Materials Handling addresses the problems that arise when high moisture, sticky ores are transported through bins and chutes and onto ships across the supply chain. In such a system, the overall performance is only as good as the weakest link. For example, a blockage in a single transfer chute can seriously disrupt the entire system, leading to significant delays and lost production costs. At sea, the liquefaction potential of iron ores needs to be identified and managed to mitigate the potential loss of ship and crew. This detrimental behaviour is strongly influenced by many factors including but limited to the presence of so-called slimes, moisture content and porosity, such characteristics make the ore complex to handle and can make it behave unpredictably. More effective designs, modelling and greater understanding of the materials physical characteristics to ensure robust design of handling, storage, transport, and dust-suppression equipment will aid the mitigation of many of these challenging problems.
This area of research will aim to identify and characterize the critical mineralogical elements leading to the cohesive and adhesive behaviours of wet-sticky iron ore. The outcomes of the study can then be utilised to understand material handling problems, such as adhesive build-up in transfer chute during mining operations. Subsequently, materials handling solutions can be formulated from the advanced wet and sticky ore characterisation methods and approaches.
1. Problematic Ores in the Materials Handling Chain
Reason: Future exploitation of ore bodies close to or beneath the water table need to be considered.
• Belt carryback
• Screen clogging
• Chute buildup
• Clogging of train wagons
• Remains in dump trucks
Wet and sticky ore
• Adherence of bulk material to handling equipment surfaces shows macroscopic effects when a number of soil particles adhere.
• Adhesion is of interest for materials which are cohesive as well.
• There is a need for rapid in-field testing capabilities of adhesion and cohesion properties of bulk solids.
3. TBS Wall Adhesion Tester
4. TBS Cohesion Tester
This area of research will develop a model to identify the dynamic adhesion response of iron ore through transfer systems and, in addition, to create a design selection criteria for optimised dynamic material transfer systems. The theoretical models will be based on a Mohr-Coulomb strength assessment based on the well-known bulk solids shear strength model. This modelling proposes a cohesive (compressive) and adhesive (tensile) strength element for the bulk material, however only the cohesive element has a well-defined measurement methodology. The definition of the adhesive element will be a focal point for this research.
Experimental test rig for iron ore build up in terms of various moisture contents
Comparison between simulation and experimental results
Recirculating impact plate system - Recirculating test rig to analyse the dynamic adhesion build-up over time.
The effectiveness of commercially available moisture reduction systems was assessed in this study. A ranking criterion was developed that would enable the optimum moisture reduction system to be selected for the specific bulk material being handled.
In addition, this study will identify the most suitable moisture reduction parameters for a hydrophilic ore of known characteristics. The outcomes of the study can then be utilised to select a moisture removal system and/or tune existing moisture removal systems in order to eliminate materials handling problems associated with handling wet material.
A correlation between energy use, adhesion reduction and flowability with respect to moisture change within the ore body will be investigated by the following aeration induced moisture reduction rig.