Implementation of the coal resource development pathway


Groundwater modelling is undertaken for 58 coal resource development pathway (CRDP) mines, comprising 41 baseline and 17 additional coal resource developments. One baseline and five additional coal resource developments were not modelled due to lack of data or scale of proposed change.

The spatial extent of each mine working is represented in the model by its maximum footprint and does not vary over time. Each working is associated with a coal seam, which defines its depth. Footprints were obtained from a number of sources.

Flow rate time series are generated from historical data and forecast estimates of annual flow rates to represent groundwater extractions over the working life of the mine. Flow rates are varied in the uncertainty analysis by scaling the time series.

Hydraulic enhancement above longwall mines is implemented over the maximum mine footprint on the first day of mining. The change is assumed to be permanent. The magnitude of and depths over which hydraulic enhancement occur is uncertain and the parameters that govern these terms are varied in the uncertainty analysis.

A no-development simulation is run for 106 years to initialise the model, prior to undertaking modelling under baseline and CRDP.

The Hunter subregion has a long history of coal mining. Baseline coal mines and additional coal resource development were defined in Section 2.3.4 of companion product 2.3 for the Hunter subregion (Dawes et al., 2018). There are 42 baseline mines and 22 additional coal resource developments included in the coal resource development pathway (CRDP), although due to insufficient data or insignificant changes in mine pumping rates from the additional coal resource development, 1 baseline mine and 5 additional coal resource developments were not included in the groundwater modelling. The potential impacts from these non-modelled mines are considered qualitatively in companion product 3-4 for the Hunter subregion (as listed in Table 2).

For the 58 modelled mines (41 baseline and 17 additional coal resource developments), each has to be defined in terms of its location, type of operation (open-cut or underground), area, depth (seam) and rates of groundwater extraction (also referred to as flow rates). A number of parameters also need to be defined to characterise changes in the hydraulic conductivity of units above and below the mine workings as a consequence of mining.

Last updated:
18 January 2019
Thumbnail of the Hunter subregion

Product Finalisation date