2 The coal resource development pathway in bioregional assessments

An important output of the contextual phase (see Figure 1) of work for bioregional assessments (BAs) is an assessment of the coal and coal seam gas (CSG) resources of each bioregion or subregion (Barrett et al., 2013). It provides the necessary background information to be used in determining and describing each coal resource development pathway (Table 2).

This submethodology provides guidance to Assessment teams on the type of information to be compiled, reported and assessed when developing a coal resource development pathway. It is a two-stage process (Table 3). Firstly, a comprehensive coal and CSG resource stocktake is undertaken for each bioregion or subregion. Secondly, an analysis of available data from this stocktake is used to develop the coal resource development pathway specific to each region.

Table 3 Process to determine coal resource development pathway for each bioregion or subregion

2.1 Stage one: Coal and coal seam gas resource assessment

The starting point for the coal resource development pathway analysis is the catalogue of potential resource developments compiled and reported in Section 1.2.4 of companion product 1.2. This captures all projects with an identified resource[2] for each bioregion or subregion, as these are considered potentially viable for development within a 20 to 25 year future time frame (Geoscience Australia and BREE, 2013). For coal, an identified resource includes those which have reported either measured, indicated or inferred resources in accordance with the guidelines in the Joint Ore Reserves Committee (JORC) Code. The JORC Code is used commonly in the coal resources industry (as well as for many other resource commodities) to report coal reserves and resources (JORC, 2012). For CSG, an identified resource for BAs generally corresponds to a published estimate for at least one of the proved (1P), proved and probable (2P), or proved, probable and possible (3P) reserves classes in the Petroleum Resources Management System (SPE et al., 2011). Further information on the national resource classification scheme is in Appendix A .

The coal and CSG resource assessment is presented as a contextual report (companion product 1.2) for each bioregion or subregion, and consists of four main sections:

2.2 Stage two: Coal resource development pathway

Assessment teams develop and describe the coal resource development pathway for each bioregion or subregion by evaluating available data and information on individual coal and CSG development proposals. This analytical work forms the second stage of the coal resource development pathway process, which is mostly undertaken during Component 2 of the BA methodology (Table 3). The results of this work are reported as part of companion product 2.3 (about conceptual modelling) (Table 2 and Figure 2). The analysis required to determine the coal resource development pathway follows-on closely from the initial stocktake of the coal and CSG resource assessment (part of the workflow in Component 1). Further discussion on the input data and assessment criteria required to analyse and understand the coal resource development pathway is outlined in Sections 3 and 4.

For resource projects that are relatively well advanced, much of the specific development information will initially be compiled from publicly available material lodged as part of environmental impact statements (EIS). These documents are produced by development companies as part of their statutory obligation under various government planning and environmental regulations. For projects that are at less-advanced stages of evaluation (such as an initial scoping or feasibility study) there is unlikely to be as much detailed information available to Assessment teams to assess and evaluate. In these cases, there will be a greater level of uncertainty around the decision to either include or exclude such coal or CSG projects from the coal resource development pathway. Ultimately, the decision on which projects are either included or excluded must be made by each Assessment team following their detailed analysis of the available data. The process for undertaking this evaluation is described further in Section 4.

As part of the reporting on the coal resource development pathway in companion product 2.3, the main areas of uncertainty relating to the progression of each development are fully described, particularly if the Assessment team recommends including the project in the coal resource development pathway. Likewise, for projects that are captured in the catalogue of potential resources (Section 1.2.4 in companion product 1.2) but subsequently determined not to be in the coal resource development pathway, sufficient justification will be reported by the Assessment team to validate their decision. This process will provide transparent and defensible decision making to underpin each coal resource development pathway.

2.3 Description of the coal resource development pathway

For BAs, the coal resource development pathway should consider all stages of proposed resource extraction operations, including exploration, appraisal, production, closure and any expected mine legacy issues (Barrett et al., 2013) that the Assessment team deems relevant. As an initial guide, the main information that should be included in the coal resource development pathway description reported in companion product 2.3 includes:

Further details on the suggested type of information and level of detail to include in the description of the coal resource development pathway are outlined in Section 4.9. As part of the coal resource development pathway it is also recommended to include a map of the bioregion or subregion highlighting names and locations of all proposed resource projects, as well as a timeline diagram (Gantt Chart) outlining the timing (and stages) of individual operations.

Importantly, all detailed quantitative information relating to the management and use of surface water and groundwater during resource extraction (including mine dewatering for coal and aquifer depressurisation for CSG) is compiled and reported elsewhere in the suite of bioregional assessment products, that is, not in companion products 1.2 or 2.3. This water-related information is initially compiled as part of companion product 1.5 for each bioregion or subregion (about current water accounts and water quality) and then reported in the water balance assessment (companion product 2.5) (Table 2 and Figure 2). The reasons for this approach are further discussed in Section 3.6.1.

2.4 Using the coal resource development pathway

Most of Australia’s coal-bearing geological basins (including those in the Bioregional Assessment Programme) are at various stages of regional-scale coal and CSG development. Some of the more geographically remote basins (e.g. the Arckaringa and Pedirka basins in the Lake Eyre Basin bioregion) are the focus of relatively greenfield exploration efforts that are working towards improved geological understanding and resource characterisation. There are no existing mining operations in these basins. In contrast, other BA regions have a very mature exploration history with many commercial coal mining operations that have been active for decades. The Hunter subregion in the Northern Sydney Basin bioregion, for example, has more than 30 currently operating coal mines. In some areas, more recent production sites may also operate within a basin that contains historical (i.e. now closed) mines.

For BAs, it is important to understand the current stage of coal and CSG resource development within each bioregion, as well as how this is likely to be transformed in the future as newly proposed developments emerge online. This is because this information is required for developing conceptual models (and associated numerical modelling simulations, if applicable) that seek to explicitly define the causal pathways that link coal or CSG developments with impacts on water‑dependent assets and their receptors. The development time frames and opportunities for coal resources within a bioregion or subregion will likely differ from those for CSG. For example, in some basins coal mining may have a long and established history over many decades, but CSG development may remain in early exploration stages without existing commercial operations. The contrast between the current and future level of coal and CSG development thus needs to be explicitly stated in the coal resource development pathway. Given the considerable regional-scale development variation that exists in the BAs, the scale and maturity of both coal and CSG operations is expected to differ between all bioregions.

The description of the coal resource development pathway is written as a concise synthesis of all expected developments at the scale of the bioregion or subregion and not simply at the level of individual mines or resource projects (Section 4.9). As a result, the regional scale cumulative effects of development can be better understood and considered in later numerical modelling stages, with individual development components integrated into a whole-of-basin resource pathway. The information requirements needed from the coal resource development pathway to support subsequent numerical modelling are outlined in Section 4.10, and these provide guidance as to the type of information that Assessment teams need to compile during the research and evaluation stages. However, as noted in the BA methodology (Barrett et al., 2013), there may be developments in some bioregional coal resource development pathways for which there is currently insufficient data or knowledge available for them to be incorporated in numerical modelling simulations. Where such situations occur, these developments are clearly noted in companion product 2.3, as well as the reasons for not undertaking surface water and groundwater numerical modelling (although it is recognised that it may be possible for Assessment teams to qualitatively assess and comment on the potential impacts of some developments which cannot be numerically modelled, and this will be done as part of BA analysis if possible). Ideally in these circumstances, it is useful to also include a summary of the type of fit-for-purpose data that is further required to satisfy the modelling requirements for these resource projects. In this way, future data collection work can be appropriately targeted, and interactions with resource development companies may assist in gaining access to datasets that can then be incorporated in modelling simulations.