No 3 UPPER SILICA MINE SN91640795 The most extensive mine in the area, and the most recent, is found on the North bank of the Sychrhyd 200m upstream of Bwa Maen, and has three entrances which face the river, and a further ten on the northern side. The triple entrance is to the left of the bridge, and is the mine most frequented by cavers. This is probably the most extensive mine in the area. The upper series is practically a veritable huge chamber where the `Pillar and Stall' method of mining is well illustrated. This large chamber leads towards several alternative entrances in the side of the hill. The large entrance chamber can be followed to the right down dip for a short distance to the flooded section. However, to the left the huge Pillar and Stall chamber leads up dip for some distance only to drop down dip again onto a passage which runs across the whole length of the mine. Above this passage various `entrances' lead to the huge chamber while below is flooded.
The flooded level consists of six levels varying in depth of up to -22m, according to the amount of rainfall, and between 80m and 250m in length. Each level has similar structure and appearance, consisting of square solid walls throughout. This mine is considered as an ideal site for underwater cave diving and photography.
In 2015 the mine, in the form of mineral estate, was acquired by Natural Amenities Ltd an associated company of Cambrian Mines Trust, NAL are committed to maintaining and preserving underground access for the benefit of the caving and mining community.
Jones, Keith and Adams, Phil