Achieving stable spoil pile landforms with optimal earthworks

Confirmation seminar presented by Camilo Cordova

The geomorphic landform design approach is a reclamation technique that may offer opportunities to improve aspects of mine rehabilitation and closure in Queensland. The design approach is based on constructing a steady-state, mature landform condition and takes into account the long-term climatic conditions, soil types, terrain grade, and local vegetation that would incur in reducing bulk earthwork volumes in relation to commonly use linear closure designs.

The purpose is to review current mine spoil closure design objectives and techniques, such as:

• The design objective for closure is often to achieve a grazing post mining land use (PMLU)
• Linear designs are not resilient over time and require ongoing maintenance
• Commonly used techniques to evaluate erosion rates
• Commonly used approaches used to evaluate the progressive closure performance and outcomes are often subjective

A new framework is proposed for mine spoil closure designs that account for:

• Regional distribution of slope lengths and angles
• Rehabilitation that focuses on functional natural habitats
• The use of Landform Evolution Models (LEMs) to improve mine spoil landform designs.
• Improve models by incorporating geotechnical slip failure into the gullie formation mechanisms.
• Improve calibration methodology and performance evaluation of LEMs using high resolution photogrammetry digital elevation models (DEM).