Mining haul road design and documentation.

Project overview

ASTCAD designed an 11 km haul road extension at a Pilbara iron ore mine, connecting a new pit area to the existing crushing facility. The route crossed two cyclonic ephemeral creek systems and required pavement design for 240 t haul truck axle loads — the heaviest in commercial mining service.

The challenge

Standard pavement design methods do not extend to 240 t haul-truck loading. The route also crossed two creek systems in Region D cyclonic catchment, requiring culvert structures capable of passing 1% AEP flood without overtopping. Construction had to occur in a phased shutdown of the existing haul road.

Our approach

• Mechanistic-empirical pavement design for 240 t loading
• Subgrade improvement design where weak material identified
• Cyclonic catchment hydrology with culvert design for 1% AEP
• Geometric design for haul truck swept paths and grade limits
• Phased construction methodology minimising mine downtime

Deliverables

• Civil drawings — pavement, drainage, structures
• Pavement design report with traffic loading analysis
• Hydrology report and culvert structural design
• Construction methodology and phasing plan
• Maintenance specification for ongoing operation

Outcome

The haul road was constructed in two phases over a 9-month period. Pavement performance after 18 months of operation is on design — no significant deformation or remediation works have been required.

How we approach mining haul road design

Mining haul road design is vehicle-driven engineering: the haul truck’s dimensions, axle loads and braking performance set the geometry, width, grade limits and pavement structure. We design running widths from the largest vehicle’s envelope with the safety margins the mine’s standards require, hold grades within the loaded-truck braking and rimpull limits, and design pavements from CBR data for the axle loads that ultra-class trucks actually impose. Drainage is treated as a production issue, not an afterthought — a haul road that closes after rain costs the mine its haulage fleet’s output until it reopens.

Haul road documentation

Deliverables include alignment plans and profiles, typical sections and pavement details, intersection and ramp designs, drainage plans with culvert and floodway details, and safety berm and delineation documentation aligned with the site’s traffic management plan. We design to the mine’s own standards where they exist and to recognised haul road design practice where they do not.

For mine planners and contractors, we can deliver haul road design as part of broader pit infrastructure documentation or as a standalone package from your mine plan surfaces — including upgrades to existing roads where truck fleet changes have outgrown the original design.

Haul road economics reward good design disproportionately: rolling resistance from an underbuilt pavement costs fuel on every cycle of every truck for the road’s entire life, and a grade half a percent steeper than necessary does the same. The design fee for getting geometry and pavement right is amortised across millions of tonnes hauled — which is why the mines that measure cost per tonne treat haul road engineering as a production investment, not a construction overhead.

We also audit existing haul road networks against current fleet specifications — a fleet upsizing decision made in the truck procurement office frequently outruns the roads it will drive on, and a geometry audit before delivery is far cheaper than the rectification program after.