Abstract:

Acid mobilization due to net percolation (NP) through overburden storage areas poses a significant water quality risk at closed mine sites. To protect groundwater, the Revegetated Cover System Program (RCSP) was organised to improve understanding of vegetation-substrate interactions that affect transpiration, and their impact on NP. The RCSP employs a cross-disciplinary approach and includes research partners from the mine owner, Okane Consultants, and the University of Western Australia. The RCSP will deliver practical and scalable solutions for optimising cover system transpiration, minimising NP, and reducing acid and metalliferous drainage risk at mine sites. The project will provide valuable insights into vegetation-substrate interactions, refine cover system design tools, and contribute to the development of sustainable mine closure practices. The target outcomes of the RCSP are to:

Quantify the effect of specific vegetation prescriptions on NP reduction through transpiration;
Define how soil spatiotemporal processes influence evapotranspiration and NP partitioning within cover systems;
Refine model parameters and test assumptions on plant traits influencing water movement; and,
Ensure research outcomes are practical and scalable for implementation.

These outcomes will be assessed through a field trial constructed at mine. The field trial includes eighteen vegetated cover trial plots, including three lysimeters. Vegetation establishment will be assisted with an irrigated germination period following seeding. To assess the risk of evapoconcentration posed by possible site water sources for the irrigation, salinity modelling was conducted. Automated monitoring collects data on site weather, soil moisture and suction, and lysimeter net percolation. Additionally, electrical resistivity tomography arrays provide an integrated soil moisture understanding at several plots. This presentation will share the objectives, approach, methodology, and initial results of the RCSP project and vegetated cover trial.

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Mr. Hal Cooper

Biography