Y chwarel yw'r rheswm am adeiladu pentrefi'r ardal. Heb y chwarel ni fuasai pobl wedi symud i'r ardal. Daeth pobl o bell i weithio yn y chwarel. Roedd cymdeithas y chwarelwyr yn ddiwylliannol iawn. Cynhelir eisteddfodau a cystadleuthau yn ystod eu hawr ginio. Mae'n siwr fod hyn wedi effeithio ar ddiwylliant yr ardal heddiw.

1772 - Dechrau gweithio Chwarel Fawr.

1869 - Adeiladu Ysbytu'r chwarel

1881 - Chwarel yn ei hanterth (6886 o weithwyr)

1895 - Agor rheilffordd y chwarel

1969 - Cau y chwarel

The quarry is the reason for the growth of the villages in the area. Without the quarry people from far and wide would not have moved into the area. The Quarrymen were very cultured and held eisteddfodau and poetry competitions during their lunch breaks.It's possible that this tradition has contributed to the culture of Deiniolen today .

1772 - The Big Quarry opens

1869 - The building of the quarry hospital

1881 -  6886 men working in the quarry

1895 - The quarry railway started

1969 - The Quarry closes

Heddiw / Today

Although the quarry is now closed, men still work on the mountain. Inside Elidir mountain there is a hydro electric power station .

Er bod y chwarel wedi cau erbyn hyn mae pobl yn dal i weithio ar y mynydd. Tu mewn i mynydd Elidir, mae gorsaf pwer trydan dwr.