SAG/Ball Mill Optimization
Better efficiency, starts with better grinding. You’ve already gone through the work to bring the ore to the mill, now it’s time to recover as much precious metal as possible.
GrindingExpert™ automatically adjust feed rate, mill speed and water addition to reduce upsets, eliminate grind-outs and increase tonnage in SAG / ball mills. We constantly maintain desired operating conditions by monitoring bearing pressure, power, recycle pebbles, mill density and mill acoustics. On average, expect a 3-6% increase in SAG mill throughput over an operator/DCS system. PlantVision™ visually monitors the feed and relays critical information about the properties of, and changes in, the incoming ore. MillScanner™ will skillfully listen to the mill to ensure it’s safe, reliable, and efficient operation. KSX will tie all of the information together to create optimal set points from which its neural network and genetic algorithms can continuously, learn, predict and further optimize SAG mill throughput.
The KnowledgeScape solutions work together to see, listen, and think about the best way to increase tonnage at all times and for all conditions. Our ball mill strategies automatically adjust sump water and mill water addition, mill speed where available and can open and close cyclones when appropriate. The strategy smooths disturbances and provides optimal particle size in cyclone overflow to flotation.
Many GrindingExpert™ solutions will include our MillScanner™ Smart Sensor. Using a highly innovative solution that is fixed in rotation with the shell of the SAG mill, MillScanner™ accurately and continuously monitors a mill’s contents to provide invaluable information regarding charge toe and media angles, liner/steel impact detection, and volumetric loading in realtime. MillScanner™ provides information to KSX via OPC communication, and displays radial trends graphically to the control room operator . Combined with traditional process variables such as bearing pressure, mill power, and recycle pebbles, the data provided by MillScanner™ allows the KSX Expert System to make the best possible decisions, in the least amount of time, for all conditions. Because you are taking control actions based on measured media angles, the time delay in system feedback from feed changes is greatly reduced, which helps increase SAG mill throughput.
The information that MillScanner™ provides to KSX ensures that the software is able to effectively optimize SAG mill set points and increase efficiency better than any other system. Control strategies can now factor in volumetric loading, charge toe angles, and steel-to-liner impacts in the decision tree along with bearing pressure, recycle pebbles, and mill power.
Compromising accuracy when selecting an acoustic sensor for your girding circuit will only compromise the integrity of the control system for future improvements. Control does not have to be what it was 30 years ago, and with KnowledgeScape leading the way in automated process optimization, higher throughput and increased reliability are now possible. Utilizing a MillScanner™ results in better grinding, clear vision of the mill contents at all times, reduced steel and power usage, longer liner life, and significantly increased profits. MillScanner is the ultimate tool for increasing SAG mill throughput and reliability.
GrindingExpert™ isn’t just about SAG mills. Our GrindingExpert™ solutions include ball mill strategies that achieve the target grind size while maximizing throughput, or when the circuit is SAG mill limited, achieve the finest grind size possible, thus increasing mineral liberation and recovery. GrindingExpert™ has been shown to typically increase throughput by 3-6%
Here are some actual results from Los Pelemres, where GrindingExpert was implemented.
Mill Line 1: Note the shift in the curve to the right and the narrowing of the tails. The shift to the right represents the shift in the mean production. The narrowing of the histogram tails is a result of the remarkably smooth operation of the control strategy. Wild feed rate fluctuations are eliminated, resulting in smoother downstream operation. Even though production was dramatically improved, the product size of the secondary ball milling was reduced and recovery increased.
The results in SAG-Mill line 2 are even more dramatic. Because of segregation on the coarse feed stockpile, SAG-mill 2 receives a higher percentage of coarse material. The KnowledgeScape strategy’s ability to maintain smooth and stable operation of the mill was more apparent when contrasted to the DCS control on the “difficult” line.
Note that these histograms represent a combined throughput increase of 13.4 % or roughly 15,000 tons per day. This increase in production resulted in an increase of gross revenue between $55 Million and $78 Million per year! The on/off tests are performed to rigorous standards, and the guidelines for the tests are from the accepted best practices found here.