The extraction of coal and coal seam gas (CSG) from Australia’s onshore sedimentary basins may have a direct, indirect and cumulative impact on water resources and water-dependent assets. This can include impacts to surface water bodies such as rivers, lakes and wetlands, as well as local to regional scale groundwater flow systems in aquifers. For example, in areas where coal mining occurs below the watertable, ongoing dewatering of aquifers is required to develop open-cut and underground mining operations. Similarly, the successful production of CSG relies on hydrostatic depressurisation of the coal-bearing strata, so that gas can desorb from the coals and then be pumped to the surface for extraction. At the scale of individual bioregions or subregions in the Bioregional Assessment Programme, the cumulative impacts of these activities may be of particular importance as they potentially affect both surface water and groundwater systems over large areas. Such impacts may extend far into the future and, in some cases, decades beyond the lifespan of resource extraction operations.
The BA methodology provides the overarching framework that sets out the scientific steps involved in undertaking bioregional assessments. The central purpose of this work is to analyse the impacts and risks associated with changes to water-dependent assets that arise in response to current and future pathways of CSG and large coal mining developments . Such impacts may affect water-dependent assets of an ecological (e.g. wetlands and rivers), economic (e.g. quantity or quality of groundwater in an aquifer tapped for agricultural irrigation), or sociocultural (e.g. Indigenous) nature. Consequently, BAs will review, analyse and evaluate both present and expected future operations for coal and CSG extraction. This information is vital to the success of each bioregional assessment and forms a significant part of the BA workflow, both contextually and for model-data analysis (Table 2).
In addition to contextual information about coal resources within each bioregion or subregion, an understanding of the most likely coal resource development pathway is a prerequisite for subsequent stages of the BA. These later phases include formulation of conceptual models that describe the causal pathways linking coal and CSG developments to impacts on water-dependent assets and receptors. Numerical modelling simulations of surface water and groundwater systems, which are intrinsically linked to the conceptual models, are then used (where data are available) to generate semi-quantitative to quantitative hydrological results (if possible) for the specified coal resource development pathway in each bioregion .
This submethodology has been developed to guide individual Assessment teams by providing a practical approach to determine the most likely combination of individual coal resource projects that together will form the coal resource development pathway for their bioregion or subregion. Importantly, the coal resource development pathway description provides relevant information on the location, type and timing of each proposed development project, so that a regional perspective of multiple future developments (and any existing operations) is clearly articulated.
This submethodology is consistent with the stated premise of the broader BA methodology in that it does not outline a prescriptive process to produce the coal resource development pathway . This approach reflects the practical considerations of assessing geological characteristics, and the variable coal and CSG resource development proposals, of the 12 coal‑bearing sedimentary basins investigated in the Programme (Appendix A). Some resource developments may have unique characteristics that will require variation from the generic framework. In such cases, each Assessment team will be best-placed to evaluate the need for and the implications of these variations using scientific judgment based on their knowledge of region‑specific geology, coal resources and proposed development pathways. Where such variations from the broader framework are needed, these will be clearly noted and explained to provide both transparency and a record of the decision-making process.
The most likely coal resource development pathway that can be described by each Assessment team is an important requirement for future components of BAs (Figure 2 and Table 2). The coal resource development pathway needs to take account of available information relating to the exploration, appraisal and proposed development of the known coal and CSG resources in the bioregion or subregion . This assessment will focus on a range of parameters that may be available for each coal or CSG project including the quantity and quality of resources, the estimated time frames for the major development stages, the types of extraction processes, and any specific regulatory conditions.
Independent regional-scale assessments of coal resources and unconventional hydrocarbons (including CSG) in Australia’s onshore basins have not yet been undertaken using a consistent and internationally recognised methodology. While it is not the purpose of the Programme to generate updated regional-scale estimates of coal and CSG resources, the Assessment teams will focus on compiling existing resource information from various sources such as exploration and development companies, relevant state government mining and resource departments, and academic research groups (see Section 3 for specific details). This information is reported within the companion product 1.2 for each bioregion or subregion (see Section 2), and this contextually focused work forms the first stage in developing the coal resource development pathway. Importantly, product 1.2 provides a catalogue of all potential coal and CSG resource developments that form the basis of further evaluation in BA Component 2: model-data analysis.
To determine the coal resource development pathway for their specific bioregion or subregion, Assessment teams must critically evaluate the relevant data available for each potential resource development listed in the catalogue (Section 1.2.4 in product 1.2). By working systematically through this evaluation process (which is the second stage of the overall coal resource development pathway framework and described in Section 4), Assessment teams will be able to evaluate and describe a valid coal resource development pathway for their bioregion or subregion. A further and important part of the overall process involves consultation of the proposed coal resource development pathway with coal mining and CSG resource development companies, as well as others who are able to provide valuable input into the coal resource development pathway assessment such as the Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development (IESC), relevant government agencies (State and Commonwealth) and local level experts.
The objectives of this BA submethodology are to:
- provide a framework for evaluating and describing the coal resource development pathway that can be applied consistently across all bioregions
- guide Assessment teams that are working on individual bioregions or subregions to maintain a practical and structured approach to determine the coal resource development pathway for their Assessment area
- present the preferred terminology to be used in BAs for various characteristics or parameters associated with coal and CSG resources
- outline the data and information required to compile a thorough coal and CSG resource stocktake (reported in companion product 1.2 for each bioregion or subregion)
- prepare the information needed to select the combination of individual resource projects and deposits most likely to form the coal resource development pathway within each bioregion or subregion
- outline the analytical considerations, criteria and concepts needed for Assessment teams to construct and validate their coal resource development pathway.
This submethodology is divided into four sections:
- Section 1: submethodology overview (this section)
- Section 2: defines the concepts and uses of the coal resource development pathway in the BA context
- Section 3: (stage one) data and information inputs, presents the type of information required in companion product 1.2 for each bioregion or subregion, to understand the geology, coal and CSG resources, as well as current and proposed coal resource developments
- Section 4: (stage two) data analysis and evaluation to determine and justify the coal resource development pathway, reported in companion product 2.3 (about conceptual modelling).
In addition, there are four appendixes in this submethodology that provide relevant contextual information (for a wider public audience). This includes an overview of Australia’s coal and CSG resources (Appendix A), coal resource definitions used in BAs (Appendix B), explanation of the coal resource development supply chain (Appendix C) and useful sources of data for assessing the coal resource development pathway (Appendix D).
METHODOLOGY FINALISATION DATE
- 1 Submethodology overview
- 2 The coal resource development pathway in bioregional assessments
- 3 Stage one of the coal resource development pathway – data and information inputs
- 4 Stage two of the coal resource development pathway – assessment
- Appendix A Overview of Australia's coal and coal seam gas resources
- Appendix B Coal and coal seam gas resource definitions for bioregional assessments
- Appendix C Supply chain of coal and coal seam gas resource development
- Appendix D Useful data sources on coal and coal seam gas resources
- Shortened forms
- Contributors to the Technical Programme
- About this submethodology