The 1st edition OS map of 1871 indicates the presence of four shafts to the southeast of the county boundary, west of Waen Farm SJ 2690 5390. Later maps, including the 2nd edition, show old levels on the slopes of the Nant-y-ffrith Woods to the northeast of Gorse SJ 2640 5370, which appears to have been the focal point of the mining activity. However, much of the evidence of these workings has been obscured or lost over time, especially in areas now affected by quarrying.

The veins worked are marked on the Brenton Symons Map of 1865.