil profile assessment

In the first year of rehabilitation the soil profile will be examined by excavation of soil pits or soil augering and physical and chemical soil characteristics assessed. This will enable any adverse characteristics to be rectified in a timely manner.

Final assessment of the rehabilitated soil profile will be performed by a suitably experienced soil scientist, several years after vegetation establishment so that plant root distribution through the profile may be assessed.


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Soil profile assessment will involve excavation of pits or drilling of auger holes until overburden or natural ground is encountered. The soil profile will be recorded with all soil horizons described and their location within the profile measured. Soil profiles will be assessed in accordance with the Australian Soil and Land Survey Handbook.

In addition to field observations, soil samples will subjected to laboratory analyses for, at least the following:

pH (1:5);

electrical conductivity;

exchangeable cations, Ca, Mg, Na, K and cation exchange capacity;

exchangeable sodium percentage;

sulphate;

chloride; and

organic carbon.

These results will be used in conjunction with field observations to calculate:

calcium:magnesium ratio; and

plant available water content.

Results obtained will be compared with those obtained from an analogue site

7.1.3. Landscape function analysis

Landscape Function Analysis (LFA) enables assessment of the long term sustainability of rehabilitated landforms and consists for the following steps:

landscape stratification collection of a continuous data set along transects oriented down slope (the dominant direction of resource mobility) with identification and measurement of zones where resources (e.g. topsoil, organic matter, seeds, water etc.) are either shedding or accumulating; and

soil surface condition classification landscape zones are assessed by ten soil surface features against established criteria. The soil surface conditions assessed are listed in the following table.


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Soil Surface Condition Assessment

Indicator Interpretation Basal cover of perennial plants Assesses vulnerability to rain splash erosion

Litter cover, origin and degree of decomposition Assesses contribution to below-ground organs to nutrient availability

Cryptogam cover An indicator of surface stability, resistance to erosion and nutrient availability

Crust brokenness Assesses loose crusted material available for wind ablation or water erosion Erosion features Assesses the nature and severity of current soil erosion features Deposited materials Recognises mobile soil deposits

Microtopography Assesses surface roughness for water infiltration, flow disruption and seed lodgement Surface resistance to erosion Assesses likelihood of soil detachment by mechanical disturbance Slake test Assesses soil stability/depressiveness when wet

The assessment results will be used to derive indices of soil stability, soil infiltration capacity and nutrient cycling. Monitoring of these indices enables the observation of trends indicating whether the landform function is sustainable (accumulating resources) or likely to fail (losing resources).

Landscape stratification and soil condition assessments will be conducted annually and continued until sustainable landscape function has been demonstrated

7.2. Vegetation

The following techniques will be utilised for vegetation monitoring:

quadrat surveys. Quadrats, of a number and size determined in consultation with rehabilitation specialists, will be established and surveyed to determine the following: o percentage foliage cover; o life stage (i.e. dormant, flowering, seedling); o life form (i.e. tree, shrub, grass); and o overall vegetation association;

transect surveys transects will be installed along the central axes of quadrats and counts will be made of all perennial species that occur within two meres either side of the transects;

photographic monitoring points. Photo-frames will be aligned along the transects;

control sites will be established to allow comparison of rehabilitated areas and undisturbed sites under the same seasonal conditions.

Vegetation surveys as described above will be conducted annually for the first three years following planting after which monitoring frequency will be reviewed and may be decreased with the approval of the relevant authorities.


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7.3. Surface Water

Following establishment of vegetation but before the surface water management facilities allow uncontrolled discharge samples of run-off from rehabilitated areas will be collected during and after rainfall events that result in such run-off with measurements of the following being made:

pH

electrical conductivity

turbidity

total suspended solids

total nitrogen

total phosphorus

7.4. Groundwater

The need for ongoing groundwater monitoring will be determined from monitoring results and hydrogeological model predictions as part of the Groundwater Monitoring and Management Program. It is expected that by the time rehabilitation works commence the data collected and validation of the numerical groundwater model will be such that assessments of potential future impacts will be able to be made with a high degree of confidence.

7.5. Radiation

Gamma radiation levels and radon concentrations in rehabilitated areas will be measured:

Following completion of topsoil reinstatement; and

One year after the first measurement.

The results will be used to calculate the dose received by the critical receptor (the person most affected)

8. Rehabilitation Criteria

In order to determine success of rehabilitation or the need for remedial works, it is necessary to establish:

the objectives of rehabilitation:

performance criteria; and

the means by which performance is to be measured against such criteria.

This information is contained in the following table.


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Rehabilitation Criteria

Objective Rehabilitation Criteria Evidence

Landform stability

Topography of landform stable Level at all points within 0.5 m of design levels

Post closure survey of landform shape

Repeated surveys of monitoring points

Landform stable in the longer term

Design landform shown to be erosion resistant Landform evolution modelling

No slope >10% variance from landform design

Post closure survey of landform shape

Erosion rates comparable with pre-mining landscape as vegetation establishes

Landscape function analysis, rehabilitated and analogue sites

Ecosystem establishment

Adequate soil profile Topsoil and subsoil profile at least equivalent to pre-mining conditions

Soil profile assessment comparable to analogue sites

Resilient and self-sustaining ecosystem.

Soil function re-established and comparable with analogue sites Landscape function analysis

Restoration of selected EVC

10 year revegetation survival target as defined in Native Vegetation - Revegetation Planting Standards, Guidelines for establishing native vegetation for net gain accounting, DSE 2006, or other relevant guideline

Vegetation surveys

Surface Water

No adverse impact on beneficial uses of surface water

All run-off to be in compliance with State Environment protection Policy - Waters of Victoria

Sampling and analysis of run-off

Agricultural productivity Agricultural productivity returned to pre-mining level or better

Pasture growth rates equal to that of analogue sites Pasture growth measurements

Public Safety

Land safe for access by members of the public

Infrastructure removed in accordance with agreed plan

Audit/inspection by regulatory authorities

Surface radiation levels below that prescribed under the Radiation Act 2005

Gamma and radon measurements


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9. Stakeholder Consultation

Prior to the commencement of rehabilitation works consultation with stakeholders will be conducted to inform of the intentions of the rehabilitation works proposed and to provide stakeholders with the opportunity to express their views in regard to the plan.

The stakeholders concerned include the following:

owners and residents of neighbouring properties;

the regulatory authorities, expected to include: o the Horsham Rural City Council; o the Victorian Environment Protection Authority; and o the Department of Health and Human Services; and

other government departments and agencies with relevant environmental responsibilities and or expertise, that may include: o Wimmera and Glenelg Hopkins Catchment Management Authorities; o Department of Environment, Land, Water and Planning (Biodiversity); and o Department of Economic Development, Jobs, Transport and Resources (Earth

Resources).

Particular issues that should be the subject of consultation include:

proposed program and schedule of work;

the adequacy of measures to protect surface waters;

selection of appropriate EVC;

rehabilitation criteria; and

rehabilitation monitoring program including performance reporting.

The process for consultation will be as follows:

Iluka will prepare a proposal addressing each of the above issues and provide details to all stakeholders;

consultation with owners and occupiers of neighbouring properties will, in the first instance, be conducted by Iluka personnel on a one on one or small group basis;

presentation of the proposal to a meeting of regulatory authorities and other government departments and agencies;

regulatory authorities to provide feedback on proposal to Iluka;

Iluka to provide details of feedback received from all stakeholders and responses to that feedback in the form of modifications to the proposal or reasons why the feedback did not lead to changes; and

all stakeholders invited to provide views on the proposal as modified to the regulatory authorities.


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10. Rehabilitation Plan Review

The Rehabilitation Plan will be subject to a review at the completion of by-product disposal to take account of:

Additional information gathered in the course of the operational phase;

Developments in knowledge and technology that have occurred in the intervening period between commencement and completion of operations.

Following this review the plan will be the subject of consultation as described above and may be further modified as a result.

During implementation of the plan, reviews that utilise the results of rehabilitation monitoring will be conducted at least every two years and modifications may be made, subject to the approval of the regulatory authorities.


ATTACHMENT A

Plans and Cross-sections of Final Landform

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APPENDIX B MSP By-product Disposal at Douglas mine site...

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