Analysis of failure modes and mechanisms of Dozer Blade Liners (DBLs) in a Kimberlite tailings environment at the Orapa Diamond Mine in Botswana

Abstract

This research investigates the premature wear and failure of dozer blade liners (DBLs) on a track dozer operating at the Orapa diamond mine in Botswana, with the aim of identifying the dominant wear mechanisms and proposing mitigation measures to improve their service life. DBLs sustain heavy abrasion as the dozer blade pushes kimberlite tailings (KT) -abrasive waste material left after diamond extraction and rich in hard minerals such as silica, alumina, and diamond, leading to accelerated wear. These minerals exceed the hardness of the steel used in DBLs, resulting in material degradation. The DBLs were observed to fail after approximately 11125 operational hours, significantly below the expected service life of 15000 hours. This resulted in cost implications of ~USD 8950 (BWP 127904) per dozer due to 5 hours of unplanned downtime, increased maintenance, and DBLs replacement. To determine the root causes of wear and failure, four worn DBL samples and one control sample were analysed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), stereo and optical microscopy, and Vickers microhardness testing. The study identified sliding abrasive wear, surface cracking, deformation, and pitting as the primary failure modes. Dominant wear mechanisms included ploughing, microcutting, plastic deformation, grooves, and spalling. The findings highlight that the abrasive mineral composition of KT is a critical factor in the premature failure of DBLs. Based on the analysis, several cost-effective mitigation measures were recommended to prevent premature failure and extend blade life: the use of wear-resistant materials with improved hardness, toughness, and refined microstructures for DBLs manufacturing; exploration of manufacturing technologies that improve the bonding of the coating materials with the substrate of the DBLs; and the implementation of routine inspections before each shift to detect early signs of wear. These measures are expected to extend the service life of DBLs and improve overall operational efficiency at the mine.