Multi-factor analysis of haul truck fuel consumption in open-pit mining: Insights from continuous real-time monitoring

As fuel consumption is a major operating cost in open-pit mining, identifying and quantifying controllable inefficiencies requires continuous monitoring under real production conditions. This study presents a comprehensive analysis of haul truck fuel consumption using an integrated onboard monitoring system installed on a Komatsu 785 truck at a copper mine. The system continuously measured fuel flow, payload, position and speed over 90 days and captured 1780 complete haul cycles over 150 shifts under varying operational, environmental and behavioural conditions. Specific fuel consumption (SFC) analysis revealed that road gradient was the dominant factor, with uphill waste-haul routes consuming 75–80 gr/t.km compared to 65–70 gr/t.km on crusher routes. An optimal payload range of 92–97 tonnes minimised the SFC, while both under-loading and over-loading reduced fuel efficiency. Spatial mapping identified specific high-consumption road segments that required maintenance. Driver behaviour significantly affected fuel use, with aggressive driving increasing the SFC by approximately 7–10% (75–77 gr/t.km) compared to normal driver behaviour (70–72 gr/t.km). Rainfall events increased SFC by 2–3 gr/t.km above the baseline due to elevated rolling resistance. Operational delays, particularly loading queues (45% of total idle time), contributed substantially to unproductive fuel consumption. The findings demonstrated that fuel inefficiencies were largely controllable through targeted operational improvements, including payload optimisation, road maintenance, driver training and dispatch co-ordination. The spatial mapping methodology provided a practical diagnostic tool transferable to other mine sites for identifying energy-intensive haulage segments and prioritising fuel-reduction interventions.