Selection and maintenance of mine haul road wearing course materials

Abstract

The drive for greater cost efficiencies in surface mining has led to the development of very large off highway trucks currently capable of hauling payloads in excess of 290 tons on mine haul road networks that have historically been designed empirically, relying heavily on local experience. With the trend in increasing truck size, haul road performance has become unpredictable, difficult to manage and costs of both maintaining the road and operating the truck have also increased prohibitively. Most surface mine operators agree that good roads are desirable, but find it difficult to translate this requirement into an effective and responsive road maintenance management system (MMS). The aim of the present paper is to present an overview of the wearing course material selection for mine haul road applications and to recommend appropriate wearing course material selection guidelines. Using the material performance models established, the paper then describes the development of a haul road MMS utilising mine haul truck operating cost models to derive an optimal frequency of road maintenance. Finally, a typical application is presented which illustrates the potential of the technique to manage maintenance as and where needed with resultant reduction in total road user costs and an improvement in service provided for the road user.