Geochemical modelling of pit lake water chemistry to support management decisions
Stage 1: Selection of appropriate model
This model will maximise the use of the currently available data for model creation and validation. The current preference is not to focus on a single pit lake and model in detail but develop a simpler model that can be easily applied to cohorts of Collie pit lakes identified by the inventory collection and conceptual modelling. This general model would be less detailed but more suited to the low input knowledge environment of the Collie groundwater region and would support important pit lake and ground water management decisions.
Stage 2: Model parameterisation and testing
There is no option for detailed validation of the model at this stage, other than through use of existing historic and collection of new data sets arising from Stage 1.
Stage 3: Scenario testing
A series of different scenarios will be run to demonstrate model outputs and to test alternative pit lake management and environmental strategies for the different pit lake cohorts.
This project is using the model MODGLUE which is a coupled model that combines the groundwater model PCGEOFIM, the lake hydrodynamic and water quality model CE-QUAL-W2 and the hydrogeochemical model PHREEQC.
MODGLUE is capable of modelling all processes that are important to pit lake water quality. The schematic model coupling in MODGLUE shows these processes that include weather induced hydrodynamics with thermal layering, heath and gas exchange with the atmosphere as well as flow, transport and chemical changes in the subsurface. In addition, a wide variety of water quality processes in the lake water such as biological processes including algae growth and nutrient dynamics as well as equilibrium and kinetic chemical reactions can be modelled. Pit lake specific chemical reactions may be defined by means of an extendable hydro-geo-chemical database and rate limited reaction paths.
MODGLUE has already been applied to a variety of different mining pit lakes under different scenarios, producing results to guide surface and groundwater management.
Hydrocomputing (Germany), Mr Mike Mueller
Hydrocomputing (Germany), Ms Katja Eulitz
Dr Clint McCullough
Associate Professor Mark Lund