Assessment of strength and stiffness properties of compacted filtered iron ore tailings-Portland cement blends field stack

Resumen

Dry stacking of iron ore tailings (IOTs) with cementitious materials is a viable disposal option, but its large scale implementation faces challenges. Therefore, this study investigates the key factors influencing compaction in real field conditions, including moisture content (optimum moisture content and less than optimum moisture content), vibration frequency (0 Hz and 35 Hz), and number of roller passes (4P and 6P). To achieve this objective, an experimental IOT stack was constructed in five different layers using a specific amount of Portland cement as a cementing agent (2.5% by dry solid weight). Then, laboratory tests, such as unconfined compression, splitting tensile, and ultrasonic pulse velocity (UPV), were conducted on undisturbed samples to evaluate the unconfined compressive strength (q_u), splitting tensile strength (q_t), and initial shear modulus (G0). Based on the laboratory
tests conducted on the field-collected specimens, it was concluded that samples with moisture contents closer to the optimum moisture content (OMC), exposed to vibration, and subjected to six-roller passes exhibited superior mechanical performance. This study provides insights into optimizing the compaction process for large-scale IOT stack structures.