When miners were being turned off Parys Mountain in the 1850s and 1860s, they found a ready market for their skills in Blaenau Ffestiniog, where slate is won from underground levels. The spectacular success of Parys Mountain had, however, already prompted established Cornish copper mines to increase their output in competition, by extending shafts and tunnels ever deeper into the ground. To do this, they had to invest in steam pumping equipment at the end of the 18th century, providing a fillip to the development of steam power, with incalculable consequences for industrialisation worldwide. Although even within the last year there has been much destruction to the industrial archaeology of the area, much has been conserved, and much more recorded. Factfile Only six slate quarries still operate in Gwynedd.
Some gold exploration continues in the North Wales gold-field.
Other accessible sites include Dorothea slate quarry near Caernarfon, Ynysypandy slate mill near Porthmadog, Hafna lead mine near Llanrwst, Glasdir copper mine near Dolgellau and the Parys Mountain copper mine near Amlwch.