Cycle Time Optimization of Coal Hauling from SWA Block to ROM Aster Using Six Sigma DMAIC Approach

This research analyzes the delay in coal transportation cycle time from SWA Block to ROM Aster at PT XYZ using the Six Sigma DMAIC approach. The average actual cycle time reached 6.46 hours, compared to the planned 3.62 hours. This deviation was caused by a combination of factors: human (lack of supervision and driver training), machine (availability below 90% and frequent tire issues), method (slow loading and queue delays), material (unavailable coal stock), and environment (non-AWR roads and narrow slopes). The research method involved observation, in-depth interviews, and document analysis. Root cause analysis was conducted using a Fishbone Diagram and NVivo qualitative tools. The DMAIC model was applied to define, measure, analyze, improve, and control the process. Improvements proposed include widening roads, increasing night-shift supervision, training drivers, and integrating stock monitoring systems. The findings highlight systemic operational inefficiencies and offer structured corrective actions for sustainable hauling performance.