I am currently compiling a PowerPoint presentation to form the basis of a talk I am to give to the science group of the local (Epsom and Ewell, Surrey) branch of the University of the Third Age.  I talked to them a couple of years ago on "Metals - where on Earth do they come from?" and have been asked to give another talk. This time my topic will be "Copper through the Ages".

Generally I am doing OK for illustrations, although I could do with a better photo than the one I have of a Chalcolithic copper hearth smelter at Timna.

My particular query to the List, however, is to ask if anyone knows where I might get a photo or drawing of the final stage of fire refining, to produce blister/anode grade metal, namely poling?

I see that Agricola mentions the practice, in which a "hazel stick" was used, but none of the illustrations in De Re Metallica seem to show it being done. I myself have witnessed it in a number of places - at the Ilo smelter in Peru they used eucalyptus tree trunks, while at Moubhandar in India they used bamboo, but I don't have photos of either.

Of the six copper smelters I visited in Japan in 1985, four used ammonia gas injections, one propane and one heavy oil - nothing like as exciting to watch as stirring the molten copper with a wooden pole!

Any helpful suggestions as to possible sources of an illustration for poling gratefully received.

A couple of photos I am including, by the way, are ones I took on a visit to the Rio Tinto mine in the summer of 1954.  One is of the open pit, where tiny trucks can be seen bringing waste rock out from the upper benches in the mine.  On the lower benches shovels are working to trains.  What you cannot see in the photo is the fact that the trains then left the open pit via tunnels into the adjoining underground mine, for the ore to be hoisted up the shafts, rather than spiral upward round a lengthy haulage road.

The other photo is of a Bucyrus steam shovel stripping waste on an upper level.  This is of the same design (and might indeed have been bought second-hand from there) as the ones which dug the Panama canal. Although loading off-road trucks, the shovel itself was rail-mounted, so what with track layers, stokers etc, if memory serves me right, it needed a crew of ten men.

From its formation in 1883 until a year or so after my visit, the Rio Tinto mine and the smelter at Huelva were, I believe, that company's main assets. Then the Spanish Government bought a controlling interest in their Spanish properties, paying them £13 million, which, seeing the company now, I guess they spent wisely!

Tony Brewis