Model code and solver

The model is run using the finite-element package, MOOSE (2016a). Many other groundwater models of coal mining in the Hunter Valley use FEFLOW or versions of MODFLOW (see Section MOOSE offers the following features:

  • open source and well tested. MOOSE has been built by the nuclear industry and, as such, is subjected to continual and rigorous testing (MOOSE, 2016b).
  • able to run in batch-mode on high-performance computing clusters in order to complete the uncertainty analysis. MOOSE is designed for efficient parallel computing on high-performance machines, so its size is limited only by the machine.
  • able to represent both fine spatial details, both horizontally and vertically around mines, as well as a large regional area. This is important in the Hunter subregion which is both large in size, but heavily mined in certain areas. MOOSE is a finite-element code: the finite-element method is the preferred numerical method of capturing such differences in length scales. The finite-element mesh can be fine around rivers and mines in plan view, as well as containing more model layers in the vicinity of mines to accurately model multi-seam mining operations, and coarse in regions of lesser interest.
  • ability to accurately model the dynamics of unsaturated flow, especially around the alluvium. MOOSE solves three-dimensional unsaturated flow.
  • ability to enhance hydraulic conductivity around longwall mines. MOOSE naturally includes spatially and temporally varying hydraulic properties
  • numerically stable so that certain parameter combinations encountered in the uncertainty analysis do not cause the program to crash. MOOSE uses a fully implicit time-stepping scheme. This means it is unconditionally stable (irrespective of the number of source/sink terms and nonlinearities), can take large time steps, and it automatically conserves mass (the mass-balance errors are of the order of machine precision which is approximately 10–13%).

In conclusion, MOOSE incorporates all the requirements of the Hunter groundwater model.

Simulations are run in parallel using 48 cores per simulation on supercomputers, chiefly the Pawsey computer ‘Magnus’ (Pawsey Supercomputing Centre, 2015) and the CSIRO computer ‘Pearcey’.

Last updated:
18 January 2019
Thumbnail of the Hunter subregion

Product Finalisation date