Entrance arch to the Lefel Fawr

Cadw's description

Location

Situated in embankment that carries the main road some 15m SE of Gwynfryn & Isfryn, about 200m S of the Old Post Office

History

Entrance arch to the 'Level Fawr' the most extensive mine drainage tunnel in central Wales. Marked on 1843 Tithe map as 'Level Fawr and mine works and sheds'. The Lefel Fawr was commenced in 1785 by John Probert to drain the Logaulas mine, one of the most ancient workings of the region. The level eventually also drained the Penygist and Glog mines.
Logaulas was working in the C18 before being leased to John Probert, former steward to the Earl of Powis. It then employed 50 men but required constant pumping. Propert and his partner John Lawrence visited the Birmingham works of James Watt to discuss using steam power to drain it in 1786, but had already begun the tunnel intended to run 360 fathoms (648 metres) to cut the seam (though still 17 fathoms (30.6 metres) above the bottom level. It did not reach the vein and after 30 years the project was abandoned before being extended the last few feet after 1824 by the Williams family, engineers. After a successful start, yields fell as did the market. The lease (from the Earl of Lisburne) passed to the great mining engineer John Taylor in 1834 and a successful few years followed. Matthew Francis, of the Cornish mining family managed the Lisburne mines until sacked in 1842, succeded by John Taylor Jr. From 1834-91 the Logaulas mine produced 39,000 tons (39,780 tonnes) of ore, second only to Frongoch in the county. The dressing floors were at the Lefel Fawr entry, where the accounting house survives (now Gwynfryn/Isfryn). The dressing floors were powered by water brought down via the mines. The Glog mines were exploited by the Williams', but further developed from 1835, closed 1840-56 and ran until 1893 and then from 1907-20. Penygist was being worked in the 1840s. The Lefel Fawr was probably extended from Logaulas after 1856, by 1863 it was 700 fathoms (1260 metres) long, 242 fathoms (435.6 metres) past Penygist but 140 fathoms (252 metres) short of Glog Fawr which it reached only in 1872.
The level is said to be still passable up to Pengwaith Eof Ysbyty Ystwyth.
It is not certain that the arch itself dates from 1785, it may be a refacing of the entry in the earlier C19, but the late C18 date seems more probable.

Exterior

Arch at entrance to the Lefel Fawr. Rubble stone jambs and ashlar segmental arch with finely cut radiating blocks and large keystone inscribed: 'This level was commenced AD. 1785' over crossed pick-axes. Arch is base of high rubble retaining wall carrying road.

Reason for designation

Included as a remarkable surviving architectural relic of one of the most ambitious lead-mining engineering works of the region.