Very old lead mine high above Winnats Pass in Castleton. The mine intersects large natural vein cavities in Faucet Rake, with the lowest point approximately at the level of Windy Bend in the pass. Recent digging work uncovered significant extensions with a huge vertical vein cavity The lowest part of this is close to the current end of Whirlpool Passage in Speedwell. There are still puzzles to be solved as to how the miners knew the caverns existed before sinking the main shaft.