Open questions: Ceredigion

Where sources disagree, MineArchive keeps both accounts rather than picking one; where a fact could not be settled, the record says so. 17 such claims on 8 records. All regions.

Bwa-Drain Mine

• The BGS / Mining Remediation Authority catalogue lists a plan titled 'Bwadrian's Mine or Dol Fawr', referenced SN77NW 8 — the same map sheet as Coflein's record for Bwa-Drain; it may be this mine. (uncertain)

Bwlchgwyn Mine

• The BGS mine-plans catalogue holds a BGS plan titled 'Bwlchgwyn Mine' (catalogue -, 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)

Cwm Rheidol Mine

• The BGS mine-plans catalogue holds a BGS plan titled 'Rheidol Mine' (catalogue -, 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)

Cwmsymlog Mine

• The Northern Mine Research Society's history records no closure in the 1840s: it has John Taylor holding the mine by 1838, losing an estimated £10,000 by 1847 while sinking Reid's and Taylor's Shafts to a deep orebody. (disputed)
• Cadw's scheduling dates the stone chimney to 1855, while its listing description says it almost certainly dates from the Cornish beam engine installed by John Taylor & Sons about 1839, and may have been a ventilation chimney. (disputed)
• Myddelton is said to have taken about £24,000 a year in silver alone from the Blaen-cwmsymlog workings (£25,000 in another account), from ore carrying around 100 ounces of silver to the ton. (uncertain)
• One account says the Taylors dissolved their company in 1882, at a time of low lead prices, when the landowner Pryse refused to lower royalties. (uncertain)

Cwmystwyth Mines

• Average miner lifespan at Cwmystwyth has been estimated at just 32 years, attributed to acute lead poisoning from the ore being worked. (uncertain)
• A September 2018 report on Level Fawr describes an original mine dram still in place underground, alongside evidence of relatively recent maintenance such as newly installed ladders. (uncertain)

Frongoch Mine

• The Northern Mine Research Society gives the Belgian-run operation's closure as December 1902, consistent with the hydroelectric plant's recorded 1899–1903 operating span. (disputed)
• Other accounts describe underground mining at Frongoch continuing until around 1910, with the extensive waste tips reworked for zinc during the 1920s before the site was finally abandoned. (disputed)
• A 2012 underground report describes extensively flooded and partly collapsed workings at Frongoch, including a collapsed false floor between two shafts, natural stoping voids, and old wooden roof supports still in place near Williams Shaft. (uncertain)
• A 2011 surface report describes the 1899 Belgian dressing mill at Frongoch surviving only as ruins, with the associated hydroelectric power station down the valley also abandoned but still structurally standing. (uncertain)
• A photograph taken on 27 July 2022 shows the Frongoch site in use as a Range Rover breaker's yard, with vehicles ranked across the former mine ground; the photographer notes how incongruous it looks in country this remote. (uncertain)

Goginan Mine

• Operation began in 1660. (disputed)
• A listed nineteenth-century house east of the village is probably the mine manager's house. (uncertain)

Gwaith Yr Afon Mine

• Gwaith Yr Afon's working period (1853-1878) overlaps the reopening of the neighbouring Cwmsymlog sett as the East Darren Mine from 1850, worked until 1882 -- the two are likely companion east/west workings of the same mid-19th-century revival of the Darren-Cwmsymlog fault system, though no source names a specific operating company for Gwaith Yr Afon itself. (uncertain)