Experimental study and numerical reproduction of self-weight consolidation behavior of thickened tailings

Abstract: Thickened tailings, defined as mineral wastes that behave as a non-Newtonian fluid, show a small yield stress and release a small amount of water following deposition. Thickening has become an increasingly used option in tailings management. This paper presents a detailed examination of gold mine thickened tailings undergoing self-weight consolidation, which is an important mechanism affecting soft soils immediately after deposition. Self-weight consolidation was evaluated using a column equipped with water pressure transmitters whereas a slurry consolidometer was employed to obtain the compressibility relationship under low vertical effective stresses. The piecewise-linear model CS2 was used to model the experimental self-weight consolidation test. This model proved very accurate in reproducing the observed behavior. Both the test results and the model results also confirmed the absence of sedimentation in the thickened tailings, which is in agreement with values reported in the literature related to similar materials

Sand Displacement and Compaction around Model Friction Piles

By means of radiography techniques the displacement and compaction of sand around strain gage instrumented model piles has been studied. Tests reveal a possible explanation for the low transfer of load through “skin friction” developed by a straight-sided pile, and the high transfer of load developed by the tapered pile. The limits of “visible” soil movement (displacement envelopes) have been determined for nine different pile conditions and a direct relationship has been found to exist between the magnitude of the displacement envelope and pile capacity, indicating interdependence of transfer of load through the pile point and pile wall. </jats:p

2013 Colloquium of the Canadian Geotechnical Society: Geotechnical and geoenvironmental behaviour of high-density tailings

The breaching of containment of conventionally deposited mine tailings impoundments, and the consequent release of tailings flows with long run-outs, unfortunately remains not uncommon and often has devastating ecological and economic consequences, occasionally including the loss of human life. Rather than the breaching of containment itself, which can result from a number of causes (poor control of the phreatic surface, unrecognized dam foundation issues), the contributing factor to the severe consequences of dam breach is the very low density and strength and / or susceptibility of the tailings to liquefy or soften under loading, combined with the driving weight of the ponded water, which allows for significant run-outs (in some cases 10â s of kilometres) to occur. Hence the motivation for alternative technologies that dewater tailings before deposition to the point where reliance on containment is minimized or eliminated. In this paper, these technologies are referred to as High Density tailings, which includes any technology that at least produces non-segregating tailings that will form a sloped stack when deposited, including thickened, paste, and filtered tailings. The paper explores a number of issues related to high density tailings, including shear behaviour, dewatering behaviour, acid generation, and surface deposition rheology. The paper concludes with some discussion on what are the limitations on this technology holding back its wider adoption, and how these limitations might be overcome.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author