The in-situ ore is separated from the waste rock in most metal mining operations. It is subjected to a series of breakage and separation processes to recover the valuable material from the waste. Profitability in this industry depends on how efficiently the in-situ rock is converted into the final helpful product.

Even though the breakage and separation processes at the mine and mill are interdependent, traditionally, mining and milling processes are managed and optimised as separate cost centres with little understanding of the impact of one method over the other. In the late 1990s, researchers at the University of Queensland have proposed a concept popularly called "Mine to Mill Optimisation" and demonstrated that all the processes in the mine to mill value chain are inter-dependent and blast fragmentation (or particle size distribution) plays a critical on downstream processes, especially on the downstream AG/SAG mills. During the initial stages, the focus was on producing finer fragmentation from blasts such that the fine particles can increase SAG/AG mill throughput where there is enough capacity in the ball mills. However, the first generation mine to mill strategy has the following limitations:

• Finer fragmentation from the blasts constrained the circuit ball mill, limiting mill throughput and making the circuit grind coarser, affecting recovery.
• Indiscriminate increase of blast energy without understanding its impact on dilution and damage leads to poor overall meal output and higher risks of wall damage.

The Advanced Mine to Mill concept recognised these limitations and developed practical strategies to address them. A brief list of some of these strategies is given below

• Produce optimum size distribution (not just more acceptable) and balance the transfer size between the SAG and ball mill to improve the overall circuit throughput (Powell et al. 2018).
• Implement production schedules and blending strategies to primary consistent and optimum feed size and hardness to the mill.
• Implement strategies to minimise dilution, ore loss and damage from blasting without compromising on fragmentation (Picorelli et al., 2018).
• Techniques to quantify the ore variability from advanced laboratory tests and measure drilling parameters from blast hole drilling (Parades et al., 2018, Faramazari et al., 2018).

This workshop is designed to explain the basic principles of Advanced Mine to Mill strategies and then how to apply them in the field. It provides practical solutions and case studies to demonstrate the potential value of these strategies. Finally, the workshop will increase the awareness and communication between mining engineers and metallurgists to work collaboratively by providing practical problem-solving exercises.

This workshop is aimed at drill and blast engineers, mine superintendents, metallurgists, plant superintendents, mine managers, concentrator managers, general managers, asset optimisation managers, and business improvement managers - personnel responsible for improving the overall productivity of operations.

MINE TO MILL 2019