Phil,

It is clear that in the UK, zinc working was in two main phases -- 
calamine (principally Smithsonite) was worked around the Mendip from the 
late C16^th in parallel with attempts to develop and English copper 
industry.Because the metal vaporised before it became molten and rapidly 
oxidised to a powdery material on contact with air, the calamine was not 
smelted into zinc, but used in a roasted state with pellets of copper in 
sealed vessels.Zinc metal was rare until the 1740s.By 1738 William 
Champion had developed a process for making metallic zinc by heating a 
mixture of calamine and charcoal in large sealed crucibles and 
distilling the fume in water.In the 18th century, mines in Derbyshire, 
at Castleton, Cromford, Bonsal and Wirksworth, also in North Wales, were 
supplying calamine to the Cheadle brass makers.As people have said, 
calamine was still being worked in the 1830s-40s -- though probably as a 
small part of zinc output then.At Malham (Yorkshire) the principal means 
of separating it from dross was by buddling.

Another important advance came in 1758 with the development of a process 
for smelting zinc from a roasted blende or zinc sulphide, which was more 
plentiful than calamine.Because the zinc making process used a high 
proportion of fuel, said to be three tons of coal to one of ore, it made 
economic sense to move the works onto a coalfield (see Ian Spensley's 
comment).

It is clearly incorrect to say that _many_ British lead mines shifted to 
blende production.It was a low value mineral and appears to have been 
worked where veins had been left unworked by lead miners or the blende 
had been separated and stowed in old lead workings - at mines with 
reasonable communications.Zinc appears to have been a nuisance to lead 
miners and was generally thrown away where separated as part of the 
19^th century dressing process.

A _few_ British mines were able to exploit blende deposits which had 
been largely developed as part of lead working.

It the C20th. the flotation process, presumably aided by shaking tables, 
made it easier to separate the zinc, but its low value probably served 
to relegate it to a minor role.I understand that the move to galvanising 
car bodies in the 1970s lifted demand/price.

Mining and smelting remains:-

Tindale zinc smelter 1845-1895

There was a zinc furnace at the Langley (lead) smelt mill around 1820.

Vieille Montagne mill at Nenthead -- processing ores of lead and 
zinc.Shell of building (part) remains.

Calamine House at Redmire 1779-1807

Calamine House, near Old Pikedaw Shaft at Malham, probably a storage 
place, traces of footings, c1780.

Calamine House, Town Head at Malham, building still standing -- now 
agricultural use.Had furnaces for roasting.

Old Calamine works/mill, near the Lister's Arms in Malham, no known 
remains.Use uncertain, probably roasting.

Calamine Pit at Bowland with Leagram, in Lancashire.Mine working shown 
on OS maps.

Mike Gill