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Summary

Site of a large 19th century arsenic works at Wheal Anna Maria mine, which was part of Devon Great Consols

Location

Protected Status: none recorded

Other References/Statuses

• Old DCC SMR Ref: SX47SW/504/5/2

Monument Type(s) and Dates

• ARSENIC WORKS (XVIII to XXI - 1751 AD to 2009 AD (Between))

Full description

Griffith, F. M., 16/12/1988, DAP/JZ, 6a-9 (Aerial Photograph). SDV241570.

Ordnance Survey, 1884, 105SW (Cartographic). SDV218129.

The extensive 19C works are recorded on the OS 6" (1884) map.

Symons, B., 1884, Untitled Source, 235 (Monograph). SDV241562.

Toll, R. W., 1953, Arsenic in West Devon and Cornwall, 85, 87, 88 (Article in Serial). SDV241561.

Goodridge, J. C., 1964, Devon Great Consols, a Study of Victorian Mining Enterprise, 242-243 (Article in Serial). SDV240773.

Dixon, T. + Matthews, A. + Pye A. R. + Slater, W. D., 1988, Gawton Mine and Arsenic Works. The Field Survey. 1988 (Report - Survey). SDV222516.

Pye, A. R. + Dixon, T.
Pye, A. R. + Dixon, t., 1989, An Archaeological Survey of the Arsenic Works and an Inventory of the Other Historic Workings at Devon Great Consols Mine, Tavistock Hamlets (Report - Survey). SDV226597.

Weddell, P. J. + Pye, A. R., 1989, Gawton Mine and Arsenic Works: The Documentary Research 1988 (Report - non-specific). SDV263249.

Pye, A. R. + Dixon, T., 1989, The Arsenic Works at Devon Great Consols Mine, Tavistock, 79-111 (Article in Serial). SDV219136.

Devon Great Consols. Reduction works set up in 1867 to reduce the low grade ore to make arsenic. Works completed and producing 50 tons a month by Dec.1868, when it was decided to enlarge them further to deal with 150 tons a month. Arsenic was obtained from 'mundic' or arsenic pyrites, which occurred in abundance on the walls of the lodes. When brought to the surface, the ore was crushed and washed to extract any copper contained in it and to prepare it for roasting. This at first was done in a brick furnace in which ore and coke were mixed together, but the direct contact with the fuel led to contamination of the arsenic. Reverberatory furnaces were later employed; avoided this by directing the heat from the burning fuel on to the ore which was spread on a circular table and mechanically revolved. This arrangement superseded by tube lined with fire bricks and raised slightly at one end. The ore was inserted at this end, and the rotation of the tube worked it steadily to the lower end, through which heat and flames from a furnace were admitted. The sulphur and other volatile materials in the ore greatly facilitated the roasting process and reduced the quantity of fuel required. In all these furnaces the ore was oxidised by the passage of large quantities of air through the furnace. The intense heat vaporised the arsenic, which was conducted in this form through a series of specially designed baffles in which it condensed to form a greyish white powder. The remaining vapour passed along a flue, which was often stacked with brushwood to trap any residual arsenic before it was discharged through a tall chimney. The baffle was opened at intervals of several weeks, when the arsenic was dug out by hand. During this period the vapour was diverted through a second set of baffles. The crude arsenic was purified in a special refining furnace in which a smokeless fuel was used. It then condensed as small white crystals of pure arsenic, which were ground to a fine powder. This was packed into 4cwt. Casks, made in the cooperage on the mine and exported from Morwellham. The works at Devon Great Consols were the largest in Devon and Cornwall, covering about 8 acres and consisting of five calcining ovens and three refineries with 4.805ft of flues. A mill for grinding the refined arsenic was driven by water power. The capacity of these works was 2,500 tons a year in 1871, but this was increased to 3,000 tons a year in 1884 and 3,500 tons a year in 1891. The arsenic was used mainly in the manufacture of paints, dyes, and glass and as a weed killer. Sales of refined arsenic rose steadily and in 1871 accounted for 20% of total receipts. In 1869 the works had 5 calcining furnaces (probably flat bed reverberatory), 3 refining furnaces and 2 separate flues. Arsenic condensers seem to have been added by 1888 along with at least one Oxford and one Brunton calciner. Enlargement continued until the works covered 8 acres with 7 calciners, 3 refiners 1654.8m of flues, a steam driven arsenic mill, stores, coopers' shops and 2 changing houses for workers. By 1899 arsenic was the main product of the mine. Prices slumped 1900-01, and the mine closed in 1902. Most buildings levelled in 1903, and area reverted to former use as pheasant covert, although some intermittent small scale activity continued, notably a revival of arsenic production in the 1920s. The area is now chiefly woodland, the waste dumps being progressively quarried away for roadstone. Detailed description of the surviving 1920s features is given. Other details: Figs 1-5, Plates 1-10.

Cherry, B. + Pevsner, N., 1989, The Buildings of England: Devon (Monograph). SDV325629.

Egan, G., 1990, Post-Medieval Britain and Ireland in 1989, 198-200 (Article in Serial). SDV241563.

Other details: Plan.

Greeves, T. A. P., 1991, An Assessment of Copper Mining in Devon (Copper, Brass, Tin), 3, 14 (Report - Assessment). SDV60709.

Arsenic works of the 1920's at Devon Great Consols are listed as Grade II Historic Buildings but other features deserve recognition including leats, railways, shafts & wheelpits.

Richardson, P. H. G., 1992, The Mines of Dartmoor and the Tamar Valley after 1913, 94-108 (Article in Serial). SDV323598.

During the heyday of the Great Consols Mine, in 1844-1903, arsenic production came to replace copper extraction as the principal function. Closed in 1903 and the original arsenic works at Wheal Anna Maria were levelled. New works were built just to the N in the 1920s.

Cranstone, D. + Hedley, I., 1995, Monuments Protection Programme: The Arsenic Industry, Step 3 Site Assessments (Report - Survey). SDV241572.

The arsenic works 'undoubtedly merit statutory protection'.

Arsenic works, operative 1921-1925, within 19th century cooper and arsenic mining complex. Preserves a wide range of calciners and condensing systems, all of masonry construction with brick.

Dyer, M. J. + Manning, P. T., 1998, Objective 5B: Lower Tamar Valley Recreation and Land Management Iinitiative: Cultural Heritage Appraisal, 35 (Report - non-specific). SDV319814.

Buck, C., 1998, Preliminary Assessment of Sites of Archaelogical Importance in the Tamar Valley, 43 (Report - Assessment). SDV241750.

Buck, C., 2002, Devon Great Consols: Archaeological Assessment, 147-151+Figs 16,17,18,38 (Report - Assessment). SDV241758.

The decision to produce arsenic at Devon Great Consols was taken in 1864 & the lease endorsed in 1866. The works were expanding by 1868 when the arsenic works at Wheal Anna Maria were the largest in Devon & Cornwall & by 1871 the works covered 8 acres with seven calciners, a steam powered grinding mill & 1.6km of flues. The 120ft high arsenic chimney was located to the west of the main works at SX42377314 & the waterfall chamber at SX42387311. Reservoir ponds to the west at SX42357313 probably supplied water to the warterfall chamber. In 1903 the complex was demolished with only two buildings remaining. The survey found rubble mounds with fragments of furnace structure, some bricks, floor tiles & 1m high remains of the chimney. Other features identified included remnants of walls, plinths, floors & flues. Other details: Sites 210,211,211/1,212.

Buck, C., 2009, Devon Great Consols Mine (Arsenic Works), Devon. Impact Assessment Report, 4-5, 20-24 (Report - Assessment). SDV347875.

Remains of the original foundation masonry for the 1860s copper crusher, steam engine and boiler house lie between the 1920s arsenic mill and bottle furnace. The site of the wheel pit for the original waterwheel is believed to be to the south-east, infilled and no longer visible above ground. Other details: Figure 3-4, 6-7.

Sources / Further Reading

SDV218129	Cartographic: Ordnance Survey. 1884. 105SW. 6".
SDV219136	Article in Serial: Pye, A. R. + Dixon, T.. 1989. The Arsenic Works at Devon Great Consols Mine, Tavistock. Proceedings of the Devon Archaeological Society. 47. Paperback Volume. 79-111.
SDV222516	Report - Survey: Dixon, T. + Matthews, A. + Pye A. R. + Slater, W. D.. 1988. Gawton Mine and Arsenic Works. The Field Survey. 1988. Exeter Museums Archaeological Field Unit Report. 89.02. A4 Stapled + Digital.
SDV226597	Report - Survey: Pye, A. R. + Dixon, T. Pye, A. R. + Dixon, t.. 1989. An Archaeological Survey of the Arsenic Works and an Inventory of the Other Historic Workings at Devon Great Consols Mine, Tavistock Hamlets. Exeter Museums Archaeological Field Unit Report. 89.08. A4 Stapled + Digital.
SDV240773	Article in Serial: Goodridge, J. C.. 1964. Devon Great Consols, a Study of Victorian Mining Enterprise. Transactions of the Devonshire Association. 96. 242-243.
SDV241561	Article in Serial: Toll, R. W.. 1953. Arsenic in West Devon and Cornwall. Mining Magazine. 89. 85, 87, 88.
SDV241562	Monograph: Symons, B.. 1884. Gazetteer of Cornwall. 235.
SDV241563	Article in Serial: Egan, G.. 1990. Post-Medieval Britain and Ireland in 1989. Post-Medieval Archaeology. 24. Unknown. 198-200.
SDV241570	Aerial Photograph: Griffith, F. M.. 16/12/1988. DAP/JZ. Devon Aerial Photograph. Photograph (Paper). 6a-9.
SDV241572	Report - Survey: Cranstone, D. + Hedley, I.. 1995. Monuments Protection Programme: The Arsenic Industry, Step 3 Site Assessments. English Heritage Report. A4 Bound.
SDV241750	Report - Assessment: Buck, C.. 1998. Preliminary Assessment of Sites of Archaelogical Importance in the Tamar Valley. Cornwall Archaeological Unit Report. A4 Bound. 43.
SDV241758	Report - Assessment: Buck, C.. 2002. Devon Great Consols: Archaeological Assessment. Cornwall Archaeological Unit Report. 2002R069. Digital + A4. 147-151+Figs 16,17,18,38.
	Linked documents:1
SDV263249	Report - non-specific: Weddell, P. J. + Pye, A. R.. 1989. Gawton Mine and Arsenic Works: The Documentary Research 1988. Exeter Museums Archaeological Field Unit Report. 89.01. A4 Stapled + Digital.
SDV319814	Report - non-specific: Dyer, M. J. + Manning, P. T.. 1998. Objective 5B: Lower Tamar Valley Recreation and Land Management Iinitiative: Cultural Heritage Appraisal. Exeter Archaeology Report. 98.60. A4 Stapled + Digital. 35.
SDV323598	Article in Serial: Richardson, P. H. G.. 1992. The Mines of Dartmoor and the Tamar Valley after 1913. British Mining. 44. A5 Paperback. 94-108.
SDV325629	Monograph: Cherry, B. + Pevsner, N.. 1989. The Buildings of England: Devon. The Buildings of England: Devon. Hardback Volume.
SDV347875	Report - Assessment: Buck, C.. 2009. Devon Great Consols Mine (Arsenic Works), Devon. Impact Assessment Report. Historic Environment Projects, Cornwall Council Report. 2009R058. A4 Stapled + Digital. 4-5, 20-24.
SDV60709	Report - Assessment: Greeves, T. A. P.. 1991. An Assessment of Copper Mining in Devon (Copper, Brass, Tin). A4 Stapled + Digital. 3, 14.

Associated Monuments

Associated Finds: none recorded

Associated Events

• EDV1486 - Gawton Mine and Arsenic Works: Documentary Research
• EDV1489 - Gawton Mine and Arsenic Works: Field Survey
• EDV1490 - DAP/JZ
• EDV1491 - An Archaeological Survey of the Arsenic Works & other works at Devon Great Consols
• EDV1492 - Objective 5B: Lower Tamar Valley: Cultural Heritage Appraisal
• EDV1493 - Devon Great Consols: Archaeological Assessment
• EDV5334 - Impact Assessment of the Arsenic Works at Devon Great Consols Mine
• EDV735 - Unnamed Event

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