The use of filtering technology has improved considerably during the past few years, and tailings disposal facilities using filtered tailings are becoming more and more commonplace. Where once this method was only deemed suitable for relatively small-scale operations, technological advances are now being realised for large-scale operators. Often this application appears to be, and in fact is, relatively simple and straightforward. As with other tailings preparation methods, the use of filtered tailings provides no inherent panacea for tailings placement. Designers are advised to adopt designs thoughtfully, using site-specific data, information and tailings properties to ensure the method is employed rationally and that the resulting facility designs are flexible enough to accommodate changes to presumed operational design criteria. Practical experiences with facilities where less than optimal performance was achieved are presented.

It is becoming increasingly common in the mining industry for either crushed ore or filtered mine waste to be stacked to a significant height (>100 m) in a moist state with little compaction, resulting in deposits that can be potentially loose and unsaturated. This paper presents a case history describing the characterization of stacked filtered tailings at a mine site in South America. Cone penetration tests with pore pressure and seismic velocity measurements (SCPTu) were carried out along with selected drilling, sampling, and laboratory testing. Compression wave velocity (Vp) and shear wave velocity (Vs) profiles were obtained and compared with laboratory values on reconstituted saturated and unsaturated samples. Results indicate that shear wave velocity is sensitive to suction hardening effects and appears to capture the correct unsaturated in situ behavior. The cone resistance, which is a large strain measurement, can destroy the beneficial effects of suction hardening and appears to be insensitive to the unsaturated in situ behavior, but may capture the correct behavior after the beneficial effects of suction are removed if the soil becomes saturated.

Filtered tailings technology has been successfully implemented only at a limited number of relatively low-production-rate mining operations. The technology, however, may be poised to make a dramatic leap forward as it is being proposed for use at several high-throughput operations. Demands from increasing regulatory scrutiny and decreasing water availability are likely to drive further adoption of the technology. This paper presents a recommended approach to select a tailings disposal method and summarises several filtered tailings design concepts and considerations that the author has found useful in his practical experience.

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