Experimental Models of Metal Leaching for Scaling-Up to the Field


Mr Mike O'Kane, Mr Cheng Huang, Mr Eben Dy, Mr Liang Ma, Mr Zhong-Sheng Liu, Mr Zhong Xie, Mr Steven Pearce

There has been limited success to date in accurately predicting water quality from waste rock dumps at mine sites. Consequently, it has cost the mining industry hugely to implement mitigating measures for minimizing potential environmental impacts. Since the length scale of waste rock dumps at mine sites is about 3-4 orders greater when compared to lab-based and leach-pad tests, the drainage chemistry of rock samples from these tests is likely to be significantly different from that of the field. Thus a question arises: how to design the experimental models (smaller-scale testing models) so that the test results can be accurately scaled-up to the field? The authors of the paper have developed a similitude approach to design experimental metal leaching models and try to ground the scaling up process on sound scientific foundation. This paper will further the concept of the similitude approach and presents experimental models of metal leaching for predicting the drainage chemistry of waste rock dumps at mine sites. The experimental setups here are the same as ordinary humidity cell, column-leaching and leach-pad tests; but they are different in that the experimental models meet similitude conditions, which involve water-infiltration rate, rock particle size, rock-sample volume (depth and diameter) and leaching kinetic constants. By doing so, the similitude between the experimental models and the field is kept, and accordingly the scaling up relations of drainage chemistry between the two would also be kept.