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HER Number:MDV9357
Name:Great Rock Mine, Hennock


Great Rock Mine worked for micaceous haematite from the 1840s - 1870s. Later re-opened in 1896 and worked throughout the early 20th century in conjunction with Hawkmoor, Plumley, Shaptor and Shuttamoor Mines, under the Ferrubron Manufacturing Company. Most of these others were closed by 1913 and from 1917 onwards, Great Rock was worked in conjunction with Kelly Mine. Devon's last 'metal' mine, it was worked until 1969 and remained very traditional, using water power and only becoming connected to mains electricity in 1950.


Grid Reference:SX 823 815
Map Sheet:SX88SW
Admin AreaDartmoor National Park
Civil ParishHennock
Ecclesiastical ParishHENNOCK

Protected Status

  • SHINE: Earthwork and structural remains of Great Rock Mine, Hennock, which was worked consistently for micaceous haematite from the later 19th century through to 1969

Other References/Statuses

  • Dartmoor Non-designated Heritage Asset (Evidential)
  • National Buildings Record: NRI01
  • National Monuments Record: SX88SW19
  • National Record of the Historic Environment: 447370
  • Old DCC SMR Ref: SX88SW/19

Monument Type(s) and Dates

  • IRONSTONE MINE (XIX to Late 20th Century - 1867 AD to 1969 AD (Between))

Full description

Ordnance Survey Archaeology Division, SX88SW 19, SX88SW 19 (Ordnance Survey Archaeology Division Card). SDV310150.

Ordnance Survey, 1904, 114NE, OS 6" 101NW (Cartographic). SDV308064.

Marked on OS 6" (1904) & OS 6" (1963) maps. Other details: Also on OS 6" (1963).

Ramsden, J. V., 1952, Notes on the Mines of Devonshire, 95 (Article in Serial). SDV60737.

Harris, H., 1968, Industrial Archaeology of Dartmoor, 196 (Monograph). SDV149229.

(SX 82758157) Greatrock Mine (NAT).
Great Rock 'shiny ore' mine is still being worked for micaceous haematite. The most important of the mines in the area which have produced this metal, it has been active since 1922.

Minchinton, W. E., 1976, Industrial Archaeology in Devon, 25 (Monograph). SDV7016.

Great Rock Mine, which operated from the 1840's to the late 1870's and again 1902-1969. Surface remains of the dressing floors and the leat survive. It was worked for micaceous haematite.

Unknown, 1977, National Register of Industrial Monuments (NRIM): 11 Devonshire, DV99 (Un-published). SDV352508.

(06/05/1972) Recorded by NRIM.

Beer, K. E., 1978, Mineralisation in the Teign Valley, 77 (Article in Serial). SDV310939.

Greeves, T. A. P., 1985, Steeperton Tor Tin Mine, Dartmoor, 119 (Article in Serial). SDV310154.

Richardson, P. H. G., 1992, The Mines of Dartmoor and the Tamar Valley after 1913, 70-4 (Article in Serial). SDV323598.

Last metal mine in Devon to close. Originally the surface works consisted of Californian stamps but these were subsequently replaced by a Ball Mill and other items such as jiggers, concentrating tables etc until the 1920s' power was provided by waterwheels. These were replaced successively by a turbine, diesel engine and electric power. Originally known as Hennock Iron and Tin Mine, it was renamed Great Rock Mine in 1902 when taken over by the Ferrubron Co.

Exeter Archaeology, 2002, Archaeological Assessment of Tottiford to Newton Abbot Trunk Main, 6 (Report - Assessment). SDV281233.

Brooks, T., 2004, Devon's Last Metal Mine: Great Rock 'Shiny' Ore Mine, figure 5 (Monograph). SDV347738.

Detailed description of Great Rock Mine by Brooks; a former worker at the mine as a mining student, which is under-represented in documentary sources, as it has no company records and is not listed in the Mining Journal and few sources mention it. The mine was worked until 1969 and interviews with many former employees of the mine are included. A small business, it employeed around 20 people at its peak and was isolated in woods outside Hennock. Most mines looked to replace steam power with electricity after the Second World War but Great Rock remained largely water powered. It never used steam power and had no mains electricity until 1950.
Map object based on this source.

Lane, R., 2015, Great Rock Woodlands Archaeological Features (Plan - measured). SDV360240.

Detailed plan of the lodes and shafts at Great Rock. Map object based on this source.

Walter, N., 2015, Kelly Mine Preservation Society Newsletter (February), 7 (Article in Serial). SDV358920.

Archive photo of the mine reservoir at Great Rock Mine in around 1951. The photograph shows the take-off spillway and the drain down sluice mechanism at Great Rock. Both Kelly and Great Rock were owned by Ferrubron Ltd at the turn of the 19th century, both mine reservoirs were probably constructed to the same design, and probably by the same engineers at about the same time.
Apart from the reversal of the relative positions of the spillway and sluice this arrangement is very similar to what appears to be present at Quarter Mile Pond.

Brooks, T., 2016, Kelly Mine and the 'Shiny Ore' Mines of the Wray Valley, 27-43 (Monograph). SDV359934.

In 1896, Great Rock was re-opened by Otto Schmidt and company, who also operated Hawkmoor Mine (from 1892). They were taken over in 1899 by G. Gartzke and Company and in 1902 by the Ferrubron Manufacturing Company Limited, who also operated Hawkmoor, Shaptor, Shuttamoor and Plumley Mines. By 1907, Hawkmoor had been closed for five years and although Plumley had just been added to the Ferrubron group it had become obvious that only Great Rock possessed enough quality reserves to support production in the long term and by 1913 Shuttamoor, Plumley and Shaptor had been closed down. Great Rock was worked in conjunction with Kelly Mine from 1917 onwards.

Bray, L., 2017, Great Rock Mine (Un-published). SDV360603.

Great Rock, originally one of two mines known as ‘Hennock Mine’, was one of a group of ventures in the Wray Valley area which exploited micaceous hematite, a rare type of iron ore. Originally, this material was employed as writing sand to aid in the drying of ink, but a significant application as an essential ingredient in anti-corrosion paint was also developed.
The date of the first exploitation of this mineral at Great Rock is unknown but documentary references point to the years around 1800, although an earlier 18th century date is also possible. Records of and references to the mine are scarce and unclear during the 19th century, but it appears to have been worked intermittently until 1896 when a period of sustained exploitation commenced which lasted until 1969 when the mine finally closed. Great Rock was thus the last metal mine in Devon to be worked.
As current records in the HER show, the remains of mining operations are scattered extensively along approximately 1km of the southern side of the wooded Beadon Valley from Beadon Lane eastwards to Twizzle Tree Cottage which is the site of the former mine’s processing plant. However, as no formal survey of the site has been undertaken, it is likely that features are present which are currently unrecorded.
Given the long mining history at Great Rock, the site has a high degree of evidential value which is enhanced by the character of the unusual commodity which was exploited here. This also elevates its potential illustrative historical value (citing Brooks, T., 2004).

Sources / Further Reading

SDV149229Monograph: Harris, H.. 1968. Industrial Archaeology of Dartmoor. Industrial Archaeology of Dartmoor. A5 Hardback. 196.
SDV281233Report - Assessment: Exeter Archaeology. 2002. Archaeological Assessment of Tottiford to Newton Abbot Trunk Main. Exeter Archaeology Report. 02.78. A4 Stapled + Digital. 6.
SDV308064Cartographic: Ordnance Survey. 1904. 114NE. 6". OS 6" 101NW.
SDV310150Ordnance Survey Archaeology Division Card: Ordnance Survey Archaeology Division. SX88SW 19. SX88SW 19. SX88SW 19.
SDV310154Article in Serial: Greeves, T. A. P.. 1985. Steeperton Tor Tin Mine, Dartmoor. Transactions of the Devonshire Association. 117. 119.
SDV310939Article in Serial: Beer, K. E.. 1978. Mineralisation in the Teign Valley. Transactions of the Devonshire Association. 110. 77.
SDV323598Article in Serial: Richardson, P. H. G.. 1992. The Mines of Dartmoor and the Tamar Valley after 1913. British Mining. 44. A5 Paperback. 70-4.
SDV347738Monograph: Brooks, T.. 2004. Devon's Last Metal Mine: Great Rock 'Shiny' Ore Mine. Devon's Last Metal Mine: Great Rock 'Shiny' Ore Mine. Paperback Volume. figure 5.
SDV352508Un-published: Unknown. 1977. National Register of Industrial Monuments (NRIM): 11 Devonshire. National Register of Industrial Monuments (NRIM): 11 Devonshire. A4 Stapled + Digital. DV99.
SDV358920Article in Serial: Walter, N.. 2015. Kelly Mine Preservation Society Newsletter (February). Kelly Mine Preservation Society Newsletter. 1/2015. Digital. 7.
SDV359934Monograph: Brooks, T.. 2016. Kelly Mine and the 'Shiny Ore' Mines of the Wray Valley. Kelly Mine and the 'Shiny Ore' Mines of the Wray Valley. Paperback Volume. 27-43.
SDV360240Plan - measured: Lane, R.. 2015. Great Rock Woodlands Archaeological Features. 1:5000. Digital.
SDV360603Un-published: Bray, L.. 2017. Great Rock Mine. Non-Designated Heritage Assets. Digital.
SDV60737Article in Serial: Ramsden, J. V.. 1952. Notes on the Mines of Devonshire. Transactions of the Devonshire Association. 84. A5 Hardback. 95.
SDV7016Monograph: Minchinton, W. E.. 1976. Industrial Archaeology in Devon. Industrial Archaeology in Devon. Paperback Volume. 25.

Associated Monuments

MDV119130Parent of: Twizzle Tree Cottage (mine bungalow at Great Rock Mine), Hennock (Building)
MDV113040Related to: Bullaton Stream Reservoir (Monument)
MDV47819Related to: Hawkmoor Mine, Bovey Tracey (Monument)
MDV8829Related to: Kelly Mine, Bovey Tracey (Monument)
MDV9369Related to: Plumley Mine, Bovey Tracey (Monument)
MDV65849Related to: Shaptor Mine, Bovey Tracey (Monument)
MDV9365Related to: Shuttamoor Mine, Christow (Monument)

Associated Finds: none recorded

Associated Events

  • EDV145 - Archaeological Assessment of Tottiford to Newton Abbot Trunk Main
  • EDV8686 - National Record of Industrial Monuments (no map feature)

Date Last Edited:May 28 2021 2:54PM