Research

Fundamental to the development of sustainable ecosystems post-mining is the requirement to align the properties and behaviour of the substrates and climate with the desired structural and functional attributes of the new target ecosystems.  SMI-CMLR research contributes to the development of rehabilitation indicators and completion criteria, developing methodologies to determine when rehabilitation is progressing on a trajectory to success.  Research considers factors that influence seed germination, substrate-plant relationships, roles of microbial and faunal assemblages, robustness and resilience to disturbance, and biodiversity values.  Recent examples of projects have included:

• Increasing the scientific rigor of flora monitoring to improve the value and accuracy of data collected to increased confidence about the presence and level of potential impacts on listed upland swamp vegetation communities as a consequence of underground coal mining.
• Assessing the structural and functional development of re-instated native plant communities following heavy mineral sand mining and their progression towards the target communities.
• Understanding how developing ecosystems are influenced by external factors such as climate and fire, and how these impacts influence the trajectories towards agreed criteria.
• Building monitoring designs that are robust, transparent and defendable with adequate power to detect ecologically significant changes in the species of interest, as well as informing adaptive management if putative impacts are observed.
• Developing pre-mine monitoring techniques for assessment of listed flora species, endangered ecological communities, and threatened fauna groups encompassing both bird species (including migratory species) and cave-dwelling microbats.
• Enhancing the management and conservation of koalas in areas impacted by mining during vegetation clearance through to specific habitat creation as a part of mine closure planning.
• Linking biogeochemistry to the occurrence and spatial distribution of tolerant plant communities growing in naturally metal-enriched environments, and identifying metallophytes and hyperaccumulating species for potential use by the minerals industry.

The topography of a landscape after mining can have a major impact on rehabilitation strategies.  Slope, elevation, aspect and drainage patterns all influence surface stability, erosion potential and land use options.  SMI-CMLR research on materials characterisation enables an understanding of, and amelioration strategies for, the chemical, physical and biological properties that may prevent landform stability and limit the establishment of sustainable ecosystems.  Recent examples of projects have included:

• Improving the design criteria and performance of engineered covers that are constructed to reduce the potential of water infiltrating into potentially acid-forming mine wastes for climates with a high risk of seasonally high volume and high intensity rainfall events.
• Developing a cellular automata run-off model as a simulation tool for assessing the hydrologic behaviours of different rehabilitation designs at spatial and temporal scales.
• Investigating if findings from natural landscapes where ecological attributes and diversity is positively correlated with landform heterogeneity are valid in post-mining landscapes.
• Testing efficient and accurate methods to quantify coal and black carbon in mine soils using thermal analysis and multivariate curve resolution so it is possible to calculate green carbon.
• Investigating the effectiveness of amendment options for ameliorating primary constraints and restoring key soil processes for reconstructing root zones in base metal tailings.

The characteristics of created landforms and substrates can have a major influence on the quantity and quality of water within a mined landscape.  An understanding of geochemical and hydrological processes through laboratory and field studies can assist the prediction and control of potential impacts under a range of climatic conditions.  SMI-CMLR research encompasses studies on contaminant mobilisation at and below the surface, in waters and sediments both on-site and downstream.  There is a focus on identifying contaminant transfer pathways and understanding risks to receptors at both ecological and human health scales.  Recent examples of projects have included:

• Quantifying sources of lead and other metals and metalloids, exposure pathways and risks to environmental and human health of emissions from base metal mining operations.
• Describing the hydro-geochemistry of tailings storage facilities to understand their long-term geochemical behaviour and potential effects of seepage on local surface and groundwater.
• Developing advanced measurement techniques to overcome the uncertainty associated with metal and metalloid loads in waterways downstream of mining operations.
• Demonstrating the relationship of bioaccessibility measurements with bioavailability of heavy metals in mine wastes and method validation with animal models to understand the risks and improve predictions of the likely chronic and acute effects on human health.
• Synthesising and testing a series of surface-functionalised polymers to stabilise heavy metals and metalloids in the pore water of mine waste to facilitate the rehabilitation process.

Gaining confidence in the success of mine site rehabilitation requires assessment of a range of spatially-explicit parameters such as vegetation cover and densities, biodiversity, growth rates, recruitment, salinity and erosion.  Using remote sensing techniques, monitoring of mine sites at temporal and spatial scales can identify changes in ecosystems and hydrological and landform processes with a high degree of confidence.  SMI-CMLR research uses remote sensing technologies and spatial analysis methods for the mapping and monitoring of pre-mining landscapes and rehabilitation throughout operational and post-closure phases.  Recent examples of projects have included:

• Using Unmanned Aerial Vehicles to capture imagery at spatial and temporal resolutions higher than possible with satellite and manned aircraft to reliably indicate condition and composition within ecological communities based on sensitivity, structure and scale.
• Provision of accurate information about the development of rehabilitation over time, including assessments of slope stability, erosion or slumping across sites.

In order to achieve effective mine closure with minimal future risk to the environment, and maximal opportunities for a positive legacy, integrated and forward planning is an essential component of the mine planning process.  Preparing for successful mine closure from pre-operational phases across all aspects of the mining process will contribute to a reduction in negative environmental outcomes and result in more efficient and more economic closure strategies.  SMI-CMLR research uses a multi-disciplinary approach to explore options for developing sustainable end land uses and for identifying knowledge gaps that could impact on successful mine closure.  Recent examples of projects have included:

• Developing strategies of integrated tailings management through using information on biogeochemical processes in the design of activities within mineral processing plants, upstream characterisation of ore and gangue, and downstream tailings management.
• Developing a national abandoned/legacy mine hub as an opportunity to implement national policy and provide a pathway to address cumulative impacts, risks and opportunities.
• Developing an approach for mined land end-use risk assessments using a Bayesian Network modelling framework and separate risk models for key hazards (e.g. erosion, fire, weeds).

Determining the Extent of Erosion using Unmanned Aerial Systems (UAS)

Using Unmanned Aerial Vehicle (UAV) technologies, CMLR can determine the extent of erosion and vegetative cover across an entire site, or selected problematic areas.

Outcomes include:
• Collection of RPA imagery with >80% overlap provides enough information for the generation of digital surface models (DSM). These DSM’s can be utilised by rehabilitation managers to measure landform metrics such as slope, elevation and problem areas such as erosion gullies.
• A thematic vegetation coverage map may also be produced to provide spatial distribution of tree, shrub and grass cover and identify areas which are failing or developing well.

Monitoring in this manner is designed to inform management decisions in order to achieve rehabilitation outcomes that are safe, stable, self-sustaining and suited to target closure criteria in the most efficient manner possible.

The online herbarium has been developed with Silver Biology and CMLR, initially enabled as a component of an industry grant. Many projects at CMLR require simple to advanced plant identifications as a fundamental step in researching the rehabilitation of disturbed land and the effects of mining. And a number of locations where we work have limited identification resources available. The aim of the CMLR Herbarium is primarily for plant identification by staff,students  and the general public by providing query-based filtering of specimens and dynamic high-resolution images, see below, as an alternative or complement to traditional forms of plant identification.

The type of specimens aim to be comprehensive site collections for long-term projects, representative collections for some mine sites in NSW and QLD and research-appropriate collection of plant specimens through other regions. A concurrent aim is to provide a demonstration of a low-cost, virtual herbarium highlighting advanced features and capabilities compatible with Australian and global herbarium online initiatives.

Since the inception of CMLR, many researchers have collected specimens across many mine sites in Queensland and NSW and validated many of these with botanists at the Queensland Herbarium and National Herbarium of New South Wales. But without digitisation, the specimens have been kept in the naphthalene-infused boxes and folders, with little chance of seeing the light. With significant advances in the technology of rapidly accessing high-resolution imagery combined with an image database, we’ve been able to digitise our specimen collection with relative ease. Specimen processing and digitisation was undertaken by CMLR staff, summer students and volunteers.

Go to the CMLR Online Herbarium

Personnel:

Peter Erskine

Features of the online herbarium

• For each specimen in the collection, you can view:
  • label information including plant family, genus and species
  • location on Google Maps
  • research-quality specimen image
• Specimen data can be viewed and exported to csv or kml files
• Images can be viewed interactively to high resolution using same ‘tiling’ technology of Google Earth

Additional resources

Managing a Coal Mine Rehabilitation Database: Dig

The Dig bibliographic database was developed to provide industry, government, researchers and other interested parties with reference information relevant to the rehabilitation of land after coal mining.  The database is an online source of annotated reference material including bibliographies of reports, books, journal articles and conference proceedings.

The major benefits of the Dig bibliographic database include:

• ready access to accumulated past and present reference information;
• a reduction in the loss of knowledge in the face of high staff turnover rates;
• the avoidance of costly repetition of past research work or previously trialled rehabilitation approaches and procedures; and
• the provision of a mechanism to effectively identify genuine gaps in the knowledge base.

Research Focus and Aims

The original aim of the development of the database was to produce a single source of references so that the large body of information on all aspects of coal-mine rehabilitation which has accumulated over several decades can be used for future reference.  In order to enable ongoing use and to maximise the benefit from efforts already invested in their establishment, continual up-dating, maintenance and improvements are necessary.  The overall objective of this ACARP funded program is to maintain a current, state-of-the-art research tool for the benefit of coal producers, environmental staff, government and researchers, and to provide the opportunity to use existing rehabilitation information to the best advantage of the Australian Coal Industry.