Open questions: Devon

Where sources disagree, MineArchive keeps both accounts rather than picking one; where a fact could not be settled, the record says so. 11 such claims on 9 records. All regions.

Beer Quarry Caves

• A 2018 report on the neighbouring Hanson Aggregates quarry — a separate, later working opposite the historic show caves — describes an extensive underground tunnel network and notes that illegal raves around 2009-10 led the operator to install motion-sensor alarms. (uncertain)

Belstone Mine

• The national mine plans catalogue lists abandonment plans titled 'Devon New (formerly Belstone)' (copper and arsenical pyrites, 1893) and 'Belstone Consols' (copper ore, 1907), later than the 1891 closure given elsewhere. (uncertain)

Bideford Black Mine

• Sources disagree on the closing year: 1969 is given by the Open University Geological Society report, the GooseyGoo site record and Kisin’s 2024 article, while the Story of Bideford Black project and accounts drawing on it give 1968. (disputed)

Devon United Mine

• Three figures are on record for the tin. The Historic Environment Record gives 367 tons of black tin for 1904-9 and 1912-22; the Geological Conservation Review gives 373 tons of tin concentrates for the group; Devon in Focus gives 387 tons of black tin for 1852 and 1905-13. (disputed)

Hemerdon Mine

• The BGS mine-plans catalogue holds a Mining Remediation Authority abandonment plan titled 'Hemerdon' (catalogue OM15351, Tin, undated in the catalogue); 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)

Hooten Wheals

• Sources disagree on closure -- one Historic Environment Record states the lease was terminated in 1896, another account has activity continuing a few years longer before a 1920 storm ended it. (disputed)

Merrivale Quarry

• The opening date is 1874. (disputed)
• The opening date is 1875, with some observers giving 1876. (disputed)

Ramsley Mine

• A Mining Remediation Authority abandonment plan for Ramsley, seam 'Copper Ore', gives an abandonment date of 9 December 1909 -- earlier than, but broadly consistent with, the wider c.1911-12 closure given by the mine's other sources; the plan most likely records a specific shaft or section abandoned while work continued elsewhere on the site for a further two years. (uncertain)

Wheal Crebor

• The Tavistock Canal tunnel, in cutting which the lode was found, is dated about 1810 and said to begin at Crebor. (disputed)
• A mine drainage adit portal stands at the foot of a mine tip in the Lumburn valley just north of Shillamill; it was photographed in winter 1978. (uncertain)