Earthworks. Dense undergrowth makes exploration difficult.

The Erwfelin Mining Company briefly made trial for lead along the Erwfelin Vein, sinking the main shaft to considerable depth. In 1928, the sett was absorbed into the larger Halkyn District United Mines. The Erwfelin Shaft continued to be used, though no longer for mining, but as a down-cast shaft in the ventilation system of the expanded mining operations.