2013 – METPLANT, Perth, WA

Abstract:

The history of mill liners has evolved over time and this paper tracks the changes and
development of liner technology. It provides an overview of the primary types of liners, the
design and the materials of construction. The design of a mill liner is driven by application,
materials of construction, casting technology and handling issues. The choice of solid steel,
grid liners, rubber or composites and magnetic liners is based on many factors.

The methods used for monitoring wear and predicting eventual change out time are many and
varied. The contribution of discrete element modeling (DEM) analysis in predicting wear
profile is discussed.

Mill trajectory and DEM software programs are used with great effect to predict the effect of
lifter height, face angle, high low lifters or mill speed. In the field, trial and operational
experience, is used or improvements/design concepts at one operation are applied to another.
Broken lifters, accentuated wear and other problems can be better understood using hardess
testing, chemical analysis and photo micrograph analysis of pearlitic or martensitic structure
along with fracture face observations form part of typical root cause analysis. However given
correct and sound liner and lifter, feed and discharge design media selection, and materials of
construction, the majority of premature liner or bolting failure is normally attributed to
incorrect operational methods such as excessive high ball to feed ratio, incorrect mill speed
relating to lifter ball throw, incorrect media selection, “tramp” material entering the mill
charge from upstream or recirculating process and understanding the specific mill operation
in question.

It is hoped that this paper will benefit mill operators who are faced with challenges of
improving wear life and at the same time optimizing mill throughput and performance.

Read the paper here