GHERG is currently working on a variety of projects and sub-projects.
The effect of water quality on the strength of brown coal
GHERG has been awarded a project by Victoria’s Department of Jobs, Precincts and Regions to investigate the effect of water quality on the strength of brown coal.
The rehabilitation and alternate use of the Latrobe Valley’s brown coal mines has become the main focus for the community, government and industry in the Gippsland region. Current options proposed for the rehabilitation of the mines involve filling the pits with water, either partially or in full. Water sourced from rivers and creeks, horizontal drains, shallow aquifers and leachate of covers have different chemical compositions to pure rainwater. The pit water quality will be dominated by water entering the pit but may also be affected by changes due to water loss by evaporation. Organic compounds like coal may be affected by a change in the chemical equilibrium of its pore fluid. Contact of this water with the pit batters and mass flow into the adjacent coal, or change of salt concentration by diffusion may affect the mechanical strength of submerged coal and, consequently, the stability of batters of the water-filled pits.
This project aims at investigating whether variation in the chemical composition of brown coal pore water influences its strength, which would impact the long-term stability of landforms in the Latrobe Valley.
Numerical investigation of coal cover stability and long rehabilitated slopes in Latrobe Valley brown coal mines
GHERG has been awarded a project by Victoria’s Department of Jobs, Precincts and Regions to undertake a numerical investigation of coal cover stability and long rehabilitated slopes in Latrobe Valley brown coal mines.
Coal slope coverage is a vital component of future mine pit rehabilitation for Gippsland’s Latrobe Valley. Mine coverage systems provide a range of beneficial properties for rehabilitated mining areas, minimising both the infiltration of surface water and the risk of fire due to coal combustion. Rehabilitated mine slope designs are typically governed by erosion rates and machinery accessibility for the purposes of maintenance. While these are important considerations for the coverage of coal slopes, the integrity of coal covers is equally important. Previous GHERG research outcomes have identified that the shear of clay soils controls the behaviour of slope clay-coal interfaces; however, the impact of potential cover degradation on pore pressures and ground movements has yet to be extensively investigated. Damage to the integrity of the cover materials may lead to tensile cracking, erosion and the infiltration of water, affecting pore pressures and soil mechanical properties that may induce ground movements.
The objective of this project to investigate potential hazards to mine cover integrity through the development of numerical models for a range of rehabilitated Latrobe Valley mine landforms and cover systems.