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Dorothea Quarry Beam Engine

A Scheduled Monument in Llanllyfni, Gwynedd

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Latitude: 53.0542 / 53°3'15"N

Longitude: -4.2435 / 4°14'36"W

OS Eastings: 249730

OS Northings: 353122

OS Grid: SH497531

Mapcode National: GBR 5K.CMMX

Mapcode Global: WH43T.SHHG

Entry Name: Dorothea Quarry Beam Engine

Scheduled Date:

Source: Cadw

Source ID: 2440

Cadw Legacy ID: CN165

Schedule Class: Industrial

Category: Engine house

Period: Post Medieval/Modern

County: Gwynedd

Community: Llanllyfni

Built-Up Area: Talysarn

Traditional County: Caernarfonshire


Dorothea Quarry pumping installation (including pump house, boiler house, fuel hopper and ramp with beam pumping engine, boilers and windlass).

Built 1904. Stopped work 1952 owing to the boilers being condemned but did work in 1956 when the electric pumps failed. It is a Cornish pumping engine.

Beam: about 30 ft long; weighs about 11 tons. Worked normally at 5 strokes per minute, the maximum rate being 9 per minute. The beam of wrought iron which is a very unusual feature. Inside stroke 10 ft, outside stroke 9 ft, giving one lift of the pumps (7ft bucket) at a depth of 460 ft.

Cylinder: 10 ft by 68 inches. (Fairly small engine). Worked at 38 psi.

Boilers: 2. Fittings by Mather and Platt, possibly/probably the boiler shells also. Lancashire type. The chimney is a recent affair. (At least it seems so). Slate in lower parts but concrete above. The boiler house roof was very derelict when we started work on the engine in March 1968. Some half of it had collapsed with the ravages of time, vandals and the elements and we subsequently demolished the remainder of the roof., removing also the vast quantities of roof, rubbish and herbage which had collected on the boilers.

Notable features. 1. Wrought iron beam 2. Only two beam engines were built after it. (In 1911 and 1919). 3. Only beam engine (still) in a quarry. 4. Only engine complete with boilers, headgear and winch. The latter is believed to be off a ship and is almost entirely of non-ferrous metal. No doubt it would be of interest to a naval historian in that it may be from one of the old dreadnoughts.

5. Almost certainly the engine is steamable given new boilers. It is complete and with only a minor amount of mechanical work, mainly with the Husbands Safety Gear, it could work. 6. The house is complete and is weatherproof. We have done a fair amount of work on the inside walls ie. rendering. Also we have painted half of the beam itself, most of the woodwork on the outside, and also some of the metalwork.

The engine was built by Holman Bros of Cambourne, Cornwall. However, there is a plate on the side of the cylinder lagging attributing the design and erection to N Trestrail, Engineer, of Redruth, Cornwall. Possibly this applies to the cylinder only.

The engine is built by Holman Bros of Cambourne, Cornwall in 1904 and is installed in a slate built house 25 ft by 19 ft 3 in internally; the front wall carrying the beam is 5 ft 9 in thick, all the others are 2 ft 6 in. The wrought iron beam is about 34 ft long; engine-end 18 ft 3 in from bearing centres. The beam is 6ft deep at the centre and about 3ft at each end. The single cylinder has a stroke of 10 ft and a bore of 5 ft 8 in; cylinder height 14 ft 8 in. It operated a boiler pressure of 38 lb per sq in and its normal working rate was 5 strokes per minute, which could be increased to a rate of 9. The bucket was 7 ft long and the pumping shaft 460ft deep.

A slate building, containing a beam engine used for pumping water from the quarry. Date stone of 1904 on exterior of building. Building in good, sound condition. Engine and interior not inspected.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

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