On dry SAG mills end liners: Physical modeling, DEM-based characterization and industrial outcomes of a new design

Abstract

The role of end liners in dry SAG mills with the objective of obtaining a thorough understanding of the effects of end liners design on the load trajectory and SAG mill performance was experimentally studied. The test works were conducted in a scale down mill with a diameter of 1 m. It was shown that the liner in the first and the last 20% of the mill length which were under the protection of the deflector liners experienced no deformation. To improve the grinding efficiency, a new design using low profile end liners incorporating radial ribs of proper height was investigated. The results indicated that the new lower height profile deflectors and 15.5 mm-height (14.5 cm in industrial scale) radial ribs improved the mill performance. A new liner design was proposed by decreasing the number of liners in each slice from 5 to 4 pieces. The thickness of the inner head liners reduced from 45 cm to 30 cm and the outer deflector liners were replaced by 14.5 cm radial ribs. The distance between feed and discharge end liners increased from 115 to 176 cm resulting in an increase of 53% in the effective mill length. The weight and volume of new end liners decreased by 9 and 23%, respectively. Installation of the new liners in Aerofall SAG mills increased the throughput from 441 to 465 t/h, decreased the product size from 519 to 480 μm and decreased the amount of recycled material from the SAG mill product from 10 to 6%. The most significant improvement was observed in the liner life; an increase of 50– 200% in liner life depending on the location of end liners was achieved. The relining time also reduced by 37.5% with the new liners.