Optimize Fragmentation with ShovelCam
Blasting is the first and lowest cost per ton stage in the comminution value chain. The basic principle that effective blast design can optimize fragmentation from the Run of Mine (ROM) ore muck pile to improve productivity through digging, loading, and crushing to grinding and increase mine site profits has been well documented. This paper discusses the use of real-time fragmentation analysis at the muck pile to optimize energy factors required for each blast.
Comminution is an energy intensive process which accounts for a major proportion of mine site costs. Effective blasting can improve comminution and deliver significant reductions to mine site unit costs, CEEC (2016).
Engineers, scientists, builders, and even philosophers have long promoted the phrase “measure to manage”; the essence being “you can’t improve what you don’t measure”.
Blast Engineers measure fragmentation in ROM ore for feedback to manage energy input in the design of blast patterns to optimize the ROM product size for downstream operations, whether they be for ROM Leach or feed into the primary crusher.
Many authors have reported:
- For mines with semi-autogenous grinding (SAG) mills, increasing fines in ROM ore can increase SAG mill throughput from 8% to 30%, Cameron, Drinkwater, and Pease (2017)
- In iron ore mines, reducing fines in ROM ore can increase lump to fines product ratio, McKee (2013)
- In heap or dump leach operations, target fragmentation is critical to maintain leach pad permeability and maximize leach recoveries.
Improved fragmentation in ROM ore can increase shovel dig rates and truck fill factors, which lead to decreased cycle times, as well as reducing maintenance costs on loading and hauling equipment.
Detecting oversize rocks at the ROM muck pile allows diversion to a secondary breakage area to avoid blocking the primary crusher causing downtime and lost production. Better still is modify the blast design to avoid producing oversize rocks.
As mining companies apply innovative technologies throughout their operations, a measure of fragmentation at the blast is critical to manage advanced fragmentation, differential blasting of ore and waste and grade engineering studies.
ShovelCam provides continuous, automatic monitoring and particle size measurement of blast fragmentation. Unique image analysis algorithms are applied during shovel operation so that quality measurements of post-blast fragmentation are calculated. The automated process avoids costly manual capturing and editing of images to provide operators statistically relevant samples for best decision making. Measured fragmentation data is tied to shovel location for comparison to blast design forecasts for overall effectiveness. ShovelCam provides immediate feedback to the mine on blast performance, feed forward to the plant or leach pad on what is coming from the mine, correlation of PSD to shovel maintenance and enhanced process control decisions.
Optimizing fragmentation of the blast is a multi-discipline iterative process which involves a thorough understanding of rock structure and strength together with modelling and simulation of the blast design and the downstream processes. Since its inception, Julius Kruttschnitt Mineral Research Centre (JKMRC) focused on developing mathematical models of all unit processes in the mining value chain, then applying these models to produce process simulators. The outcome was three innovative technology tools, JKSimBlast, the JKMRC Blast Fragmentation Model and JKSimMet, which were fundamental to the development of the Mine-to-Mill technologies in the 1990s. Following demonstrations of significant increases in mine site productivity and profits, Mine-to-Mill projects were widely adopted by the global mining industry then largely forgotten during the mining super cycle, Cameron, Drinkwater, and Pease (2017).
Mine-to-Mill and other available technologies are again in favour as companies are driven to restore productivity, mine site profits and return on capital invested.
By measuring PSD on-line from the mine through to the mill, ShovelCam, TruckCam, and ConveyorCam are among available technologies currently in demand.