Open questions: Torfaen

Where sources disagree, MineArchive keeps both accounts rather than picking one; where a fact could not be settled, the record says so. 22 such claims on 12 records. All regions.

Big Pit

• Sources disagree on some detail of the shaft's early history. The Blaenavon World Heritage Site's own account and welshcoalmines.co.uk both describe the elliptical shaft itself as the former Kearsley's Pit, sunk in 1860 and later deepened to reach the Old Coal seam at 293 feet (dated 1878 by welshcoalmines.co.uk, 1880 by the Blaenavon World Heritage Site and by Coflein, the Royal Commission's monuments record for Wales). The Northern Mine Research Society's more technical listing instead treats Kearsley's Pit — sunk c.1800, 5 feet in diameter — as a separate, older shaft from the elliptical Nos.1 and 2 Pits sunk 1860–1863, of which No.1 was the 18 by 13 foot shaft that became known as Big Pit. (disputed)

Blaentillery Colliery

• Blaentillery No. 2 Drift Mine closed in 2010. (disputed)

Cwmbran Colliery

• The BGS mine-plans catalogue holds a Mining Remediation Authority abandonment plan titled 'Cwmbran' (catalogue 1983, Meadow., dated 1886); the catalogue gives no location and the plan's details do not clearly tie it to this working, so it may belong to another of the same name. (uncertain)

Elled Colliery

• The mine operated from at least 1872 to 1943. (uncertain)

Glyn Pits, Pontypool

• The pits were sunk to a depth of 190 yards. (disputed)
• The two shafts were sunk side by side to 190 feet (58 m). (disputed)
• Production stopped in 1932. (disputed)
• Glyn Pits Nos. 1 and 2 ceased coal winding in 1928 and became a pumping site for Hafodyrynys, finally closing in 1949 under NCB ownership. (disputed)
• The pit was still used as a pumping station for Hafodyrynys until the 1960s; a 2012 account says electric pumps were in use until the site was abandoned in 1966. (uncertain)

Glyn-nant-ddu Colliery

• The 1830 Greenwood map shows buildings on the site, and the pit was probably at work by then. (uncertain)

Golynos Colliery

• The Golynos pit closed in 1909. (disputed)
• Golynos was closed down in 1913. (disputed)

Llanerch Colliery

• The colliery began about 1830 as Cwmnantddu, a level working the Tillery seam; the earliest traced mention is a county-court case of December 1833. (uncertain)
• The Varteg Iron and Coal Company sank new shafts about 1853, each 253 yards deep, with 45-foot pitch-pine headgear and furnace ventilation. (uncertain)
• Llanerch provided the downcast ventilation for the neighbouring Blaenserchan colliery until that pit developed its own downcast shaft in 1913. (uncertain)
• Llanerch employed 913 men in 1923, producing from the Elled, Big Vein, Three Quarters, Old Coal and Black Vein seams, and 325 men by 1938. (uncertain)

Lower Varteg Colliery

• The slope closed on 1 January 1957. (disputed)
• Production ceased on 26 January 1957 and closure was completed on 23 May 1959. (disputed)

Tirpentwys Colliery

• Tirpentwys Colliery, originally known as Cwmffrwdoer Colliery or Gelli, was the largest in Cwmffrwdoer, working from 1877 to 1969 and including a small level known as Black Vein. (disputed)

Varteg Hill Colliery

• The BGS mine-plans catalogue holds a Mining Remediation Authority abandonment plan titled 'Varteg' (catalogue SWR670, Red, dated 1964); the catalogue gives no location and the plan's details do not clearly tie it to this working, so it may belong to another of the same name. (uncertain)

Varteg Red Ash Level

• It was opened in 1907 by the Varteg Deep Black Vein Collieries as the Varteg Red Ash Level. (disputed)
• The drift was opened in 1922 and worked by John Vipond and Company. (disputed)