Application of the Welsh Mine Water Strategy:

Minewater emanating from two adits at the Cwmrheidol abandoned metal mine site is contributing significant quantities of lead and zinc to the Afon Rheidol watercourse. As part of a new strategy to deal with such waters, the Environment Agency commissioned SRK Consulting to provide remedial designs for the management of the mine site and the protection of the local watercourses. This is the first set of mine sites to be treated under the new strategy and the risk-based approach adopted to derive remedial designs is described. The minewaters have a pH of approximately 3 and contain a cocktail of elevated metals, including iron, copper, zinc, cadmium and lead. The preferred minewater treatment option is the use of limestone dissolution, ochre precipitation, and a Reducing and Alkalinity Producing System. Other remedial measures are also recommended that reduce the volume of minewater requiring treatment