Parc Mine Essay

Parc mine is a larger site than the Bwlch Glas mine. The area can be split into two distinct sections; the north and south. The south section of the mine is home to the underground mine entrance. From this, contaminated, red coloured water flows northwards. It flows through a number of limestone buttresses to neutralise the pH. This water flows into a valley (figure *). On the sides of the valley, trees can be seen growing, although appear to be experience stunted growth. Also on these slopes, fragments of galena are visible (Warren et al., 1984). At the far end of the mine, the area is capped and appears as a large dome structure. This dominates the site with an elevation of approximately 10m from top to bottom. The capping is topped with vegetation, primarily grass. In some areas, the grass has died away and has allowed moss to establish. In some areas, grass is bleached by contamination.
In the Conway Valley, rocks are folded gently into a compound syncline. The axis of this fold runs from southwest to northeast (BGS, 2010). Unconsolidated clays, silts, sands and stratified gravels form the alluvial deposits from the Afon Conwy and its various tributaries. Individual clasts are mostly comprised of local Lower Palaeozoic turbidites with a component of Ordovician volcanic rock derived from the Harlech Dome and Snowdonia (Warren et al., 1984).
Until the capping at Parc mine was introduced, approximately 13,000 tons of spoil containing 104 tons Zn, 43 tons Pb and 1 ton Cd had been lost from the primary tailings dam. Once this reached the river, it caused damage to the river ecosystem, killing flora and fauna, and contaminating agricultural pastures downstream. In 24 hours, 15 kg Zn, 0.27 kg Pb and 0.1 kg Cd was leaking into the River Conwy with 250,000 tons of tailings slowly entering the ecosystem (Gao and Bradshaw, 1995 and Johnson and Eaton,