Mendip Hills In some areas the limestone and the dolomitic conglomerate have been mineralised with lead and zinc ores. From the time of Roman Britain until 1908, the hills were an important source of lead. These areas were the centre of a major mining industry in the past and this is reflected in areas of contaminated rough ground known locally as "gruffy". The word "gruffy" is thought to derive from the grooves that were formed where the lead ore was extracted from veins near the surface. Other commodities obtained included calamine (zinc ore), manganese, iron, copper and baryte. The eastern area reaches
Ore Mountains last silver mines closed and the company was disbanded. Mining in the Ore Mountains was given new life during the First and Second World Wars in order to supply raw materials. The Third Reich also saw the resumption of silver mining. Afterwards the people returned to the manufacture of wooden products and toys, especially in the Eastern Ore Mountains. The clock industry is centred on Glashütte. In the Western Ore Mountains, economic alternatives were offered by the engineering and textile industries. In 1789 the chemical element uranium was discovered in St. Joachimsthal; then in pitchblende from the same area, radium