Abstract:
The Transportable Moisture Limit (TML) is a regulatory parameter of great relevance for the mining industry, firstly because it is related to the safety of maritime transport, preventing the occurrence of instability in mineral cargoes, and because it is a regulatory/technical restriction on shipments, requiring accurate moisture content control. The TML is not a fixed value, it is determined by laboratory tests and varies with the ore characteristics, being important to study which ore characteristics influence its value. The present work investigated the influence of the solids density on the TML of iron ore fines determined by the PFD80 method, considering two approaches: theoretical and experimental. It was found that, for the same void ratio, the lower the solids density, the higher the TML, and that ores with the same volumetric relationship between solids, water and voids may have different TMLs due just to the difference in solids density. This finding demonstrates that if an ore has a higher TML, it does not imply that this ore is safer. The safety of a cargo is much more related to its moisture content, and to the distance between the moisture content and the TML.