Mechanical Behaviour of Fibre-Reinforced Cemented Iron Ore Tailings Across the Compaction Curve.

Tailings disposal is a major concern of the mining industry worldwide. After the recent upstream dam failures, the main tailings disposal method studied in Brazil is dry stacking. The mechanical behaviour of tailings disposed of by dry stacking can be enhanced by ground improvement techniques such as compaction effort, cement, and fibre insertion. Accordingly, the study was carried out herein to analyse the mechanical behaviour of a fibre-reinforced cemented iron ore tailings (IOT) through unconfined compression tests in specimens moulded at different points on the compaction curve using 1%, 3% and 5% of Portland cement and zero and 0.5% of polypropylene fibres as an alternative to enhance the overall performance of dry tailings storage facilities. The results showed that compacted fibre-reinforced cemented IOT strength and stiffness vary according to the dry unit weight and moisture content moulding point on the standard Proctor compaction curve. In addition, adding fibres to the compacted cemented IOT turns the brittle behaviour into a ductile one, especially for 1% of cement. Such enhancement is fundamental to guarantee the safety of iron dry stacks. Also, failure patterns are directly related to the moulding point on the compaction curve. Moreover, adding fibres has increased the strength of cemented and uncemented IOT, thus allowing the adoption of smaller cement contents. Therefore, for the first time, the behaviour of fibre-reinforced cemented IOT was presented and its dependency on moulding characteristics based on compaction curves position. [ABSTRACT FROM AUTHOR]