Amlwch Industrial Heritage Trust

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The Parys Mountain penny was first struck in 1787 and continued in various forms (and a number of forgeries) until 1817.  Halfpennies were also made.  It is believed that altogether over 10 million coins were issued.
Parys Mountain - A Special Place

Geology and Biology of Parys Mountain

The following description of the geology at Parys Mountain is not necessarily endorsed by Anglesey Mining plc

The rocks of Parys Mountain originated as muds in the margins of a sea basin around 440 million years ago. At that time submarine volcanoes were erupting lavas and ashes, and the fumes they exhaled produced rich deposits of metals on the sea floor. These metals occur as the sulphide minerals chalcopyrite (copper & iron), galena (lead), sphalerite (zinc), with abundant pyrite (iron), and they form an ore deposit which is unique in Britain. During later distortion of the earth's crust (the "Caledonian Orogeny" circa 400 million years ago) the ore deposit was deformed by being tilted steeply down to the north, folded (synclinal structure) and fractured (faulting), although this interpretation is currently under revision. During these phases of deformation some of the metals were remobilised, giving rise to a complex ore body.

The weathering of this deposit has produced very acidic conditions (pH 2). The abundant iron has been redeposited in different forms to give the striking red and brown colours of the mountain: there is little surface sign of copper today, but lead was redeposited as its sulphate ("anglesite") for which Parys Mountain is the type locality.

This extreme, harsh, acidic setting has resulted in a unique environment supporting unusual forms of life. Special bacteria derive their energy from the chemical alteration of minerals (oxidation of sulphides), and a rich flora of lichens, including rare metal-tolerant species, can be found coating rock surfaces and the copper-rich mortar of buildings, whilst heather survives over most of the mountain. Bats, including the rare lesser horse-shoe bat, have used the mine workings, and among the birds to be seen soaring over the opencasts are ravens and the choughs with their distinctive red bills and legs.

Parys Mountain - A Special Place

© 1996-2010
  Anglesey Mining plc
Parys Mountain, Amlwch,
Anglesey, LL68 9RE, UK
  Phone  +44 1248 361333