By Keith Vining
At Iron Ore 2017, a common concern across the industry was managing the short-term variability of ore characteristics within deposits in iron ore processing, the flow-on effects of unplanned processing issues, and the resulting downtime across the production cycle. Unlike long-term trends, these incidents are less predictable and require swift action to resolve to minimise output losses.
Our conversations at Iron Ore 2017 identified materials handling and processing control as the two areas most impacted by short-term ore variability. In this month’s blog, we discuss how ore variability across these two key areas affect your output quality and production, and how we can work with you to overcome these challenges.
As above-water-table, high-grade ore deposits decrease in abundance, and producers increasingly start to extract ore from below the water table, the wet and sticky ore problem is having an increasing impact on the iron ore value chain.
Wet and sticky ore can lead to a disrupted flow during processing and transport. When equipment cannot run at capacity or experiences unplanned downtime because of blockages, this has flow-on effects across the production cycle.
The increasing occurrence of problematic ore types can be accounted for in long-term planning. However, the characteristics that determine how wet and sticky ores behave during the production process are not as well understood. In order to minimise unexpected stoppages you need to:
With ores becoming generally finer in size, the increasing proportion of ultrafines in some ore types is likely to result in increased short-term variability in your site performance.
It is generally accepted that fine clays can cause problems in ore handling and processing. However, the influence of other ultrafine ore components is not so clear. For example, hematite blue dust can cause blockages due to poor flow properties. It is likely that any ultrafine ore component will have similar issues if sufficiently abundant, but the influence of different ore components and their critical thresholds are not well characterised.
Without a comprehensive understanding of ultrafines in the form of ore texture and composition, in addition to chemistry, processes cannot be adjusted as required to minimise their effect on plant performance.
While grade (i.e. total chemistry) is the primary measure of ore quality, grade alone does not guarantee product quality or consistency in downstream processing behaviour. There is an increasing awareness that these factors are also closely affected by local variations in complex mineralogy and texture of ore-bodies.
The increased need to mine below the water table, and finer sizing of some ores, creates a greater need to better understand iron ore processing characteristics, beyond just grade control, to ensure that short-term variations in ore deposits do not detrimentally affect output levels and quality.
We have extensive experience in ore characterisation, and classification can be used across your organisation to identify the causes of ore handling problems and develop better strategies to deal with them.
Given the nature and variability of ore deposits, short-term problems will always occur. However, we can take action to minimise the effects by developing a deeper understanding of the key mineralogical and textural characteristics of iron ore, beyond its chemistry. With an improved understanding of the texture and composition of ore deposits, you will have the insight to proactively foresee the warning signs, and deal with changes more efficiently and effectively.
The Carbon Steel Futures team at CSIRO, through our research and breakthrough science, is uniquely positioned to add value to your operation. Through ongoing analytical support, training, or product development, we can help you reshape your understanding of iron ore classification to support the management of short-term ore variability and produce superior outcomes.
To discuss how short-term variability in ore deposits is playing out in your organisation give me a call on +61 07 3327 4761 or email me directly at Keith.Vining@csiro.