The Carbis Bay Crew spend hours deep underneath Cornwall, even digging out old tunnels and diving through flooded sections to reach new areas.
Members admit their hobby has the potential to be extremely dangerous so they are all qualified in rescue techniques and are careful not to reveal where they access the old mine workings, to prevent other less-qualified people following in their footsteps.
The film maker, Dan Simpkins, had to complete safety training with them before going underground – it took him two years to capture the footage he needed.
After collecting the award Mr Simpkins said: “This film isn’t just about mine exploration – it’s about what we carry with us and the places we feel safe enough to let go.
“The men at the heart of this story opened their world to me, and this award honours their honesty as much as the filmmaking.”