Welcome to the summer edition of the Mine Land Post.

In this edition, we have decided to present some of the important ongoing research into mine rehabilitation, and the many organisations and partnerships focused on delivering new knowledge needed to develop safe, stable, and sustainable landforms benefiting the Latrobe Valley community into the future. We have chosen to concentrate on research that is being undertaken in the Latrobe Valley, or being undertaken by local research groups. The research that is being undertaken is targeted on creating fundamental knowledge that can be used widely and confidently, to ensure we deliver the best outcomes for the region.

The research projects and programs described here represent only one part of the total program of work that is being undertaken to develop regulatory, socio-economic, and environmental frameworks needed to build the landforms that will support future beneficial uses, and ensure that after mining a positive and enduring legacy remains for future generations. Each of the mine operators, and Victorian government departments are undertaking a wide range of studies that are needed to infill the gaps in knowledge that exist at the present time..

Many of the studies are being supported or undertaken by specialist consulting firms with extensive experience in rehabilitation, environmental, and socio-economic processes.

We can’t bring you information on all of these studies here, but in future editions we will ensure that you are aware of any relevant reports and study outputs that will inform the rehabilitation of the mines as they are published.

The Mine Land Rehabilitation Authority (MLRA) is approaching six months old, and we have been busy throughout this time overseeing the work of the mine operators, and the implementation of the Latrobe Valley Regional Rehabilitation Strategy (LVRRS). The government’s implementation actions are all in full swing, and we look forward to providing an update on these in the new year. We have also been active in building our capacity, as we grow to meet future rehabilitation needs for the region, and Victoria.

In the meantime, enjoy reading this edition, and do feel free to contact us if you want any further information, or clarification of the content of this Post.

On behalf of the MLRA Board and the staff of the Authority, I wish you all a safe, enjoyable time as we all take a well earned break, and look forward to continuing the conversation in the new year. Until 2021!

Yours,

Rae Mackay
Board Chair

Current options proposed for mine rehabilitation include, filling the pits with water, either partially or in full.

The pit water quality will be dominated by the sources of water supply, as well as by evaporation. This research project explores the potential for the strength of coal in the pit faces to be affected by infiltration of pit lake water into the pores of the coal and changing the chemistry of the pore waters.

A large number of core samples are immersed in different quality water baths in a

temperature controlled laboratory, to represent the possible ranges of pit lake water quality, and to allow diffusion of the waters into the core samples.

The samples are then tested at a range of time intervals to examine whether there are observable changes in compressive strength. This research will assist in ensuring that rehabilitation of Latrobe Valley’s three coal mines will result in stable landscapes in the long-term. For more information contact GHERG.

Maintaining stability of mine batters (mine walls) with horizontal bores.

Horizontal bores are a requirement of maintaining the stability of mine batters (mine walls) of the Latrobe Valley’s open-pit brown coal mines, by reducing the likelihood of catastrophic slope failure by lowering groundwater pressures within the coal batter.

Although a common management measure for ensuring slope stability, there seems to be limited information available on the assessment of horizontal bore performance in brown coal over time, and maintenance scheduling to ensure their effectiveness.

Performance of horizontal bore drainage is being investigated by studying water discharge rates, and the internal features and changes with age of bores. Owing to complexities in surveying long horizontal bores (up to 400 metres in length) using standard drain inspection methods, GHERG has developed, with EnergyAustralia, a technique for inserting an optical borehole camera over the whole length of a horizontal bore.

The technique has proven to be effective for inspecting a range of borehole performance variables, including the identification of fractured or jointed material, borehole geometry, and features, and location-dependent water outflow, and drainage paths. Comparison of the identified physical borehole features with drainage performance facilitates an understanding of how these variables are correlated.

Research outcomes will improve understanding of horizontal bore operation, and enhance future brown coal slope stability management programs. This study is being funded by Yallourn Mine, Energy Australia, and conducted by Professor Thomas Baumgartl, and Cristhiana Perdigão. For more information contact GHERG.

A framework for environmental, economic, and social impact assessments for Indigenous and non-Indigenous Australians.

Australia will see a substantial change in mining activity and management as 50% of current mines are expected to close over the next 25 years, resulting in significant changing land uses (e.g. production systems, conservation of native ecosystems, alternative land uses).

Major impacts are anticipated, particularly in regional and indigenous communities where mining activities are typically concentrated. Building capacity to manage regional land use changes and impacts (i.e. environmental, economic, and social) on mining communities, requires a platform that dynamically and digitally assesses the cumulative regional impacts.

CRC TiME’s foundation project on CRIA examines best practice, hurdles, and how industry and other end users are using CRIA throughout the life of a mine (LoM), particularly at the regional level as mines move towards closure.

The 12-month project is being led by Dr Renee Young from the Western Australian Biodiversity Science Institute. Twelve project partners supporting the project with local contributors including Dr Jess Reeves, Federation University, and Anthony Feigl, Director of Coal Resources Victoria.

The project comprises a detailed literature review of published and grey literature (i.e. unpublished or non-commercial literature) synthesising the current knowledge base, conducting end-user surveys/interviews, undertaking a gap analysis, and outlining research priorities. The aim being to build a strategic framework(s) to inform future research priorities and programs, including the proposed future research phases for CRIA. For more information contact CRC TiME.

The Mine Rehabilitation Trials Online (MRTO) is a foundation project exploring the question, “Can we find a way to share mine rehabilitation trial data?”

The project aims to establish and pilot agreed data stewardship and governance frameworks, that allows Australian mine rehabilitation trials data and information from all sources (private and public), to be discoverable. The project will pilot two case studies – one in Western Australia’s Pilbara region, and the other in Victoria’s Latrobe Valley precinct, to demonstrate the potential rewards for the industry, and test the social and technical architectures.

Project participants include CSIRO, Fortescue Metals Group, Rio Tinto Services, Energy Australia, Rangelands NRM WA, WA Biodiversity Science Institute, and government departments in Victoria, SA, and Queensland. The most significant research challenge is expected to be finding a clear incentive for the participants to share their data. For such knowledge management projects to succeed and endure, data custodians need to see high rewards, no penalty or cost, and require little effort to participate.

A key aspect of success is determining what the industry participants would like to get out of the research, and how the proposed federation of data might provide them with new insights, or save them time and money.

The expected outcome will be an online portal for the pilot case studies, that demonstrates tangible value in supplying data, and information related to mine closure, and mine closure planning, that can benefit the industry and society. 

The project is led by Associate Professor Peter Dahlhaus, Principal Research Fellow, Centre for Research and Digital Information, Federation University. For more information contact CRC TiME.

Mapping the regulation of mine closure, relinquishment, and repurposing across all Australian jurisdictions.

Identifying how the regulatory framework facilitates mine rehabilitation and repurposing is this project’s aim. In particular, when and where elements of the framework may block, undermine, or conflict with goals of mine rehabilitation and repurposing, contributing to regional development. It will also seek to ascertain if there are regulatory gaps that frustrate the achievement of those goals, and the potential for defining principles to harmonise the applicable state and national mining, environmental, water resources, and land use regulation.

The project will enhance the community, industry, and government understanding of: 

1. Core concepts and goals of mine rehabilitation and repurposing, and the institutions that administer the relevant regulatory frameworks in pursuit of those goals;

2. Regulatory frameworks (state, territory, national) for mine rehabilitation and repurposing; and

3. Experience with current mine rehabilitation and repurposing plans and processes, their consistency with existing regulatory frameworks, and any regulatory reforms to achieve an equitable, efficient, and effective framework for mine rehabilitation and repurposing.

The regulatory framework will be tested with case studies, including the Latrobe Valley Regional Rehabilitation Strategy. Professor Alex Gardner, from the University of Western Australia, is leading the project with co-researcher is Dr Yvonne Haigh, from Murdoch University. For more information contact CRC TiME.

A 0.8 full-time equivalent (FTE) 11 month research associate position is available in the UWA Law School working with Professor Gardner. The position is scheduled to run from 27 January to 24 December 2021. For more details contact Professor Gardner at alex.gardner@uwa.edu.au.

Creating artificial soils from industrial waste products.

As the Latrobe Valley’s three brown coal mines have grown in size over the years, they are experiencing both an insufficiency of natural topsoils, and challenges in the management of hostile (for plant and soil organisms’ growth) post-mining soils for the progressive rehabilitation of the mines. Artificial soils have been created by utilising waste products from three different industries located in the Latrobe Valley, namely mining (e.g. overburden, subsoil, waste brown coal and fly ash from the power plant), paper and pulp (e.g. effluent sewage recovery and recycling waste) and wastewater industries (e.g. compost).

Waste products were mixed in different proportions and tested in a laboratory (Photo 1) greenhouse, and field conditions to establish the best artificial soil type, which has properties suitable for plant growth, is safe for the environment, and is self-sustaining in the long term.

Initial experiments (Photo 2) revealed that the mixture of overburden and fly ash can mitigate acid mine drainage, and immobilise heavy metals. Adding paper mill compost and brown coal increased the content of essential macronutrients enabled plant growth. 

The outcome of the initial field trial’s plant growth was suboptimal due to high salinity, alkalinity, and low seasonal rainfall. Replacement of paper mill compost with green waste compost, and reduction of fly ash significantly improved the soil chemical properties, and supplied additional nutrients, which boosted plant growth. Preliminary results from a current field trial at Loy Yang mine are showing that plant growth in artificial soil is better than in natural topsoil. 

The project is led by Mohan Yellishetty, Associate Professor, Resources Engineering, Department of Civil Engineering, Monash University, along with Dr Alena Walmsley, and Dr Likitha Mundodi. For further information contact Resources Engineering, Monash University.

Established in 2016 by the Latrobe Valley coal mine operators AGL Loy Yang, ENGIE Hazelwood, and EnergyAustralia Yallourn, the IMRG’s mandate is to fulfil the requirements from the Hazelwood Mine Fire Inquiry (HFMI) 2015/16, Volume IV Mine Rehabilitation, Recommendation 18. The IMRG’s Steering Committee, comprising six senior representatives, two from each of the three Latrobe Valley mine operators, is responsible for approval of research topics and projects, funding and resources, stakeholder engagement, and communication with government authorities.

An integrated research plan has been developed by the IMRG which identifies common research areas and priorities for a ten-year period, and is reviewed every three years. The research plan details: collaboration between the mining operators, common research areas, prioritisation of research, research scopes, and delivery timelines for the research projects, as well as consultation with regulators, research bodies, and stakeholders. 

Research projects, developed through stakeholder consultation relate to four overarching areas of research: landform evolution modelling/geomorphology, water, fire mitigation, and long term considerations. The original research projects include: 

• Cover on coal: stability, water quality, fire, and vegetation.
• Full lake benefits and interconnectivity with three lakes: water, and stability.
• Lake fill rates (rebound/recharge): water, and stability.

• Horizontal drains: stability, water quality, and fire.
• Long term pit lake water quality.
• Research existing rehabilitation experiences: stability, water quality, fire, and vegetation.
• Social and economic closure effects: social, and economic.
• Spontaneous combustion: fire, and stability.
• Stability: stability, water quality, fire, and vegetation.
• Timelines for maintenance and monitoring: water quality, and stability.
• Wave action, beaching and shoreline treatment including vegetation: stability, water quality, fire, and vegetation.

In 2019 the IMRG held a milestone workshop with stakeholders to review the work completed to date, consider the planned priority activities, and coordinate the research areas between the three entities for the remaining seven years of the research plan, particularly in light of changes that have occurred since the original plan was developed in 2016.

Each mine licensee undertakes research within each research area, and as it relates to the mine’s current stage in their lifecycle. For example, ENGIE Hazelwood have progressed their research more than AGL Loy Yang or Energy Australia Yallourn, as the mine has already ceased operations and is in its active rehabilitation phase. Results from the research projects are shared between the licensees, and other stakeholders, including the Latrobe Valley Regional Rehabilitation Strategy and the MLRA For more information contact IMRG.

The Latrobe Valley Mine Rehabilitation Commissioner 2019 – 20 Annual Report was tabled in both Houses of Parliament, and is the third and final report of the work of the Commissioner and his team. Read more and download here