Fatigue and alertness monitoring is increasingly deployed across the mining industry as a physiological complement to hours-of-work and roster-based fatigue management. Common solutions include in-cab camera systems that track behavioural indicators of fatigue, wearables that monitor heart rate, blink rate, or brainwave activity, and in-vehicle motor control features that detect motion-based deviations. Published evaluations of these technologies consistently note that validation, signal interpretation and confounding factors remain unresolved challenges for the sector. This paper specifically examines the use of brain wave activity to flag unexpected changes in operator alertness, as well as the confounding factors that must be managed before an alert is treated as a fatigue event. Three de-identified operator cases are presented as illustrative examples in which an electroencephalography (EEG)-flagged alert prompted an escalation process that identified a previously unrecognised physiological, psychosocial or lifestyle contributor to reduced alertness. Specifically, the cases relate to undiagnosed obstructive sleep apnoea, psychosocial stress following bereavement, and nutritional change associated with a strict vegan diet. The paper situates these observations within the published literature on occupational fatigue causation, sleep related cognitive impairment, psychosocial stress and nutrition-cognition relationships, and discusses how this evidence base has informed threshold-setting and confound-mitigation practice. The intent is to support technical discussion of EEG-based fatigue monitoring as one input within a broader, human-centred fitness-for-work framework, rather than as a standalone solution.