Autonomous and Semi-autonomous Machines (ASAM) can benefit mining operations. However, demonstrating acceptable levels of safety for ASAMs through exhaustive testing is not an easy task. A promising approach is scenario-based testing, which requires the OperationalDesign Domain (ODD) definition, i.e., environmental, time-of-day, and traffic characteristics. Currently, an ODD specification exists for automated Driving Systems (ADS), but, as it is, such specification is not adequate enough for describing the mine nuances. This paper presents a context-specific ODD taxonomy called ODD-UM, which is suitable for underground mining operational conditions. For this, we consider the taxonomy provided by the British Publicly Available SpecificationPAS 1883:2020. Then, we identify attributes included in the standard ISO 17757:2019 for ASAM safety and use them to adapt the original odd to the needs of underground mining. Finally, the adapted taxonomy is presented as a checklist, and items are selected according to the data provided by the underground mining sector. Our proposed ODDUM provides a baseline that facilitates considering the actual needs for autonomy in mines by leading to focused questions.