Tega is delivering epic performance in giant sized mills creating one of the most interesting case studies in the history of the mill lining, featuring Tega DynaPrime, a product of Tega DynaMax range. The case study is being presented at the SAG Conference 2019 held in Vancouver from 22nd September 2019 to 26th September 2019. The abstract for the paper being presented is as below.
“A Chilean Copper mine with 40 feet diameter SAG mill processing 4300 tph was facing very low avaliabilty due to continues unexpected shutdowns for failures on liners by cracks. Several kinds of alloys and designs were provided but results were out of control producing low production levels. Reasons of the criticity are related to the mill operation with high ball charge level and ball size till 6.25” diameter, producing cracks on liner, bolts breakeage, etc
Failure analysis on steel liners and some hybrid design shown the failure mechanism were related mainly to the third ring of the shell produced by the direct impact of grinding media on the liners. The amount of impact energy was over the capacity of design of the liners used and therefore the failures were happening uncontrolled and randomly through the life time since the second month of operation.
The 6.25” ball size were producing adiabatic cracks because the huge amount of energy transmitted to the liner in very short time lapse. There was no time to disipate this amount of energy by the mechanical deformation of steel creating the crack and the failure of the liner.
Due to the design of the shell liner, the cast liner was designed considering a huge mass of lifter bar with shell plate incorporated at the both ends adding another problem due to the differences of thickness betweel lifter and shell plate portions making more complicated the manufacturing of cast liners.
Cast manufacturer tried to avoid the cracks by using alloys more ductile but sacrificing the wear life and also producing cold welding by impact making a very tough task for removal of liners.
Some hybrid solutions were applied to try to solve the problem but many failures were continued appearing due to wrong design concept without enough capacity to absorve the impact energy and failed also.
A complete analysis and study of forces applied and the evaluation of impact energy was done by Tega and an amazing floating design was developed, combinig the best characteristic of every material in the different zones of the liner according to the mechanical behaviour expected. DEM and FEM simulation demostrated the solution was the rigth one and severals on field trials were conducted to validate the solution and the results were great.
This paper is a journey through the complete process of the study, analysis, solution, validation and on field trials to improve the avaliability of the mill using the state of art on composite material solution for the toughest application on the largest SAG mill.”
Please join in Tega in the remarkable journey and meet the representatives in the exhibition at JW Marriot Parq Vancouver, Fairview Ballrooms Salon B
