Reconciliation of grade and tonnage is a critical component of mining operations, enabling the completion of the Plan-Do-Check-Act (PDCA) cycle. This process ensures that learnings from unexpected deviations—often arising from uncertainties in geological and reserve models are captured, ultimately improving resource recovery and mining efficiency. In coal mining, where individual seam packages vary stratigraphically in grade and thickness and are blended to form a single product, geological reconciliation presents unique challenges. The existing F-Series Reconciliations (Factor Series Reconciliations) provide a systematic and ongoing assessment of the reliability, accuracy, and validity of reserve model estimates by comparing them with actual production performance. These reconciliations support compliance with reporting requirements and are used to calibrate modifying factors within the reserve models. However, distinguishing coal loss and dilution due to geological factors (eg seam thickness uncertainty, model assumptions, and interpolations) from non-geological factors (eg blasting, plan compliance, wedge loss, floor dilution, and spillage) remains complex. These factors are often aggregated as singular under the F2 reconciliation process, which compares process plant feed with reserve model predictions. To isolate and understand the geological contribution, particularly thickness uncertainty, this study employs conditional simulation on coal seam thickness. Simulations were conducted across various seams at appropriate mining block scales to quantify uncertainty and trace its volumetric contribution to overall loss and dilution within mining strips. This approach enhances understanding of coal uncovery (coal exposure after removal of overburden) and mining performance by identifying key geological drivers of deviation, such as in situ thickness variability and drill hole spacing. Integrating simulation-based validation of thickness variations into geological models strengthens the feedback loop to resources, which is an otherwise challenging task in coal mining.