In most metal mining operations the in-situ ore is separated from the waste rock and 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 valuable product.
Despite of the fact that the breakage and separation processes that take place at the mine and mill are inter-dependent, traditionally, mining and milling processes are managed and optimised as separate cost centres with little understanding of the impact of one process over the other. In the late 1990's, 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) play 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 makes the circuit ball mill constrained - limiting mill throughput and/or resulting in a coarser grind, effecting recovery.
- Indiscriminate increase of blast energy without understanding its impact on dilution and damage leads to poor overall metal output and higher risks of wall damage.
The Advanced Mine to Mill concept recognises these limitations and is developing practical strategies to address them, such as listed below:
- Develop operational strategies, practical guidelines and tools for applying the solutions in day-to-day operation.
- Produce optimum size distribution (not just finer) to balance the transfer size between the SAG and ball mill and thus improve overall circuit throughput.
- Implement production schedules and blending strategies to main consistent and optimum feed size and hardness to the mill.
- Implement strategies to minimise dilution, ore loss and damage from blasting without compromising fragmentation.
- Techniques to quantify the ore variability from advanced laboratory tests and by using the measure while drilling parameters from blasthole drilling.
Due to the travel restrictions from COVID 19 crisis, an online workshop has been developed to explain the basic principles of Advanced Mine to Mill strategies and then how to apply them in the field. This online workshop is designed to provide practical solutions using case studies. The workshop is designed with assignments and practical problem solving exercises to increase the communication and collaboration between mining engineers and metallurgists. It will also have a panel discussion with experts from different fields (blasting, comminution, flotation, etc.) to share their experience and knowledge with the participants.
This workshop is aimed for drill and blast engineers, mine superintendents, metallurgists, plan superintendents, mine managers, concentrator managers, general managers, asset optimization managers and business improvement managers - personnel responsible to improve the overall productivity of operations.