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Abstract
Grinding remains the major constituent of the total cost of processing minerals in most applications. As a result, many studies have been carried out with the aim of determining the effect of various operating parameters on the mill power draw. Charge motion is one of the major parameters affecting grinding efficiency and mill power draw. Although there have been numerous investigations on the effect of liner design on charge motion, the effect of charge profile due to liner wear during mill operation has not received much attention. In this research, the Powell’s analytical approach to calculate the charge trajectory with respect to the liner profile was used to develop a software based on Microsoft Excel©. As a case study, the liner wear profile of the Sarcheshmeh copper complex SAG mill was used to model the liner wear rate and calculate the changes of lifter face angle and lifter height during mill operation. Results were then used to determine charge motion in the SAG mill at any given operation time. The results indicated that after 3000 hours of operation the lifters face angle increased from 14 - 34.6 degrees and the height of lifters decreased from 15.2 - 8.6 cm. Simulation of charge motion in the mill after 3000 hours of operation showed 34 degrees difference between the maximum and minimum of angles of impact along the mill due to the non uniform wear profile. It was also found that the variation in the pattern of the charge motion depends on the mill working hours and the distance of the desired point from the feed end. It was determined that the ratio of spacing to the height of lifters (S/H) plays an important role in the grinding efficiency and throughput. During 3000 hours of operation, S/H ratio of the Sarcheshmeh SAG mill increased from 1.7 - 3.2.

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		KMPC Hemmat A Mineral Processing Digital Library
	All Years to Access Full-Text Export citations SPREADSHEET BASED MODELLING OF LINER WEAR IMPACT ON CHARGE MOTION IN TUMBLING MILLS By M Yahyaei and S Banisi Published in International Mineral Processing Congress (IMPC) at 2010 Direct link: http://kmpchemmat.ir/pii/39549 Abstract Grinding remains the major constituent of the total cost of processing minerals in most applications. As a result, many studies have been carried out with the aim of determining the effect of various operating parameters on the mill power draw. Charge motion is one of the major parameters affecting grinding efficiency and mill power draw. Although there have been numerous investigations on the effect of liner design on charge motion, the effect of charge profile due to liner wear during mill operation has not received much attention. In this research, the Powell’s analytical approach to calculate the charge trajectory with respect to the liner profile was used to develop a software based on Microsoft Excel©. As a case study, the liner wear profile of the Sarcheshmeh copper complex SAG mill was used to model the liner wear rate and calculate the changes of lifter face angle and lifter height during mill operation. Results were then used to determine charge motion in the SAG mill at any given operation time. The results indicated that after 3000 hours of operation the lifters face angle increased from 14 - 34.6 degrees and the height of lifters decreased from 15.2 - 8.6 cm. Simulation of charge motion in the mill after 3000 hours of operation showed 34 degrees difference between the maximum and minimum of angles of impact along the mill due to the non uniform wear profile. It was also found that the variation in the pattern of the charge motion depends on the mill working hours and the distance of the desired point from the feed end. It was determined that the ratio of spacing to the height of lifters (S/H) plays an important role in the grinding efficiency and throughput. During 3000 hours of operation, S/H ratio of the Sarcheshmeh SAG mill increased from 1.7 - 3.2.