3.6 Commentary for coal resource developments that were not modelled

Summary

When the coal resource development pathway (CRDP) for the Gloucester subregion was finalised in October 2015, the Gloucester Gas Project Stage 2 and beyond was identified as an additional coal resource development. Yet due to quantitative information (such as (i) geographic location(s) of the subsequent stage(s), (ii) number of wells in the subsequent stage(s), and (iii) depth of coal seam gas (CSG) wells in subsequent stage(s)), not being publicly available at the time, the Gloucester Gas Project Stage 2 and beyond were not able to be numerically modelled. Due to operational factors, if such subsequent stage(s) were to go ahead they would likely be located to the west and south of Gloucester Gas Project Stage 1. The hydrological effects of these subsequent stage(s) can be evaluated with the model framework documented in companion product 2.6.2 for the Gloucester subregion (Peeters et al., 2018), provided production bore locations and timing are known.

In February 2016 AGL formally announced that they were not pursuing the Gloucester Gas Project.

When the coal resource development pathway (CRDP) for the Gloucester subregion was finalised in October 2015 (see Table 8 in Section 2.3.4.1 in companion product 2.3 for the Gloucester subregion (Dawes et al., 2018)), the Gloucester Gas Project Stage 2 and beyond was identified as an additional coal resource development. Yet due to quantitative information (such as (i) geographic location(s) of the subsequent stage(s), (ii) number of wells in the subsequent stage(s), and (iii) depth of coal seam gas (CSG) wells in subsequent stage(s)), not being publicly available at the time of the CRDP finalisation, the Gloucester Gas Project subsequent stage(s) were not able to be numerically modelled.

If subsequent stage(s) of the Gloucester Gas Project were implemented, it is envisaged that they would be located to the west of and further south of Stage 1 for a number of reasons. Firstly, part of the Gloucester Gas Project Stage 1 plan was to build a pipeline south from Gloucester to Hexham (near Newcastle) for post-extraction processing/purification, so any subsequent stages would likely be south of Stage 1 to optimally connect to this pipeline. Secondly, Stage 1 is located in the north-east of PEL285 and the NSW Government exclusion zone around urban areas, including the town of Gloucester, essentially diminishes the likelihood of CSG development north of the town where the geological Gloucester Basin narrows (Dawes et al., 2018, Section 2.3.4.1). In other words, going north from Stage 1 would mean additional pipeline would need to be built and, with limited areas from which to extract CSG, this appears to be not economically viable.

Groundwater numerical modelling for the Gloucester Basin (companion product 2.6.2 for the Gloucester subregion (Peeters et al., 2018)) does not allow for attributing drawdown or changes in surface water – groundwater flux to individual developments. It is therefore not possible to separate the hydrological impacts of CSG extraction from those of coal mining. It is therefore not possible to extrapolate the current model results to provide an indication of what the hydrological impacts of subsequent Gloucester Gas Project stage(s) would be, although the model framework can be used to simulate these changes if bore locations and production schedules are known.

In general, the groundwater modelling results (from this subregion and other regions) indicate that open-cut coal mining results in large drawdowns in close proximity to the mine footprints, whereas CSG operations tend to result in smaller drawdowns, but with a larger spatial extent.

In February 2016, AGL formally announced that they were not pursuing the Gloucester Gas Project (AGL Energy Limited, 2016). As a result, neither Stage 1 nor Stage 2 are likely to proceed.

Last updated:
9 November 2018
Thumbnail of the Gloucester subregion

Product Finalisation date

2018