Slate quarrying was a major industry for many years in the Moelwynion. Moelwyn Mawr's flanks have several major quarries on them. To the north is Croesor Quarry perched high above Cwm Croesor. To the north east is Rhosydd Quarry on the col between Cwm Croesor and Cwm Orthin. Within Cwm Orthin, Conglog and Wrysgan quarries are located on the north slope of the mountain. Within Cwm Ystradau to the east lies Moelwyn Slate Quarry.[4]
The walk over the main peaks in the Moelwyns, those being Moelwyn Mawr and Moelwyn Bach involves a walk up a disused incline, before gaining the grassy slopes of Moelwyn Mawr and onto the rockier Moelwyn Bach, before walking back down the road from the Stwlan Dam. Both the Snowdonia and HarlechOrdnance Survey maps are needed to cover the walk. Transport to the beginning may be done by car to Tanygrisiau or Ffestiniog, or by train from Llandudno Junction.[5]
^Boyd, James I.C. (1975) [1959]. The Festiniog Railway 1800 - 1974; Vol. 2 - Locomotives and Rolling Stock; Quarries and Branches: Rebirth 1954-74. The British Narrow Gauge Railway. Blandford: The Oakwood Press. ISBN978-0-85361-168-4. OCLC874117875. B1B.
^Nuttall, John & Anne (1999). The Mountains of England & Wales - Volume 1: Wales (2nd edition ed.). Milnthorpe, Cumbria: Cicerone. ISBN1-85284-304-7.