At a Glance
Global mining trends such as decreasing ore grades, energy shortages and costs, increasing rock hardness, environmental regulations and shortages in skilled labor are all contributing to a more complex mining environment for drilling and blasting. Hence, an effective fragmentation strategy needs to account for these factors and requires collaboration from both mine and mill managers to ensure manageable rock sizes at the mill for optimal throughput.
Many mining companies face challenges in creating a comprehensive rock fragmentation strategy, one in which various mine departments are aligned. Nevertheless, the costs for failing to get aligned on fragmentation KPIs and processes cannot be overstated, with high variability of blast fragmentation significantly impacting downstream processes including flotation, leaching and smelting. Suboptimal ore characteristics, in turn, affect the energy efficiency of milling processes and the overall quality of the final product, leading to further losses. According to this study, the average energy efficiency of mills across the US stood at a mere 1% in 2022.
Additionally, global mining trends such as decreasing ore grades, energy shortages and costs, increasing rock hardness, environmental regulations and shortages in skilled labor are all contributing to a more complex mining environment for drilling and blasting. Hence, an effective fragmentation strategy needs to account for these factors and requires collaboration from both mine and mill managers to ensure manageable rock sizes at the mill for optimal throughput.
Misalignments between the mine and the mill
While the profitability of the mine relies on the sales of tons of metal produced, mine managers and mill managers often have other short-term targets and KPIs to meet that can contradict this overarching goal. For example, at the mine, managers need to ensure that a set number of tons are extracted and delivered to the crusher. Meanwhile, at the mill, managers need to ensure that the tonnage of ore delivered by the mine is processed at a high metal recovery rate for delivery to customers.
However, a higher amount of ore extracted and delivered by mine managers often does not result in ideal conditions to be processed by the mill. Subpar drilling and blasting processes to meet targets can often lead to high levels of variations in rock size, in turn reducing the recovery rate at the mill.
To make matters worse, a common target for cost reduction is often drilling and blasting, with explosives easily decreased with minimal impact to tonnage extracted. However, this then comes at a cost to the mill and the overall yield of minerals, because subpar rock fragmentation leads to difficulties in processing at the crusher.
If production rate KPIs were to be maintained for the mill, energy and maintenance costs would then be impacted to process the same number of ore, resulting in higher costs for the mine – often several times the savings on the earlier drilling and blasting procedure.
Hence, in this situation, setting KPIs for both departments that lead to a more aligned performance to meet a shared goal is needed.
Foster Behavioral Change Through Aligned and Strategic Mine-to-Mill KPIs
To avoid situations such as the above, mine and mill management need to collaborate to define KPIs in a way that will foster the desired behaviors of workers at both locations. Primarily, performance metrics must factor in the goal of the mine, only then followed by those of the department. Secondly, metrics must then be aligned to ensure that the success of one does not compromise the performance of the other.
Achieving the correct energy distribution in the blast is also crucial to ensure an optimal level of rock fragmentation that minimizes the cost of processes downstream. By formulating a fragmentation strategy that encompasses the goals of the mine, the mill and each step in the value chain, companies can better mitigate their costs and maximize their yield and profitability.
Foster continuous improvement with strategically defined KPIs and drill and blast processes.
