Common ways tailings laboratory test programs go wrong

Dr David Reid

There has been a significant increase in the in-situ investigation and laboratory characterisation of tailings over the past decade. Similarly, there are more advanced laboratory testing devices and testing centers available for use by those seeking to characterise tailings mechanical behaviour. While these advances are undoubtedly beneficial, there are nonetheless many occasions where a significant quantity of laboratory tests on tailings are carried out using sample preparation approaches, test methods, or stress conditions such that the results obtained may misrepresent actual in situ behaviour to various degrees. Often these issues are only identified in third party review (if at all), after the available material obtained from depth has been exhausted.

This presentation first outlines the series of decisions that the engineer and/or testing centre must make in order to carry out a laboratory test program on tailings. Particular emphasis is placed on means to manage saturated samples from depth in terms of the effects of sample management, sample disturbance, and subsequent reconstitution procedures. Examples are presented demonstrating how some attempts to test in situ samples “intact” – i.e., assuming negligible disturbance – and the use of inappropriate sample preparation methods can provide misleading results. Finally, the important differences between below-slope plane strain conditions and typical axisymmetric laboratory tests are highlighted and means to relate these two situations in the application of laboratory test results are outlined.

About the speaker

Dr David Reid Research Fellow, UWA

David is a Research Fellow at The University of Western Australia.  He was 20 years’ experience in the design, in situ and laboratory characterisation, and analysis of tailings and tailings storage facilities.  His area of focus is on improving laboratory and in situ methods to characterise tailings behaviour.

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