Not a very big mine, although a very important one in its day. An unforgetable experiance to the community below occured in the 1980s, I refer to it as the Tynyfron Tsunami.
The mine was abandoned, and the level by the stream blocked. However, in the 1980s, the water within exploded out of the level, washing half of the ravine side along with it! A few hundred yards downstream, the Cwm Rheidol lane crosses the stream by Aberddwynant house. The tsunami rushed down and the earth got stuck where the pipe begins. The force gathered, and in a few minutes, the bridge was swept away! The comunity gathered at the gap in the lane, and the stream was now back to its normal flow. However, there was not much left of Aberddwynant's garden for the stream flows right through it! The bridge of course was rebuilt but it's an event that the community will never forget. As for the mine, A huge chunk of the crumbling hillside is gone, and what we see as the adit now is what used to be the middle of the tunnel - the first section went down with the tidal wave. The mine is hard to access, and the tramway that lead to Cwmrheidol mine is severely overgrown.