Towards Smarter Haulage Operations in an Open-Pit Limestone Mine
Quantifying the Impact of Dynamic Dispatching and a Single Autonomous Unit Using a Data-Driven DES
M.B.B. Vermeer (TU Delft - Civil Engineering & Geosciences)
M.W.N. Buxton – Mentor (TU Delft - Resource Engineering)
M. Keersemaker – Mentor (TU Delft - Resource Engineering)
F.S. Desta – Mentor (TU Delft - Resource Engineering)
M. Ramgraber – Mentor (TU Delft - Reservoir Engineering)
K. Pashna – Mentor (TU Delft - Resource Engineering)
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Abstract
This thesis quantifies the operational impact of two interventions at the Flandersbach limestone mine: a tuned heuristic dynamic dispatch strategy and autonomy-related fleet changes. A discrete event simulation digital twin was developed and calibrated using telemetry-derived empirical inputs and site-confirmed operating rules, and scenarios were evaluated over two representative operating weeks. The model is used to compare throughput, waiting and congestion behavior, and target adherence under consistent assumptions.
The results show that the implemented dynamic dispatch policy is not an effective mechanism to increase production volume in its current form. While the compliance metrics indicate that dynamic dispatch can enforce relatively tight adherence to shift-level bench targets under the thesis definition, it does so at a throughput cost. Compared to the fixed-assignment baseline, dynamic dispatch reduces total moved tonnage by about one percent and increases congestion, most notably through substantially higher loader queue time and headway-related waiting.
Single-agent autonomy produces asymmetric benefits across subsystems. Introducing a single autonomous hauler or loader yields limited gains in a mixed fleet because productive time remains bounded by shared schedules and downstream constraints. In contrast, the autonomous load-and-carry scenario produces the largest throughput increase in the core scenario set, nearly eight percent, consistent with the fact that this intervention expands the effective operating window by operating through periods that are otherwise constrained by breaks and shift transitions. This result should be interpreted in light of scope, since the load-and-carry unit is modeled as a dedicated crusher-feeding unit, whereas in practice it also performs auxiliary duties.
Overall, the findings indicate that improving a single component often yields diminishing system-level returns when the haulage cycle remains constrained by shared resources, schedules, and interaction effects. The discrete event simulation digital twin provides a validated sandbox for relative comparison of dispatch and autonomy concepts, and the results motivate future concepts that change system-level constraints more directly.