Cwmnewydion metal mine project

Overview

The Cwmnewydion project is focused on Graig Goch mine and Frongoch Adit, which are situated within the Cwmnewydion valley, located approximately 1.5 km southwest of Trisant village and 3.75 km northwest of Pont-rhyd-y-groes in Ceredigion.

The Nant Cwmnewydion watercourse flows along the valley floor immediately adjacent to the northern boundary of Graig Goch mine.

Upstream to the east of Graig Goch mine is Frongoch Adit and Wemyss mine. 

Frongoch mine is further to the north east and is in a different surface water catchment (Nant Cell), although the groundwater within the mine system discharges from Frongoch adit. A number of phases of remediation work have already been undertaken at Frongoch mine, which have addressed multiple surface water issues with designs currently being advanced at Wemyss mine.

The Graig Goch mine produced lead and zinc ore from 1840 to 1889 and worked the same mineral vein as nearby Wemyss and Frongoch mines to the east, although the mine workings are not connected sub-surface.  

The Frongoch Adit is driven in a roughly north-easterly direction for approximately 1.5km and drains both Wemyss mine within the same catchment, and Frongoch mine.

The Nant Cwmnewydion is heavily contaminated with zinc, lead and cadmium with the largest source being the Frongoch Adit. The stream is a significant source of metals to the Nant Magwr and Afon Ystwyth, causing failures in standards for zinc, lead and cadmium.