The industrial quarrying of igneous rock (diorite) at Penmaenan began in 1830 with the opening of the Penmaen Quarry and the subsequent, competing Graiglwyd and 'Old' quarries which were amalgamated by 1888 under Colonel Darbishire. Most of the production in these early years was of setts and paving, but from 1881 the advantage of crushed rock for railway ballast was demonstrated and new crushing mills were built to provide for that market. In 1911 Darbishire merged these operations with the quarries of Trefor to form the Penmaenmawr & Welsh Granite Co.. As the industry grew, workers and their families flocked to Penmaenmawr from all over north-west Wales and beyond. The link was especially strong with Trefor, the home of Trefor granite quarry on the slopes of Yr Eifl. The community which sprang up in the present day wards of Penmaenan and Pant-yr-afon was close-knit and almost entirely Welsh-speaking. By the early years of the 20th century about 1,000 men worked in the quarry and its associated workshops. Neighbouring Llanfairfechan was an integral part of this process.