Kemp A.,OKane Consultants Pty Ltd |
Taylor I.,OKane Consultants Pty Ltd |
Scott P.,OKane Consultants Pty Ltd |
O'Kane M.,OKane Consultants Pty Ltd
AusIMM Bulletin | Year: 2015
A foremost challenge in mine waste storage management is effective design of stable waste landforms that provide geochemical and geotechnical stability that resist long-term erosion and degradation of cover systems. Surface instability can expose reactive waste, lead to acid metalliferous drainage (AMD) and increased sedimentation of downstream waters, and cause poor revegetation or related environmental impacts. The landform surfaces are the interface between the mine landform and the surrounding environment and therefore affect long-term environmental impact. This article examines practical design guidance from early concept development through to the quantitative assessments required for detailed design. This extends to discussion on overall geometry of landforms, veneer stability, cover system design and the selection of cover system materials. These factors should be considered together and integrated with internal waste landform design to provide confidence in design and improve closure outcomes. Embankment stability is affected by geometry, including slope lengths, gradients and catchments. Longer, shallower slopes have larger catchments and potentially more runoff, whilst shorter steeper slopes have less catchment but (owing to the steep grade) require less energy to mobilise waste. A balance needs to be reached for best performance, which is unique for the specific material types and hydrological setting.