The Slate Industry of North and Mid Wales

Underwater at Dorothea Quarry

When Dorothea Quarry near Nantlle closed in 1969 the pumps used to empty the pit were switched off.  The water level rose until it reached a constant level below the edge of the pit.  Over the years the resulting cold dark pool has become a mecca for divers.  Diving in such deep water obviously carries risks and sadly there have been a number of fatalities over the years.  The situation has not been helped by a lack of facilities for divers at the pool and constant changes of ownership.  The following photos, by Paul Higgins, are intended to give some impression of conditions below the surface.

A map of the quarry. The blue line marks the extent of the flooded area.

Seen here is the tunnel that runs through the headland underneath the cable tower approximately 18 metres deep.

For Sale - Ground floor Flat - a few damp spots!  This is one of the workmens huts directly under the tunnel entrance, around 20 metres deep.

Another view of the hut with the wooden roof supports still in place.  Taking gnomes under water has become something of a tradition and there are now probably several hundred down there.  Santa Claus and friends can be seen here.

Here is the entrance to the tunnel, the entrance has partially collapsed.  The black square in the middle is the entry point.  This is at approximately 60 metres depth.

At about 50 metres depth are these ladders which are bolted to the sheer rock face between the different working levels. 

This view is looking into an old building at 40 metres below the surface from one of the platforms. Note the wooden roof support.

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