The mountain has a history of copper mining going back 3500 years. However, it was in the 18th and 19th Centuries that the greatest amount of copper was produced. It is thought that in 150 years over 3.5 million tons of ore was raised, mostly by hand, from the Mona and Parys mine both located on the mountain. Parys Underground Group is kindly offering CATMHS a tour of the Mona mine, a rare opportunity not to passed by.