Evaluating the Operational Impact of Drive-by Loading on Spotting Time and Excavator Productivity in Open-Pit Mining

Abstract

Loading and hauling operations strongly influence equipment utilization, production efficiency, and operating cost in open-pit mining. Although simulation, dispatch optimization, truck-shovel allocation, and Double Side Loading (DSL) have improved fleet performance, field evidence for Drive-by Loading (DBL) a continuous forward truck-approach strategy that targets the positioning micro-cycle at the loading point remains limited. This study evaluates DBL in an open-pit coal mine in South Kalimantan, Indonesia, using a quantitative before-and-after design involving two excavator classes and 100–110-ton rigid dump trucks. The screened dataset comprised 1,440 valid loading cycles (720 per condition). Cycle-level records were used for descriptive analysis and aggregated into 28 matched shift-level analysis blocks for inferential testing. Matching considered excavator–truck configuration, operator team and shift type, haul-distance category, material domain, production target, and trafficable weather and road conditions. Records with incomplete or non-chronological event timestamps or externally interrupted cycles were excluded without imputation. Average spotting time decreased from 30 s to 17 s (−43.3%), loading cycle time decreased from 167 s to 152 s (−9.0%), and excavator productivity increased from 859 BCM/h to 1,120 BCM/h (+30.4%). Paired tests on the 28 matched blocks produced df = 27 and confirmed significant improvements in spotting time and productivity (p < 0.001). The scientific contribution is field-based, statistically validated evidence linking a redesigned truck-approach sequence to both micro-cycle time and excavator productivity. DBL therefore offers a practical, low-capital operational option where mine geometry, traffic control, and safety conditions permit a continuous forward approach.