This large mine lies in the Aberllyn gorge between Betws-y-coed and Llyn Parc.

The Shale lode, which is a major fault that marks the eastern extent of the orefield passes south from the Parc area along the line of Llyn Parc where it splits into two parallel branches known as Aberllyn Soft Lode (to the east) and the Aberllyn Hard Lode to the west. The Soft Lode is mostly barren.

It is approached via a forestry track from a caravan site on the Llanrwst to Betws-y-coed road. The most apparent surface feature are the large floors visible from the forestry track, behind which the Brunner-Mond haulage level can be followed to the portal of the 6 level.

Further on up the gorge, more entrances can be found, level 4 being the one that was used by explorers. This is to the right of and below the path. The 3a level is just up the path and on the left.

Level 4 commences through some deep sludge. This soon lowers and disappears, and quickly reaches the Cathedral Stope. To the left is the bottom of an open shaft, to the right is the main mine. If followed as far as possible, the 4 level gets underneath Llyn Parc, evidenced by the large amounts of water coming through the roof and walls. Near the end of the Cathedral Stope, a ladder in the left wall goes up to the three level, and another ladder in the right floor descends with water to the 5 level.

Level three is the most complicated, at the Southern end there is access to an open shaft from where daylight is visible. It is also possible to get up to the 2 level by climbing up a shaft from one of the tunnels.

The five level is much wetter than the three level, and can be followed to a collapse near the old 5 adit. There is also a shaft down to level no. 6.

The majority of working - for zinc was carried out by Messrs. Brunner Mond at the turn of the 20th century. By 1905 it was abandoned.

| 1878-81 | Aberllyn Mining Company |
| 1881-83 | Gwydyr Amalgamated Mines Company Ltd. |
| 1896-1905 | Brunner Mond. |
| 1917-19 | Aberllyn Zinc Mines Ltd. |
| 1919-23 | Aberllyn Ltd. |

CROW. Open