dominated the world's copper market during the 1780s, when the mine was the largest in Europe. Its rise severely damaged the mining industry in Cornwall. The copper from the mine was used to sheath the British Admiralty's wooden ships of war, to prevent the growth of seaweed and barnacles and to protect the wood from attack by shipworms. This increased the speed and manoeuvrability of the vessels, and enabled them to remain at sea for longer as there was less need to return to port for maintenance. In response to a national shortage of small currency, the Parys Mine Company produced its own coinage between 1787 and 1793. The Parys Penny, also known as the Anglesey Penny, was used by the mine to pay workers, and also by the populace at large. It is thought that around ten million pennies and half pennies were minted. The mineral Anglesite, with the chemical formula PbSO4, was first recognised by William Withering in 1783, who discovered it in the Parys copper-mine; the name was given by F. S. Beudant in 1832. Modern day There is a waymarked trail around the mountain, giving views of Amlwch Port to the north and the nearby Trysglwyn wind farm to the south. Those wishing to explore the historic mine levels need to contact the Parys Underground Group. Since 1988, Anglesey Mining plc, which owns the western part of the mountain, has discovered resources of 6,500,000 tonnes containing 10% combined zinc, lead and copper with some silver and gold. It has permits and a plan to restart mining operations at 350,000 tonnes per year. In the late 1990s, surveys of the mine's hydraulic systems revealed that a large reservoir held back by a dam in an underground working was in poor condition. An assessment made at the time considered that failure of the dam was likely and that catastrophic failure could inundate parts of Amlwch, causing loss of life and substantial damage to property. An added complication was that the water in the underground reservoir was highly polluted by copper and other metals and was very acidic. In 2003, a carefully controlled drainage operation was carried out which dropped the water levels by , releasing the pressure on the dam and enabling its removal. The removal of the reservoir also gave access to many more passages and to a connection to the nearby previously inaccessible Mona Mine. The