The Old Coal Pits are generally accepted as being the first shafts sunk at Blaenavon and together with Engine Pit, are recorded as being pre-1800 in date. Sunk in the middle of the Blaenavon Trough to the Old Coal Seam, to a depth of about 290 feet, they were worked for both coal and ironstone. By 1829, they were connected to the Upper River Row Drift. They are thought to have lapsed into disuse as access shafts when Hill's Pits were sunk, around 1835, but were retained for ventilation purposes, and from 1863 ventilated Cinder Pit.
The shafts were partially capped during the first half of the 20th century and in the early 1960's as a safety precaution each shaft was surrounded by a high brick wall. Photographs supplied by Peter Walker (Big Pit Mining Museum), taken before a roof was put on top of the walls show the shafts to have had a circular lining at the top at least, consisting of 9-inch brickwork. Below this, according to the scheduling description, they are stone-lined. A 1:500 survey of the site was undertaken by RCAHMW in November 2004, at the request of Cadw, prior to the shafts being recapped. The shafts were subsequently re-capped in September 2005, with archaeological monitoring and recording carried out by Archaeological Investigations Ltd, Hereford.
David Percival & Louise Barker, RCAHMW, 12th Jan 2006