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Overview Bloomery Fire

Bloomery Fire 2006


During the days, we will all be constructing our ovens, crucibles et cetera. In the evenings, we will have a programme with films and presentations. Besides that, on one evening, we would like to discuss what the symposium should lead us to. This discussion will be followed by a party.

If anybody wants to add or withdraw a presentation, that is still possible.

Wednesday 13-9

Evening programme open: possibly an excursion

Thursday 14-9

20:30h: Jonathan Thornton (Buffalo State College, Buffalo NY, USA): Crooked Knives

and Adzes: Economy and versatility in metal use

21:00h: Julia Wiecken (University of Exeter, UK): Casting Copper Axe-Adzes

from the Carpathian Basin – missing moulds and fragmented axes

21:30h: Wladyslaw Weker (National Museum, Warsaw, PL): Influence of the feature

of turf on the iron ore on the reduction process in ancient smelting furnaces

22:00h: Georg Petau (D): Last year’s Iron Smelting Symposium, a film impression

Friday 15-9

21:00h: Patrice de Rijk (NL): The bloom from the Roman Period settlement of Raalte

21:30h: Arne Espelund (NO): Iron smelting as a two step process

22:00h: Skip Williams (USA) (Presentation co-authored by Evelyne Godfrey): The effect of

draft on reduction, agglomeration and carburisation in an iron bloomery furnace

Saturday 16-9

20:30h: Peter Seinen (NL): investigation of a broken pile-shoe from a roman bridge



21:00h: Eddie Daughton (UK): From Stone to Iron - a short history of Metal

21:30h: Vladimir Sokhonevich (RUS): Historical metal in Russia

22:00h: Jens Jørgen Olesen (DK): Running a slagpit furnace of the

Sharnbech / Drengsted type

Sunday 17-9

21:00h: Discussion: Setting targets for the future, discussions how and what

further, a possible publication?

22:00h: Party

Description of the presentations

Wednesday 13-9

Program open: possibly an excursion

Thursday 14-9


Crooked Knives and Adzes: Economy and versatility in metal use

Jonathan Thornton (Buffalo State College, Buffalo NY, USA)

The metal tools of American Indians show great economy in the use of metal, as well as versatile and sophisticated ergonomic  function in any particular tool. Since this is partially based on relative scarcity of metal, it seems to reflect early use of metals everywhere. The mechanics of use are noteworthy  (body-holding of work pieces and cutting on the pull stroke) and may also reflect the earliest tool-use traditions. The discussion will focus on two types of tools; the “crooked knife” and the hand-adze in order to illustrate broader concepts and points.

Slide projector


Casting Copper Axe-Adzes from the Carpathian Basin – missing moulds and fragmented axes

Julia Wiecken (University of Exeter, UK)

The transition from the Neolithic to the Bronze Age in Europe represents one of the most profound technological changes in later prehistory. In Eastern Europe, the technological transition is more pronounced than elsewhere in Europe with copper being used before the full development of tin-bronze from about 4700 BC to 3500 BC. In the Carpathian Basin, the large numbers of copper axe finds, some of the most emblematic artefacts of the period and region, are not matched by an equal number of moulds. There are no moulds for copper axe-adzes or hammer axes and just a few moulds made out of stone or clay for flat axes. However, axe-adzes are by far the most common type during the Copper Age, making the discrepancy between finished objects and moulds even more puzzling. The solution to this problem has to be the use of materials which might not survive in the archaeological record. To explore these issues in greater detail, I have embarked on a program of experimentation and skill acquisition, casting these copper axe-adzes into different clay moulds, and sand. Two part clay moulds sealed around the edges would have to be broken to extract the finished object, leaving pottery sherds, easily overlooked or misinterpreted. Low firing might mean the total loss of the moulds due to taphonomic processes. And a thin layer of sand in an excavation context is difficult to interpret as a mould. These are all as yet working hypothesis as I have not carried out the actual casting. But in September I will be able to report on the outcome of these experiments and their wider implications.


Influence of feature of the turf iron ore on the reduction process in ancient smelting furnaces

Wladyslaw Weker (PL)

The large centre of iron production about 2000 years ago was found in the Swietokrzyskie Mountains (Holy Cross Mountains) and in the Mazovia region in Poland (the Barbaricum - beyond the Roman provinces). Only in the Swietokrzyskie Mountains region a huge production complex consisting of over 6,000 smelting sites has been recorded (by prof. Kazimierz Bielenin). There are accomplished by a group of around 50 smelters’ villages of various sizes, grouped in 5-6 settlement micro regions. It has been postulated that in the Roman times a careful control of fuel-to-ore relations could have had a great influence to the production steel directly from the smelting process.

The experiments carried out in the smelting furnace have not led to full reconstruction of the ancient process, which was used to iron produce about 2000 years ago. The technological process of iron ore reduction is complicated and depends on many parameters. The prime of them are properties and form of the ore using.

The physical and chemical features of the turf iron ore are the purpose of our investigations. It was assumed that physicochemical properties of ore are influenced on range and rate of reduction process in smelting furnace.

The turf ore coming from the Mazovian region (PL) has been examined. The turf ore are crumbled, sifted out and washed to verify the possibility of the profitable fraction obtained. After selection each part of ore was tested in laboratory conditions on a range of reduction processes. Results of these investigations will be presented.

We will try to answer the question: “Were the ancient smelters prepared the iron ore before reduction process in the shaft type furnace?”

Overhead + PowerPoint


Last year’s Iron Smelting Symposium, a film impression

Georg Petau (D)

Friday 15-9


The bloom from the Roman Period settlement of Raalte

Patrice de Rijk (NL)

In the municipal of Raalte, prov. Overijssel (NL), large parts of a roman Iron Age settlement have been excavated. Large concentrations of iron production slag were found, indicating large scale iron production. Little slag can be attributed to the second stage of iron production, i. e. the reheating of the bloom. Up to now it is assumed that this process took place in contemporary settlements nearby, e. g. in Olst-Weseperenk. As a consequence, the Raalte settlement must have been part of a complex society in that iron production was a specialised craft. However, the examination of the iron production remains shows that the bloom could have been reheated in the Raalte settlement also. Possibly, the Germanic reheating process left just little evidence compared to the reheating process in medieval times. The quantity of slag set free during this process depends on the quality of the bloom produced.


Iron smelting as a two step process

Arne Espelund (NO)

It is a common experience that good iron requires a running slag. Such slag is of a fayalite type requiring reaction between intermediate FeO and silica in the charge. This probably can be achieved by a long retention time / moderate temperature, but a pre-treatment seems to have been a part of the early practice in Norway, as documented by some finds of slag, which chemically remind of ore with a low content of SiO2. The end slag found in amounts up to more than 50 tons is remarkably uniform in composition: about 24% SiO2 and 62% (FeO + MnO), telling that our forefathers mastered iron making.

It should be noticed that the only process recorded when they were in use (The Catalan process and the ‘Nordic’ Evenstad process) also were aware of the problem and had different solutions. A two-step process is common in copper metallurgy, so that a transfer of technology is conceivable.

Note from e-mail: Is there some room for "cultural activities"? I know the German dance "Die Hammerschmiedsgesell'n", which I would be pleased to instruct. I would be pleased to bring along Glückauf, and also like to exchange songs and fairy tales with the participants. I am also relatively well informed about the etymology of iron and steel in many languages.


The effect of draft on reduction, agglomeration and carburisation in an iron bloomery furnace

Skip Williams (USA) (Presentation co-authored by Evelyne Godfrey)

Saturday 16-9


investigation of a broken pile-shoe from a roman bridge

Peter Seinen (NL)

A Roman pile-shoe made from four iron bars had breaks in three bars. One break was a recent impact fracture. A sample containing one of the fracture surfaces was broken into large fragments with a hammer. These were investigated fractographically, metallographically, and by surface and bulk chemical analyses. The fractures were brittle and primarily intergranular. The metal was a coarse-grained phosphoric wrought iron (0.52 wt.% P) with very low silicon, manganese and sulphur contents, and extremely low carbon content (0.0033 wt.% C). The extremely low carbon content and coarse grain size indicate decarburisation during smithing. Furthermore, the combination of extremely low carbon and high phosphorus contents is concluded to be the most probable reason for the impact brittleness. This could have been facilitated by a notch effect due to surface corrosion. The significance of the embrittlement is considered with respect to conservation of archaeological iron objects, including similar pile-shoes.


From Stone to Iron - a short history of Metal

Eddie Daughton (UK)

I have long held a theory about the origins of Iron smelting. It seems to have been discovered by the Hittite Empire in about 1500 BC. Closely controlled by these people it doesn’t really leave their territory until after the Hittite Empire breaks down in 1200 BC.

An Iron Smelter is not a piece of technology that is created by accident and therefore has to have been born of something else.

My guess is that this “something else” is a copper smelter (the Hittites had a continuous process copper smelter by 1500BC, using red iron oxide to flux the slag).

It is therefore my intention to build and run a Hittite model copper smelter continuously for two days (48 hours) and see if there is (as I suspect) a very small bloom of Iron near the tuyere.

If this is present then it will give experimental weight to this theory and, hopefully, shed some light into this dark corner of the history of technology.


Historical metal in Russia

Vladimir Sokhonevich (RUS)


Running a slag pit furnace of the Sharnbech / Drengsted type

Jens Jørgen Olesen (DK)

In the past 12 years, we have made some experiments with a slagpit furnace, of the Sharnbech / Drengsted type.

So far we have not made a big slag block, an “elephant foot ” but our last experiments have made us sure that the time is near. In the week of the 22<sup>nd</sup> we hopefully, pas the matrix line. We run the furnace with natural draft, maybe combined with short periods, when we use the bellows, while the slag runs into the slag pit. We intend just to use wood, like in the Evenstad furnace.

The combination of natural draft, and using wood, maybe can make the slag run, without using bellows. Our last experiment, – last Summer – made us believe that could work.

If it doesn’t work with natural draft, we have found “The Method” and this method we figured out, when we make 2 experiments with a smaller slag pit furnace.

How? –You may wait and see.


Sunday 17-9



Setting targets for the future, discussions how and what further, a possible publication?



Last change: 08-30-2006
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