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Alligator Rivers Region Technical CommitteeMeeting 33

4 – 6 November 2014

Meeting Summary

This document is a detailed summary record of the scientific information presented to, and the discussion and actions arising from, the 33rd meeting of the Alligator Rivers Region Technical Committee. ARRTC meeting summaries are used to inform planning and prioritisation of scientific research activities.

Alligator Rivers Region Technical Committee - Meeting 33 Agenda

Wednesday 5 November 2014 (0900 -1700)1. PRELIMINARY SESSION (CHAIR)

1.1 Welcome and Introductions1.2 Apologies and Observers1.3 Correspondence1.4 Conflict of Interest Declarations1.5 Governance

2. ARRTC31 OUTCOMES (CHAIR)2.1 ARRTC32 - Summary Record2.2 ARRTC32 - Actions Arising

3. STAKEHOLDER REPORTS3.1 Uranium Equities Ltd - Nabarlek (Mr Williamson)3.2 Environment NGOs (Dr Mudd)3.3 NT Department of Mines and Energy (Ms Strohmayr)3.4 Northern Land Council (Mr Thompson)3.5 A/g Supervising Scientist (including Monitoring) (Mr Tayler)3.6 Parks Australia (South Alligator Valley) (Ms Morgan)3.7 Gundjeihmi Aboriginal Corporation (Mr O’Brien)

4 RESEARCH STATUS4.1 ITWC update (including schedule of key activities, closure criteria and knowledge needs) (Dr Sinclair/Ms Iles/Ms Paulka)4.2 eriss 2013-14 research outcomes and priorities (Dr van Dam)4.3 Research addressing Key Knowledge Needs during operational and rehabilitation/closure phases (ERA/eriss)

Activity Presentations Presenter/sRANGERRisk assessment for closure

Ecological risk assessment & ecological processes Dr Bartolo (eriss)

Pit#3 tails Toxicity of ammonia to local freshwater biota Dr Harford (eriss)Water quality closure criteria (solutes, suspended sediment) for surface waters

Dr Humphrey (eriss)

Groundwater solute transport modelling: Response to stakeholder questions

Dr Sigda (Intera for ERA)

Pit 1 final tailings level, bulk backfill and landform

Toxicity and guideline values for uranium in billabong sediments Dr Harford (eriss)Erosion studies on the trial landform Dr Saynor (eriss)Landform evolution modelling for the trial landform Mr Lowry (eriss)

Pit#1 & 3 capping and final landform

Radon exhalation from a rehabilitated landform Dr Bollhoefer(eriss)

Environmental media concentration limits for terrestrial wildlife Dr Bollhoefer(eriss)

JABILUKARehabilitation Progress on UAV R&D and Jabiluka revegetation Dr Bartolo, Dr Lu (ERA)

Thursday, 6 November 2014 (0900 - 1700)5. STRATEGIC OVERVIEW

5.1 PresentationsSeepage water quality investigations to the west of the TSF Ms Kate Turner (SS SAP)Aquatic ecosystem establishment – revised direction and workplan Dr Amy George (eriss)Update on research and monitoring for Ranger revegetation Dr Chris Humphrey (eriss), Dr Ping Lu (ERA)

5.2 Summary Discussion (Chair to lead)6. OTHER BUSINESS7. NEXT MEETING

ARRTC33 Meeting Summary of 21

Attendance MembersDr Simon Barry Independent Scientific Member and ChairpersonMs Jane Coram (by video linkup) Independent Scientific MemberProf Paul Boon Independent Scientific MemberProf David Mulligan Independent Scientific MemberDr Jenny Stauber Independent Scientific MemberDr Gavin Mudd Environment NGO stakeholder memberDr Greg Sinclair Energy Resources of Australia Ltd Mr Adam Thompson Northern Land CouncilMs Sally-Ann Strohmayr NT Department of Mines and EnergyMr Keith Tayler A/g Supervising ScientistApologiesMr Andrew JohnstonMr Gavin Williamson

Independent Scientific memberUranium Equities Limited

Mr Justin O’Brien Permanent Observer - Gundjeihmi Aboriginal CorporationMs Anna Morgan Parks Australia Division

Presenters/Observers Dr Geoff PickupMr Phil Hausler

Consulting GeomorphologistNT Department of Mines and Energy

Ms Melanie Impey Permanent Observer - Gundjeihmi Aboriginal CorporationMs Shelly Iles Energy Resources of Australia Ltd Dr Ping Lu Energy Resources of Australia Ltd Dr Graeme Esslemont Energy Resources of Australia LtdDr Stephen Booth Energy Resources of Australia LtdMs Kyla Valdron-Clark Energy Resources of Australia LtdDr John Sigda Intera Inc (per ERA)Mr Jean-Pierre Issaverdis Parks Australia DivisionMs Ally Sinclair Office of the Supervising ScientistMs Sarah Marshall Office of the Supervising ScientistMr John Miller Office of the Supervising ScientistDr Rick van Dam Environmental Research Institute of the Supervising ScientistDr Andrew Harford Environmental Research Institute of the Supervising ScientistDr Andreas Bollhöfer Environmental Research Institute of the Supervising ScientistDr Chris Humphrey Environmental Research Institute of the Supervising ScientistDr Amy George Environmental Research Institute of the Supervising ScientistDr Renée Bartolo Environmental Research Institute of the Supervising ScientistMs Lucy Lytton Environmental Research Institute of the Supervising ScientistDr Mike SaynorMr John Lowry

Environmental Research Institute of the Supervising ScientistEnvironmental Research Institute of the Supervising Scientist

SECRETARIATMs Kate Dixon Office of the Supervising Scientist Ms Bessie Roach Office of the Supervising Scientist


1 Preliminary Session

1.1 WELCOME AND INTRODUCTIONSThe Chair (Dr Barry) welcomed members to the 33rd meeting of the Alligator Rivers Region Technical Committee (ARRTC). Dr Barry thanked Energy Resources of Australia (ERA) for arranging the tour of Ranger mine prior to the meeting and noted that ARRTC members and observers continue to find such tours informative and highly valuable. Dr Barry welcomed Dr Geoff Pickup as an observer to the meeting and noted he has been nominated for appointment as the Independent Scientific Member - Geomorphology. Dr Pickup provided a brief overview of his expertise and research interests in relation to ARRTC’s work.

1.2 APOLOGIES AND OBSERVERSApologies from the following members were noted:

Mr Gavin Williams Mr Andrew Johnson

Uranium Equities LimitedIndependent Scientific Member

Ms Anna Morgan Parks Australia

1.3 CORRESPONDENCENo correspondence was tabled.

1.4 CONFLICT OF INTEREST DECLARATIONSDr Pickup declared he had recently been commissioned to undertake a review of the eriss landscape modelling work. Dr Mudd advised that he is continuing to provide technical advice to GAC in relation to Ranger mine. Dr Stauber advised that she is continuing to work with eriss in relation to the development of a Guideline Value for uranium in sediments. Ms Coram noted that Geoscience Australia (GA) periodically provides advice on uranium mining to the Department of the Environment and that two GA staff are currently on secondment with eriss. Dr Sinclair asked if there is sufficient separation between GA and eriss given Ms Coram’s membership of ARRTC. He noted that this is important as the key strength of ARRTC is its independence. Ms Coram noted the GA officers seconded to eriss are working independently from GA. Ms Coram advised that to date she had had no correspondence with the officers concerned but she would be happy to remove herself from any conversations in ARRTC should a potential conflict of interest arise. Mr Tayler confirmed that Ms Coram has very minimal interaction with the seconded GA officers’ work. Dr Sinclair advised he was happy with the current level of separation between GA and the seconded GA officers within eriss. ARRTC agreed that maintaining such separation should be actively managed in future and that ARRTC members should not be reviewing their own work.

1.5 GOVERNANCEDr Barry confirmed that all ARRTC members have signed the Terms of Engagement and all observers present had signed Deeds of Confidentiality. Ms Dixon gave an overview of current membership status. Dr Mudd asked whether there is any value in still having a UEL member. Mr Tayler suggested that UEL membership would be valuable given there are still issues remaining at Nabarlek that need to be addressed. ARRTC members also agreed that there was still information needed on the management of Nabarlek. Dr Mudd suggested ARRTC may get better value from other options such as having Cameco as a member. Mr Tayler suggested that Cameco and UEL each have their own issues so it’s not necessarily a straight swap. Dr Barry agreed it was disappointing that UEL doesn’t attend but suggested any proposals to include other new members on ARRTC should be considered on their own merits. Dr Barry noted that ARRTC would like UEL to attend meetings but unless there were specific scientific uncertainties to address, there was probably no requirement for Cameco to attend. Dr van Dam noted there is a KKN related to baseline studies but suggested this could be undertaken opportunistically.

ARRTC noted that in relation to the risks associated with uranium exploration, an update on the status of current activities in the ARR would be useful. Mr Tayler noted that exploration in the ARR is of small scale and that associated environmental risks are relatively low. He suggested that given the relatively small scale of disturbed areas involved, there was probably no pressing need for ARRTC to spend much time on this and that ARRTC’s efforts would be better spent on issues regarding Ranger. Dr Mudd noted that weeds and culture are big issues associated with exploration but agreed that ARRTC should keep a watching brief rather than make this a major focus. Mr Tayler noted that the science around weeds is well defined already so there’s no need for ARRTC scientific input. However, it was noted that environmental impacts associated with weeds are also covered under regulatory requirements and Professor Mulligan agreed this is important.


2 ARRTC32 Outcomes2.1 ARRTC32 - SUMMARY RECORDThe ARRTC32 draft Meeting Summary was approved as tabled without amendment. Members agreed the meeting summary was comprehensive and well presented. The Chair noted that the new format with embedded presentations was helpful in recalling the meeting’s detail and would like to see the format continue. The secretary confirmed that advice would be sought from ERA on which links to commercially confidential material will need to be disabled before the meeting record, including embedded/linked presentations, was posted on the Departmental website.

ARRTC33-1: ARRTC approved the ARRTC32 Meeting Summary as tabled.ARRTC33-2: ERA to advise secretary which links in the ARRTC32 meeting summary need to be disabled, prior to being made public via Departmental website


No. ARRTC32 ACTIONS ARISING Outcome from ARRTC33

ARRTC31-3 ARRTC requested UEL to provide a copy of the Nabarlek vegetation closure criteria report once finalised. Overtaken by the action item on getting the info from UEL before they close.

ARRTC31-4 ARRTC agreed there would be significant value in having a synthesis of the key learnings from the SAV rehabilitation work and that the next steps are to (a) secure a suitably qualified internal graduate to develop a high level project scope, timeline and consolidated bibliography; and (b) explore options for funding this work going forward.

Almost completed. Will be finished by next ARRTC

ARRTC31-6 ARRTC requested that Parks Australia provide a presentation to next meeting on the SAV monitoring approach for groundwater, vegetation management and cap integrity aspects including aims, rationale and results.

Carried forward

ARRTC31-9 ARRTC thanked Dr Sigda for his presentation and requested the final reports arising from this work be provided to ARRTC members for information. Dr Sinclair noted that groundwater reports in ARRTC31-9 would be provided by next meeting as they are not yet finalised.

Completed.

ARRTC31-13 Dr Mudd requested that an update on the status of the Ranger 3 Deeps EIS and assessment process be provided to the next meeting.

Completed

ARRTC32-1 ARRTC approved the ARRTC30 Meeting Summary as tabled subject to minor corrections. Completed

ARRTC32-2 Members requested UEL to provide interpretation round the significance of the anomalous results identified in their report, particularly sulfate. Also contextualisation of the low survival rate of plantings at the waste rock dump and old plant area and references to closure criteria.

Overtaken

ARRTC32-3 Members requested that SSD consider including in the work program of Sarah Marshall, who is on temporary secondment from Geoscience Australia, some research work to fill in the gaps identified in the UEL report

Considered. But not progressed yet due to priorities. So, completed.

ARRTC32-4 Mr Issaverdis to provide a response to the committee regarding causes of cap settlement, at the next meeting.

Minimal subsidence due to newness of cap. Revisit discussion at next ARRTC. Consolidate this action item into the discussion round monitoring.

ARRTC32-5 Question from Dr Coram: Are modellers exploring the sensitivity of the model to geological structures using broad (i.e. hydrostratigraphic unit wide) variations in hydraulic conductivity, or are they looking at preferential flow through linear structures as well? If not, what has been done to systematically assess the presence and characteristics of linear geological structures to act as a potential transport pathway for contaminants to the surface? ERA to respond.

Completed

ARRTC32-6 Dr Sinclair to draft and distribute a Table of Contents for pit 3 tailings application in addition to making available to members, early input data

Completed

ARRTC32-7 Dr van Dam undertook to examine the appropriateness of Gulungul monitoring site and communicate any decisions re that site at next ARRTC

Completed (see agenda item 4.2)

ARRTC32-8 Dr van Dam to report more fully on the SAV monitoring approach for groundwater, vegetation management and cap integrity at next ARRTC

Completed and ongoing (see agenda item 4.2)

ARRTC32-9 ARRTC requested a copy of David Parry’s recommendations re sediment sampling program for future. Carried over ERAARRTC33 Meeting Summary of 21

ARRTC32-10 Regional groundwater questions to be drafted for use in KKN review methodology. Provided to next ARRTC.

Carried forward-ERA/SS

ARRTC32-11 Run a qualitative risk assessment process for decommissioning. Provide an update at the next ARRTC meeting

Carried over - ERA

ARRTC32-12 Dr Lu to provide a presentation at next ARRTC meeting, on the implications of his ecohydrology study, for Pit 1, including advice on how to explore learnings for Pit 1’s future.

Carried over - ERA

ARRTC32-13 Run a workshop on aquatic ecosystem establishment to determine the types of waterbodies that need to be assessed, what are the risks, what is known, what are the knowledge gaps and assess the applicability of the existing sumps to any future investigations?

ERA & SS Completed

ARRTC32-14 ERA to identify appropriate methodologies to investigate subsurface profile of Magela Creek sand channel and assess potential for solute migration.. Also discuss rationale and recommendations with SSD.

ERA/SS progressing – carried over

ARRTC32-15 Dr Bollhöfer to liaise with Ms Impey regarding questions for a questionnaire Murray Garde will be taking to TOs

Dr Bollhöfer completed -

ARRTC32-16 ARRTC noted and endorsed the scientific publication lists provided by SSD and ERA ERA/SS completed

ARRTC32-17 ARRTC agreed the next meeting (ARRTC33) would be held in late Nov early Dec. To be determined by email.

All completed


3 Stakeholder Reports

3.1 URANIUM EQUITIES LTD (APOLOGY)No report.

Discussion: Members discussed whether ongoing UEL membership is still considered useful to ARRTC objectives. Dr Mudd noted that DME could cover Nabarlek issues. It was noted that the DME Environmental Monitoring unit is working with Charles Darwin University on groundwater data revisions regarding Nabarlek and will bring to next ARRTC. DME will also work with the Supervising Scientist on this. Dr Mudd suggested the remaining issues at Nabarlek should be handled by the NT government as a legacy mine matter. Mr Tayler noted that these are essentially regulatory matters and ARRTC doesn’t have much traction regarding this and, from a scientific perspective, ARRTC’s role should be limited to reviewing planned responses to matters. Dr Mudd suggested ARRTC should keep a watching brief on Nabarlek. It was agreed that Ms Strohmayr would approach UEL and ask for a compendium of their information on Nabarlek.

ARRTC33-3: ARRTC requested DME to report on Nabarlek ground water data at next meeting.ARRTC33-4: ARRTC agreed Ms Strohmayr will approach UEL and request a compendium of their information on Nabarlek

3.2 ENVIRONMENTAL NON-GOVERNMENT ORGANSIATIONS (DR MUDD)Dr Mudd provided a verbal report on behalf of environmental NGOs. He noted the funding of the progressive rehabilitation of Ranger remains a key issue of concern. He also noted that Ranger 3 Deeps, McArthur River mine and whether Ranger mine will close in 2020 or continue after that date are also issues of ongoing interest and concern to environment NGOs.

3.3 NT DEPARTMENT OF MINES AND ENERGY (MS STOHMAYR)Ms Strohmayr gave a presentation on NTDME regulatory activities during the reporting period. She offered to provide an update on audits at next ARRTC.

Discussion: Dr van Dam noted he was pleased that DME is getting into applied research and that this creates additional capacity. Mr Tayler noted the need to avoid duplication regarding work on Ranger. Ms Strohmayr is using the Mining Technology Group (MTG) recently established with Charles Darwin University to do a technical review which is generating good input. The MTG will operate for the period 1/08/2014 – 31/07/2017 and involves Professors Ken Evans and David Lilley. The MTG is assessing impacts from tailings level and staff are assisting also DME with statistical review and analysis of groundwater data reported to ARRAC. CDU submits quarterly reports of observations, findings and recommendations to assist DME in improving regulatory process. It was noted that Professor Evans had attended the Pit 3 modelling meeting and raised a number of additional questions. Ms Strohmayr advised that the key research topics of interest to DME include: groundwater solute modelling to inform final tailings level, further investigation into sources of high EC and supporting finalisation of completion criteria – especially surface water and groundwater. ARRTC members congratulated DME on a valuable initiative. Mr Tayler asked if Supervising Scientist could collaborate with the MTG in relation to EC in Gulungul Creek. Ms Strohmayr advised that DME would not be getting CDU to look at that issue as they are focusing more on engineering designs and closure studies rather than day to day regulatory actions. Dr Mudd noted that this work deals with some of the most important questions to be answered.

ARRTC33-5: ARRTC requested Ms Strohmayr to provide an update on DME audits at next meeting

3.4 NORTHERN LAND COUNCIL (MR THOMPSON)Mr Thompson advised NLC had nothing to report.

3.5 SUPERVISING SCIENTIST BRANCH (INCLUDING MONITORING) (MR TAYLER)Mr Tayler provided a verbal update on Supervising Scientist operations. He noted Supervising Scientist is no longer a Division in its own right and is now a branch in the new Science Division within the Department. He noted the changes provide a range of potential opportunities for scientific collaboration and access to other expertise in the division. Mr Tayler advised the new Division Head, Dr Diana Wright, will commence on 24 November. Mr Richard McAllister is returning to his substantive position but will retain the statutory role of Supervising Scientist. He noted that the changes should not affect the work of ARRTC at this stage. Mr Tayler noted that the leach tank incident impacted on Supervising


Scientist’s capacity to undertake other standard work. The leach tank package of work has now largely finished from an eriss perspective. Mr Tayler noted that the pending closure of Ranger also changes the work focus and brings the research and supervisory arms of the Supervising Scientist closer together. He noted that closure is now a significant focus for the branch and will remain so for the foreseeable future. Mr Tayler advised that groundwater is also an increasing issue of focus and Supervising Scientist would like to establish a more permanent in-house expertise in this area. He noted that Supervising Scientist was very grateful to have GA secondments in place for this at present.

Discussion: Dr Mudd asked if there are any moves towards amending the EPARR Act at this stage. Mr Tayler advised nothing specific was proposed at this time. He noted that constant reviews from the department are occurring but to date no significant changes affecting Supervising Scientist have been proposed. Members agreed that ARRTC would surely be seen as a cost effective forum. Mr Tayler noted that any changes to ARRTC would be made known to members. Dr Pickup asked whether eriss has sufficient resources allocated to groundwater issues. Mr Tayler noted that the current level of resources was still inadequate but Supervising Scientist will be seeking to strengthen resources and expertise in this area. Members agreed to highlight the need for further groundwater expertise and resources in the Chair’s report to the Parliamentary Secretary on the outcomes from this meeting. Dr Sinclair noted that although ERA has groundwater expertise, it uses consultancies to supplement the small core of intellectual expertise. Dr Mudd noted that regional issues will govern the final rehabilitation outcomes at Ranger, so research requirements also need to focus on the post rehabilitation requirements rather than just direct operational needs. Mr Tayler noted the need to balance between regional versus operational needs. Ms Coram agreed noting that various hydrogeology models are available and it’s currently a good time to attract good people. She suggested the first step is to work out what needs to be done and then be flexible regarding how you achieve resourcing. Ms Coram suggested there is a particular need to look at data adequacy for predictive modelling.

3.6 PARKS AUSTRALIA (MR ISSAVERDIS PER MS MORGAN)Mr Issaverdis provided a verbal report on the status of the South Alligator Valley rehabilitation project. The written report will be circulated post meeting. He noted that Parks has been through another dry season and the containment site is looking mostly fine. He advised that Dr van Dam would report in more detail later as Supervising Scientist has visited the site recently. Mr Issaverdis noted that discussions with Supervising Scientist in relation to the monitoring program moving forward have occurred but no decisions have been made as yet. He noted that Parks may engage the existing consultants for further 12 months to do the work. Mr Issaverdis advised that normally staff don’t get into the area until about June to October and the area is very hot and rugged so need to be careful with regard to OHS.

Discussion: Dr Mudd asked if there is a possibility of a field trip to the site noting that Ranger is logistically much easier. Mr Issaverdis advised that Parks would have no objection to ARRTC visiting the site but noted that this would be a significant logistical exercise and may involve camping. Dr Pickup noted that narrowly focussed field trip with just a sub-group of ARRTC might be an option worth considering. Dr Mudd suggested there would also be potential value for ARRTC to visit Nabarlek. It was agreed to further discuss field trips under other business.

ARRTC33-6: ARRTC noted that the Parks Australia ARRTC33 report would be circulated following the meeting.

3.7 GUNDJEIHMI ABORIGINAL CORPORATION (MR O’BRIEN)Ms Impey advised that GAC had nothing to report

4 Research status Reports4.1. ITWC UPDATE (DR SINCLAIR/MS ILES)Dr Sinclair acknowledged the Traditional Owners of the land on which Ranger is located (the Mirarr) and presented the ERA Business Update. Additional discussion points are summarised below.

Approvals process-stakeholder engagementDiscussion: Dr Stauber asked whether ERA is interested in mining more of the known resources at Ranger. Dr Sinclair noted this would require a separate proposal. Dr Mudd asked if it did get to that stage, what sort of proposal would be required. Dr Sinclair advised this would be determined by the regulatory authorities who determine the level of assessment needed. He noted that the resource-to-reserve ratio depends on processing and modifying factors including lease arrangements and stakeholder and regulatory requirements. He also advised that the estimations of maximum radiation doses were done collaboratively using expert consultants. Dr Sinclair noted the communication process to stakeholders regarding the EIS had, at the time of this meeting, generated only low levels of interest in Darwin and Jabiru.


Pit 1 preload & catchment conversion etc. Discussion: Ms Impey asked how work is going to continue in Pit 1 through the wet season. Dr Sinclair responded that last year work stopped in rain because tailings were soft and ERA ran out of geofill. He noted that the long term forecast from BOM is that El Nino has developed weakly, so it is expected to remain drier than average till the end of November. Dr Sinclair noted that he is comfortable that ERA can work with the available laterite and advance the rock cap. He advised that if heavy rain eventuates, ERA will bund the affected area off and drain it to the sump. He advised however that ERA remains optimistic that the BOM prediction is accurate.

Tailings and Brine management projectDiscussion: Dr van Dam asked if ERA is able to continue to capture water from Pit 1 up until the proposed/revised 2017 deadline. He also noted the longer timeframe for Pit 1 than for Pit 3 and asked if ERA is leaving enough time. Dr Sinclair advised the timing and sequencing is related to cash flow so timing comparisons are not so accurate. He noted it is a complex, adaptive process and everything has to line up, and there are interdependencies and still some unknowns that need to feed into the works schedule. Professor Mulligan asked about specific drainage paths. Dr Sinclair detailed the proposed adaptive process for Pit 1 backfill and rehabilitation and advised that knowledge gained regarding methodology will be applied to the Pit 3 works. Dr Mudd asked about plans for funding closure. Dr Sinclair noted that there is a provision put aside for the planned closure of the mine. This was costed through the Interim Tailings, Water and Closure (ITWC) major study. The tailings and brine management project is one part of the ITWC plan and is funded through the ITWC provision. There is also Annual Plan of rehabilitation and money set aside against that to cover costs of immediate closure, such as if ERA were to cease operations.The government would take carriage and this. The plan and amount is signed off each year by the MTC. He noted that, ERA still gets revenue when processing stops. Dr Sinclair noted that forward cash flows also factor in closure costs.

JABILUKA

Jabiluka area – pre and post rehabilitation Discussion: Dr Barry asked whether there is much in the way of structured learnings regarding vegetation at Jabiluka that can be applied to Ranger. Dr Lu advised there limited learnings to be gained as there is not much overlap and different soils and rocks on both sites. Dr Bollhöfer asked how thick is the rock cover going to be on Pit 1 and Dr Sinclair advised in excess of 10 metres.

CLOSURE CRITERIA – MS ILES

Ms Iles presented a table of work requiring MTC approval

Ms Iles advised a focus for the Closure Criteria WG is Quarter 1 2015.

Closure Criteria Technical Working Group. Ms Iles ran through developments in each of the groups, who is on the committee, recent work outputs etc

Discussion: Dr Humphrey sought definition of the RPA boundary catchment. Ms Iles clarified that Gulungul Billabong is outside the RPA, while GS009 and Corridor Creek are inside the boundary. Dr van Dam noted that some environmental requirements may need to be adapted to ensure they are still appropriate. Members sought clarification regarding what the RPA boundaries would be post closure and how ERA liability might be affected. Mr Tayler noted that the Minister is unlikely to release ERA from liability post closure in 2026, and the bond would be released only after closure criteria have been achieved. Dr Mudd noted legislative cross referencing of RPA definitions may need to be clarified. There was discussion around requirements in the RPA post closure and it was noted that there will be minimised effect, not a zero effect.

4.2 ERISS 2013-14 RESEARCH OUTCOMES AND PRIORITIES (DR VAN DAM)Dr van Dam provided a presentation which covered an overview of wet season WQ, the focus of the eriss research program over the course of the year and related performance, constraints and opportunities.

2013-14 wet season monitoring in Magela and Gulungul creeks - Water quality (EC) in both creeks was presented in the context of the previous three wet seasons. Key message was that downstream EC remained well above upstream EC for much of the wet season relative to previous years. There was only one exceedance of the EC limit at the Magela downstream site, and three exceedances at the Gulungul downstream site. Generally poorer water quality at Gulungul downstream appeared to be due to the poor water quality originating from the GCT2 tributary (see special presentation in Agenda item 5.1 from Kate Turner). Toxicity monitoring using in situ snail 4 day reproduction tests, with plots representing upstream and downstream egg production. No significant difference in Magela values pre and post leach tank incident. Same for Gulungul – no significant difference from previous wet season. Subtle differences in EC and water


temperature can lead to increases in egg production, and this might explain some of the results where downstream egg production was higher than upstream.

2013-14 research focus.

eriss priority research informs and is informed by numerous key activities. It is aligned with the key activities at Ranger and their timelines. Commercial activities within eriss have been scaled back due to resource constraints and the need to work on core priorities. Project management has been rationalised commensurate with staffing resources. Research program suffers when resource constraints or unexpected workloads arise.

Research program performance

Adequate progress on most (76%) projects. When resources are constrained, the research program is affected, whereas monitoring resources are maintained. Active management of the research program (including project suspensions) is essential. Nevertheless, another good year for outcomes in terms of publications.

Issues constraints

Items briefly discussed here included; budget constraints; ERA-led activities that eriss is involved in (e.g. Closure Criteria Technical Working Groups); Ranger leach tank failure; KKN revision; assisting the Department on other activities – e.g. EPBC, Aust/NZ Water Quality Guidelines.

Notable research milestones

Projects highlighted here included: CAESAR landform evolution modelling review; trial landform erosion and chemistry studies; developing UAS-based monitoring methods; water and sediment quality trigger values; and the BRUCE database.

Previous Action items

ARRTC32-7 (Gulungul Creek downstream monitoring site location) - Dr van Dam described the issue and the Supervising Scientist’s proposed addition of two new sites, both on the east bank of Gulungul Creek, to better capture water quality perturbations related to GCT2 inflows.

ARRTC32-8 (El Sherana radiological containment) - Dr van Dam outlined discussions between Supervising Scientist and Parks for Supervising Scientist to undertake the monitoring program, described a visit by Supervising Scientist staff to the site, and highlighted the high resource requirements to manage 180 continuous monitoring data streams. The Supervising Scientist has proposed to seek advice on how to rationalise so many data streams.

Discussion: Dr Stauber asked if any water quality variables could be measured using UAV technology. Dr Bartolo advised that there is currently an Honours project with CDU to establish a method to determine turbidity of billabongs from UAV imagery. Professor Boon asked if the work of graduates would be published in the literature. Dr van Dam indicated most of our work is intended to be subject to peer review. Dr Mudd asked what process is being used to prioritise the 180 data streams from the SAV containment. It was noted that expertise in unsaturated ground would be required to determine which data are useful – i.e. this is more related to geotechnical-rather than groundwater. Dr van Dam advised that eriss does not currently have anyone with this expertise to provide the necessary advice, and it is proposed to seek external advice. Some enquiries had already been made. Dr Mudd offered to assist with this or nominate other suitably qualified scientists that might help. Professor Mulligan also offered to advise on what data are most useful. Dr Mudd noted that different lines of investigation are required in order to gauge infiltration rates. Mr Issaverdis noted that the ARPANSA licence conditions were very general. Andreas Bollhöfer noted that it is up to the licence holder to demonstrate compliance with those conditions, but there is no restriction or guidance by ARPANSA on which methodologies to use and which investigations are needed to demonstrate this compliance. Dr van Dam agreed to discuss the matter further with Professor Mulligan and Dr Mudd out of session.

ARRTC33-7: ARRTC noted Dr van Dam will discuss prioritisation mechanisms for 180 data streams on cap integrity with Professor Mulligan and Dr Mudd out of session.

4.3 RESEARCH ADDRESSING KEY KNOWLEDGE NEEDS DURING OPERATIONAL AND REHABILITATION/CLOSURE PHASES (ERISS/ERA).


TECHNICAL PRESENTATIONSEcological risk assessment & ecological processes - Dr Bartolo Discussion: Dr Mudd asked whether radionuclides were chemical or biological. Ms Iles advised that radionuclides were a specific category, but that uranium is treated as a toxicant because its chemical toxicity is greater than its radiotoxicity. The list of identified ecological processes was discussed and it was noted that microbial processes are covered by the relevant ecological process as biogeochemical. Dr Stauber noted that microbial processes (biogeochemical process) was presented under “abiotic” but could also come under biotic processes. Dr Sinclair sought clarification on how residual risk works. Dr Bartolo stated that residual risk is taken into account during the risk screening process where the key risks are selected for quantitative analysis. Dr Barry noted that KKNs can resolve high uncertainty, i.e. where unacceptable risks exist a KKN determines what information we need to manage it. He suggested it’s about targeting what are the things that can go wrong, working out why and how we can fix it. He noted the committee needs to keep that goal in place as a clear framework to ensure we are targeting the work appropriately. Dr van Dam noted that the risk assessment process is still quite broad and unwieldy because a risk screening to focus and prioritise has not been done as yet. Dr Sinclair asked if the process will include decadal risk profiles. There was discussion around at what point in a risk profile like this could stakeholders be happy that the risks are the same as the surrounding profile . Dr van Dam noted that the process doesn’t quite go to decadal predictiveness. Dr Bartolo noted that two of the boxes in the final slide would inform the KKN process and Dr Barry agreed with this. Dr Stauber asked if any quantitative risk assessment work was being done. Dr Bartolo replied that a Relative Risk Modelling approach will be used to address the issue of cumulative risk assessment, while quantitative risk analysis (most likely a Bayesian Belief Network approach) will be used to assess key risks.

Toxicity of ammonia to local freshwater biota - Dr HarfordSources of Ammonia

Interim GV value etc Nomenclature clarification: Guideline value = trigger value

A GV for ammonia will be derived using 6 local species and so far three have been completed. A pH of 6 was calculated to be the median pH of Magela Creek and will be the pH used for toxicity testing. Drifting pH is problematic in Magela Creek Water due to the softness of Magela Creek water. Hence, buffering of the test solutions to control pH is an important issue. The two most sensitive species from international studies were mussels which are important bush foods so the eco-toxicology team are investigating the development of a toxicity test. The exposure of duckweed to ammonia led to a pH drop to 4.5 and more work is needed to troubleshoot this issue so that pH stays at 6.

Discussion: The two most sensitive international species to ammonia were freshwater mussels, which has led to eriss investigating the development of a mussel toxicity test. We have been improving methodological design for toxicity tests to control pH. Dr Sinclair noted there are off the shelf pH controllers that correct automatically and Dr Harford agreed to consider that approach to managing problematic pH if the methods under investigation proved insufficient. Dr Stauber asked whether there were any changes in development regarding the definition of a chronic toxicity test for the snails. Dr Harford responded that we are investigating differences between 4 and 14 days for exposure for uranium and will consider other needs following that. Acute to chronic ratios might be employed but the use of a chronic snail test would mean a big resource requirement and it is unlikely to become a routine test. The cost benefit balance is unclear but we’ll know more when the uranium data has been analysed. Dr Barry asked what the change to chronic toxicity estimates would mean for the Guideline Values. Dr van Dam noted that with regards to fish it was always an acute test so not changing anything, just asking what’s appropriate for use in a water quality guideline. The new methods recommended during revision of the national water quality guidelines allow for more flexibility but recommends that more data is beneficial, as this increases certainty. Dr Stauber asked how many times was brine distillate measured and how much effort was required. Dr Harford stated that the distillate did not previously contain a lot of ammonia but the Guideline Value was also important for Pit 3 modelling. Ms Iles also noted there had not been much ammonia measured and that there was a correlation with EC, which is closely monitored and won’t be discharged if it is over 20 µS/cm. Professor Boon asked if the Guideline Value will be relevant for billabongs, which might have a much higher pH. Ms Chandler noted that large diurnal pH spikes occur in the afternoon with pH reaching 9. Professor Boon noted that photosynthesis by algae drives the pH spikes in afternoon. Dr Mudd asked if organic content has any influence on pH and processes. Dr Harford said the current project is relevant to the creek when it is in flow and that billabongs would be a different situation. Investigation of ammonia toxicity at pH 9 is the project’s current scope but we will look at the pH of billabongs to assess this against the work being done. Dr van Dam noted that depending on results, we might be able to use quite simple calculations to determine the Guideline Values for the billabongs at pH 9 using the USEPA algorithms Mr Tayler noted there is no need for a guideline when you’re not discharging, but when coming through groundwater its worth thinking about.


Water quality closure criteria - Dr HumphreyDr Humphrey acknowledged work by Lisa Chandler and advised some of the results to be presented were very recent and are not in the paper provided. Dr Humphrey noted the results are confounding in field studies: In Georgetown Billabong magnesium is the dominant contaminant driving biological change. However, potential confounding factors due to the change in sample processing method after 2006, as well as possible aquatic vegetation (key habitat) changes, require such artefacts to be assessed. He noted these issues are detailed in the paper provided.

Discussion: Dr Sinclair asked if manganese in GTB is a potential confounding problem. Dr Humphrey advised it is not. Dr Pickup noted from the PCA ordination that it looks like a very noisy data set and asked if the approach should be more discriminatory. Dr Humphrey advised that the PCA exploratory approach was not designed to be discriminatory but to assess the influence of all possible environmental factors, water quality, habitat, geomorphological and locational, in explaining the patterns observed. Despite throwing all these variables into the analysis (at the cost of low explanatory power in the Axes, i.e. PC 1 is explaining only 20% of the variation), a strong EC gradient through water bodies was still evident, giving weight to the conclusions that impacts upon macro invertebrate communities in GTB were water quality related. Dr Barry noted the correlation but asked what about causation: which factors are confounders and which should you remove. Dr Humphrey reiterated that this was not the purpose of the initial PCA: all potential environmental correlates were thrown into the analysis yet we still come up with a strong water quality gradient. Turbidity closure criteria information for receiving waterbodies is required for pit capping and landform design and performance.

Dr Stauber suggested it would be good to know the mechanism of magnesium toxicity and asked if there is anything that tells us why Mg at that concentration changes community structure. Dr Humphrey advised that staff sampling in Coonjimba Billabong where Mg concentrations are high, noted a lack of epiphytes and biofilm so Mg effects may be indirect from lack of important food sources for macroinvertebrates. However, the same anecdotal evidence suggests epiphytes and biofilm are found at RP1 where Mg concentrations are even higher. Dr van Dam noted that lab work suggested phototrophs weren’t sensitive to Mg but there is a limited species subset. Mg is known as a calcium antagonist so crustaceans might be affected. Sulfate has been shown to be much less toxic compared to Mg and it is ruled out as a key toxicant. Dr Harford noted that snails are sensitive at chronic concentrations but were not sensitive to pulse exposures. Dr Humphrey noted that whatever the mechanism, the field information is corroborating lab results.

Dr Sinclair noted that Georgetown Billabong has a major pigrooting issue and asked how we factor that in as a confounding influence of the results observed. eriss staff noted that this (feral animal) issue was also evident in other reference waterbodies and that the habitat sampled (including GTB in 2011) was not noted for pig damage. Both observations diminish the role of pigs in explaining GTB impacts.

With respect to turbidity thresholds at which biological effects have been noted in field studies, Dr Humphrey noted that the effects were associated with steady and sustained increases over weeks and months which would be unrepresentative of erosion events in the flowing creek environment at least. As such, the criteria would be difficult to apply in the creeks in terms of duration and exposure, and would certainly be worst case. In any event, sedimentation in backflow billabongs would occur well before turbidity effects were observed. Mr Tayler noted the need to account for seasonal variation, and while a turbidity closure value in the creeks is relevant for the period of flow, in a billabong you would need seasonal values because turbidity increases naturally over the dry season. Hence there is no need to worry about mine-derived turbidity values in dry season in billabongs as there is no minesite runoff and in any case, pigs and geese influence turbidity, regardless of season. Dr Sinclair suggested the need for different criteria for landform evolution and final landform phases. Dr George advised the turbidity project is examining temporal variability, including short-term pulses and different values and turbidity ranges for different seasons and years. We have two wet seasons of GTB turbidity data which show highest turbidity at initial flush (i.e. at start of wet season). Report is in draft form but we are considering these things. Billabongs are different from connecting (creek) systems. Mr Tayler noted the need to be differentiating between the drivers of events – e.g. first flush, pigs, geese, bushfires, mine influenced events.

Groundwater solute transport modelling - Dr SigdaNegligible flow going through the deep bedrock system. 90,000 years for one kilometre. Dr Sigda suggested that there was no need for concern about linear faults enhancing transport of solutes.

Discussion: Ms Strohmayr asked about the implications of including brine given it is denser than water and moves slower. Ms Coram questioned the assumptions around model parameterisation in terms of the horizontal and vertical hydraulic conductivity and asked how the ten x increase in hydraulic conductivity relates to what has been measured locally. Dr Sigda noted the model is consistent with the real range (10-3 to 10-9) all values are in appendix A of the report. There are not many measures in the weathered rock and therefore there is less confidence is this aspect of the model. However, Intera believe a ten-fold increase in conductivity (one order of magnitude) is a sufficient test of model sensitivity. Dr Pickup commented that the accuracy of modelling outputs depend very much on the calibration. Dr Sigda


stated that, in all cases, the recharge is the driving force, so the water coming in has to go somewhere and isn’t changing (Qin = Qout). The proportion of precipitation that becomes recharge is modelled at 10% which is the upper end of the literature review for the NT. Only the resistance can change and affect proportions of where the output goes. Ms Coram noted that the Sigda response says that whilst the rate will change, there won’t be a significant increase in solute concentrations reaching Magela Creek. Dr Sigda agreed. Dr Pickup asked if there are possible fast paths of throughflow through the unsaturated zone connecting the final landform with Magela Creek Sands. Dr Sigda noted this zone has a max thickness in Pit 3 of around 10 metres and that he used MODFLOW SURFACT to get the water table position, acknowledging this is not true vadose zone flow. Unless you have something in there that intercepts incoming flow, it prefers to go vertically than horizontally. ERA’s model for simulation is a low permeability cap on top of the pit. Ms Marshall asked if the fault modelled is 25 metres wide and only slightly higher hydraulic conductivity, how does it accurately represent a natural fault, which is narrow and may be many orders of magnitude greater hydraulic conductivity, which could allow for enhanced flow. Ms Marshall also noted that on the site we see the impact of faults acting as conduits of fluid flow in the fractured bedrock, such as around the TSF and in Ranger 3-Deeps, and that fractures were observed in the drill cores for Ranger 3 deeps. Dr Sigda commented that the groundwater flow at 3 Deeps is due to deep structures far below the current surface. He also commented that faults in brittle rock are never consistently conduits and that Ranger rocks are very specific – being ductile, they slip and glide. We don’t see brecciation in the bedrock faults. Dr Sigda also commented that if EC impacts observed to the north of the TSF were due to faults, why wouldn’t the same be seen from Pit 3. Pit 3 is not in the Nanambu Complex, as the western part of the mine, including the TSF, is, and the faults are different. Dr Sigda advised Intera is using ERA’s very detailed maps to develop localised predictions. Dr Mudd expressed an interest in these detailed maps for the regional context, taking the exploration drilling and mapping the geology and structure over the whole site. He also commented on the possibility that the deeper system is part of the regional system and fault may play a significant role while the shallow system is a faster system. There was reference to an MSc thesis that showed carbonates were part of the regional system. Further discussion referred to the groundwater through saturated waste rock having Mg of 1000mg/l and groundwater through the unsaturated waste rock had Mg of around 60mg/l which is considered to be background concentration. Discussion followed around who had been provided access to the modelling report. Keith Taylor commented that GA had not been asked to review the modelling work but that the Supervising Scientist was intending to get it reviewed. The meeting noted that the modelling report had not yet been tabled for ARRTC committee members.

Toxicity and guideline values for uranium in billabong sediments - Dr Harford Aim of project to derive a sediment quality guideline value for U in billabongs. Numbers: Conservative with the titan U value the 5th percentile, Permanova P 100mgU/kg

Discussion: Professor Boon asked about the rate of take up of heavier isotopes over lighter isotopes. Dr Harford advised that both are up-taken equally. He also noted the interesting method of bacteria using filaments for electron transfer, which means that U isn’t taken into the cell where toxicity might occur. Dr Harford and the CSIRO/Macquarie University team are currently working on finer details for stable isotope probing method (e.g. substrate to be used) to determine function of sediments e.g. nutrient, carbon cycling. Professor Boon asked if there is a more direct way of measuring productivity or sulfate production and photogenesis, and suggested a need to look at the question that’s driving the project rather than allowing the technology to drive the project. Professor Boon suggested bacterial productivity can be investigated more simply in the field using chemical assays. Dr Harford noted that the function of the project is about linking the genomics to the whole function of the sediment not just a few chemical pathways. He also noted that genomic data can only be used to infer function and direct chemical assays will be required to validate the methods for doing this. These are being considered. Professor Boon advised he is keen on direct investigation but Dr Harford advised the purpose of this project is assessing the usefulness of the techniques and that analysing the metagenome has the potential to quickly measure a broader range of functions. Ms Iles asked if the project will lead to a post closure monitoring programme or sediment closure criteria. She noted that we are going for as low as reasonably achievable impacts, not zero impacts on the minesite. She also asked if this technique would go for a more stringent measure – e.g. all biofunctions present is more than we need. Dr Harford advised the project would help us understand the guideline value better but that there was the potential to develop monitoring tools in the future. It allows us to understand the fundamentals of what makes healthy sediments. Dr Stauber noted the work gives confidence that the guideline is protecting the function of bacteria. Dr Harford noted the function of the bacteria is the most important parameter for a billabong. Ms Iles highlighted the need to differentiate between onsite and offsite guidelines. Dr Barry suggested the technique provides higher level of resolution to inform future debates. Dr Mudd asked if the value of 100-400 mg/kg assumes sub-mineralised material eroding and escaping the RPA. Dr van Dam noted the value is based on best science available regarding what is needed to protect sediment communities and is not necessarily indicative of what will happen in the real world. Dr Bollhöfer noted the bioavailabilty of U is going to be a lot lower for something eroding off the site. Ms Iles noted that bioavailability varies according to the source of sediment. Ms Valdron-Clark expressed concern about the interpretation of community data from the low number of sediment spiking treatment replicates of 4. Dr Harford responded that the design of increasing


treatments and sacrificing replicates allowed for better modelling of the concentration-response effect and that sampling might be an issue leading to artefacts in the dataset, which might be shown in the 800 mg/kg group. Ms Valdron-Clark noted that with a small number of replicates it is possible that the response noted at 800mg/kg may not be an artefact. It is possible that the anomalous response is indicative of something that might have been missed in the other treatments. Ms Valdron-Clark noted that sediments are non-homogenous along both the horizontal and vertical plane. Dr Harford said that the sample design attempted to control these issues and he’d be happy to discuss this further. Ms Valdron-Clark also asked what level of confidence is attached to the ecogenomic data set. Dr Harford indicated he was not as confident in the data set as he’d like to be and at this stage they are investigating the techniques in order to understand the mechanisms better and then confidence will grow. He noted they do see the expected response that correlates to the concentration gradient. Dr van Dam noted that current international knowledge of the effects of U in sediment is massively increased by this dataset.

Erosion studies on trial landform - Dr Saynor

Discussion: Dr Pickup asked what the gradients are and what are you expecting in the final landform. Dr Saynor noted it’s currently a 2 percent gradient and there will be gradient issues with the final design. Dr Pickup asked if rip lines will be possible given the final landform steepness. Dr Saynor advised that any interruption to the slope will reduce sediment run off but this is up to the mine operators. Dr Sinclair noted this is really good data and helps determine how big we design sedimentation basins. Dr Pickup noted that this sort of study is very labour intensive. Dr Saynor concurred. Dr Barry asked if there are ways of extrapolating gradient data to larger scales. Dr Saynor noted that there was no option early on as were given a 2 percent gradient trial landform. Dr Saynor noted it is possible to run simulations on a revised surface model with slopes greater than 2 percent using the CAESAR model. Dr Saynor noted there are other datasets that need to be looked at to determine their relevance and usefulness. Dr Pickup noted in relation to the effects of slope on sediment, that increased slope gives a squared response to sediment load, and increases gullying potential. That leads to an exponential increase in load. It was noted that Mr Lowry has done desktop models that show that increased slope results in increased gullying potential. Professor Mulligan indicated he wasn’t sure how easy it is to get confidence in gullying potential. Ms Coram asked what works have been done or are planned regarding throughflow waters (rather than run off). Ms Iles noted the water in the seepage interception trench round western stockpile, during the dry season would all be seepage, and allow for back calculations based on the volume of water in stockpile. Dr Sigda described work he had done to set a high point value for throughflow, and discussed the geochemical modelling referred to in section 4 of the Pit 3 report and data in Appendix E. Ms Coram advised she is pleased that modelling is tied to some real data. Dr Barry asked whether small builds at different gradients would be a way to check out effects. He indicated he understood the scale issues but wondered if it would work. Dr Pickup noted that what you get from a plot is more than what you get from along slope. Dr Sinclair noted that a 400 hectare landform is expensive to rip and maintain, and using smaller smarter designs to model best practice would be preferable. Professor Mulligan noted that there will likely be greater stability where you have ground cover on laterite. Dr Sinclair noted laterite is not as important as leaf litter accumulates in depressions.

In discussing the Intera solute transport model Mr Tayler noted that the Djalkmarra fault is one we know about. He asked, based on information you have regarding 3 Deeps, if there were faults there, would we know about them and is the mapping good enough to provide this information. Dr Sigda confirmed the mapping provides this information and noted that the faults that matter are deeper than the tailings by a good deal. Dr Barry noted that the current situation is that there is a model which has been tested, sensitivity analysis has been applied to certain sensitivities and there are a few remaining issues that need to be worked out. Mr Tayler noted that work to do this is underway and the Supervising Scientist is looking at getting the modelling reviewed and will continue to liaise with ERA as necessary. Ms Coram suggested to not just emphasise how good the model is internally but also how well it maps to the real data based on the evidence. Ms Iles advised the Pit 3 report went to MTC and via GAC to Dr Mudd. ERA had assumed that Geoscience Australia staff working with the Supervising Scientist would distribute the report to Ms Coram. Mr Tayler advised that Supervising Scientist had not given this undertaking and that as applications from ERA were not routinely provided to ARRTC, he was unclear as to why ERA would have assumed this would occur. Dr van Dam suggested the report should be distributed to ARRTC members and ERA undertook to do so.

ARRTC33-8: ERA agreed to circulate the Intera report to ARRTC members out-of-session.

Second part of the presentation: Sensitivity Modelling of Pit 3 Solute Egress: Effects of Regional Flow – in answer to Dr Mudd’s question from the November 2013 meeting.

Discussion: Dr Mudd highlighted the need to look at regional groundwater as well. He raised the issues of deeper layers, if you’re looking at deeper layers, the escarpment is providing that hydraulic edge, and carbonates if there is a preferential faster pathway. He suggested that local topography on deeper flow paths is not as important as regional features. The


response from Dr Sigda included discussion on recharge in the model, orders of magnitude and diversion of flow. Dr Barry suggested further discussion on this issue be held out of session.

Landform evolution modelling for the trial landform - Mr Lowry Discussion: Mr Lowry clarified the process for obtaining lines of best fit to compare field with model data. Dr Humphrey noted the most relevant model for vegetation cover is what is on the waste rock because framework species need 5 years before ground cover is put in. Professor Mulligan noted that landscape is most vulnerable to erosion when vegetation is absent. Mr Lowry noted that while the model may be run with or without vegetation parameters i.e. with bare ground, further work is required to develop the vegetation parameters in the model. Dr Pickup noted the model is useful as an engineering design tool but the trick with sediment modelling is model validation. He noted the work contains good validation results and the next step needs to be to run the model without vegetation as the extreme case, which would provide a good engineering safety zone. Dr Pickup noted simulation procedures are standard engineering practice, and the one weakness is looping 20 years rainfall. He suggested some extreme cases could also be inserted Dr Pickup noted the work by Mr Lowry et al is one of the best pieces of work he had seen anywhere. He suggested that with the range of slopes and rainfall you have here, the model pushed to extreme should work ok. Dr Pickup noted that CAESAR vegetation growth function is uniform, which doesn’t reflect reality. He suggested that Landscape function analysis (LFA) does it with better spatial differentiation and referred to the Tongway work at Nabarlek. Professor Mulligan noted the principles of LFA regarding vegetation in landscape are good, particularly in Rangeland settings, however applying them to the environments that we are working with is contestable. Ms Iles advised that the Landform Closure Criteria Technical Working Group will be reviewing the input data and agreeing on scenarios to run and are already looking at the 22 year rainfall data set. She noted that, in terms of particle size distribution, ERA provided reports using photographic software to estimate particle size from photos. Ms Iles noted that the Working Group already has the information required to optimise this data.

Dr van Dam asked if, looking at vegetation and biomass, biomass can be calculated using remote sensing. Dr Bartolo advised this was possible. Ms Impey asked how well climate change is integrated into the model. Mr Lowry advised that the model is able to incorporate rainfall variables from actual extreme rainfall events, and is able to incorporate and replicate a range of climate change scenarios, which distinguishes it from other models. However, only 22 years worth of rainfall data has been used in the modelling to date, which represents a limited selection of climate scenarios. Dr Mudd noted that weathered soil develops better moisture holding capacity and asked if this can be added to the model’s functionality as it impacts on vegetation? Dr Lu advised that ERA is looking at leaf area index rather than biomass, though these are correlated. Mr Lowry noted that modelling doesn’t take account of natural species assemblages. Dr Sinclair noted that material balance and type needs to be reviewed once there is clarity from the modelling. He noted that ERA needs to develop a material movement schedule to build the landform and that 120 million tonnes of material would need to be scheduled. Dr van dam suggested that ERA put up front the volumes and types of materials available and let the modellers shape their planning processes around that. Mr Tayler noted the landform design is primarily ERA’s responsibility. He noted that Supervising Scientist can test and advise on appropriateness but it’s not appropriate for Supervising Scientist to do the work for ERA. Dr Sinclair agreed and noted that ERA has done this already and also has the cultural overlay to incorporate (e.g. Traditional Owner preferences regarding locating large rocks on final landform). Ms Impey noted that Murray Garde is having that conversation with TOs.

Dr Barry suggested it would be useful for ARRTC to specify the things required to do the assessment and articulate how the process can progress. Ms Coram noted ARRTC is focusing a lot on surface processes but queried the level of current understanding of processes occurring within the landform, particularly hydrodynamics of through-flow. Ms Coram asked if this has been taken account of and Mr Lowry advised it hasn’t been part of landform modelling activities to date. Ms Coram asked if there has been investigation into unsaturated flow through the landform and associated solute release and transport issues. She noted that this is a much slower process but will ultimately mean solutes go elsewhere. Ms Strohmayr advised that aspect has been looked at in pit backfill modelling for saturated and unsaturated zones geochemical models, characterising solute generation sources. She noted there will be seepage water quality expressing from edges of waste-rock. So there are many data available to characterise water in the system. Dr Sinclair noted that physico-chemical processes are well described and the sulfide weathering profile has been developed. He noted this will feature in the closure and post closure risk analysis. Ms Iles noted there is already a KKN and past reports covering this. Dr Sinclair noted that all of this detail is presented in the Intera report. Dr Barry asked if there are any other things that ARRTC think need to be looked at more closely. Dr Pickup noted the model is on the verge of being a working tool so his advice would be to not put too much detail into it and just run some extreme cases. He suggested that as it’s a broad brush assessment, small variations shouldn’t affect it much.


Radon exhalation from a rehabilitated landform – Dr BollhöferDiscussion: Dr Mudd asked if the columns were nearly dry and Dr Bollhöfer confirmed they were. Dr Mudd suggested the level of radon flux measured was unusually low for dry material. Dr Bollhöfer advised that moisture is not a factor here but compaction and larger radon diffusion length affects rate of diffusion from the radon columns. Dr Mudd noted that Cameron Lawrence was measuring radon flux off waste rock and was looking at the effect of moisture on the radon exhalation. Professor Boon asked if plants shorten or lengthen the radon exhalation. Dr Bollhöfer advised that plants can create preferential pathways for radon originating from deeper sections within the soil profile.

Presentation of indigenous language videos - Ms DixonDiscussion: ARRTC commended the Supervising Scientist communications team on a good initiative and product. Ms Iles noted that it would have been helpful to also include reference to the work ERA is doing in environmental monitoring. Ms Dixon responded that the videos are intended to familiarise local indigenous people with the work of Supervising Scientist.

Environmental media concentration limits for terrestrial wildlife - Dr Bollhöfer

Discussion: Dr Mudd noted the reason why the limits for wildlife are now considered different to human limits is related to bioaccumulation understandings. He asked if all radiation pathways were included, not just gamma? Dr Bollhöfer confirmed that all pathways are included except for the radon inhalation pathway. Professor Boon asked how the exposure of a tree would be assessed. Dr Bollhöfer noted that in the case of vegetation the ingestion pathway equivalent is uptake through roots. Dr Harford asked what and how many species are used for the species sensitivity distribution, and are they representative of Australian species? Dr Bollhöfer advised that no Australian species were included but it is ‘extrapolated’ for Australian species (e.g. a wallaby would be similar to a rabbit). He noted there are about 15-20 species in the distribution. Dr Harford noted that the differentiation between background and additional doses is different to how toxicological studies work. Dr Bollhöfer confirmed that this is an important difference to traditional toxicological studies.

JABILUKA

Progress on UAV R&D and Jabiluka revegetation - Dr BartoloDiscussion: Dr Pickup noted there are loads of measures of texture but they are mostly not useful. Dr Pickup noted the NVDI becomes less successful as vegetation dies off as it’s a greenness index. Dr Pickup advised that he had some success looking at red/blue index and asked if shadow length with sun angle could be used to estimate tree height? Dr Bartolo noted that multiview stereopsis generates multi views for height assessment (generates a point cloud indicating height). Dr Boon asked whether data format may become an issue in the future as data formats have become obsolete in the past. Dr Bartolo noted that all data captured is raw and then stored as geotif. Dr Bartolo indicated she is confident that the raw data is archivable. Storage volume is also a challenge. Dr Barry noted that finding partners in the algorithms and processing is a good way to go. Dr Bartolo stated that eriss could try to process much of their data using other means such as cloud processing rather than using their own infrastructure which becomes expensive.

4.4 ERA AND ERISS PUBLICATIONS LISTSERA Publications list was tabled.

eriss publications list was tabled.

5. STRATEGIC OVERVIEWA report was tabled.

5.1 TECHNICAL PRESENTATIONS

Investigation of water in the Gulungul Creek catchment to the west of Ranger’s tailings storage facility - Ms TurnerDiscussion: Ms Coram asked if there was any parallel groundwater assessment done with the investigation. Ms Turner indicated there was but these data haven’t been analysed yet. The next step is to work with Graeme Esslemont to review groundwater quality monitoring data. Mr Tayler noted that Supervising Scientist started looking at this in 2010/11. He noted that Supervising Scientist is not certain that previous analyses fit with what is being observed now so further investigations are underway to reconfirm earlier work or potentially find new conclusions. Dr Mudd noted in relation to


the series of trenches along the western wall, some are dry while some show high EC, so very localised effects. He indicated it’s not clear what is going on in this very interesting system. Mr Thompson asked if U content was elevated. Ms Turner advised U levels were not as high as other elements. Dr Mudd noted it would be interesting to map it out looking at groundwater heads and surface topography together to see whether the two intersect. Ms Turner noted that the GCT2 site is wet long after the end of the wet season, pointing to a groundwater contribution. Dr Sinclair noted that S isotope ratios might be useful since those at the bottom of the TSF represent processes used several years ago which are different to what is in the current tailings (see Dr Sinclair PhD thesis).It would be good to bring this into the investigation. Ms Iles noted that some tailings cores and possibly some soils from the base of the TSF a few years ago could contribute to the dataset. Ms Turner commented on load estimation and the potential to use geophysics to delineate faults. Dr Sinclair noted that geological interpretation is very important as the fault lines may only be inferred, not real. Ms Iles advised that 12 test pits were dug from north of the sump to south of the sump, a few hundred metres in each direction. She noted that some were dry and some had varying levels of EC, up to 7000S/cm. Test pits went down to the rock at 3-3.5 metres. . Dr Mudd indicated that while he didn’t disagree with Dr Sinclair that a geologist should get involved, input specifically from a hydrogeologist would be more essential. Ms Turner clarified that the contamination is inside the lease boundary. There was general discussion about previous studies, characteristics of the spring and how long ago the salts were identified. Mr Tayler noted that the salts have been around a while but the conductivity readings have stepped up in the last wet season and that is why Supervising Scientist is having another look. Dr Sinclair advised ERA response is to put in some interception drains but noted that until we know more about it we won’t know if that is a final solution or not. He noted that it may turn out to be a combination of shallow seepage and runoff, we had an issue with solutes coming off the Western stockpile and we developed some interception drains which worked perfectly. Dr Sinclair advised that ERA has some good data nowand has put a temporary measure in place for this wet season but may have to go further. Professor Mulligan noted that once the mitigation measure takes effect you would expect the source to dissipate. He noted it is fine to just control it now but the closure strategy should remove the source. Mr Tayler advised that the source is the tailings dam, but it is not clear why. He suggested that in some ways the exact location is academic, but from an impact assessment perspective there is sufficient information to warrant action. Dr Mudd noted that the TSF wall and tailings seepage have different signatures which will act differently over time: EC from wall rock seepage will decline over time and EC from the tailings will increase over time. Mr Tayler advised the first priority is to get it cut off and then work out exactly where it’s from and whether it will remain as a residual problem post closure. He noted that closure assessment of water below the TSF will need to be done once the TSF is closed and we can assess whether some sort of intervention is required. Ms Coram noted this work could be relevant for validating some of the hydraulic and attenuation coefficients that have been used and provide a reality-check as a measure of how rapidly contaminants can move through the system if there is a pathway. Dr Sinclair noted that low pH is characteristic of boggy areas and suggested sulfate is the key issue. It was noted that rubidium1 is also associated with a uranium body so might be a good tracer. Dr Mudd suggested it is also important to map soils and soil composition to help understand the geochemical processes, noting that this mapping would underpin the modelling. It was noted that all of the suggestions raised should be integrated.

Aquatic ecosystem establishment – revised direction and work plan - Dr GeorgeDiscussion: Ms Iles advised that there has not been a final decision yet on what, if any, water-bodies would be retained or replaced onsite. She noted that modelling of Djalkmarra indicates it’s not a good idea to reinstate that waterbody . Dr Pickup asked, with respect to proposed seed-bank studies, how relevant is the local seed-bank compared to surrounding areas given the dispersal mechanisms in these areas? Dr George noted there are no existing studies on this. While we know we have a few types of seed-bank, we don’t know how they differ. She indicated she suspects they don’t differ much given the dispersal mechanisms; a seed-bank can only tell you the potential of what can grow there. Mr Tayler noted the seed bank also reflects what has washed into the area from other sources. Ms Iles suggested this knowledge could be derived from resident plants rather than the seed-banks and this may be a more reasonable approach. Dr George noted that the water quality may have impacted on resident vegetation over time so it’s important to assess the effects of water quality. Dr Bartolo noted that there may also be seeds in the seed-bank that will never germinate so how do you tease out the information for what should be on a rehabilitated site. Professor Boon cautioned against narrowing the approach too early. He noted there is clearly a very serious knowledge gap and the priority should be on working out what we need to know. Dr van Dam noted further clarity is required around which water-bodies we need to rehabilitate etc, then we will have parameters to work on. Dr Mudd noted the need to also understand how the seed-bank relates to rehabilitated land as the removal of disturbance pressures may increase germination potential of existing seed banks. It is important to understand the relationship between seed banks and disturbance pressures. Dr Barry asked what level of detail is required and whether this includes processes and types of water features. He stressed the need to define an end use for the information. Dr Harford asked how good are the existing aquatic plant survey data and do they need to be bolstered. Dr George agreed the data need to be analysed to determine how good they are. Dr Barry noted it’s also important to look at what the data don’t show in terms of what information we need to know. The desktop analysis of vegetation monitoring data and its comparison with onsite vegetation data provide a means of evaluating what data are available and how they

1 This is likely meant to be a comment on rhenium as a tracer, as reported by Barry Noller in several papers/reports.ARRTC33 Meeting Summary of 21

may be used. Dr Pickup suggested analysis of the existing data provide a good basis for decision making and ARRTC generally agreed with this proposal. It was suggested that Dr George pursue the desk top analysis of existing vegetation data, as well as comparing ERA’s onsite vegetation data with eriss’s vegetation data collected in existing monitoring programmes.

Update on research and monitoring for Ranger revegetation - Dr HumphreyDr Humphrey spoke to a draft report (i.e. no slides) prepared by several members of the (yet to be convened) Flora and Fauna subgroup of the Ranger Closure Criteria Working Group, i.e. Drs Humphrey, Bartolo, Lu and Gardner. (Dr Gardner is a vegetation ecologist who worked for ERA and will now represent GAC on the Flora and Fauna subgroup). A lot of work has been going on to address revegetation at Ranger. Dr Humphrey outlined the key 14 steps associated with Ranger’s revegetation strategy, and the learnings and risks associated with each of the 14 steps.

Discussion: Professor Mulligan agreed that the issue of the amount of water in the profile is a major risk. The current plan is for 10 to 16 metres of waste-rock on top of laterite in pit 1. In pit 3 the waste rock depth will be limited with implications for plant water availability.

5.3 ARRTC SUMMARY DISCUSSIONSDr Barry suggested the key strategic questions arising from the discussion appear to be (1) what are the significant risks during closure and post closure and (2) do we have the knowledge to mitigate these risks. He noted the Environmental Risk Assessment (RA) has grown to be a bigger thing than what ARRTC initially envisaged but conceded it serves a broader purpose. Dr Barry sought members’ views on next steps. Professor Boon suggested the discussion over the course of the two day meeting has addressed most of the questions and most of the earlier criticisms appear to have been resolved. Dr Barry noted this but asked if ARRTC now has the required level of understanding to be certain as to what are the key knowledge needs are and whether these are able to/will be addressed. Professor Boon noted he thought that Dr Bartolo’s and Dr George’s topics seemed to cover that. It was noted there is a need to involve ecological processes and use them to inform monitoring. Dr van Dam noted that RA is a KKN in its own right and a degree of conceptual underpinning was still missing from the KKNs. He noted the RA framework is being done to provide the basis for updating and refining the KKNs. That process should cover off on the things ARRTC believes might be missing. He suggested Supervising Scientist and ERA are heading where ARRTC thinks we need to get to, but agreed we are still in the broad space and noted that progress has been slowed due to resource constraints. Mr Tayler indicated he shared Dr Barry’s view that the work so far is excellent and has ways to go but given the limited resources, there is a legitimate question of do we need to scale it back (i.e. can we get to 95% of the result for another 10% effort?) Dr van Dam suggested Mr Tayler was mixing up time with actual resources applied and noted that really it’s just time that has dragged out. He noted the process is already strategically yielding knowledge gaps. Dr van Dam suggested its worth going through the process but agreed it’s been in the broad space too long. Mr Tayler noted this but suggested need to be careful that we don’t end up with a great result too late to drive the work - we may have to settle for less rigour to get a more timely output. Dr Harford noted much of the delay was because we chased down ecological processes. Dr van Dam agreed the process needs to be dealt with in the next 6 months. We should compartmentalise it up, do the decommissioning screening assessment, then remap the outcomes against the KKNs, and then considered carefully which key risks should be quantitatively modelled. Renee put up a proposed work-plan. ARRTC agreed that progress on the risk assessment and revision of KKNs should be presented at the next ARRTC meeting.

Dr Pickup suggested that, outside of routine monitoring, there should be a move towards predictive modelling. Each project should take a look at where it is now, when it will be able to predict in a reasonable time, and if not, the question is why you are doing it. Dr Pickup suggested that once available resources reduce post closure, we need to work out how to move to monitoring done by communities. Legacy item. Each project should look at it. Sort of like citizen science. Ms Iles noted the example of cultural health index monitoring and Ms Impey noted this was occurring in Jabiluka already. Dr van Dam noted that there is an existing responsibility through the closure criteria WG process. Need to ask what do we need to satisfy the requirements of environmental protection? He suggested that in amongst the monitoring program, we should identify any bits that lend themselves to community-based monitoring. Mr Tayler noted this may be important for the sake of clarity, however it won’t happen until the mining company is released from its responsibility; so at least 50 years from now. He suggested therefore the timeline is possibly too far off for current priority. Post 2026 money will still be around for several decades of monitoring. We should get the Mirrar involved well ahead so they are well positioned with skills come the time of need. Professor Boon suggested ARRTC should consider how to progress ecological processes in the rehabilitation/closure context including looking at possible visits to other rehabilitation sites. It was agreed that ARRTC consider other possible relevant sites for fieldtrips and to discuss this at next meeting.

ARRTC33-9 ARRTC requested a report on the status of the Environmental Risk Assessment and associated KKN revision process be provided next meeting.


ARRTC33-10: ARRTC agreed that all ERISS research activities should have a clearly articulated rationale describing how the outputs of the work contributes to ERISS’s core business and strategic knowledge requirements associated with the Ranger rehabilitation and closure.

ARRTC33-11: ARRTC agreed to defer further discussion regarding sites for future fieldtrips to next meeting.

Professor Mulligan suggested there is a need to scale up from the trial landform to the next stage. He noted there is lots of knowledge out there and in order to know what the final landform is going to look like, we need to get to more detail on all the end uses. It was agreed that all current knowledge should be used to ensure the landform works. Dr Pickup suggested the need to look at larger catchments and steeper slopes and start filling that data requirement in. He noted this is a huge amount of work and suggested, as a first step, going to the literature and running some models with extreme cases – i.e. big hydrological events etc. He also suggested there is sufficient information already to know where all the main features sit – slopes, drainage lines etc. Dr Pickup suggested the critical modification is to enhance the sinks. Mr Tayler noted this is already known. Ms Iles suggested the constraining parameters are already known – e.g. don’t go outside the disturbed footprint and how much of each material we have. It was noted that significantly progress is happening in background but there is progress still to be made. Professor Mulligan asked if ARRTC could look at what is already known for the landform, and identify knowledge gaps and risks. Dr Mudd suggested these issues be covered in the Chair’s letter to the Minister. ARRTC agreed the letter should include the reduction in sitting fees, resourcing of eriss to do groundwater, and stressing the importance of getting closure right – long term results therefore a lot at stake.

ARRTC33-12: ARRTC agreed the Chair’s report to the Minister should include reference to the implications of the reduction in sitting fees due to the revised Remuneration Tribunal Determination, resourcing of eriss to do groundwater work and stressing the importance of getting the science around closure right.

6 Other BusinessNo other business.

7 Next MeetingARRTC33-13: ARRTC agreed the Secretariat would determine the date for next meeting (ARRTC34) by email.

The meeting closed at 4.50 pm.

[Note: This meeting summary is based on the original notes taken by Ms Kate Dixon, Acting ARRTC Secretary, on 5 and 6 November 2014. The document has been edited to remove any Confidential Information in accordance with ARRTC governance requirements.]


CARRIED OVER ACTION ITEMS ResponsibilityARRTC31-6 ARRTC requested that Parks Australia provide a presentation to next meeting on the SAV monitoring approach for

groundwater, vegetation management and cap integrity aspects including aims, rationale and resultsParks

ARRTC32-4 Mr Issaverdis to provide a response to the committee regarding causes of cap settlement, at the next meeting. ParksARRTC32-9 ARRTC requested a copy of David Parry’s recommendations re sediment sampling program for future ERAARRTC32-10 Regional groundwater questions to be drafted for use in KKN review methodology. Provided to next ARRTC. ERA/SSARRTC32-11 Run a qualitative risk assessment process for decommissioning. Provide an update at the next ARRTC meeting ERAARRTC32-12 Dr Lu to provide a presentation at next ARRTC meeting, on the implications of his ecohydrology study, for Pit 1, including

advice on how to explore learnings for Pit 1’s future.ERA

ARRTC32-14 ERA to identify appropriate methodologies to investigate subsurface profile of Magela Creek sand channel and assess potential for solute migration.. Also discuss rationale and recommendations with SSD.

ERA/SS

No. ARRTC33 ACTIONS ARISING Responsibility

ARRTC33-1 ARRTC approved the ARRTC32 Meeting Summary as tabled. Complete

ARRTC33-2 ERA to advise secretary which links in the summary are to be disabled, prior to being made public via Departmental website. ERA

ARRTC33-3 ARRTC requested DME to report on Nabarlek ground water data at next meeting DME

ARRTC33-4 ARRTC agreed Ms Strohmayr will approach UEL and request a compendium of their information on Nabarlek DME

ARRTC33-5 ARRTC requested Ms Strohmayr to provide an update on DME audits at next meeting DME

ARRTC33-6 ARRTC noted that the Parks Australia ARRTC33 report would be circulated following the meeting. Parks

ARRTC33-7 ARRTC noted Dr van Dam will discuss prioritisation mechanisms for 180 data streams on cap integrity with Professor Mulligan and Dr Mudd out of session..

ARRTC (Dr van Dam, Dr Mudd and Prof Mulligan)

ARRTC33-8 ERA agreed to circulate the Intera report to ARRTC members out-of-session. ERA

ARRTC33-9 ARRTC requested a report on the status of the Environmental Risk Assessment and associated KKN revision process be provided next meeting.

ERISS/ERA

ARRTC33-10 ARRTC agreed that all ERISS research activities should have a clearly articulated rationale describing how the outputs of the work contributes to ERISS’s core business and strategic knowledge requirements associated with the Ranger rehabilitation and closure.

ERISS

ARRTC33-11 ARRTC agreed to defer further discussion regarding sites for future fieldtrips to next meeting. ARRTC Secretariat

ARRTC33-12 ARRTC agreed the Chair’s report to the Minister should include reference to the implications of the reduction in sitting fees due to the revised Remuneration Tribunal Determination, resourcing of eriss to do groundwater work and stressing the importance of getting the science around closure right.

ARRTC Secretariat/Chair

ARRTC33-13 ARRTC agreed the Secretariat would determine the date for next meeting (ARRTC34) by email. ARRTC Secretariat


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