This challenge becomes particularly critical in high-tonnage iron ore operations, where ultra-class haul trucks exceeding 400 t gross vehicle weight operate at frequencies approaching 800 cycles per day. Under these loading conditions, even moderate pavement deformation can reduce haul speeds, increase rolling resistance, accelerate equipment wear, and generate unplanned downtime. In climates characterized by intense seasonal rainfall, these effects are amplified, as water infiltration weakens already low-strength subgrades and rapidly deteriorates unbound granular structures, leading to rutting, traffic instability, and recurring rehabilitation cycles. Traditional responses in mining environments typically rely on increasing the thickness of granular layers or importing higher-quality rock. While such approaches may temporarily restore trafficability, they require large material volumes, extensive hauling, higher diesel consumption, and longer construction times, factors that conflict with the industry's need to improve efficiency while reducing environmental impact. This paper presents a field-validated approach implemented in collaboration with an operating iron ore mine in Minas Gerais, Brazil, where multidirectional rigid geogrids were introduced to address recurring haul road degradation at critical production zones. Rather than increasing material thickness, the solution focuses on improving mechanical stabilization of locally available materials, enabling the mine to maintain operational continuity during adverse weather, reduce maintenance interventions, and optimize resource use. The work integrates practical design methodology, monitored field performance, vehicle response data and carbon footprint analysis to demonstrate how a relatively simple engineering intervention can simultaneously enhance productivity, reduce material demand, and support more responsible mineral delivery. 2. PERFORMANCE IMPROVEMENT IN MINING HAUL ROADS 2.1 Operational Failure Mechanism Observed in Conventional Mine Roads In the studied operation, haul roads were constructed primarily using locally available materials placed and compacted by operational traffic, a common practice in large open-pit mines where speed of construction is prioritized over strict compaction control. Under repeated loading from ultra-class trucks, this type of structure becomes highly susceptible to progressive deformation, particularly when founded on weak subgrades with low bearing capacity. During rainy periods, water infiltration reduces interparticle friction and promotes lateral displacement of granular materials. This leads to rapid rut formation, trapping of water within wheel paths, and progressive loss of surface stability. Once this cycle begins, frequent grading and material replacement are required to restore trafficability, increasing maintenance demand and interrupting ore haulage.
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