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Summary

Powder Mills gunpowder factory was in operation from 1844 until the late 19th century. The monument includes buildings, leats and historic settlements

Location

Protected Status

• Scheduled Monument 1016635: Gunpowder factory at Powder Mills, a partially enclosed stone hut circle settlement and round cairn
• SHINE: Earthwork remains of part of the 19th century leat supplying Powder Mills gunpowder factory, as well as a leat and reave on Chittaford Down

Other References/Statuses

• National Monuments Record: 442786
• Old DCC SMR Ref: SX67NW/51
• Old SAM County Ref: 921
• Old SAM Ref: 28731(P)
• Ordnance Survey Archaeology Division: SX67NW99

Monument Type(s) and Dates

• GUNPOWDER WORKS (XVIII to XIX - 1800 AD to 1900 AD)

Full description

Ordnance Survey Archaeology Division, SX67NW99 (Ordnance Survey Archaeology Division Card). SDV248159.

Site visited on 5th October 1979. buildings are widespread over about 33 hectares but the factory is concentrated within 9 hectares centred at SX62807730 alongside Cherry Brook. All are now roofless although the majority are in good condition with dressed and mortared stone walling standing to roof level. South of this area are the converted buildings which form the complex of Powder Mills Farm and its cottages with isolated ruined structures. The leat, six wheel houses and other buildings are shown on Ordnance Survey 25 inch map of 1885, and also on Ordnance Survey 25 inch map of 1952. A hollow at SX62767728 is shown as water-filled in 1885, and may be a reservoir for fire fighting.

Ordnance Survey, 1906, 99SW (Cartographic). SDV336746.

'Powder Mills (disused)' shown on early 20th century map.

Royal Air Force, 1951, 540/483, 3048-9 (Aerial Photograph). SDV248164.

Ordnance Survey, 1954, SX67NW (Cartographic). SDV350080.

'Powder Mills (disused)' shown on map.

Brown, T., 1961, Tales of a Dartmoor Village: Some Preliminary Notes on the Folklore of Postbridge, 196 (Article in Serial). SDV238060.

Harris, H., 1968, Industrial Archaeology of Dartmoor, 128-133 (Monograph). SDV149229.

The powder mills were built in 1844 and closed circa 1890, due to the invention of dynamite.

Devon County Council, 1974, Survey of Watermills in Devon: Gazetteer (Report - Survey). SDV83967.

Minchinton, W. E., 1976, Industrial Archaeology in Devon, 26 (Monograph). SDV7016.

A proving mortar for the gunpowder can still be seen from the road. The mills were driven by a leat from the East Dart.

National Monuments Record, 1979, SF1509, 289-292 (Aerial Photograph). SDV346618.

Ordnance Survey Archaeology Division, 1979, SX67NW99 (Ordnance Survey Archaeology Division Card). SDV350197.

The leat, six wheel houses and other buildings are shown on 1885 and 1952 Ordnance Survey maps. A hollow at SX62767728 is shown as water-filled in 1885, and may be a reservoir for fire fighting.

Hemery, E., 1983, High Dartmoor, 435-7 (Monograph). SDV249702.

Water-powered mid 19th century gunpowder factory. Built by George Frean of Plymouth. The mills flourished for some decades; gunpowder was in demand for blasting at the large tin mines and quarries, and by farmers clearing enclosures of rock. Gunpowder was made by finely grinding and mixing sulphur, saltpetre and charcoal. The millstones were of hard border rock rather than granite. The efficiency of the finished powder was tested and graded by firing a measured shot from a mortar which is still to be seen. Rows of alder trees planted around the mills provided both a windbreak and wood for charcoal. Workers' cottages were built at a minimum safe distance from the mills. The remains of these houses, known as Sunnyside Cottages, lie beside the original road connecting the mills to the turnpike road. The manager and foreman lived closer to the mills in the terrace of buildings seen from the road. Following the invention of dynamite in 1867 the trade in gunpowder began to decline and twenty years later the mills closed.

Robinson, R., 1983-1984, Survey Drawings of Powdermills (Report - Survey). SDV248162.

Royal Commission on the Historical Monuments of England, 1985, Aerial Photograph Project (Dartmoor) - Dartmoor Pre-NMP (Cartographic). SDV319854.

A detailed survey has been carried out for the surrounding buildings in 1983-4. Copies of survey drawings are in parish file. Powder Mills buildings clearly visible along with the three wheel houses with the leat running through them. Also visible on Royal Air Force 1951 and National Monument Record 1979 aerial photographs.

Greeves, T. A. P., 1985, Steeperton Tor Tin Mine, Dartmoor, 114, figure 4 (Article in Serial). SDV310154.

Plymouth and Dartmoor gunpowder company. The first known proof of gunpowder from these works being sold direct to Dartmoor tin mines is the provision of a 50lb barrel of powder for 18s to Steeperton Tor Mine in 1877.

Griffith, F. M., 1986, DAP/HP, 1-4 (Aerial Photograph). SDV304235.

Department of National Heritage, 1986, Scheduled Monument Consent (Correspondence). SDV248145.

Scheduled Monument Consent granted on 2nd September 1986 for refurbishment of chimney stacks.

Department of Environment, 1987, Lydford, 9 (List of Blds of Arch or Historic Interest). SDV266265.

Ruins of gunpowder mill established 1844. Originally an extensive complex running up the valley with several waterwheels powered by a leat, and with two chimneys. All buildings now in varying degrees of ruin although one chimney survives and three main groups are recognisable of granite rubble with granite lintels, all roofless. Chimney with stringcourse near top and plinth. Covered channel runs downhill from it towards the largest ruinous building.

Royal Commission for the Historical Monuments of England, 1987-1993, Duchy Farms Project Survey Visit (Report - Survey). SDV350839.

Griffith, F., 1988, Devon's Past. An Aerial View, 108 (Monograph). SDV64198.

The location of the powder mills right out in the middle of the moor was deliberately chosen because of the hazardous nature of the operations. An air view shows the entire layout of this establishment, since the buildings are well spread out to minimise the risk of one explosion setting off others. See extract for further details of the buildings.

Pye, A. R. + Robinson, R., 1990, An Archaeological Survey of the Gunpowder Factory at Powdermills Farm, Postbridge, Devon (Report - Survey). SDV254157.

Physical and documentary survey describes 18 individual structures.

Department of National Heritage, 1992, Scheduled Monument Consent (Correspondence). SDV248154.

Scheduled Monument Consent granted on 30th April 1992 for consolidating existing remains and some rebuilding to prevent further collapse following storm damage.

Pye, A., 1994, An Example of a Non-metalliferous Dartmoor Industry: The Gunpowder Factory at Powdermills, 221-240 (Article in Serial). SDV248175.

Dawson, T. + Hambley, J., 1995, A Survey of the Service and Accommodation Buildings belonging to the Powdermills Gunpowder Factory, Postbridge, 1-3, 14 (Report - Survey). SDV351071.

Survey of the occupied buildings and ruined cottages at Powdermills undertaken in 1995.
Powder Mills include the ruins of a gunpowder mill which were listed on 28th October 1987. Established in 1844 by a Plymouth alderman George Frean. Originally quite an extensive complex of buildings running up the valley with several water wheels turned by water from a leat and with two chimneys. All the buildings are now in varying degrees of ruin although one chimney survives and three main groups are recognisable of granite rubble with granite lintels, all roofless. The chimney is well constructed with stringcourse near the top and plinth. It has a covered channel running downhill from it towards the largest ruinous building. The invention of dynamite in 1867 rapidly superceded gunpowder. And the mills, which employed about 100 men and closed in the 1890s.

Department of National Heritage, 1996, Scheduled Monument Consent (Correspondence). SDV248176.

Scheduled Monument Consent granted on 19th December 1996.

Department of National Heritage, 1996, Scheduled Monument Consent (Correspondence). SDV248156.

Scheduled Monument Consent granted for works concerning consolidation of masonry to buildings 1, 2, 3, 7, 9, 10, 14, 18 at Powdermills.

Bodman, M., 1998, Water-Powered Sites in Devon (Report - non-specific). SDV305931.

National Monuments Record, 1999, 442786 (National Monuments Record Database). SDV248155.

Site visited on 15th August 1989. The buildings at Powder Mills farm were also part of the original complex though distanced from the powder making buildings. The long building on the extreme east is the former cooperage and there is also a manager's house and a smithy. All are well maintained. The proving mortar, used for testing the grade of gunpowder, has been placed on a reconstructed base at SX62797680, adjacent to the modern approach road (citing Pattison).

Ordnance Survey, 2012, MasterMap (Cartographic). SDV348725.

'Powder Mills (disused)' shown on modern mapping.

English Heritage, 2012, National Heritage List for England (National Heritage List for England). SDV348729.

Ruins of gunpowder mill at Powder Mills. Established in 1844 by a Plymouth alderman George Frean. Originally quite an extensive complex of buildings running up the valley with several water wheels turned by water from a leat and with two chimneys. All the buildings are now in varying degrees of ruin although one chimney survives and three main groups are recognisable of granite rubble with granite lintels, all roofless. The chimney is well constructed with stringcourse near the top and plinth. It has a covered channel running downhill from it towards the largest ruinous building. The invention of dynamite in 1867 rapidly superceded gunpowder. and the mills, which employed about 100 men closed in the 1890s.

Ancient Monuments, 5/10/1972, Gunpowder Factory at Powder Mills (Report - non-specific). SDV248140.

Site visited on 5th October 1972. Powder Mills near Higher Cherrybrook Bridge. Set in a typically secluded valley setting with its buildings scattered and widely spaced for safety. This powder mill built in granite is presumably of 19th century build and usage. Two boiler buildings are present with chimneys and leats, now blocked from the cherry brook. The brook is bridged by a clapper bridge. There are four further isolated granite buildings representing mills on the mill leat which brings water 4 kilometres from the East Dart river. Workers in the mill presumably resided in the powder mill cottages with a tied house at the end of this isolated terrace being reserved for the mill foreman. Cottages at present in occupation.

English Heritage, 9/10/1981, Gunpowder factory at Powder Mills (Schedule Document). SDV350194.

The gunpowder factory at Powder Mills survives well and contains a complete range of buildings and other structures and features associated with the industry. Many of the buildings remain essentially intact, with only the roofs and machinery having been removed. The system of leats and trackways provides useful additional information concerning the character of the factory. The unique survival of the associated proving mortar emphasises the quality of the surviving archaeology. Together with a comprehensive historical background this represents a fine example of a gunpowder production site. The prehistoric settlement and cairn associated with the Powder Mills are of national importance in their own right and contain information relating to the exploitation of the central part of Dartmoor during the Bronze Age.
The monument, which falls into five areas, includes a gunpowder factory, a partially enclosed stone hut circle settlement and a round cairn situated adjacent to the Cherry Brook. The gunpowder factory, which is Listed Grade II, comprises at least 18 buildings involved in the production, storage and management of gunpowder. Many of these buildings contained machinery which was powered by water which was carried to the site by three large leats from the East Dart and Cherry Brook rivers. These are included in the scheduling. A system of trackways link the buildings and the river was crossed by way of clapper bridges. The gunpowder factory established in 1844 by George Frean, was certainly operational by 1846 and remained in use until 1897, when it closed as a result of increasing competition from dynamite and a slump in local mining activity. The production of gunpowder involved combining a mixture of saltpetre, sulphur and charcoal and the buildings in which the different stages of the process were carried out survive at Powder Mills. The process was inherently dangerous and to reduce the chances of cataclysmic explosions, the buildings were situated at a safe distance from each other and each had a flimsy roof which would have allowed any explosion to be carried upwards. Several explosions are known to have occurred at Powder Mills and fortunately these precautions may have ensured that no workers were ever killed. Amongst the buildings identified at Powder Mills are: grinding mills, where the ingredients were crushed separately between horizontal rotating millstones; blending mills, where the ingredients were mixed in rotating barrels; incorporation mills, where the material from the blending mills was mixed further into a single compound; a range of buildings where the gunpowder was broken, pressed, corned, dried, dusted and glazed; and finally charge magazines, where the gunpowder was stored. Further buildings on the site may have been used as storage or office accommodation. The quality of the finished gunpowder had to be tested and at Powder Mills this appears to have been carried out using two very different techniques. At SX 63777681 a proving mortar, which was used to test the strength of the gunpowder, still sits on a restored carriage. Whilst at SX 62757750 a number of large boulders have been split using a single charge, possibly the result of of testing. To the south west of the gunpowder factory stands an isolated rectangular building in which finished gunpowder was stored prior to transportation. Within the vicinity of the gunpowder works there are four quarries from which material was derived during the construction of the buildings. Parts of the valley bottom contain earthworks related to tin streamworking. Modern post and wire fences, a shed and piles of sand and other materials associated with a consolidation programme are excluded from the scheduling, although the ground beneath them is included.

Sources / Further Reading

Associated Monuments

Associated Finds: none recorded

Associated Events

• EDV6029 - An Archaeological Survey of the Gunpowder Factory at Powdermills Farm
• EDV6128 - Survey of the Service and Accommodation Buildings associated with Powdermills Gunpowder Factory (Ref: 95.63)
• EDV8644 - Cherrybrook and Longford Newtake, Duchy Farms Survey
• EDV8645 - Powder Mills and Gawler Newtake, Duchy Farms Survey
• EDV8409 - Dartmoor Royal Forest Project
• EDV8423 - Duchy Farms Project

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