Ynys Pit & Leat

Cadw's description

Summary description and reason for designation

The following provides a general description of the Scheduled Ancient Monument.

The monument comprises the remains of a water powered colliery of the early 19th century and the leat which supplied it. Many mines were assisted by water power from the 17th century to the late 19th century. Waterwheels above or below ground were used to power pumps, or to wind in shafts. Surviving colliery sites with remains of water power systems are now very rare. The leat was constructed c. 1800 by Sir John Morris and runs down the north-east side of the Clyne Valley, from south-east to north-west. It is wide in section and well formed, averaging about 2m from bank to bank. There is a stone overflow on the site of a mill, and the leat is widened at this point to form a millpond. The colliery appears to have been sunk in the 1840s and was out of use before 1877. Its site consists of a curving stone wall below the leat, with a flat area in front which formerly contained buildings, a waterwheel and shafts. The area is heavily silted and the complete layout of the colliery is likely to survive beneath.

The monument is of national importance for its potential to enhance our knowledge of the early nineteenth century coal mining industry. The structures may be expected to contain archaeological information in regard to chronology, building techniques and functional detail. A colliery may be part of a larger cluster of industrial monuments and their importance can further enhanced by their group value.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.