Mine operation haul roads and ultra-heavy dump trucks should be considered as two
components of a single transportation system, with interactions between them. The interactions
of this system’s components are becoming more important to the operations they serve as the
gross vehicle mass (GVM) of the available trucks increases. To illustrate, the maximum GVM of
one manufacturer’s trucks has approximately doubled in the last 20 years, to exceed
600 tonnes.
The paper focuses on the road component of the transportation system, examining the influence
of road conditions on ultra-heavy truck performance. Of the truck power requirements, grade
resistance and rolling resistance power demand depend on road inputs, and they dominate the
other power requirements. Stiffening granular haul road pavements will reduce rolling
resistance and fuel consumption. While placing geosynthetics in the pavement cross section
was shown to increase pavement life substantially, it did not increase road stiffness appreciably.
Other methods of stiffening haul road pavements are discussed.
The paper advocates the use of more sophisticated pavement design methods such as the
Critical Strain Method (CSM), over traditional CBR methods. The displacements, stresses, and
strains predicted by the CSM for these ultra-heavy truck loadings should be verified. A full-scale
trial is called for and the paper provides the design of a full-scale experiment.
