One trial of four in the valley. This one is up the active mountain stream. One will spend more time trying to find it than exploring it as it is only 5 or so meters long. There is one interesting formation and a drill hole, beyond that it is one hell of a nice valley so worth a visit. Visit the lake over hill and the cairn on top of the hill to make a day of it.
It is thought that this trial and the other three were driven to find a possible extension of of the Llanfair silver-lead lode being worked on the other side of the hill.