Application of geographic information systems to the assessment and management of mining impact

Abstract

SIBERIA requires calibration of both hydrology and sediment transport components. The HEC-HMS model is used to extend the runoff record in the Ngarradj catchment and a flood frequency analysis performed to identify the 1 in 2.33yr peak discharge required for calibrating SIBERIA. The sediment transport component of the SIBERIA model is calibrated for both natural and mine surface conditions. Natural sediment loss parameters are derived from stream gauged data for three sub-catchments in Ngarradj that have distinct geomorphological characteristics. Mine impacted parameter values are derived for four potential surface conditions using rainfall simulation experiments.

This research develops a GIS based approach for assessing the potential impact of post-mining landforms on sediment movement and hydrology within a catchment. The methodology is applied to the Jabiluka Mine in the Northern Territory of Australia. The research first develops a GIS based simple erosion risk assessment model that is able to rapidly estimate erosion risk based on widely available spatial data. The SIBERIA landform evolution model is investigated as a tool for analysing more advanced geomorphological change. SIBERIA is linked to the Arc View GIS software package through the development of ‘ArcEvolve’, a GIS extension that simplifies application of the model.

The on-site and off-site impact of two potential post-mining andform designs at Jabiluka is assessed using the GIS based tools and SIBERIA. The proposed landforms are found to significantly impact the minor tributaries draining the mine affected catchment, but are not found to have a significant impact on sediment loads downstream in Ngarradj. Simulations, however, indicate that careful selection of the surface material of the final landform is required to mimic pre-mining surface conditions as both less and more stable surfaces can have a significant impact on the surrounding catchment. Further investigations suggested from this research include; 1) quantification of error propagation within SIBERIA, 2) sensitivity of geomorphometry based analysis and; 3) the validity of plot versus field derived parameter values in SIBERIA.

Date of Award	Apr 2003
Original language	English
Supervisor	Ken Evans (Supervisor)