Cwm Rheidol Lead & Zinc Mine

Overview

The Cwm Rheidol mining complex is 15km east of Aberystwyth, Ceredigion, and includes the mines of Ystumtuen, Penrhiw, Bwlchgwyn and Llwynteifi.

The earliest definitive reference to mining in the area dates from 1698 at Ystumtuen, and over the following centuries the mines were developed and worked intermittently under numerous owners and various combinations.

By the late 19th century these four mines were all connected underground, enabling the extensive workings to drain to the River Rheidol via adits No. 6 and No. 9, which emerge on the steep valley slopes at Cwm Rheidol.

Here, a mill processed the ore to remove the waste rock before it was carried on an aerial ropeway to the Vale of Rheidol Railway on the opposite side of the valley, and then on to Aberystwyth.

Today the underground workings continue to drain from adits No. 6 and No. 9, both of which are highly acidic and contain significantly elevated concentrations of metals including zinc, lead and cadmium.

These discharges are subsequently contributing to the River Rheidol failing European Water Framework Directive (WFD) standards for zinc and cadmium for 18km downstream of the mine to its tidal limit.

The Rheidol catchment is impacted by many other abandoned metal mines and also fails WFD standards for zinc and cadmium upstream of Cwm Rheidol.

In 2007 we diverted a stream to prevent it flowing into a shaft, reducing the volume of contaminated discharge.

This was followed in 2008 by the draining down of adit No. 9 to reduce the risk of a catastrophic minewater blowout, which has occurred periodically in the past.

In 2009 we captured the discharges from both adits in pipes, preventing them from eroding the spoil tips and mobilising more metals. 

Following further collapses in adit No. 9, we are currently undertaking works on the mine to ensure a continuous flow of mine water and prevent a blockage and a subsequent minewater blowout.