Soil-Plant-Atmosphere Numerical Modelling of a Cover System in North-western Australia Utilizing the Moisture Store-and-Release Concept - Simulation of Seven Years of Field Performance Monitoring

摘要

An open-cut iron ore mining operation located in the Northern, semi-arid, region of Western Australia has waste rock material within some dumps which contain material considered to be net acid generating. Two cover system field trials, TP1 and TP2, were constructed in July 2003 consisting of a 4 m thick coarser textured run-of-mine (ROM) and a 2 m finer textured ROM, respectively. Performance monitoring of soil temperature, suction and water content within the covers has been collected continuously at the trials since construction. Consequently, a unique set of monitoring data has developed over the seven-year period as the covers evolve from bare-surface to fully vegetated conditions. Numerical modelling was undertaken to simulate measured field responses at the two field trials. Simulating the measured field responses was challenging due to the numerous variables influencing soil-plant-atmosphere systems. Despite these difficulties, the calibrated models were able to acceptably simulate field responses, with TP1 and TP2 having coefficient of determination (R2) values of 0.86 and 0.92, respectively, over the period.This paper describes the methodology used to calibrate the model to accurately simulate measured field responses over the seven-year period. Field performance monitoring data is presented for the two cover system field trials.