INDUSTRY INSIGHTS
DESIGNING BETTER LINE�S
WITH DEM SIMULATION TO REDUCE MINING EQUIPMENT WEAR By Dr Daniel Grasser, Associate Research Fellow (IFM) and ITTC manager (mineAlloy), Deakin University
The mineAlloy Industrial Transformation Training Centre (ITTC) is funded by the Australian Research Council (ARC) and operates out of Deakin University's Institute for Frontier Materials (IFM). The Centre represents a consortium of manufacturing companies who supply goods to the mining sector. Target outcomes are job growth, increased efficiency, sustainability, and cost reduction. To reduce wear in the mining sector, the Centre’s research involves efficient alloy development and selection, based on experimental and numerical investigations. This article presents a case study using Discrete Element Modelling (DEM) to simulate the rock flow and wear behaviour of chute liners. Micro rock-boxes for wear protection – A Discrete Element Modelling (DEM) study Mining requires processing of solid particles that cause severe wear on the equipment. Every year, wear in mining results in worldwide economic losses
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of the order of hundreds of billions of dollars and the remanufacturing of worn parts contributes a significant share of this. Chute wear is often a critical issue that affects cost and productivity. Rock-boxes are a well-known approach to reduce wear in chutes. Here, the chute design aims to trap particles at the wearing surface and form a “box” of rocks that protects the surface during operation. The goal is to foster a flow regime with particles flowing over themselves rather than on the wear surface. The current state of the art for rock-box design is based on trial-and-error approaches. This can result in expensive re-designs, inefficient rock transportation and clogged chutes. Moreover, the application of conventional rock-boxes can be limited due to constraints of the available space within a chute. An alternative approach is to add inserts consisting of highly wear resistant materials. With thoughtful design, the two approaches can be combined with inserts fostering rock-on-rock flow regimes to further reduce wear. The governing principles for the design of the rock-boxes and the insert placement remain unknown. For this reason, Discrete Element Modelling (DEM) (ESSS Rocky) was used for the investigation of the rock flow inside a transfer chute. DEM is a numerical tool used to investigate the interactions of up to several millions of rocks. Moreover, a
wide range of rock shapes can be applied to represent the actual rocks found on mine sites. In addition to chutes, DEM has been used to investigate mining applications including bins, hoppers and diggers exposed to abrasive wear. Using DEM allowed the systematic comparison of 35 wear plates with inserts and a conventional wear plate. A benefit of DEM is that the important rock flow parameters such as the sliding and rolling velocity, and most importantly, the effectiveness of an evolving protective rock layer (which is an important measure for the micro rock-box design), can be assessed. A non-spherical particle shape representing the rock shape was used as shown in Figure 1. The sieve size of the investigated cases ranged from 3.5mm to 32mm.
Figure 1: Example of non-spherical rocks implemented in the DEM study. www.miningmagazine.com.au