Mapping and surveying of underground mines can be a challenging and dangerous task. In many cases it simply isn’t possible to map certain areas because of access issues. Examples include mapping of stopes, drives, ore passes and draw points. Traditional surveying tools such as total stations and Cavity Monitoring Systems have their limitations in terms of point density, shadowing and the need to have surveyors enter dangerous areas. To overcome these issues, the CSIRO/Data61 Robotics Group have developed Hovermap – a UAS payload which provides GPS-denied navigation, autonomy and SLAM-based LiDAR mapping capabilities. This talk will provide an overview of the Hovermap payload and present results from a number of flight trials in underground mines, including the numerous challenges that these environments poses for autonomous flight.