County Geological Site

Site reference no. WSX46SW2 Name: South Tamar Consols

District: Parish:

National grid ref: SX 43576449 OS sheets: 1:50k 201 1:25k 108 1:10k SX46SW GS 1:50k

GridRef x y Lat Long SX435645 243500 64500 50.459398 -4.206183

Locality description (address): South Tamar Consols, Weir Quay, Bere Alston.

Nature of site: Disused lead mine, including waste dumps, shafts and a small area of estuarine foreshore with representative mineralisation.

Geological / geomorphological features: Also known as Bere Old Mine and Cleeve and Birch Mine, South Tamar Consols is the southern-most of a suite of former lead mines on the west side of the Bere Alston peninsula. Despite being abandoned in 1856 due to flooding, it still retains prominent dumps which contain an excellent representation of the typical mineralogy of the Bere Alston lead mines, including abundant sphalerite with some galena in a fluorite and quartz veinstone. Signficantly, chalcedony is also a very significant component of the veinstone. In addition, probable tetrahedrite is not uncommon as small specks associated with sphalerite, galena and occasional chalcopyrite. In addition there is some evidence of possible secondary lead and zinc minerals, although mineralogical analysis would be needed to confirm what mineral types might be present. Inclusions in fluorite and quartz have been dated, however, and reveal a Triassic age for the mineralisation. An additional area of the mine lies beside the road on the edge of the estuary, including a filled shaft, and dump material with the characteristic mineralogy is very common around High Water mark. Additional dumps are present further north, and although not currently included in the CGS, may contain a similar mineralogy.

Reasons for registration as a County Geological Site: The combination of significant dump material with a full suite of characteristic minerals, plus representative material in an adjacent area on the shore, with public access, confirms the sites potential as a CGS. The site is therefore selected as representative of the geology of the Bere Alston silver-lead mines.

Site sensitivity: Although the site includes extensive dumps, digging by mineral collectors is not likely to be sustainable and may significantly deplete the sites scientific resources if not controlled. Mineral vein material on the shore provides a more accessible resource but as supply is very limited, any significant collecting could very rapidly deplete the amount of materials available for visitors to examine.

Safety: The area of mine dumps includes several shafts, at least one of which is collapsing.

Interest groups: Schools. Years 5-11: Years 12-16: Years 17-18. University. Undergraduate - Research Professional geologists - Amateur geologists - General public.

Access and Parking: The mine is privately owned and there is no public access to the dumps, which are used for military training; the shore, however, has public access and there is an adjacent permissive car-parking area.

Date of assessment (V = visited) : V Sep 2004

Site owner : The mine is privately owned and there is no public access to the dumps and associated workings.

References: DINES, HG. 1956. The metalliferous mining region of South-West — Volume 2. Memoirs of the Geological Survey of Great Britain, England and Wales. HMSO. London, pp.684; LEVERIDGE, B.E., HOLDER, M.T., GOODE, A.J.J., SCRIVENER, R.C., JONES, N.S. and MERRIMAN, R.J. 2002. Geology of the Plymouth and south-east Cornwall Area . Memoir of the British Geological Survey, Sheet 348 (pp.6, 95); USSHER, W.A.E. and FLETT, J.S. 1907. The geology of the country around Plymouth and Liskeard (Sheet 348 J. Memoirs of the Geological Survey, England and Wales , p.134.