At 16:48 19/06/2007, Trevor Dunkerley wrote:
>This material is mixed with the debris of wood, coal ash (we have
>ascertained through analysis that smelters were using coal to smelt
>galena on this site in 16/17th century), and pieces of roasted
>galena. It is certainly bone ash which has taken on a yellow colour
>but does not appear to have absorbed the lead oxides.
Trevor,
Sarah Paynter has attributed the high phosphor levels in some of the
slag residues from the site at Combe Martin to the return of litharge
cakes, containing bone ash, to the hearth to recover the lead (see
http://www.people.exeter.ac.uk/pfclaugh/mhinf/contents.htm#south-west
and go to North Devon, item 8). What you are seeing is probably
unused bone ash discarded during or at the termination of the refining process.
Peter
______________________________________________
Dr Peter Claughton,
Blaenpant Morfil, nr. Rosebush, Clynderwen, Pembrokeshire, Wales SA66 7RE.
Tel. +44 (0)1437 532578; Fax. +44 (0)1437 532921; Mobile +44 (0)7831 427599
Research Fellow - School of Geography, Archaeology and Earth Resources
Hon. University Fellow - School of Humanities and Social Sciences
Office address - Department of Archaeology, University of Exeter,
Laver Building, North Park Road, EXETER, EX4 4QE Tel. +44 (0) 1392 263709
E-mail: [log in to unmask]
Co-owner - mining-history e-mail discussion list.
See http://www.jiscmail.ac.uk/files/mining-history/ for details.
Mining History Pages - http://www.people.exeter.ac.uk/pfclaugh/mhinf/
_____________________________________________
|