A reservoir and leat system built to supply water for use by the two steam engines at Glyn Pits (NPRN: 33566). Water was held in a small circular reservoir, 25m in diameter that lay to the south of the pits. The reservoir was contained on the north by a dam, constructed of earth and revetted on both sides by walls of dressed stone. It has been breached in its centre. This may have been following the fire in the mine on the 23rd January 1890 when the reservoir was breached and its contents allowed to flow down the up-cast shaft to flood the mine workings. The reservoir was supplied by leats that ran in from the east and west. That from the west ran along the hillside from the Glyn Quarry; the eastern leat appears to have used water from the Upper Race Ironworks (ST27509953), which was supplied by the Cwm Lickey stream and carried along the contours, past the Balance Pits (ST27319995) and through a series of feeder ponds before discharging into the Glyn Pits reservoir.

The reservoir together with a section of the leats feeding it, were surveyed as part of a detailed survey of the colliery by RCAHMW during 2005-2006.

Sources
Tilley, G 2005 The Surviving Engines of Glyn Pits, Pontypool: Early Steam and Water Power in Local Industry.
Palmer, M & Neaverson, P 1990 `The Steam Engines at Glyn Pits Colliery, Ponypool: an Archaeological Investigation'. Industrial Archaeology Review: 13, 7-34.

David Percival & Louise Barker, RCAHMW, March 2007.